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1 KARNATAKA STATE OPEN UNIVERSITY ENVIRONMENTAL SCIENCE B.TECH IN ELECTRICAL ENGINEERING, B.TECH IN CHEMICAL ENGINEERING SEMESTER: IV SUBJECT CODE: CH4004,EE4004

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Page 1: Environmental BTECH

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KARNATAKA STATE OPEN UNIVERSITY

ENVIRONMENTAL SCIENCE

B.TECH IN ELECTRICAL ENGINEERING, B.TECH IN CHEMICAL ENGINEERING

SEMESTER: IV

SUBJECT CODE: CH4004,EE4004

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INDEX BLOCK 1 Water Unit 1: Water Supply Unit 2: Quantity of water Unit 3: Collections and conveyance of water Unit 4: Quality of water BLOCK 2 Water Treatments Unit 1: Layout of treatment plants Unit 2: Filtration Unit 3: Treatment processes Unit 4: Distribution system BLOCK 3 Collections and conveyance of sewage Unit 1: Definition of terms Unit 2: physical and chemical bacteriological BOD, COD Unit 3: Estimation of quantity of sewage – problems Unit 4: Laying of sewers lines & Sewage pumps BLOCK 4 Treatments and disposal Unit 1: Treatment of sewage Unit 2: Sedimentation Unit 3: Septic tanks Unit 4: Disposal of Septic Tank effluent BLOCK 5 Environmental pollution and control Unit 1: Industrial waste Unit 2: Treatment Processes Unit 3: Water pollution Unit 4: Land Pollution Unit 5: Control of Air Pollution

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Block I – Introduction- Water

When Neil Armstrong saw the Earth from the Moon, which was blue! This is because water covers more than two thirds of the Earth's surface. But fresh water represents less than 0.5% of the total water on Earth. The rest is either seawater or locked up in icecaps or soil, so we often hear of water shortages in many areas. The water is continually moving around the Earth and change its shape. Evaporating from soil and water bodies and is also produced by all forms of life on Earth. This water vapor moves through the atmosphere, condenses into clouds and precipitates as rain and snow. Over time, the water returns to its origin, and starts the process. Although water is constantly moving, its total amount on the surface of the Earth is constant. Forms of water Water is found in three different forms - liquid, solid or gas depending on temperature, but is constantly changing from one form to another. Changes in temperature will determine which of these forms predominates in a particular region. Liquid Water is usually encountered in the liquid state, because this is its natural state when temperatures are between 0° C and 100° C. 'Fresh' or drinking water is found as groundwater in underground aquifers, and on the surface in ponds, lakes, and rivers. Seas and oceans account for 97% of all water on Earth; but their waters contain dissolved salts and are therefore unfit to drink. In regions of young volcanic activity, hot water emerges from the earth in hot springs (examples are Garampani in Assam and Badrinath in Uttaranchal). How does this phenomenon occur? Surface water percolates downward through the rocks below the Earth's surface to high-temperature regions surrounding a magma reservoir, either active, or recently solidified but still hot. There the water is heated, becomes less dense, and rises back to the surface through fissures and cracks. Solid Ice is the frozen form of water. It occurs when temperatures are below 0°C (32°F). For a given mass, ice occupies 9% more volume than water, which is why when water enters cracks in rocks and freezes it causes the rocks to crack and split. Being less dense than water, ice floats. This property of ice is vital to aquatic life in cold regions. As the temperature drops, ice forms a protective, insulating layer on the surfaces of streams, pools and other water bodies, allowing water to remain liquid in the layers beneath and life to survive. Glaciers, icebergs, and ice caps are all frozen water. Gas Water is found in the atmosphere in its gaseous form, water vapour. Steam is nothing but vaporized water. In certain hot water springs called geysers, jets of steam and hot water rise one hundred feet or more from the ground. Geysers are found in Iceland, the North Island of New Zealand and in USA's Yellowstone National Park.

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UNIT 1 WATER SUPPLY

Structure 1.0 Objective 1.1 Introduction 1.2 History 1.3 Water Supply 1.4 Let us sum up 1.5 Some Useful Books 1.6 Answer to Check your Progress 1.7 Glossary 1.0 OBJECTIVE

In this lesson we are going to discuss in detailed manner about : Water resources are scarce in Saudi Arabia. It is a desert country lying within the

continental zone where temperatures are high in summer and low in winter. It is also characterized by low annual rainfall. The scarcity of water was the reason

behind many tribal conflicts until King Abdul Aziz recognized that provision of water was essential for the stability of his newly unified country. In the early 1930s, he recruited international experts to conduct geological surveys for underground water.

He also decided to build dams to retain rainwater for irrigation and drinking after purification.

Under King Fahd, the need for water has increased dramatically as agriculture, industry and the population have expanded. No expense has been spared to meet demand for this most essential resource. There are currently four major programs for water provision in the Kingdom.

1.1 INTRODUCTION

The industry distribution of water is very important not only to preserve the health of the community, but for the sustainability of the industry, business and agriculture. Without adequate water supply in our society today would never have evolved, and our life today would be unrecognizable. Our dependence on treated water is now incalculable, and threats to supply comparable to the worst natural and man. The amount of water consumed daily by agriculture, industry and the public is enormous and requires a huge infrastructure to meet demand. Like other suppliers, electricity, telephone and water supply Gas supply their products at home, which requires a distribution network to serve each home, but unlike other utilities, they are isolated from local or regional networks, rather than integrated national grid. Delgado in England and Wales, there are 26 private water companies, which together provide 52.7 million consumers in 2004 / 5 with 15 807 million liters (ml) of water every day. Sixty-eight percent of this came from surface water and the rest (32%) of groundwater. 1344 is required for treatment plants of this volume of water supplied to consumers through 326,471 km of distribution lines. When this breaks down by region, the greatest demand is in the southeast and northwest areas, which have the largest population. However, areas of high demand not usually correspond to areas where adequate water resources must be found to lack. The current demand for water in England and Wales currently has stabilized and 91% of peak demand in

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1990 / 1 (Table 1.1). 1.2 HISTORY

The population of Mumbai was few thousands and used to fetch water from the wells and shallow tanks. These sources tended to dry up in summer and people used to face shortage of water. On 22 nd June 1845,the local residents agitated against the shortage and bad quality of water. The British rulers appointed a 2-man commission to look into the grievances of the natives. The 2-man commission reported back within 24 hours that the water supply of Mumbai needed immediate attention. Vihar Scheme: This was the first piped water supply to Mumbai. Vihar lake is located in the valley at the origin of Mithi river, near village Vihar. The work started in the year 1856 and was completed in the year 1860. The total quantity supplied was 32 million liters per day (MLD). The height of the dam was raised in the year 1872 and the water supply through the lake was increased to 68 MLD. Tulsi Scheme: Tulsi lake is situated on the north side of the vihar lake. It is located on the upstream of vihar lake on the river Mithi. It supplies 18 MLD water to the city. In the year 1879, this scheme was commissioned. Powai scheme: Water famine was expected in the year 1891 so Powai Lake was constructed on a tributary of Mithi river. The 4 MLD water supplies is used in Aarey dairy and for agricultural purpose because the water quality is not upto the mark. Tansa scheme: It was decided in the year 1886 to develop this scheme, which was at a distance of 110km from the city. This scheme was developed in 4 stages. It supplies 541 MLD of water Vaitarna-cum-Tansa scheme: Vaitarna-cum-Tansa scheme came into existence in the year 1957 to meet the increasing demand of Mumbai city. It comprises of 500 m. long and 90 m. high concrete dam across the river Vaitarna. 7.2 km long tunnel was constructed between lakes Vaitarna and Tansa. The diameter of pipeline was 2400 mm. from Tansa to the city for a distance of 76 kms. The Corporation in the memory of the invaluable services has named the impoundage on Vaitarna river after notable Municipal Engineer late Shri N.V. Modak as ‘Modak Sagar'. Ulhas river scheme: The ulhas river scheme was started in the year 1965 to mitigate the drought conditions. The water supply to the city was increased by 90 MLD after completion of this scheme in the year 1967. At present, as per the Govt. Instructions, this source has been handed over to Kalyan Municipal Corporation from the year 1994. Upper Vaitarna scheme: This project was fully commissioned in the year 1972-73 and daily supply increased by 554 MLD. It is a dual-purpose scheme, which was created in the upper reaches of Vaitarna River by constructing two dams. The water in the river was used to generate 60 MW of power and the

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residual quantity was used by MCGM for water supply Bhatsa Scheme: The rate of growth of the population during the year 1950's and 1960's led to development of water supply and sewerage facilities. The plan was implemented in three phases, each of these phases envisaged additional water supply from the Bhatsa river. The project also consisted construction of pumping, treatment and distribution facilities at Pise, Panjrapur and Bhandup. International Development Association and the World Bank funded the project. Stage I: This stage of project was commissioned in 1981. It comprised of weir at Pise,. It had seven pumps each of 90 MLD. Stage II: The stage was commissioned in 1989. This stage comprised of expansion of the pumping station at Pise and construction of pre- chlorination plant at Pise. Stage III: During this stage additional pumps were introduced at Pise and Panjrapur. This stage was completed in 1997. The city's total water supply has reached 2950 MLD. 1.3 WATER SUPPLY

Rural Water Supply Programme Clean drinking water is a basic necessity of life. Supply of clean drinking water in the rural areas has always been one of the highest priorities of the government. A Technology Mission on drinking water named "National Drinking Water Mission" (NDWM) was launched in 1986, which subsequently was rechristened as "Rajiv Gandhi National Drinking Water Mission (RGNDWM) - File referring to external site opens in a new window" in 1991 with three key objectives:

i. Providing safe drinking water to all villages, ii. Assisting local communities to maintain sources of safe drinking water in good condition,

and iii. Giving special attention for water supply to Scheduled Castes and Scheduled Tribes.

To achieve the objectives, Accelerated Rural Water Supply Programme (ARWSP) is being implemented to resolve the drinking water problem in rural habitations. The Central Government supplements the efforts of the states by providing financial and technical support. The Tenth Plan emphasizes participatory approach where PRIs should be the key institutions for convergence of drinking water supply programmes at the ground level. The strategy to achieve the Tenth Plan objectives can be briefly summarised as:

a. Accelerating coverage of the remaining Not Covered and Partially Covered habitations including those slipped back from fully covered to partially and not covered categories, with safe drinking water systems.

b. To tackle problems of water quality in affected habitations and to institutionalize water quality monitoring and surveillance systems.

c. To promote sustainability, both of systems and sources, to ensure continued supply of safe drinking water in covered habitations

Accelerated Rural Water Supply Programme (ARWSP) aims at achieving this objective. Considerable success has been achieved in meeting the drinking water needs of the rural population through the said scheme. There are more than 4 million hand pumps and 2 lakh piped water schemes in the rural areas. The ARWSP was launched during 1972-73. It is currently being implemented through the Rajiv Gandhi National Drinking Water Mission. The scheme aims at coverage of all rural habitations

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with population of 100 and above, specially the un-reached ones, ensure sustainability of the systems and sources, tackle the problem of water quality and institutionalise water quality monitoring and surveillance through a Catchment Area Approach. As on 1 April 2005, 96.13 per cent of rural habitations have been Fully Covered (FC) with drinking water facilities and 3.55 per cent are Partially Covered (PC) and 0.32 per cent is Not Covered (NC) with drinking water facilities. There are slippages of FC into NC or PC due to various factors such as lowering of ground water table, systems outliving their lives, increase in population, etc. Drinking water supply is one of the six components of Bharat Nirman, which has been envisaged to build strong rural infrastructure in four years (2005-06 to 2008-09). The task ahead is to cover all the remaining uncovered habitations and also to cover the slipped back as well as the water quality affected ones. Action Plans from State/UT Governments for achieving the goals of Bharat Nirman in a time bound manner have been obtained. For ensuring sustainability of the systems, steps were initiated in 1999 to institutionalise community participation in the implementation of rural drinking water supply schemes by incorporating the following three basic principles:

i. Adoption of a demand-driven responsive and adaptable approach based on empowerment of villagers to ensure their full participation in the project through a decision making role in the choice of scheme design, control of finances and management arrangements.

ii. Increasing role of government for empowering user groups/gram panchayats for sustainable management of drinking water assets and integrated water management and conservation.

iii. Partial capital cost sharing either in cash or kind or both and 100 per cent responsibility of Operation and Maintenance by end-users.

Sector Reforms Projects, based on the above principles were sanctioned in 67 districts on pilot basis. With the experience gained from these pilot projects, reform process has been scaled up in the entire country through Swajaldhara launched on 25 December 2002. A notable feature of Swajaldhara is involvement of Village Water and Sanitation Committee (VWSC)/Panchayati Raj Institutions (PRIs) in planning, implementation, operation and maintenance. This would in turn ensure sustainability of the system. 10 per cent contribution is made by the community and 90 per cent funds are provided by the Central government. In case of SC and ST habitations, community contribution can be in the form of cash, kind, labour or land or a combination of these. Rajiv Gandhi National Drinking Water Mission (RGNDWM) adopts an integrated approach so that conservation and augmentation of water sources is interrelated with rural water supply schemes to provide sustainable supply of safe drinking water to the rural population. The Mission seeks to provide supply of 40 liters of safe drinking water in rural areas. An initiative has been taken by Government of India in February 2006 by launching the National Rural Drinking Water Quality Monitoring and Surveillance Programme which envisages institutionalisation of community participation for monitoring and surveillance of drinking water sources at the grass-root level by Gram Panchayats and Village Water and Sanitation Committees, followed by checking the positively tested samples at the district and State level laboratories. Another initiative taken by the Government is that from 2006-07 onwards focused funding to tackle drinking water has been started. Up to 20 per cent of ARWSP funds are to be earmarked separately for tackling water quality problems. For 2006-07, 20 per cent of ARWSP funds have been allocated for funding under water quality.

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In India’s urban areas access to drinking water considered safe by the Government’s standards rose from about 82% of the population in 1991 to 90% in 2001. This figure, which includes access to non-piped water, could rapidly reach 100%, consistent with the aim of the th Ministry of Urban Development to achieve 100% coverage in 2007 (end of the 10 Plan). But in an urban environment non-piped water may not be considered a safe source. Thus progress toward Target 10 of the Millennium Development Goals (MDGs) of halving, by 2015, the proportion of people without sustainable access to safe drinking water and basic sanitation would need to be measured on the basis of access to piped water. This indicator, which rose from 68.5% in 1990 to 74% in 2001, would need to improve to 86.5% by the end of the 12th five-year Plan (2017) if India is to meet the MDG target. The record of progress indicates that development of the piped water supply infrastructure may be slightly behind schedule, suggesting a need to accelerate investment. The urban population share with access to basic sanitation, which rose from 43% in 1990 to 61.5% in 2001, is likely to improve to 81.5% at the end of the 12th Plan, thus exceeding the theoretical MDG target of 71.5%. Here India appears to be on track. Based on preliminary estimates, meeting the MDG target in urban areas would require investment of about Rs 425 billion and Rs 500 billion (US$10 billion and US$11.8 billion) for the 11th and 12th Plans, and recurrent expenditures of the same order of magnitude of about Rs 390 1billion and Rs 505 billion (US$9.2 billion and US$11.9 billion). In rural areas access to drinking water increased from about 65% of the population in 1990 to about 90% in 2001. Thus it appears likely that if India sustains investment at a level similar to that of the past decade, it could achieve 100% coverage of water supply infrastructure if not by 2007, as targeted by the Rajiv Gandhi National Drinking Water Mission, then probably by 2012. The rural population share with access to basic sanitation, which may have been as low as 5% in 1990, rose to about 20% in 2001. If it is to reach 53% at the end of the 12th Plan to meet the MDG target, India may be somewhat behind. Meeting the MDG target in rural areas would require investment of about Rs 370 billion and Rs 330 billion (US$8.7 billion and US$7.8 billion) for the 11th and 12th Plans, and recurrent expenditures again of the same order of magnitude of about Rs 305 billion and Rs 355 billion (US$7.2 billion and US$8.4 billion). Reliable? Whether in small towns or mega-cities, or in single- or multi-village schemes, piped water is never distributed for more than a few hours a day, regardless of the quantity available. In urban areas raw sewage often overflows into open drains because sewers are blocked or pumping stations not functioning. And in rural areas hand pumps can remain out of order for months, while latrines too often are used for purposes other than that for which they were designed. Financially sustainable? A few mega-cities recover from user charges the full cost of water supply and sanitation service, including operation and maintenance and capital costs. But most urban operations and all rural schemes still survive on large operating subsidies and capital grants provided by the states. Environmentally sustainable? Most cities must compete with the agricultural sector to secure water rights, and very few contribute to the abatement of pollution in receiving bodies. Villages relying on groundwater suffer from the rapid depletion of aquifers, whose mining for irrigation purposes is encouraged by highly subsidized power rates.

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Affordable? Most households, forced to cope with poor quality water supply and sanitation service, spend time and money on expensive and unsafe substitutes and on treatment for waterborne diseases. User charges are low by international standards, but the cost of the alternatives on which users must rely far exceeds the full cost of providing good quality service. And while the poor may be the intended beneficiaries of the low user charges, they suffer most from the poor quality of service that results. Improving reliability. Improving the reliability of service would require clarifying the roles of the actors in the sector (policymakers, regulators, financiers, asset owners, and service operators) and establishing enforceable contractual relationships between them so as to increase transparency in decision making and accountability to end users. In addition, full responsibility for service provision would need to be devolved to the lowest appropriate level of government. As part of this, the function of “promoter of infrastructure”, now the responsibility of state engineering agencies, such as Public Health Engineering Departments or State Water Boards, would need to be consolidated with that of “provider of service,” to ensure that water supply and sanitation projects correspond to what service providers can afford and can operate. The revenues and expenses of water supply and sanitation operations would need to be separated from those of the local government and “ring-fenced”; clarifying the financial situation of service providers is deemed to be essential to design appropriate financial recovery programs. To further increase accountability, the “beneficiaries” of a nearly free (but very poor-quality) service would need to be transformed into “paying customers” with the right to express concerns and preferences. Finally, private sector participation would need to be promoted. The initial emphasis should be on service and management contracts, since the main issue is increasing the efficiency of day-to-day operations rather than raising private equity and commercial debt to finance the extension of infrastructure. Achieving financial sustainability. Achieving financial sustainability would require establishing sound principles for pricing water supply and sanitation service so as to meet financial, economic, equity and simplicity objectives. Aiming at full recovery of operation and maintenance costs from user charges by the end of the 11th Plan (2012) is probably feasible for both urban and rural service. Going beyond and contributing to capital costs could be envisaged in a second phase; preliminary estimates show that it is likely that user charges needed to cover operation, maintenance and capital costs would, as an average, be lower than those in comparable countries. The transition from today’s highly subsidized sector to a much less dependent one would need to be financed in a transparent and targeted manner, with any operating subsidies still provided by the states linked to actual improvement in the performance of service providers. To tackle the cost side of the equation: (i) to reduce operation and maintenance costs: efforts would need to focus on creating appropriate financial incentives mostly by increasing private sector participation; (ii) to reduce capital costs: the dimensioning of sector infrastructure should be limited to what is strictly needed and the quality of construction should be improved to extend useful life of assets; and (iii) to reduce financing costs: financing conditions should be adapted to what the sector debt servicing capacity. State financing programs would need to be designed to support the recovery of the urban water supply and sanitation sector, not merely to fill gaps in infrastructure. The role of the Government of India in supporting the reform should be extended: a financing mechanism similar to the rural sector’s

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Swajaldhara may have to be created for the urban sector. Finally, external financing needs would have to be harnessed primarily to support implementation of new policies, institutional arrangements, and fiscal incentives, not just to rehabilitate and extend infrastructure. Achieving environmental sustainability. To achieve environmental sustainability, bulk water would need to be priced according to sound economic principles, to give consumers the right signals about the actual cost of this increasingly scarce commodity. Water rights would need to be strengthened and water rights markets developed to: (i) allow water-starved cities an official access to water resources that are now used, often inefficiently, by agriculture; and (ii) ensure proper compensation of farmers. Depletion of groundwater, still the main source of water for rural schemes, would need to be limited by pricing the electricity delivered to farmers according to sound principles and ensuring that power bills are actually paid. Water quality would need to be protected by paying as much attention to proper waste water collection as to waste water treatment; a large share of the waste water now generated never reaches treatment facilities. Infrastructure would need to be planned to achieve realistic environmental objectives: waste water treatment to the highest level often fails to improve the water quality in the receiving bodies enough to be economically justified. Finally, efforts to support behavioral change toward better sanitation practices should be continued, particularly those aimed at eliminating open defecation. Improving affordability. Improving the affordability of service would require first of all reducing costs, as already mentioned above. Cost recovery strategies would need to include transparent, well-targeted subsidies for the poor, both to help obtain connections to service and to encourage the consumption of a minimum quantity of water. In the urban water supply and sanitation sector an important step toward building capacity would be to create an identity for the “urban water supply and sanitation industry.” A professional association of service providers could play a key role in disseminating best practices, implementing full scale benchmarking, and providing training and certification for sector professionals. Training institutions would need to adapt their programs, currently focused mainly on technical design issues, to the new needs of the urban sector. And special information programs would need to be developed for key stakeholders, i.e., local politicians, consumer associations, and the many nongovernmental organizations with a special interest in water supply and sanitation. In the rural sector special training programs would also need to be developed to build the capacity of local governments (Panchayati Raj Institutions – PRI). In the urban water supply and sanitation sector the World Bank could target its assistance primarily to a few selected projects that would support the reliability, sustainability, and affordability agenda; to mega-cities (Delhi, Chennai, Mumbai…), where it has traditionally been involved; and to selected reforming states with smaller urban centers, mainly with the aim of designing options that can be easily replicated. In the rural sector, where the Bank is providing support through three ongoing projects and three projects under preparation, it should gradually move toward a sector-wide approach (SWAp) in states where full agreement can be reached on policies, investment plans, implementation arrangements, and monitoring and evaluation mechanisms.

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The Water and Sanitation Program, which has a significant budget for policy dialogue for both urban and rural water supply and sanitation, should continue to disseminate best practices and to assist selected states in formulating the concept of sustainable projects and developing detailed procedures for sector reform, including for the preparation of financing applications for Indian and international lending agencies and independent appraisal procedures. Check your progress-1

1. Where does our household water come from? 2. Where does it go after we are done with it? 3. How much water does the average person use at home per day? 4. How is water supplied to our homes? 5. How the water I drink is made safe? 6. Is it true that water coming out of sewage treatment plants is used for other purposes? 7. I live on a hill, how does water get to my house? 8. How many baths could I get from a rainstorm? 9. Does a little leak in my house really waste water?

1.4 LET US SUM UP

Looking at water, you might think that it's the most simple thing around. Pure water is colorless, odorless, and tasteless. But it's not at all simple and plain and it is vital for all life on Earth. Where there is water there is life, and where water is scarce, life has to struggle or just "throw in the towel." So what is it about water that makes it so important to us? And what is it about water that makes it water? This section of Water Science for Schools explores the physical and chemical properties of water and why water is so critical to living things. 1.5 SOME USEFUL BOOKS

1. Centers for Disease Control and Prevention. Public Health Service report on fluoride benefits and risks. Journal of the Americal Medical Association 1991; 266(8):1061–1067.

2. Centers for Disease Control and Prevention. Achievements in public health, 1900–1999: Fluoridation of drinking water to prevent dental caries. Morbidity and Mortality Weekly Report 1999; 48(41):933–940.

3. Bucher JR, Hejtmancik MR, Toft JD, et al. Results and conclusions of the National Toxicology Program’s rodent carcinogenicity studies with sodium fluoride. International Journal of Cancer 1991; 48(5):733–737.

4. Committee to Coordinate Environmental Health and Related Programs. Review of Fluoride Benefits and Risks: Report of the Ad Hoc Subcommittee on Fluoride. Public Health Service, Department of Health and Human Services, 1991.

5. National Research Council. Carcinogenicity of flouride. In: Subcommittee on Health Effects of Ingested Fluoride, editor. Health Effects of Ingested Fluoride. Washington DC: National Academy Press, 1993.

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1.6 ANSWER TO CHECK YOUR PROGRESS

Check your progress-1 1. All of the water that we use in our homes comes from either a ground-water source, such

as a well, or from a surface-water source, such a river, lake, or reservoir. In the U.S. in 2000, about 240 million of the 285 million people in the United States got their home water delivered by a public supplier, such as the county water department. At other homes, people provide water for themselves from sources, such as a well, a cistern, a pond, or a stream.

2. Water leaving our homes generally goes either into a septic tank in the back yard where it evaporates or seeps back into the ground, or is sent to a sewage-treatment plant through a sewer system. In 1995, the last year for which consumptive-use data was compiled, about 26 percent of the water coming from our homes was "consumptively used." That is, it was evaporated or traspired from yards. The other 74 percent was discharged to septic tanks or sewage-treatment plants, where it was cleaned and sent into streams, or sometimes reused for other purposes, such as watering golf courses and parks.

3. Estimates vary, but each person uses about 80-100 gallons of water per day. Are you surprised that the largest use of household water is to flush the toilet, and after that, to take showers and baths? That is why, in these days of water conservation, we are starting to see toilets and showers that use less water than before. Many local governments now have laws that specify that water faucets, toilets, and showers only allow a certain amount of water flow per minute. In fact, if you look real close at the head of a faucet, you might see something like "1.5 gpm,", which means that the faucet head will allow water to flow at a maximum of 1.5 gallons per minute.

4. In a modern society such as ours, much work goes into supplying our houses with water. Many years ago when everyone lived in rural areas, they would have to get their own water from rivers or from local wells. Nowadays, most people in the U.S. live in towns and cities, and communities have installed an organized structure called a public water-supply system to provide water to homes (and to some businesses and industries, too). Now, even many rural areas have similar systems. In 2000, the U.S. had a population of about 285 million. About 240 million people had their water delivered from a public-supply system, and about 45 million people supplied their own water (over 90 percent of these people use water from their own wells).

5. Different treatment is used depending on the source of your water. Ground water taken from wells has been filtered through rocks, so it is usually quite free of particles. It can still contain chemicals and organic matter that must be taken out, though. If your water comes from a surface-water source, such as a river, some work must be done to get rid of particulate matter. In this case filters are used to screen out large particles, and at a minimum, chlorine is added to kill dangerous bacteria and microorganisms. Some systems have additional water treatment, such as adding chemicals to make matter bunch up (flocculate) and fall out of solution and adding chemicals to make the water less corrosive to metal.

6. Yes, it is called reclaimed wastewater, though its use is limited. Before you start to feel ill, no, it is not used further down the line as drinking water. It is most often used for irrigation and for water parks and golf courses. In the U.S. in 1995 (the last year for which wastewater-treatment data was compiled) about 44,400 wastewater-treatment

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plants sent about 44,600 million gallons per day of treated water back into the environment. About 983 million gallons per day was used again (reclaimed) after treatment, mainly as irrigation water.

7. Let's assume that you get your water from the local water department through pipes buried below the streets. In other words, you don't have your own well in your back yard. Chances are that you get your water through the magic of gravity or pumps. Cities and towns build those big water towers on top of the highest hills and then fill them with water. So even if you live on a hill, there's a good chance the water tower is higher than your house. Water goes down a large pipe from the tower and through an intricate network of pipes that eventually reaches your house.

8. In other words, when I have a big storm over my house, just how much rain am I getting? Let's say your house sits on a one-half acre lot. And let's say you get a storm that drops 1 inch of rain. You've just received 13,577 gallons of water on your yard! A big bath holds about 50 gallons of water, so if you could save that inch of water that fell you could take a daily bath for 271 days! (Careful now, that 13,577 gallons of water weighs over 56 tons ... so don't put it in your bathtub all at once). Let's expand that to a city. Atlanta, Ga. has corporate boundaries that cover about 84,100 acres (U.S. Census Bureau). A 1-inch rainstorm deposits 27,154 gallons on one acre, so during this storm Atlanta receives 2.28 billion gallons of water. Don't miss our Challenge Question, where you can find out how much water falls during a rainstorm.

9. It's not the little leak that wastes water -- it is the little leak that keeps on leaking that wastes water. And the fact that the leak is so little means that maybe you ignore it. So, how can a little leak turn into a big waste? Many of our toilets have a constant leak -- somewhere around 22 gallons per day. This translates into about 8,000 gallons per year of wasted water, water that could be saved. Or think of a leaky water line coming into your house. If it leaks 1 gallon of water every 10 minutes that means that you are losing (and paying for) 144 gallons per day, or 52,560 gallons per year.

1.7 GLOSSARY

A water supply system is a system for the collection, transmission, treatment, storage and distribution of water from source to consumers, for example, homes, commercial establishments, industry, irrigation facilities and public agencies for water—related activities (fire—fighting, street flushing and so forth).

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UNIT 2 QUANTITY OF WATER

Structure 2.0 Objective 2.1 Introduction 2.2 History 2.3 Quantity of water 2.4 Let us sum up 2.5 Some Useful Books 2.6 Answer to Check your Progress 2.7 Glossary 2.0 OBJECTIVE

In this lesson we are going to discuss in detailed manner about : The quantity of water required for municipal uses for which the water supply scheme has to be designed requires following data:

1. Water consumption rate (Per Capita Demand in litres per day per head) 2. Population to be served.

Quantity= Per capita demand x Population 2.1 INTRODUCTION

Much of the western United States have an average annual rainfall of less than 15 inches, while Illinois has an average annual rainfall of 38 inches, and relatively abundant water resources. Why do so for the past 80 years there have been repeated calls for better planning and management of water throughout the state and why more progress has not been done? This article discusses the history and status of the planning and management of water in Illinois, legal issues, constraints and considerations to be addressed and guidelines for the establishment of a process planning and management. Here we will provide a limited overview of data flow gauge to examine trends in freshwater streams in terms of annual flows and daily timing of flows, low flow and float above guidelines flow reserved. This is to complete a review of published information, but we caution that the full analysis of these data and the study of appropriate safety methods and interpretations are needed to fully assess the condition of freshwater streams. It is our intention that these data collection and analysis used to identify data limitations and other key uncertainties regarding the priorities of its partnership Puget flow. Data sources It is about 90 measuring stations controls the U.S. Geological Survey (USGS) is the Puget Sound Basin, located in unregulated reaches of rivers and streams that can benefit from stream-flow analysis of the state and trends (2010b U.S. Geological Survey ). Full analysis of all available data is not made in this report. Instead, information on at least one measure is not regulated the location of each water resource inventory Area (WRIA) were included as possible. This selection is based on the desire to capture a broad regional coverage. We are involved in all the data available to measure the positions Skagit unregulated reaches of the river basins in order to determine whether basin-wide correlation of hydrological indicators.

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Previous reports have linked the flow of data from several rivers flow to assess the regional trends (Puget Sound Partnership 2009). A strong correlation between the streams and rivers in the pool itself may suggest that this is a good approach. We review the evidence for this correlation using simple descriptive statistics, but stresses that further analysis is warranted. 2.2 HISTORY

In 1920, Illinois State Water Survey Chief Arthur M. Buswell proposed "a comprehensive study of the volume of groundwater available in Illinois" (Hays, 1980, p. 122). Twelve years later, Buswell has expanded its proposal to include all the state's water resources and to estimate future demand (Hays, 1980, p. 145). "Although this project was included in budget requests for several years, has been funded by the legislature" (Hays, 1980, p. 203). "" In 1965, Illinois Governor Otto Kerner appointed Chief William C. Water Study Ackermann as director of a working group to develop a comprehensive plan for the state of water resources "(Hays, 1980, p.171). An ambitious state plan of water was released in 1967, but was not implemented due to budgetary constraints (Illinois Technical Advisory Committee, 1967). Governor of Illinois, George H. Ryan has published two decrees on water resources in the last two years. On June 6, 2000, Governor Ryan has set up water resources in the Governor's Advisory Committee to focus on water resources and their use, including water use by plants Peaker. The Committee met on several occasions, but not a report. However, in my opinion, the Committee has made substantial progress in identifying a set of principles for a consensus on water resources planning and management. On April 22, 2002, Governor Ryan called IADC Groundwater (ICCG), led by the Illinois Environmental Protection Agency, to report each January on the progress in establishing a planning process the amount of water. Initially, the chairman of the Subcommittee a CICG of Illinois Department of Natural Resources (IDNR) is to produce an agenda of Water Integrated Resource Management (groundwater and surface) and an evaluation report. Martin Jaffe has identified water supply for the handling of Northeastern Illinois (Jaffe, 2001). Survey Illinois State Water and Geological Survey of Illinois also continued to make progress by providing a scientific basis for improved planning and management of water resources in Illinois. In November 2001, produced every time a report on the scientific need for improved planning of water supply and management (Illinois State Water Survey, 2001, the Illinois Geological Survey, 2001) in response to two resolutions May 2001: Senate Resolution 0137 and House Resolution 0365th Director IdNr options also sent to the governor's budget office to implement the relevant scientific studies. Given the need for fiscal restraint in the state budget, however FY03 budget contains no new funding for planning studies of water. 2.3 QUANTITY OF WATER

Legal Issues At the heart of the legal issues relating to the supply of water in Illinois is the individual's right to reasonable use of water is not impeded by government regulations. This is rooted in common law water rights of coastal States. When water resources are abundant and there is little competition between users, the distribution of water in accordance with the principle of fair use works well. But when disputes arise and lack water, often because of competition and drought,

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the courts usually decide what is reasonable and beneficial use of scarce water resources. In some cases, described the court's decision unfair. West is less rainfall and a variety of water law. Private property ownership is based on the first water and water rights can be traded. Some economists argue that the taking of private water rights, and that we can trade these rights provides a method for sound economic use of scarce resources. Over the decades in Illinois, he was a strong voice representing the constituency of those who want to maintain a reasonable use of water resources without excessive government regulation. This raises some important questions. Is there a need for better management of water resources throughout the state? If so, the improvement of governance, must be treated in the strictest government regulations? Or communities can voluntarily join together to protect water supplies for present and future generations, to distribute these supplies to meet different requirements, and to manage effectively the increasing competition? The Authorities Act Water (70 ILCS 3715/0.01 et seq.) Already contains a mechanism for some of these actions at the local level, and some, most small communities in the water, already exist. However, they provide a basis for water conservation and regional water management, water authorities are likely to be substantially modified. Another option would be to go toward a Western system of private ownership of water rights and allow the market trading system to allocate scarce resources efficiently. However, all attempts to appropriate the water rights now could lead to a political bloodbath. In October 1996, a conference on "Water Law Illinois: Challenges and Opportunities" held in Bloomington (Damon, undated). Before Paul and Janice Beecher described the legal structures of Illinois which is the cause people to rethink water management. They noted that the distinction between river systems and ownership seems to be declining, and many eastern states are adopting water detection systems , permissions, and a targeted approach to regulation. Professor Joseph Dellapenna reference to these developments as a system of regulated riparian rights to manage water resources and said that about half of the eastern states had adopted this system (Damon, undated). The State Water Plan Task Force identified the following five issues for review: emergency powers and drought management, protection rates codification of the laws of water, the future needs of public water supply, and access to the sequence of recreation (IDNR Office of Water Resources). Constraints and Considerations in Water Quantity Planning and Management The following list of constraints and considerations need to be considered, if some form of statewide water-quantity planning and management is to become a reality.

i. well-defined and deeply serious reasons to change the value of planning and management, which is convincing enough to lead to a consensus on various elements of the groups are presented in the state. Attempts to separate legislation on specific issues have failed. Although recent projections, Northeastern Illinois Planning Commission to see the potential shortage of water 12 black Chicago metropolitan area (www.nipc.cog.il.us), and deep into the aquifer rock is probably already overpumped, we do not know to which power is likely to increase demand for the entire state, since no such predictions may have been made in other parts of the state and hundreds of other safe aquifers are not defined. Often the problems are regional or local in nature.

ii. There is a tendency to propose controlling legislation before a vision and goals have been set, before appropriate analyses have been conducted (e.g., supply-demand projections), and before the details of policy and regulation have been specified.

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iii. The status quo has great momentum. The reasonable-use doctrine has been in place for more than 150 years.

iv. There has been a lack of sustained political leadership and support for changes in planning and managing water resources in Illinois.

v. The U.S. Supreme Court restricts water diversion from Lake Michigan. Illinois can not request the Supreme Court to increase the current allocation of 3,200 cubic feet per second until it has demonstrated that all other water supplies have been utilized and best available water- conservation and reuse practices have been adopted. vi. Concentrations of natural chemicals, pollutants, and sediments in water (e.g., arsenic, nitrate, chloride, radium) can restrict the availability of water at reasonable cost. vii. Management of water quantity is fragmentary and decentralized making comprehensive management virtually impossible. viii. Aquifers and rivers are linked and should be considered jointly. Especially at low flow, most of the water in rivers is from groundwater. ix. Aquifers and watersheds do not coincide geographically, and neither coincide with political units. I believe that natural resource boundaries (e.g., watersheds and aquifers), overlaid with appropriate political boundaries, should provide the basis for regional water planning. x. Many major uses of water are not reported. In the absence of full reporting, planning and management cannot be comprehensive. xi. Technical data and models needed for water-quantity planning and management often are outdated, inadequate, or nonexistent. A Planning Procedure Leading to Water-Quantity Management There are two inter-related steps to protecting and managing water resources: i) water planning, and ii) water management. Management provides the methods and means to achieve the ends evaluated in a planning process. Management without a plan can be chaotic, ineffective, and inefficient. Under Governor’s Executive Order Number 5, the ICCG is charged with developing “a water-quantity planning procedure for the State.” An ICCG subcommittee is formulating a water quantity planning and management framework, with consideration of many of the factors mentioned above and the following common-sense approaches: i) Planning and management should be science based. a) Existing scientific data and information should be marshaled as a basis for statewide planning and management efforts. b) Scientific research and monitoring that fill important data gaps are essential to provide an improved basis for planning and management. ii) Planning and management should be iterative and adaptive, based on progress made, understanding gained, evolving priorities and science, and changing needs. iii) There are roles for state, county, and local governments, with perhaps a need for regional water authorities based on aquifers and watersheds. The subcommittee also should recommend who should prepare more detailed plans, what the powers and duties of planners should be, who is to review and approve the plans, and the human and financial resources needed to prepare and revise the plans. The traditional components of planning, e.g., identifying a mission, vision, goals, objectives, and strategies could provide a suitable framework for water planning and management. Topics to be addressed in water plans should include oversight of the planning process, political boundaries which overlapping natural resource boundaries, regional powers and duties, supply-demand projections, climate variability and change, surface-water- and groundwater-supply options, safe yields, water conservation and

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reuse options, scientific research and monitoring, water-use reporting, and decision support to identify and evaluate water management options. Topics to be addressed in water-management plans should include state oversight, regional powers and duties, overlapping resource boundaries, reasonable use, adverse impacts, competition among multiple water users, emergency and drought management, in-stream flow protection, conjunctive use of resources, organizational structure, conflict resolution, and management instruments (e.g., policies, laws, regulations, standards, guidelines, and cooperation). Water Consumption Rate It is very difficult to accurately assess the amount of water required by the public as there are many variable factors that affect water consumption. The different types of water demands of a city can have, can be divided into the following classes: Water Consumption for Various Purposes: Types of Consumption Normal Range

(lit/capita/day) Average %

1 Domestic Consumption 65-300 160 35 2 Industrial and Commercial

Demand 45-450 135 30

3 Public Uses including Fire Demand 20-90 45 10

4 Losses and Waste 45-150 62 25 Fire Fighting Demand: Demand per capita fire is much less than average, but the speed of the water required is very large. The application rate of fire is sometimes traeted depending on the population and was prepared from the following empirical formula:

Authority Formulae (P in thousand) Q for 1 lakh Population)

1 American Insurance Association

Q (L/min)=4637 ÖP (1-0.01 ÖP) 41760

2 Kuchling's Formula

Q (L/min)=3182 ÖP 31800

3 Freeman's Formula

Q (L/min)= 1136.5(P/5+10) 35050

4

Ministry of Urban Development Manual Formula

Q (kilo liters/d)=100 ÖP for P>50000

31623

Factors affecting per capita demand: a. Size of the city: Per capita demand for big cities is generally large as compared to that for

smaller towns as big cities have sewered houses. b. Presence of industries. c. Climatic conditions.

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d. Habits of people and their economic status. e. Quality of water: If water is aesthetically $ medically safe, the consumption will increase

as people will not resort to private wells, etc. f. Pressure in the distribution system. g. Efficiency of water works administration: Leaks in water mains and services; and

unauthorised use of water can be kept to a minimum by surveys. h. Cost of water. i. Policy of metering and charging method: Water tax is charged in two different ways: on

the basis of meter reading and on the basis of certain fixed monthly rate. Fluctuations in Rate of Demand Average Daily Per Capita Demand = Quantity Required in 12 Months/ (365 x Population) If this average demand is supplied at all the times, it will not be sufficient to meet the fluctuations.

Seasonal variation: The demand peaks during summer. Firebreak outs are generally more in summer, increasing demand. So, there is seasonal variation .

Daily variation depends on the activity. People draw out more water on Sundays and Festival days, thus increasing demand on these days.

Hourly variations are very important as they have a wide range. During active household working hours i.e. from six to ten in the morning and four to eight in the evening, the bulk of the daily requirement is taken. During other hours the requirement is negligible. Moreover, if a fire breaks out, a huge quantity of water is required to be supplied during short duration, necessitating the need for a maximum rate of hourly supply.

Therefore, sufficient water should be available to meet peak demand. To cope with all the fluctuations, supply lines, depots and service distribution network must be properly provided. Water is supplied by direct pumping and pumps and distribution system should be designed to meet peak demand. The effect of monthly variation in the design of storage tanks and hourly variations influence the design of pumps and service reservoirs. As the population decreases, the rate of change Maximum daily demand = 1.8 x average daily demand Maximum hourly demand of maximum day i.e. Peak demand = 1.5 x average hourly demand = 1.5 x Maximum daily demand/24 = 1.5 x (1.8 x average daily demand)/24 = 2.7 x average daily demand/24 = 2.7 x annual average hourly demand Design Periods & Population Forecast This quantity should be worked out with due provision for the estimated requirements of the future . The future period for which a provision is made in the water supply scheme is known as the design period. Design period is estimated based on the following:

Useful life of the component, considering obsolescence, wear, tear, etc. Expandability aspect. Anticipated rate of growth of population, including industrial, commercial developments

& migration-immigration. Available resources.

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Performance of the system during initial period. Population Forecasting Methods The various methods adopted for estimating future populations are given below. The particular method to be adopted for a particular case or for a particular city depends largely on the factors discussed in the methods, and the selection is left to the discrection and intelligence of the designer. Arithmetic Increase Method This method is based on the assumption that the population increases at a constant rate; i.e. dP/dt=constant=k; Pt= P0+kt. This method is most applicable to large and established cities. Geometric Increase Method This method is based on the assumption that percentage growth rate is constant i.e. dP/dt=kP; lnP= lnP0+kt. This method must be used with caution, for when applied it may produce too large results for rapidly grown cities in comparatively short time. This would apply to cities with unlimited scope of expansion. As cities grow large, there is a tendency to decrease in the rate of growth. Incremental Increase Method Growth rate is assumed to be progressively increasing or decreasing, depending upon whether the average of the incremental increases in the past is positive or negative. The population for a future decade is worked out by adding the mean arithmetic increase to the last known population as in the arithmetic increase method, and to this is added the average of incremental increases, once for first decade, twice for second and so on. Decreasing Rate of Growth Method In this method, the average decrease in the percentage increase is worked out, and is then subtracted from the latest percentage increase to get the percentage increase of next decade. Simple Graphical Method In this method, a graph is plotted from the available data, between time and population. The curve is then smoothly extended upto the desired year. This method gives very approximate results and should be used along with other forecasting methods.

Comparative Graphical Method In this method, the cities having conditions and characteristics similar to the city whose future population is to be estimated are selected. It is then assumed that the city under consideration will develop, as the selected similar cities have developed in the past. Ratio Method In this method, the local population and the country's population for the last four to five decades is obtained from the census records. The ratios of the local population to national population are then worked out for these decades. A graph is then plotted between time and these ratios, and extended upto the design period to extrapolate the ratio corresponding to future design year. This ratio is then multiplied by the expected national population at the end of the design period, so as to obtain the required city's future population. Drawbacks:

1. Depends on accuracy of national population estimate. 2. Does not consider the abnormal or special conditions which can lead to population shifts

from one city to another.

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Logistic Curve Method 3. The three factors responsible for changes in population are :

(i) Births, (ii) Deaths and (iii) Migrations. Logistic curve method is based on the hypothesis that when these varying influences do not produce extraordinary changes, the population would probably follow the growth curve characteristics of living things within limited space and with limited economic opportunity. The curve is S-shaped and is known as logistic curve.

Intake Structure The basic function of the intake structure is to help in safely withdrawing water from the source over predetermined pool levels and then to discharge this water into the withdrawal conduit (normally called intake conduit), through which it flows up to water treatment plant. Factors Governing Location of Intake

1. As far as possible, the site should be near the treatment plant so that the cost of conveying water to the city is less.

2. The intake must be located in the purer zone of the source to draw best quality water from the source, thereby reducing load on the treatment plant.

3. The intake must never be located at the downstream or in the vicinity of the point of disposal of wastewater.

4. The site should be such as to permit greater withdrawal of water, if required at a future date.

5. The intake must be located at a place from where it can draw water even during the driest period of the year.

6. The intake site should remain easily accessible during floods and should noy get flooded. Moreover, the flood waters should not be concentrated in the vicinity of the intake.

Design Considerations 1. sufficient factor of safety against external forces such as heavy currents, floating

materials, submerged bodies, ice pressure, etc. 2. should have sufficient self weight so that it does not float by upthrust of water.

Types of Intake Depending on the source of water, the intake works are classified as follows: Pumping A pump is a device which converts mechanical energy into hydraulic energy. It lifts water from a lower to a higher level and delivers it at high pressure. Pumps are employed in water supply projects at various stages for following purposes:

1. To lift raw water from wells. 2. To deliver treated water to the consumer at desired pressure. 3. To supply pressured water for fire hydrants. 4. To boost up pressure in water mains. 5. To fill elevated overhead water tanks. 6. To back-wash filters. 7. To pump chemical solutions, needed for water treatment.

Classification of Pumps Based on principle of operation, pumps may be classified as follows:

1. Displacement pumps (reciprocating, rotary) 2. Velocity pumps (centrifugal, turbine and jet pumps) 3. Buoyancy pumps (air lift pumps)

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4. Impulse pumps (hydraulic rams) Capacity of Pumps Work done by the pump, H.P.=gQH/75 where, g= specific weight of water kg/m3, Q= discharge of pump, m3/s; and H= total head against which pump has to work. H= Hs + Hd + Hf + (losses due to exit, entrance, bends, valves, and so on) where, Hs=suction head, Hd = delivery head, and Hf = friction loss. Efficiency of pump (E) = gQH/Brake H.P. Total brake horse power required = gQH/E Provide even number of motors say 2,4,... with their total capacity being equal to the total BHP and provide half of the motors required as stand-by. Conveyance There are two stages in the transportation of water:

1. Conveyance of water from the source to the treatment plant. 2. Conveyance of treated water from treatment plant to the distribution system.

In the first stage water is transported by gravity or by pumping or by the combined action of both, depending upon the relative elevations of the treatment plant and the source of supply. In the second stage water transmission may be either by pumping into an overhead tank and then supplying by gravity or by pumping directly into the water-main for distribution. Free Flow System In this system, the surface of water in the conveying section flows freely due to gravity. In such a conduit the hydraulic gradient line coincide with the water surface and is parallel to the bed of the conduit. It is often necessary to construct very long conveying sections, to suit the slope of the existing ground. The sections used for free-flow are: Canals, flumes, grade aqueducts and grade tunnels. Pressure System In pressure conduits, which are closed conduits, the water flows under pressure above the atmospheric pressure. The bed or invert of the conduit in pressure flows is thus independant of the grade of the hydraulic gradient line and can, therefore, follow the natural available ground surface thus requiring lesser length of conduit. The pressure aqueducts may be in the form of closed pipes or closed aqueducts and tunnels called pressure aqueducts or pressure tunnels designed for the pressure likely to come on them. Due to their circular shapes, every pressure conduit is generally termed as a pressure pipe. When a pressure pipe drops beneath a valley, stream, or some other depression, it is called a depressed pipe or an inverted siphon. Depending upon the construction material, the pressure pipes are of following types: Cast iron, steel, R.C.C, hume steel, vitrified clay, asbestos cement, wrought iron, copper, brass and lead, plastic, and glass reinforced plastic pipes. Hydraulic Design The design of water supply conduits depends on the resistance to flow, available pressure or head, and allowable velocities of flow. Generally, Hazen-William's formula for pressure conduits and Manning's formula for freeflow conduits are used. Hazen-William's formula U=0.85 C rH

0.63S0.54 Manning's formula U=1/n rH

2/3S1/2

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where, U= velocity, m/s; rH= hydraulic radius,m; S= slope, C= Hazen-William's coefficient, and n = Manning's coefficient. Darcy-Weisbach formula hL=(fLU2)/(2gd) The available raw waters must be treated and purified before they can be supplied to the public for their domestic, industrial or any other uses. The extent of treatment required to be given to the particular water depends upon the characteristics and quality of the available water, and also upon the quality requirements for the intended use. The layout of conventional water treatment plant is as follows:

Depending upon the magnitude of treatment required, proper unit operations are selected and arranged in the proper sequential order for the purpose of modifying the quality of raw water to meet the desired standards. Indian Standards for drinking water are given in the table below.

Indian Standards for drinking water

Parameter Desirable-Tolerable If no alternative source available, limit extended

upto Physical

Turbidity (NTU unit) < 10 25 Colour (Hazen scale) < 10 50

Taste and Odour Un-objectionable Un-objectionable Chemical

pH 7.0-8.5 6.5-9.2 Total Dissolved Solids mg/l 500-1500 3000

Total Hardness mg/l (as CaCO3) 200-300 600 Chlorides mg/l (as Cl) 200-250 1000

Sulphates mg/l (as SO4) 150-200 400 Fluorides mg/l (as F ) 0.6-1.2 1.5 Nitrates mg/l (as NO3) 45 45

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Calcium mg/l (as Ca) 75 200 Iron mg/l (as Fe ) 0.1-0.3 1.0

The typical functions of each unit operations are given in the following table: Functions of Water Treatment Units

The types of treatment required for different sources are given in the following table:

Check your progress-1

1. How much water is available on earth and how much of this water is available for humans?

2. How much freshwater will be available for one person? 3. What is the total world annual consumption of potable water and seawater? 4. What are the projected needs for water in the next 10 to 50 years? 5. How many people do not have access to clean water? 6. What is the average cost of water per cubic meter in different countries? 7. How much does a cubic meter of desalinated water cost in various countries? 8. What will happen to the cost of desalinated water in the next 10 to 50 years? 9. How will population increases influence water use?

Unit treatment Function (removal) Aeration, chemicals use Colour, Odour, Taste

Screening Floating matter Chemical methods Iron, Manganese, etc. Softening Hardness Sedimentation Suspended matter Coagulation Suspended matter, a part of colloidal matter and bacteria Filtration Remaining colloidal dissolved matter, bacteria

Disinfection Pathogenic bacteria, Organic matter and Reducing substances

Source Treatment required 1. Ground water and spring water fairly free from contamination

No treatment or Chlorination

2. Ground water with chemicals, minerals and gases

Aeration, coagulation (if necessary), filtration and disinfection

3. Lakes, surface water reservoirs with less amount of pollution

Disinfection

4. Other surface waters such as rivers, canals and impounded reservoirs with a considerable amount of pollution

Complete treatment

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2.4 LET US SUM UP

Water planning and management is the way to protect water supplies and provide a reliable supply of clean water at reasonable costs for current and future generations of citizens, industry and wildlife in the condition. Illinois has another opportunity in the coming months to prove that its interest and commitment to achieving these objectives are sufficient to take appropriate action. 2.5 SOME USEFUL BOOKS

Damon, L. (Undated). Conference Summary, Illinois Water Law: Challenges and Opportunities, October 23, 1996, Bloomington, IL.

Hays, R.G. (1980). State Science in Illinois: the Scientific Surveys, 1850-1978. Southern Illinois University Press for the Board of Natural Resources and Conservation of the Illinois Institute of Natural Resources, Carbondale, IL.

Illinois State Geological Survey (2001). Response of the Illinois State Geological Survey (ISGS) to Illinois Senate Resolution 0137 & House Resolution 0365. Champaign, IL.

Illinois State Water Survey (2001). A Plan for Scientific Assessment of Water Supplies in Illinois. Illinois State Water Survey Information/Educational Material 2001-03, Champaign, IL.

Illinois Technical Advisory Committee (1967). Water for Illinois: a Plan of Action. Illinois Technical Advisory Committee on Water Resources, Springfield, IL.

Jaffe, M. (2001). Water Supply Management Options for Northeastern Illinois. Great Cities Institute, University of Illinois at Chicago, Chicago.

2.6 ANSWER TO CHECK YOUR PROGRESS

Check your progress-1

1. Approximately 1385 million cubic kilometres of water are available on earth. 97,5% of the water is salt water that can be found mainly in oceans. Only 2,5% is freshwater that can be used by plants, animals and humans. However, nearly 90% of this freshwater is not readily available, because it is centred in icecaps of the Antarctic. Only 0.26% of the water on this world is available for humans and other organisms, this is about 93.000 cubic kilometres. Only 0.014% of this water can be used for drinking water production, as most of it is stored in clouds or in the ground.

2. Increases in world population means increased water use and less availability on a per capita basis. In 1989 there was some 9,000 cubic metres of freshwater per person available for human use. By 2000, this had dropped to 7,800 cubic metres and it is expected to plummet to 5,100 cubic metres per person by 2025, when the global population is projected to reach 8 billion.

3. People already use over half the world's accessible freshwater now, and may use nearly three-quarters by 2025. Over the twentieth century, the world annual water use has grown from about 300 km3 to about 2,100 km3 (see chart).

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In this chart the annual water consumption is shown, as withdrawal and use. These two concepts are separated, because much of the withdrawn water is later returned to the water cycle, after application. An example is cooling water; it is used for power generation and is immediately released for further use downstream. Each country has a different equivalent use per person.

The annual per capita water use for each part of the world: - North Americans use 1,280 cubic meters - Europeans and Australians use 694 cubic meters - Asians use 535 cubic meters - South Americans use 311 cubic meters - Africans use 186 cubic meters Water is used for three main purposes; agricultural uses, industrial uses and domestic uses. Each country uses a different amount of its available water for these three main purposes. In percentages, the global use for the three main purposes is divided up as follows: - Agriculture (mostly irrigation) = 69 % - Industry = 23 % - Domestic use (household water = drinking water, sanitation) = 8 % Current global water withdrawals for irrigation are estimated at about 2,000 to 2,555 cubic kilometres per year. The annual water volume used by industry is estimated 975 km3. The water that humans use for drinking water preparation is mainly freshwater. But freshwater availability has become a problem over the years, as only 0.014% of the water on earth is readily available freshwater for drinking purposes. In some countries they are trying to solve this problem by withdrawal and desalination of seawater. Right now, 0.1% of the water that is used by humans is desalinated seawater.

4. Global consumption of water is doubling every 20 years, more that twice the rate of human population growth. According to the various water research agencies, the world water use is expected to triple in the next 50 years. Almost half of the world's population lives in 263 international river basins, but two-thirds of these basins have no treaties to share water. Because of this, wars over water are extremely likely

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to happen in the future, when water becomes scarcer. Disputes could also consist over aquifers in time. The world's population of six billion people is already using about 54 per cent of all the accessible freshwater found in rivers, lakes and underground aquifers. By 2025 the human share will be 70 percent, based on the population increase. If per capita consumption of water resources continues to rise at its current rate, humankind could be using over 90 per cent of all available freshwater within 25 years.

5. Water scarcity is caused by dry climates, drought, desiccation, or water stress. Water scarcity caused by drought has killed over 24,000 people a year since the 1970's. Over 40% of the world's population now experiences water shortages that threaten their agriculture and industry and also their personal health. Today over a billion people do not have access to clean drinking water and by 2025 at least 3 billion people in 90 different countries are expected to face severe water stress. The main problem that causes this is not a shortage of water, but the wasteful and unsustainable use of available water supplies.

6. The costs of a cubic meter of water are known to differ between countries. In this chart, the costs of one cubic meter of water are shown, for 14 different countries.

7. When water is desalinated through the Reverse Osmosis (RO) treatment, the costs are as follows: Depending on the site of the plant, total costs of desalinated seawater vary between 0.5 and 0.8 dollars/ cubic meter. This makes desalinated water a more expensive resource than freshwater for many countries, but it is definitely not an unnecessary resource. It has to be noted that the above-mentioned costs do not include distribution towards points of use (houses, factories, etc.).

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8. The costs should decline within the next 10-50 years, as membranes become cheaper and more efficient. However, the costs are mostly energy related, so the energy use should be taken into account.

9. Global population now exceeds 6.2 billion, more that double what it was in 1950, and is currently projected to rise to between 7.9 billion and 10.9 billion by 2050. Even when the population does not increase, water use will still grow. A population increase will only make the global water use rise faster. An important issue here is that the water of our world is not divided up fairly between all its inhabitants. Water shortages are most likely to occur in developing countries, which have the highest population rates. In the developed world the per capita use is much higher than the projected need. The people in developed countries that use too much water tend to blame people in developing countries, because developing countries experience the largest population growth. But in developing countries, over a billion people have no excess to clean drinking water.

2.7 GLOSSARY

Accumulated overdraft. The amount of water necessary to be replaced into the groundwater basin to achieve a full condition. AF/acre-foot. The amount of water needed to cover an acre (approximate a football field) one foot deep, or 325,900 gallons. One acre-foot can support the annual indoor and outdoor needs of between one and two households per year, and, on average, three acre-feet are needed to irrigate one acre of farmland. AFY. Acre-foot per year. Alamitos Barrier. Joint project between OCWD, Los Angeles County Dept. of Public Works, and the Water Replenishment District of Southern California (WRDSC) for injection of imported water into a geologic gap at the Orange County-Los Angeles County boundaries subject to seawater intrusion. Alluvium. A stratified bed of sand, gravel, silt, and clay deposited by flowing water. AMP. Allen McColloch pipeline, operated by the Metropolitan Water District of Southern California to transport imported water within Orange County. Annexation. The inclusion of land within a government agency's jurisdiction. Annual overdraft. The quantity by which the production of water from the groundwater supplies during the water year exceeds the natural replenishment of such groundwater supplies during the same water year. Aqueduct. A structure for transporting water form one place to another by means of a pipeline, canal, conduit, tunnel or a combination of these things. Aquifer. A geologic formation of sand, rock and gravel through which water can pass and which can store, transmit and yield significant quantities of water to wells and springs. Artesian. An aquifer in which the water is under sufficient pressure to cause it to rise above the bottom of the overlying confining bed, if opportunity to do so should be provided. Artificial recharge. The addition of surface water to a groundwater reservoir by human activity, such as putting surface water into recharge basins. (See also: groundwater recharge and recharge basin.)

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UNIT 3 COLLECTIONS AND CONVEYANCE OF WATER

Structure 3.0 Objective 3.1 Introduction 3.2 History 3.3 Collections and conveyance of water 3.4 Let us sum up 3.5 Some Useful Books 3.6 Answer to Check your Progress 3.7 Glossary 3.0 OBJECTIVE

In this lesson we are going to discuss in detailed manner about : Intake - Types of intakes - description of canal intake reservoir intake, river intake -

methods – conveyance of water – methods - pipe materials - cast iron, steel, G.I, cement concrete & R.C.C and P.V.C pipes - advantages and disadvantages of different pipes - joints in pipe lines.

Spigot and socket joint, Expansion joint, Flanged joint, Collar joint and joint for A.C. pipes – Laying and testing of pipe lines - Recharging ground storage- Rain water harvesting.

3.1 INTRODUCTION

CH2M HILL's conveyance experts plan, design, and implement systems for the distribution of raw and treated water, and the collection and management of wastewater and stormwater. We provide asset management and planning, system optimization, compliance assistance, design, and implementation services.

Wastewater and wet weather collection systems Water distribution systems Conveyance design Condition assessment and rehabilitation Tunnels and trenchless technology Dams and levees Construction management

Tunnels & Trenchless Technologies Microtunneling Bore and jack Tunneling Horizontal directional drilling In-situ replacement (lining, pipe bursting, etc.)

Water Transmission & Distribution Pressure Pipelines

Pressure reducing stations and other conveyance structures Pumping stations and diversion facilities Storage reservoirs (not dams)

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Wastewater Systems Wastewater interceptors Collection gravity pipelines Force mains Siphons and low pressure systems Storage facilities Transient analyses and computer modeling Rehabilitation of existing wastewater systems Pumping stations

Storm Water Systems Storm drains, catch basins Flood control retention basins Open channel facilities Subsurface drainage facilities

Wet Weather Management Capacity enhancement Operational controls High rate treatment Long-term control plan Sewer evaluation and capacity assurance Water-in-basement programs Source control

Infrastructure Replacement & Rehabilitation Condition assessment Life cycle analysis Prioritization Infrastructure replacement and rehabilitation programs Trenchless technologies

3.2 HISTORY

This article describes the collection of water facilities and transmission construction (c. 1450 AD) by the Incas to Machu Picchu - high in the mountains of Peru. These means of transport, stone and sealed with clay, are still in operation today, a tribute to the ingenuity and skill of the Incas and the sustainability of their efforts. Source: Reprinted with permission from Water Environment and Technology, vol. 20, No. 9, 78-87. Copyright 2008 Water Environment Federation: Alexandria, Virginia; www.wef.org. This document can be downloaded for personal use. Any other use requires prior permission of the Water Environment Federation. 3.3 COLLECTIONS AND CONVEYANCE OF WATER Collection and Conveyance Sewerage Systems Sewers Sewage collection systems shall be designed and constructed to achieve total containment of the predicted sewage flows contributed from the established service area and population.

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Capacity. New sewer system capacity shall be designed on the basis of an average daily per capita flow of sewage of not less than 100 gpcd .These figures are assumed to include infiltration but do not address inflow. When deviations from the foregoing per capita rates and established peak flow factors are proposed, a description of the procedure used to establish those design flows shall be included with the submission for the purpose of this chapter, the following list defines the various collection system components that are to be designed to transmit peak flow rates:

1. "Lateral" means a sewer that has no other common sewers discharging into it. 2. "Submain" means a sewer that receives flow from two or more lateral sewers. 3. "Main or trunk" means a sewer that receives sewage flow from two or more submain sewers. 4. "Interceptor" means a sewer that receives sewage flow from a number of gravity mains, trunk sewers, sewage force mains, etc.

The minimum peak design capacity for lateral and submain sewers should be 400% of the average design flow.

Minimum peak design capacity of main, and trunk, sewers should be 250% of the average design flow.

Minimum peak design for interceptor sewers shall be 200% of the average design flow. Sizing. For the purpose of this chapter the gravity sewer design details as described herein

represent the best available standards of practice. Hydraulic computations and other design data should clearly establish the capacity of proposed sewers that do not conform to the minimum standards included in this section.

1. Sewer size shall not be less than eight inches in diameter, except under the following conditions:

a. Laterals serving six connections or fewer on cul de sacs or as sidewalk collector lines may be six inches in diameter. b. Sewer lines carrying settled sewage, such as septic tank effluent, may be as small as 1-1/2 inches in diameter.

2. Engineering calculations and justifications indicating that reduced line sizes are adequate shall be included with the submission.

Materials. . The pipe material shall conform to applicable ASTM, AWWA, ANSI, or other appropriate standards and the pipe is to be marked with an approved identification such as the specifications standard.

Installation. Gravity sewers shall be installed such that their design capacity is maintained and

infiltration and exfiltration is held within allowable values. 1. Sewers shall be installed at a sufficient depth to prevent ice formation due to cooling of the wastewater flows, resulting in blockage of the flow channel. Sewers carrying nonsettled sewage and sewers carrying settled sewage shall be designed and constructed to give mean velocities, when flowing full, of not less than two feet per second and 1.3 feet per second, respectively, based on Manning's formula using a pipe material roughness coefficient ("n") value of 0.014. Use of other "n" values and slopes less than those specified herein shall be justified on the basis of pipe material specifications, research, or field data, presented with the submission for approval.

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2. The following list represents the minimum slopes, which should be provided for gravity sewers; however, slopes greater than those listed are desirable:

Sewer Size Minimum Slope in Feet per 100 Feet Nonsettled Sewage Settled Sewage

3 inch Not Allowed 0.53 4 inch Not Allowed 0.47 6 inch 0.49 0.21 8 inch 0.40 0.15 10

inch 0.28 0.12

12 inch

0.22 0.086

14 inch

0.17 0.068

15 inch

0.15 0.063

16 inch

0.14 0.058

18 inch

0.12 0.050

21 inch

0.10 0.040

24 inch

0.08 0.034

27 inch

0.067 0.029

30 inch

0.058 0.025

36 inch

0.046 0.020

Sewers shall be installed with uniform slope between manholes. Sewers constructed on 20% slope or greater shall be anchored securely with concrete anchors or equal. Suggested minimum anchorage is as follows:

a. Not over 36 feet center-to-center on grades 20% and up to 35%. b. Not over 24 feet center-to-center on grades 35% and up to 50%. c. Not over 16 feet center-to-center on grades 50% and over. Gravity sewers shall normally be installed with a straight alignment between manholes. Gravity sewer size shall normally remain constant between manholes.

Where velocities greater than 15 feet per second are expected, special provisions shall be made to protect against internal erosion by high velocity. The pipe shall conform to applicable ASTM, AWWA, ANSI, or other appropriate standards or specifications, which provide protection against internal erosion.

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The pipe material shall conform to applicable ASTM, AWWA, ANSI, or other appropriate standards and the pipe is to be marked with an approved identification such as the specifications standard.

Construction details. Pipe joints. The method of joining pipe and the material used shall be included in the design

specifications in accordance with ASTM or other nationally recognized standards and the joint material and joint testing shall conform to the appropriate standards and specifications.

1. Sewer joints shall be designed to prevent infiltration and to prevent the entrance of roots. 2. When concrete pipe is used, single rubber ring gasket joints shall conform to the appropriate ASTM specification. 3.. When ductile iron pipe is used, joints using couplings and gaskets shall be made in conformance with the requirements of the appropriate ASTM specification. 4. Joints for plastic material pipe may be of compression gaskets, chemical welded sleeves, or chemical fusion joints per manufacturers' recommendations.

5. Heat fusion joints may be used for high density polyethylene pipe. Leakage. An acceptance test shall be specified for all gravity sewer lines. The test may be

either a hydrostatic test or an air test. 1. Where hydrostatic testing is specified (infiltration or exfiltration), the leakage outward or inward shall not exceed 100 gallons per inch of nominal pipe diameter per mile per day (2,400 gpd/mi maximum) for any section of the system. Manholes should be tested prior to pipeline testing. Where the exfiltration test is employed, the line shall be subjected to a minimum of four feet of head, or up to the head to the top of the previously tested manhole, whichever is the lesser, above the crown of the pipe at the upstream manhole of the section being tested. 2. The infiltration test shall be allowed only when it can be shown that the hydrostatic head outside the pipe is a minimum of four feet or exceeds the upstream manhole depth, whichever is the lesser, above the crown of the pipe for the entire length of the pipe being tested. 3. Where air testing is specified, test methods and acceptability criteria shall be in accordance with the appropriate ASTM specification. Air testing shall generally be acceptable for all types of pipe materials. If air testing is employed, the manholes shall be tested by exfiltration. 4. Manhole leaking standards as specified in ASTM standards or other established standards shall be utilized.

Building sewers. Sewerage service lines from buildings (sewers) shall be constructed in accordance with either the Uniform Statewide Building Code of Virginia or the standards contained in this chapter, depending upon local jurisdictional ruling..

1. Connections shall be made to sewers by replacing a length of pipe with branch fittings, or a clean opening cut with tapping equipment and a "y" type of connection completed and sealed. In some instances a tee-saddle or tee-insert may be attached to the sewer submain to provide a connection.

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2. All connections to sewers and manholes shall be made so as to prevent structural damage and infiltration. To meet future needs, stubs, wyes, and tees may be installed if plugged tightly. 3. Building sewers shall be four inches in diameter for raw sewage. Settled sewage can be conveyed in three inch diameter pipelines. Treated effluent from residences can be conveyed in two inch pipelines. 4. Cleanouts shall be installed at every alignment and directional change. Cleanouts shall be installed every fifty feet on straight runs of pipe.

Trench construction. Class A, B, or C bedding (American Society of Civil Engineers (ASCE) Manuals and Reports on Engineering Practice--No. 36, 1974, Water Pollution Control Federation (WPCF) Manual of Practice--No. 9, 1970, and American Waterworks Association (AWWA) for Installation of Ductile-Iron Water Mains and their Appurtenances (ANSI/AWWA C600-82), 1982, bedding class shall be provided for rigid pipe, and appropriate installation shall be provided for flexible pipe material in accordance with recognized standards and manufacturers' recommendations. Specifications must include reference to OSHA safety requirements.

1. Trenches shall be carefully backfilled with excavated materials approved for backfilling, consisting of earth, loam, sandy clay, sand and gravel, soft shale, or other approved materials free from large clods of earth or stones larger than one inch in diameter, deposited in six inch layers, and thoroughly and carefully tamped until the pipe has a cover of not less than one foot. 2. The remainder of the backfill shall be placed in the trench in layers not exceeding two feet and thoroughly tamped. No stone or rock larger than five inches in its greatest dimension shall be used in backfilling. 3. Trenches in public roadways shall be excavated, backfilled and compacted in accordance with the standards specified in the Virginia Department of Transportation's Road and Bridge Specifications or other acceptable criteria.

Manholes. Location. Manholes shall be installed at the end of each line of eight-inch diameter or greater; at all changes in grade, size, or alignment; at all intersections; and at distances not greater than 400 feet for sewers 15 inches or less in diameter and 500 feet for sewers 18 inches to 30 inches in diameter. Terminal cleanouts may be acceptable in place of manholes, on lines eight inches in diameter or less, on a case-by-case basis. Cleanouts may be used in lieu of manholes for collection of settled sewage. Manholes are required where four or more sewers intersect, or where two or more sewers intersect at depths greater than eight feet. Cleanouts shall be installed at distances not greater than 400 feet for settled sewage systems.

Materials. Manholes shall be constructed of precast concrete. Manhole wall and bottom construction shall be such as to ensure water tightness. Details. The base inside diameter of manholes and vertical pipe tees used for maintenance access shall be a minimum of 42 inches. The clear opening in the manhole frame shall be a minimum of 24 inches. Larger base diameters are preferred.

1. The manhole foundation shall be adequately designed to support the manhole and any superimposed loads that may occur.

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2. The flow channel through manholes shall be of such shape and slope to provide smooth transition between inlet and outlet sewers and to reduce turbulence. Benches shall be sloped to the channel to prevent accumulation of solids. 3. When the flow direction or horizontal deflection of a sewer line varies significantly, elevation changes may be necessary to provide for head losses. The minimum vertical change in elevation from upstream to downstream should provide for a head loss of up to 3 inches or more, when ninety degrees of deflection is specified. 4. Watertight manhole covers or watertight manhole inserts shall be used whenever the manhole tops are prone to periodic flooding. As a minimum, watertight manhole covers or watertight manhole inserts shall be used when the manhole top is below the elevation of the 100-year flood/wave action. 5. Inlet and outlet pipes shall be joined to the manhole with a gasketed flexible watertight connection or any watertight connection arrangement that allows differential settlement of the pipe and manhole wall to take place without destroying the watertight integrity of the line connections. 6. Ventilation of gravity sewer systems shall be provided where continuous watertight sections greater than 1,000 feet in length are incurred. 7. A drop pipe should be provided for an upstream sewer entering a manhole at an elevation of 24 inches or more above the manhole invert unless sewer pipe crowns match elevations, or as may otherwise be required to conform to the use of standard fittings in the drop pipe construction. Where the difference in elevation between the incoming sewer and the manhole invert is less than 24 inches, the invert shall be filleted to prevent solids deposition. A drop pipe shall be used when the upstream to downstream invert difference exceeds 24 inches and the sewer deflects horizontally at a manhole. The drop through the manhole should be a maximum of four inches for a 90° horizontal deflection.

Leakage testing. Manholes may be tested for leakage at the same time that gravity sewer lines are being hydrostatically tested for leakage. For manholes greater than four feet in depth whose entire depth was not included in the hydrostatic testing of the sewer line, the manholes shall be tested by exfiltration. Inflatable stoppers shall be used to plug all lines into and out of the manhole being tested. The manhole shall be filled with water to the top of the rim. A maximum 12-hour soak shall be allowed. Leakage shall not exceed 0.25 gallon per hour (gph) per foot of depth.

1. If air testing of sewer lines is employed, the manholes shall normally be tested by exfiltration. Inflatable stoppers shall be used to plug all lines into and out of the manhole being tested. The stoppers shall be positioned in the lines far enough from the manhole to ensure testing of the untested portions of the lines. The manhole shall then be filled with water to the top of the rim. A maximum 12-hour soak shall be allowed. Leakage shall not exceed 0.25 gph per foot. 2. Air testing or vacuum testing of manholes for leakage may be considered on a case-by-case basis. It is important that the entire manhole from the invert to the top of the rim be tested. Stream Crossings:

Design integrity. The tops of all sewers entering or crossing streams shall be at a sufficient depth below the natural bottom of the streambed to protect the sewer line. In general, one foot of suitable cover shall be provided where the stream is located in rock and three feet of suitable

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cover in other material. Less cover will be considered if the proposed sewer crossing is encased in concrete. Sewers shall remain fully operational during the 25-year flood/wave action. Sewers and their appurtenances located along streams shall be protected against the normal range of high and low water conditions, including the 100-year flood/wave action. Sewers located along streams shall be located outside of the streambed wherever.

1. Sewers entering or crossing streams shall be constructed of watertight pipe. The pipe and joints shall be tested in place and shall exhibit zero infiltration. Sewers laid on piers across ravines or streams shall be allowed only when it can be demonstrated that no other practical alternative exists. Such sewers on piers shall be constructed in accordance with the requirements for sewers entering or crossing under streams. Construction methods and materials of construction shall be such that sewers will remain watertight and free from change in alignment or grade due to anticipated hydraulic and physical loads, erosion, and impact. 2. Depressed sewers or siphons shall have not less than two barrels, with a minimum pipe size of six inches and shall be provided with necessary appurtenances for convenient flushing and maintenance; the inlet and outlet chambers shall be designed to facilitate cleaning; and, in general, sufficient head shall be provided and pipe sizes selected to secure velocities of at least three feet per second for average flows. The inlet and outlet details shall be arranged so that normal flow is diverted to one barrel and so that either barrel may be removed for service or cleaning.

Protection of Water supplies. No general requirement can be made to cover all conditions. Sewers shall meet the requirements of the appropriate reviewing agency with respect to minimum distances to structures and pipelines utilized for drinking water supplies. There shall be no cross connection between a drinking water supply and a sewer.

1. The requirements of the Virginia Waterworks Regulations (12 VAC 5-590 is this the current number?) shall be satisfied. 2. No sewer line shall pass within 50 feet of a drinking water supply well, source, or structure unless special construction and pipe materials are used to obtain adequate protection. The proposed design shall identify and adequately address the protection of all drinking water supply wells, sources, and structures up to a distance of 100 feet of the sewer line installation. 3. Sewers shall be laid at least 10 feet horizontally from a water main. The distance shall be measured edge-to-edge. When local conditions prohibit this horizontal separation, the sewer may be laid closer provided that the water main is in a separate trench or an undisturbed earth shelf located on one side of the sewer and the bottom of the water main is at least 18 inches above the top of the sewer. Where this vertical separation cannot be obtained, the sewer shall be constructed of water pipe material in accordance with AWWA specifications and pressure tested in place without leakage prior to backfilling. The hydrostatic test shall be conducted in accordance with the most recent edition of the AWWA standard (ANSI/AWWA C600-82) for the pipe material, with a minimum test pressure of 30 psi. 4. Sewers shall cross under water mains such that the top of the sewer is at least 18 inches below the bottom of the water main. When local conditions prohibit this vertical separation, the sewer shall be constructed of AWWA specified water pipe and pressure tested in place without leakage prior to backfilling, in accordance with the provisions of this chapter. Sewers crossing over water mains shall:

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a. Be laid to provide a separation of at least 18 inches between the bottom of the sewer and the top of the water main. b. Be constructed of AWWA approved water pipe and pressure tested in place without leakage prior to backfilling, in accordance with the provisions of this chapter. c. Have adequate structural support to prevent damage to the water main. d. Have the sewer joints placed equidistant and as far as possible from the water main joints.

5. No water pipe shall pass through or come into contact with any part of a sewer manhole. Manholes shall be placed at least 10 feet horizontally from a water main whenever possible. The distance shall be measured edge-to-edge of the pipes or structures. When local conditions prohibit this horizontal separation, the manhole shall be of watertight construction and tested in place.

System access. Sewer location should be within streets, alleys, and utility rights-of-way. Approvals shall be

obtained from the appropriate jurisdictions for placement of sewers within these boundaries. Where it is impossible to avoid placing sewers (and manholes/cleanouts) on private property,

the owner shall have recorded easements or have filed certificates of condemnation from all parties possessing or having legal interest in an adequate right-of-way necessary for proper installation, maintenance, operation, and removal of sewerage facilities. These easements shall include provisions for controlling the location of fences, buildings, or other structures within the easement and shall be shown on the plans.

Sewage Pump Stations. Sewage pumping.

A. Features. Sewage pump stations should be located as far as practicable from present or proposed built-up residential areas, and an all-weather road shall be provided. Stations should have a proper zone of controlled or limited use surrounding them.. Provisions for noise control and odor control should conform to site requirements.

All mechanical and electrical equipment which could be damaged or inactivated by contact with or submergence in water (motors, control equipment, blowers, switch gear, bearings, etc.) shall be physically located above the 100-year flood/wave action or otherwise protected against the 100-year flood/wave action damage. All stations shall be designed to remain fully operational during the 25-year flood/wave action.

1. Where it may be necessary to pump raw (untreated) or unsettled sewage prior to grit removal, the design of the wet well shall receive special attention. The discharge piping shall be designed to prevent grit settling in the discharge lines when pumps are not operating. 2. At least two pumping units shall be provided. Where two units are provided, each shall be capable of handling flows in excess of the expected maximum flow or a minimum of 2-1/2 times the average design flow, whichever is greater. When the station is expected to operate at a flow rate less than one-half times the average design flow for an extended period of time, the design shall address measures taken to prevent septicity due to long holding times of untreated sewage in the wet well. 3. Treatment works pump stations should be designed so that sewage will be delivered to the treatment works at approximately the same rate it is received at the pump station. At least

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two pumping units shall be provided. Treatment works pump stations are those stations which discharge to sewage treatment works without dissipation of flow through a gravity collection system 4. Pumps handling raw sewage should be preceded by readily accessible bar racks with clear openings not exceeding 2-1/2 inches, or have other means protect the pumps from clogging or damage. Where the size of the installation warrants, a mechanically cleaned bar screen with either a grinder or comminution device is recommended. Where screens are located below ground, convenient facilities must be provided for handling screenings. For the larger or deeper stations, duplicate protection units of proper capacity are preferred. Interceptor or separation basins may be necessary prior to pumps handling raw sewage. 5. Pumps in which the solids pass through the impeller(s) shall be capable of passing spheres of at least three inches in diameter. Pumping equipment having integral screens for preventing solids from passing through the impeller shall be capable of passing spheres of at least two inches in diameter. Pumping equipment preceded by grinding equipment shall be capable of passing the solids discharged from the grinding mechanism. 6. Pumps shall be so placed that under normal start conditions they will start with a positive suction head, except as specified for suction lift pumps. Each pump shall have an individual intake and suction line. Wet well design should be such as to avoid turbulence near the intake. Pump suction and discharge piping shall not be less than four inches in diameter except where design of special equipment allows. The design velocity in pump piping should not exceed (i) six feet per second in the suction piping, and (ii) in the discharge piping, eight feet per second. All pumps should be provided with an air relief line on the pump discharge piping. 7. For the purpose of designating liquid levels for alarm requirements, high liquid level in the wet well is defined as a level of sewage in the wet well above normal operating levels such that either: (i) a backup of sewage in the incoming sewer may occur, or (ii) an overflow may occur, or (iii) standby pump(s) may be required to be activated. In the case of a duplex pump station with limited wet well volume, the alarm design should include activation at the time of simultaneous operation of both pumps, initiating when the second alternating pump starts (referred to as the lag pump). 8. Pumps shall be able to be isolated by valving, where applicable.. A check valve is to be placed on each discharge line, between the shut-off valve and the pump. No shut-off valve need be placed on the suction side of suction lift or submersible pumps 10. System pump stations should have the provision for installing flow measuring devices or hour-meters. Consideration should be given to installation of such devices in system pump stations whose flow rate can affect the proper operation of the treatment works.

B. Ventilation shall be provided in accordance with VOSH requirements and shall comply with this chapter for enclosed spaces within pump stations during all periods when the station is manned. Where the pump is permanently mounted below the ground, mechanical ventilation is required and shall be arranged so as to independently ventilate the dry well.

1. As a minimum, ventilation of the wet well shall be accomplished by the provision of a properly screened vent, with the end either turned downward or provided with a "mushroom" cap. The vent shall be at least four inches in diameter. If screens or mechanical equipment, which might require periodic maintenance and inspection, are located in the wet well, then it shall be mechanically ventilated at the time of access by maintenance personnel.

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2. There shall be no interconnection between the wet well exhaust flow and the dry well ventilation systems. In pits over 15 feet deep, multiple inlets and outlets are desirable. Dampers shall not be used on exhaust or fresh air ducts, and fine screens or other obstructions in air ducts shall be avoided to prevent clogging. In climates where excessive moisture or low temperature are problems, consideration should be given to installation of automatic heating and dehumidification equipment. 3. Switches for operation of ventilation equipment shall be marked and conveniently located above grade and near the pump station entrance. Consideration should be given also to automatic controls where intermittent operation is used. The fan drive shall be fabricated from nonsparking material in accordance with applicable codes and standards. 4. Where heat buildup from pump motors may be a problem, consideration should be given to automatic cooling and ventilation to dissipate motor heat. 5. Ventilation of wet wells in accordance with VOSH requirements may be either continuous or intermittent. Ventilation, if continuous, shall provide at least 12 complete air changes per hour; if intermittent, at least 30 complete air changes per hour. Such ventilation shall be accomplished by mechanical means.

C. Water supply. There shall be no cross connection between any potable water supply and a sewage pump station which under any conditions might cause contamination of the potable water supply. Any potable water supply brought to the station shall comply with conditions stipulated in the Virginia Waterworks Regulations (12 VAC 5-590). An approved reduced pressure zone backflow prevention device on the water supply line to the pump stations shall be provided to protect potable water. Non-potable water may be used for pumping station maintenance.

D. Service. Provisions shall be made to facilitate removing pumps, motors, and other equipment without interruption of system service while providing all necessary worker safety features.

1. In accordance with VOSH requirements, suitable and safe means of access shall be provided to dry wells and wet wells containing equipment requiring inspection or maintenance. Compliance with all applicable VOSH and Uniform Statewide Building Code requirements is recommended. All ladders shall have slip-resistant rungs. 2. If the dry well or wet well floor is more than 10 feet below the entrance, special consideration shall be given to safety features such as harness lifts, ladder cages, spiral stairways, or intermediate landings. Intermediate landings should not exceed 10 foot vertical intervals.

E. Wet wells. Proper design of wet wells is essential to effective pump station operation. 1. The wet wells at major pumping stations and in those located in critical areas should be divided into two sections properly interconnected to facilitate repairs and cleaning. 2. The wet well size and control settings shall be designed and operated so as to avoid heat buildup in the pump motor due to frequent starting and to avoid septic conditions due to excessive detention time. 3. Provisions shall be made to prevent solids deposition. Where used, wet well fillets shall have a minimum slope of one-to-one to the hopper bottom. The horizontal area of the hopper bottom shall be no greater than necessary for proper installation and function of the inlet.

Reliability. A. Purpose. Reliability provisions are based on a measurement of the ability of a component or

system to perform its designated function without failure or interruption of service. Overflow

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criteria, such as a period of discharge, are utilized solely for the establishment of reliability classification for design purposes and are not to be construed as authorization for, or defense of, an unpermitted discharge to state waters.

1. The objective of achieving reliability protection is to prevent the discharge of raw or partially treated sewage to any waters and to protect public health and welfare by preventing backup of sewage and subsequent discharge to basements, streets and other public and private property. Provisions for continuous operability of pumping stations shall be evaluated in accordance with the appropriate reliability classification. 2. For Class I Reliability, alternate motive force sufficient to operate the station at peak flow rates being received shall be operating the station prior to the expiration of an allowable time period. The maximum allowable period will be the time transpiring between the high liquid level alarm and the occurrence of an overflow, or backup and subsequent discharge, at flow rates being received (except when an emergency holding basin is provided to satisfy the requirement for continuous operability). The transpired time to be considered allowable may be the critical (shortest) transpired time (peak flow rates) or a spectrum of transpired times keyed to the 24 individual hours of the day. Certain Reliability Class I pump stations, for which it is feasible to shut down or discontinue operation during periods of power failure without bypassing or overflowing, may be exempted from the continuous operability requirement. Pump stations which may qualify for the exemption can be broadly categorized as those which serve facilities or institutions which would be closed during periods of power failure, such as certain industrial plants, schools and recreational and park areas. 3. For Class II Reliability, alternate motive force sufficient to operate the station at peak flow rates being received shall be operating the station prior to the expiration of a 24-hour period commencing at the time an overflow or discharge subsequent to a backup begins. 4. Reliability Class III pump stations are not limited to a specific period of overflow or discharge, and will be considered on a case-by-case basis.

B. Continuous operability. The owner shall demonstrate, to the satisfaction of the department, that the time allowances for continuous operability will be met on a 24-hour basis. This information shall accompany the plans and specifications when submitted and shall be subsequently modified and resubmitted at any time in the future that the actual allowable time (transpiring between the high liquid level alarm and the time that an overflow or backup and subsequent discharge will occur at flow rates being received) becomes less than the allowable time claimed in the original submission. The demonstration shall include provision of instructions indicating the essentiality of routinely maintaining, and regularly starting and running, auxiliary and reserve units under field conditions. The following means for provision of continuous operability shall be acceptable:

1. Alternate power sources or auxiliary stand-by generator that can operate sufficient pumps to deliver the design peak flow. 2. Alternate drive arrangements whereby all pumps are backed by internal combustion motors with "Y" mechanical couplings to the pump drive shafts or to permanently mounted reserve pumps capable of delivering total peak flows. 3. Portable pump resources in accordance with this chapter. 4. An emergency overflow holding basin with capacity to retain a minimum of one day of station design flow and having provisions for recycling flow to the pump station.

C. Electrical power. The sources of electrical power required to operate pump stations shall be evaluated in accordance with the reliability classification of the pump station.

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1. For Class I Reliability, electric power shall be provided by alternate feed from distribution lines which are serviced by alternate feed from transmission lines (e.g., 115 KV) where possible. The transmission lines shall have alternate feed from the generating source or sources. The capacity of each power source shall be sufficient to operate the pumps during peak wastewater flow conditions, together with critical lighting and ventilation. The requirement for alternate feed can be satisfied by either a loop circuit, a "tie" circuit, or two radial lines. Where alternate feed lines terminate in the same substation, the circuit feeding the pumping station shall be equipped with two or more in-place transformers. Where alternate feed is not possible, provision of auxiliary power sources will be considered. 2. External alternate distribution lines shall be completely independent. The two sets of alternate feed distribution lines should not be supported from the same utility pole and, if used, should neither cross over, nor be located in an area where a single plausible occurrence (e.g., fallen tree) could disrupt both lines. A minimum separation of 25 feet for underground routes shall be maintained unless a properly designed and protected conduit bank is utilized. This shall apply to service connections into the pump station. Devices should be used to protect the system from lightning. 3. For Class II Reliability, a single source feed is acceptable. If alternate power sources are provided for a Class II or III station, one in-place transformer and capability for connection of a mobile transformer may be provided where the alternate feed lines terminate in the same substation.

D. Power distribution. The design of power distribution circuitry and equipment provided within pump stations shall be in accordance with the reliability classification of the pump station.

1. Reliability Class I pump stations shall have the following features: a. Final stepdown transformer on each electric feed line with adequate physical separation to prevent a common mode failure. b. In addition, Reliability Class I pump stations shall be provided with separate buses for each power source. c. Each power source shall remain separate and from separate distribution substations up to the transfer switch to preclude a common mode failure of both sources.

2. Reliability Class II and Class III pump stations may be equipped with a single final stepdown transformer, a single bus, a single motor control center, and a single power distribution system. 3. Breaker settings or fuse ratings shall be coordinated to effect sequential tripping such that the breaker or fuse nearest the fault will clear the fault prior to activation of other breakers or fuses, to the degree practicable.

. Alarm systems. A. The alarm system provided to monitor pump station operation shall meet the appropriate

reliability requirements. B. Class I. For Class I reliability, the alarm system shall monitor the power supplies to the

station, auxiliary power source, failure of pumps to discharge liquid, and high liquid levels in the wet well and in the dry well, and shall include a test function. An on-site audio-visual alarm system shall be provided such that each announced alarm condition is uniquely identified. In addition, provisions shall be made for transmitting a single audible alarm signal to a central location where personnel competent to receive the alarm and initiate corrective action are either: (i) available 24 hours per day, or (ii) available during the periods that flow is received at the

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pump station. A sign indicating notification procedures (responsible persons, telephone numbers, etc.) to be followed in case of alarm actuation shall be displayed conspicuously.

C. Classes II and III. For Class II or III reliability, the alarm system shall monitor high liquid levels in the wet well. An on-site audio-visual alarm signal shall be provided. A sign indicating notification procedures (responsible persons, telephone numbers, etc.) to be followed in case of alarm actuation shall be displayed conspicuously.

D. Backup. A backup power supply, such as a battery pack with an automatic switchover feature, shall be provided for the alarm system, such that a failure of the primary power source would not disable the alarm system. A backup power supply for the alarm system should be provided for a Reliability Class I facility with dual electrical feed sources. Test circuits shall be provided to enable the alarm system to be tested and verified to be working properly. PUMPS

. Wet well-dry well pump stations shall meet the applicable requirements for both types of systems. Both wet and dry wells shall be separated to prevent leakage of gas into the dry well. A separate sump pump or suitable means shall be provided in the dry well to remove leakage or drainage, with the discharge above the high water level of the wet well. Vacuum ejectors connected to a potable water supply will not be approved. All floor and walkway surfaces shall have an adequate slope to a point of drainage. Drainage shall be unobstructed by conduit, piping, etc., installed on the dry well floor.

B. Suction lift. Suction lift pump installations shall be designed to meet the applicable requirements of this chapter.

1. The capacity of suction lift pump stations shall be limited by the net positive suction head and specific speed requirements as stated on the manufacturer's pump curve under the most severe operating conditions. 2. All suction lift pumps shall be provided with an air relief line on the pump discharge piping. This line shall be located at the maximum elevation between the pump discharge flange and the discharge check valve to ensure the maximum bleed-off of entrapped air. Air relief piping shall have a minimum diameter adequate to purge air during priming. The use of 90° elbows in air relief piping should be avoided. A separate air relief line shall be provided for each pump discharge. The air relief line shall terminate in the wet well or suitable sump and open to the atmosphere. 3. Valving to prevent recycle of flow to the wet well should be provided on all relief lines. The air relief valves shall be located as close as practical to the discharge side of the pump. Automatic operating air relief valves may be used if the design of the particular valve is such that the valve will fail in the open position under varying head conditions. Unvalved air relief piping may lead to air entrainment in the sewage and will materially affect pump efficiency and capacity. Air entrainment shall be considered accordingly by the design consultant. 4. All pumps, connections, shut-off valves, and check valves shall be located in a separate vault either above or outside of the wet well, allowing accessibility to both the wet well and pump/valve vault for inspection, maintenance, etc. 5. Access to the wet well shall not be through a sealed vault. The dry well shall have a gas-tight seal when mounted directly above the wet well.

C. Submersible. Submersible pump station installations shall be designed to meet the applicable requirements of this chapter.

1. Submersible pumps shall be provided with equipment for disconnecting, removal, and reconnection of the pump without requiring personnel to enter the wet well.

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2. Owners of submersible pumping facilities shall provide a hoist and accessories for removing the pumps from the wet well. 3. Electrical controls shall be located in a suitable housing for protection against weather and vandalism. 4. The shut-off valve and check valve on the discharge lines of pumps operating at flows greater than 25 gpm shall be located in a separate vault outside of the wet well allowing accessibility for inspection and maintenance.

E. Grinder. Grinder pump installations shall be designed to meet the applicable requirements of

this chapter. 1. Maintenance and operation service arrangements shall be identified to the division. Acceptable service arrangements shall include:

a. Right of access. b. Adequate spare parts, spare units and service tools.

2. A single pumping unit for a single home or equivalent flow is acceptable, but the wet well capacity for a single family residence should be a minimum of 60 gallons. 3. Duplex pumping units shall be provided where two houses or equivalent flow are served by a single installation. The wet well or holding tank capacity shall be twice the requirements for a single house. 4. The alarm system should provide notice to residents of pump failure, including excessive high liquid levels. The alarm system should alert the operating staff of the location of pump failure. 5. Pumping equipment shall be capable of delivering flows at the design pressure of the sewer system. Cutter blades shall be driven with a minimum motor size of two horsepower, unless performance data, evaluated by the department, verifies that a smaller motor is suitable.

F. Septic tank effluent pump. Septic Tank Effluent Pumps (STEP) may be located within the effluent end of a single tank or within a separate vault external from the septic tank. The design for STEP facilities is described in published literature, such as the USEPA Technology Transfer Manual "Alternative Wastewater Collection Systems" (EPA/625/1-91/024), which may be used as a reference. . Force mains.

A. Capacity. The minimum size of force mains shall be four inches in diameter, except for grinder pumps and septic tank effluent (settled sewage) pumping systems, which shall be provided with a minimum diameter of one inch.

1. At pumping capacity, a minimum self-scouring velocity of two feet per second shall be maintained unless provisions for flushing are made. A velocity of eight feet per second should not be exceeded unless suitable construction methods are specified. 2. Air relief valves shall be placed at the high points in the force main to relieve air locking and shall be periodically exercised and maintained.

B. Connections. Force mains shall normally enter a gravity sewer system at a point no more than one foot above the flow line of the receiving manhole with a curved section to prevent air from traveling up into the force main. The force main should enter the receiving manhole with its center-line horizontal, and shall have an invert elevation which ensures a smooth flow transition to the gravity flow section. Special attention shall be paid to the design of the termination in order to prevent turbulence at this point. Whenever existing force mains are connected within a

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sewerage system in a manner that results in increased flow rates or pressure increase to the existing force mains, those existing force mains shall be examined by the owner. Existing force mains may be examined by internal visual inspections, flow or pressure testing, or other suitable means to verify hydraulic and structural adequacy to convey the actual or projected flow. The results of such inspections and tests shall be submitted with the design documents.

C. Materials. All pipe used for force mains shall be of the pressure type with pressure type joints. The force main shall be constructed of materials with a demonstrated resistance to deterioration from corrosion, acidity, and other chemical action.

1. Consideration should be given to the use of inert materials or protective coatings for either the receiving manhole or gravity sewer to prevent deterioration as a result of hydrogen sulfide or other chemical attack. These requirements should be provided for all force mains. 2. All force mains shall be tested at a minimum pressure of at least 50% above the design operating pressure for at least 30 minutes. Leakage shall not exceed the amount given by the formula contained in the most current AWWA Standard C-600.

D. Installation. Class A, B or C bedding (ASCE Manuals and Reports on Engineering Practice--No. 36, 1974 and the WPCF Manual of Practice--No. 9, 1970) or AWWA pipe installation conditions 3, 4 or 5 (ANSI/AWWA C600-82) shall be provided for installation of pipelines in excavated trenches. Installation of pipelines of flexible materials shall be in accordance with recognized standards.

Force mains shall be sufficiently anchored within the pump station and throughout the line length. The number of bends shall be as few as possible. Thrust blocks, restrained joints, or tie rods shall be provided where restraint is needed. Cement Concrete Pipes Cement concrete pipes may be either plain or reinforced. Plain cement concrete pipes are used for heads up to 15m. R.C.C pipes are used for heads up to 75m. Above this head prestressed

concrete pipes are used. Advantages:

They are more suitable to resists external loads Maintenance cost is less The inside surface is smooth hence less frictional

losses The problem of corrosion is not there. Pipes can be cast at site hence no transportation. They are more durable. Not easily affected by soil and atmospheric action. The expansion coefficient of concrete pipe is very

minimum. Disadvantages:

Unreinforced pipes are liable to tensile cracks It is very difficult to repair them. Affected by acids, alkalies and salty water Making connection is difficult Porosity may cause leakage. May get damage during handling and transporting to site.

Intake

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The main function of the intakes works is to collect water from the surface source and then discharge water so collected, by means of pumps or directly to the treatment water. Intakes are structures which essentially consists of opening, grating or strainer through which the raw water from river, canal or reservoir enters and carried to the sump well by means of conducts water from the sump well is pumped through the rising mains to the treatment plant. The following points should be kept in mind while selecting a site for intake works.

1. Where the best quality of water available so that water is purified economically in less time.

2. At site there should not be heavy current of water, which may damage the intake structure.

3. The intake can draw sufficient quantity of water even in the worest condition, when the discharge of the source is minimum.

4. The site of the work should be easily approchable without any obstruction 5. The site should not be located in navigation channels 6. As per as possible the intake should be near the treatment plant so that conveyance cost is

reduced from source to the water works 7. As per as possible the intake should not be located in the vicinity of the point of sewage

disposal for avoiding the pollution of water. 8. At the site sufficient quantity should be available for the future expansion of the water-

works. Types of Intake structures: Depending upon the source of water the intake works are classified as following

Lake Intake Reservoir Intake River Intake Canal Intake

PVC Pipes How to install PVC Pipes:

Rain Water Harvesting Accumulate rainwater harvesting and storage of rainwater. It was used to supply drinking water for livestock, irrigation or aquifer recharge in a process called recharge. Rainwater collected on the roofs of houses, tents and local institutions, or the specially prepared area of ground can make a significant contribution to safe drinking water. In some cases, rainwater may be the only source of water available or economically. Rainwater systems are simple to build from local materials inexpensive and potentially effective in most places habitable. Take the rain can be good and may not require treatment before consumption. Although some roofing materials can produce rainwater that is harmful to human health, it may be useful in the toilet flushing,

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laundry, garden watering and car washing, these uses only half the amount of water used by a typical house. Collection systems are adequate rainfall households in areas with average rainfall exceeding 200 mm (7.9 inches) per year, and no other water source available. Check your progress-1

1. Why do we need a sewer? 2. Is the project on schedule? 3. Does the project have enough funding to start construction? 4. Is design of the project facilities complete? 5. How much will it cost to convert from septic to sewer and connect to the system? 6. How big is the sewer system? How many properties could be connected to it? 7. What is an ERU (equivalent residential unit)? 8. I heard the County has sized the plant to provide sewer service to SKIA and Bremerton,

is that true? 9. Who will operate the sewer utility? 10. How will County employees reach the treatment plant? 11. If I live near one of the treatment facilities – pump stations or treatment plant - will I be

able to smell it? 3.4 LET US SUM UP

Open the transfer channel, the hydraulic analysis of culverts, road overtopping, flood, structural, and storm sewers transfer all items were assessed as part of water quality testing. Figure ES-2 on the next page shows the areas that were judged to transfer problems based on the results of the model output. Most of the transport of elements were considered &quot;problems&quot; during storms larger (for example, 50 years of events). Alternatives to resolve transportation problems with the system includes improvements pipe, detention only, and a combination of pipes and detention improvements. Pipe improvements designed to improve the physical transport (pipes and culverts) and allowances to eliminate problems such as the floor of the filling. Detention Alternatives evaluated the measures that could be used to reduce the amount of water in the pipes or the river at a time. Detention is to alleviate problems such as flooding, the rate of channel erosion and filling. These transportation alternatives were modeled in the model XPSWMM to determine their effectiveness. The City has evaluated the results of this analysis, and alternatives that best meet the criteria for replacement have been recommended for inclusion in CIP in the city. 3.5 SOME USEFUL BOOKS

Water supply and Sanitary Engineering by S.K. Garg, Kanna publishers, Delhi Water supply and Sanitary Engineering by K.S. Rangwala Water supply and Sanitary Engineering by G.S. Birdie and JS. Birdie, Dhanpat rai

Publishers Environmental Studies by Suresh K.Dhamija, S.K.Katarial Sons Delhi Industrial waste water treatment by Rao & Dutta

3.6 ANSWER TO CHECK YOUR PROGRESS

Check your progress-1

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1. Septic systems have been identified as one of the causes of nitrogen-pollution in Hood Canal. The wastewater utility offers a sustainable approach to water management, protects the health of Hood Canal and provides economic development potential for the Belfair community. On a long-term basis, the project will support the backbone for urban infrastructure in the Belfair Urban Growth Area (UGA), as mandated by the Growth Management Act.

2. The project remains on schedule to break ground in late summer or early fall of 2009. It is anticipated that the project will be completed, with the treatment facility coming online in Spring 2011. How much will the project cost to build? I heard total project cost went up. Recent cost estimates pegged the project at $40 million in total. This cost includes planning, design, environmental compliance, permitting, environmental studies, wetland surveys, biological assessments, cultural surveys, topographic and property surveys, financial analysis and planning, property acquisition, construction management, inspection of construction work, construction of a membrane bioreactor treatment plant, construction of three pump stations, construction of public sewer lines, construction of a storage pond to support water reuse, construction of a spray irrigation system, escalation and contingency. Based on the bidding climate in the current economy, Mason County is anticipating the total cost of the project to be less. Project engineers are currently reevaluating project costs to take into account for design refinements from the value engineering study and competitive bidding climate. Early in the Belfair sewer project planning phases, the total project costs were projected to be approximately $24 million dollars, which offered a basic understanding of the project and allowed the County to begin to obtain funding for further design and construction of the project. As with many projects, this project’s complexities and realities were revealed during the field study and design process.

3. Yes. The project has secured $38.13 million in funding for the project, and the project is moving forward.

4. Project designs for the treatment plant and the wastewater conveyance system are over 90 percent complete. The Washington State Department of Ecology has notified the County that they have no comments on the treatment plant and the conveyance design submittal. Bidding documents and final plan sheets for construction are now being finalized. Locations of pump stations, treatment plant, and lines for conveyance are essentially “set.”

5. Connecting to the new sewer system does have associated fees that property owners will be responsible for: • There will be a one-time conversion fee per connection to the mainline sewer. The conversion connection fee is being developed and will likely be between $3,000 and $5,000 per equivalent residential unit (ERU) for homes and businesses with a septic system of record. • There will be costs to re-plumb your sewer to connect to the public system and disconnect from your septic tank. Sometimes this is referred to as “building a side sewer.” The costs for this work vary and depend on a number of property specific factors including your property’s topography, distance from the building to the property line, and the contractor you use. The average costs are estimated to be approximately $3,000. • Once the system is operational, the average household can expect to pay $86-$100 per month for sewer service.

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6. The wastewater system was designed to be able to expand to ultimately serve the Belfair UGA. Pipelines were sized to handle flows predicted to be generated within the Belfair UGA in the future. The wastewater treatment plant is being designed to provide enough treatment capacity for design flows of 500,000 gallons of wastewater per day in a maximum month. That will be approximately 2,000 equivalent residential units, or “ERU.” Since much of the cost of installing the pipelines is in the digging and backfill of the trenches, and in restoration of the road, it makes sense to size pipes underground and in roadways large enough that they do not need to be replaced for a long period of time. The wastewater treatment plant itself was designed so that it can be expanded as new customers come online, allowing the plant to grow over time to meet the needs of the community. Some elements of the treatment plant are not easily expandable and generally these elements were sized so that they would not have to be replaced for a long period of time. To reduce cost, maintain flexibility, and allow more opportunities for future water reuse, the irrigation system is sized for approximately 500 ERUs. The County could expand the irrigation system when needed, however is actively working to develop a customer base for the reuse water.

7. An ERU is a way to think about the amount of wastewater generated. One single family house is considered “one ERU.” For the purpose of this discussion, an ERU is considered to be one single family house, with 2.5 people, each generating approximately 100 gallons per day of wastewater, including the water that leaks into the system from the environment (groundwater and water from storms). A business could have multiple ERUs depending on the amount of water they use.

8. No. The plant is sized for the County’s plan to provide service to the Belfair UGA. During the facility plan development process, Alternative 4 – South Kitsap Industrial Area (SKIA) was considered and dropped for future planning.

9. Mason County Department of Utilities and Waste Management will build and operate the sewer utility. Mason County currently operates the Rustlewood Water and Sewer System, Harstene Pointe Water and Sewer System, Beards Cove Water System and the North Bay/Case Inlet Water Reclamation Facility/Sewer Collection System.

10. An access road will approach the wastewater treatment facility from the north, turning off SR 3 just north of the railroad trestle that crosses SR 3.

11. Modern odor controls have been designed into the conveyance system and the wastewater treatment plant. It is unlikely that noticeable odors will be associated with any of these facilities for neighbors, or those who may live “down wind.”

3.7 GLOSSARY

Conveyance [general]: The systematic and intentional flow or transfer of water from one point to another. Conveyance types include water instream conveyance, water distribution, and wastewater collection. Conveyance loss [general]: Water that is lost in transit from a pipe, canal, conduit, or ditch by leakage or evaporation. If the water is lost due to leakage, it may be considered return flow if it percolates to an aquifer and is available for reuse. If the water evaporates, it is considered consumptive use. Cooling pond [power]: A cooling pond is a shallow reservoir having a large surface area to allow heat to be removed from water.

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Cooling tower [power]: A structure designed to remove as much heat from water as possible per unit of space occupied by the structure. Cooling water [power, industry]: Water used for cooling purposes, such as of condensers and nuclear reactors. UNIT 4 QUALITY OF WATER

Structure 4.0 Objective 4.1 Introduction 4.2 History 4.3 Quality of water 4.4 Let us sum up 4.5 Some Useful Books 4.6 Answer to Check your Progress 4.7 Glossary 4.0 OBJECTIVE

In this lesson we are going to discuss in detailed manner about : Meaning of pure water – Requirements of potable or domestic water - Impurities in water

- Sources, causes and effects of different types of impurities – Water Analysis -physical, Chemical and Bacteriological tests - standards laid down by B.I.S.I for drinking water – Living Organism in water-W.H.O standards - Maintenance of purity of water - water borne diseases and their causes.

4.1 INTRODUCTION

Water Quality in the Rural Drinking Water Supply has emerged as a major issue. There was no proper emphasis on water quality till the end of the 6th Five Year Plan and even in the Seventh Plan before launching the National Drinking Water Mission in 1986. The primary objectives of the National Drinking Water Mission set up in 1986 was to improve the performance and cost effectiveness of the on-going programmes in the field of rural drinking water supply and to ensure the availability of an adequate quantity of drinking water of acceptable quality on a long term basis. The primary objectives of the Mission included monitoring the quality of water after identification of problems, tackling the same by the application of science and technology to ensure that the water available is of acceptable quality and ensure that the quantity and quality of water is sustainable on a long term basis by proper water management technique and implementations of management information system. 4.2 HISTORY

There is no doubt that water and sustainable development are intimately linked. Once considered an infinite resource and water define today&#39;s generation of human development, social and economic development. Without an adequate supply and management of new and salt water resources, socio-economic development simply can not take place. If you look at the current scenario, we are moving towards a crisis. About 85% of the rural population in India is the only

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depends on groundwater, which are being depleted at a rapid pace. In urban areas, while 60% of the population depended on surface water sources, availability and quality is questionable. Population growth should translate into a decrease in per capita availability of fresh produce from March 3 Water: In 1947, measured in meters 5150. In the year 2000 was 2200 m. It has been recently estimated that by 2017 India&#39;s &#39;water stress&#39; - the per capita availability will be reduced to 1,600 m. Cu Studies put the amount of water available for the total annual consumption of India, surface water and groundwater, and, about 1100 BCM. However, these figures are somewhat misleading, since a considerable spatial and temporal variation of rainfall. Some areas received light rain, while the conditions of the experiments monsoon, which often result in flooding, loss of life and increased poverty. 4.3 QUALITY OF WATER

Water Quality Improvements for the KBCCIP Improvement of water quality are common to all alternatives. Improve water quality on the proposal to build a new collection of transport and infrastructure, leading to water treatment and disposal facilities identified in the development project proposed Kings Beach Watershed (WIP). Water quality parameters that will be installed include, but are not limited to the following products:

Constructing grass-lined swales where they can be supported to convey runoff along the Right Of Way (ROW) and promote infiltration; Constructing rock lined channels to convey water along the ROW and promote

infiltration; Installing basins to collect and retain runoff; Constructing infiltration galleries to retain runoff; and Installing media filters, or advanced treatment technologies, to treat runoff from KBCC

and Brockway Vista Avenue. In the streets upstream of SR 28, curbs and gutters installed as best management practices (BMPs) to help collect and direct runoff from the sites of potential on-street parking and the flow of runoff areas upstream of the GB of the CCIP. These improvements will serve to mitigate the increased runoff due to the creation of new hardcover from the car parks. Currently there are no functions of collection and transportation of these streets adequately directly upstream runoff upstream through the area GB, but rather than run directly through the GB and Lake Tahoe. With the installation of curbs and gutters as part of the CCIP, the runoff directed to collection ponds, vaults and media filters that will be upgraded and installed as part of GB, and water would not flow untreated into Lake Tahoe, as under current conditions. In addition, improvements associated with the proposed WIP will further increase water treatment capacity. Parking for potential off-site or transfer does not improve culverting be constructed to direct runoff from these lots off-site. Instead, the runoff would be quite content on the site with the addition of BMPs (eg underground infiltration beds) in the design of the parking lot. Parking lots outside the premises that are designed to contain runoff from a 20 - the flow of the storm of the year an hour in the place, while the anti-erosion measures to protect water quality would also be incorporated in the design . Water harvesting and infiltration functions integrated into the parking lots outside the site are designed to mitigate the runoff associated with the additional unit cover from the parking lot. And because the water would be fully contained on site, off-site lots will not worsen the water quality in the region.

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Along SR 28, curbs and gutters installed to help direct the flow through the IPC, when the storm drain on income and interceptors are constructed directly by collecting runoff water collection tanks, vaults, and media filters that are updated and installed as part of the IPC. Sometimes proposed, and the filter media, border brown figure 2-2 are not connected to IPC. On the contrary, they are considered the water quality improvements, which will be implemented under the proposed WIP, which will further increase the treatment capacity of the water. Sometimes, the media and filters are installed under the Placer County roads (Coon Street and SECLIN Road / Brockway Vista Avenue) is located entirely outside the street. Construction activities, including staging equipment and parking should be completely online, and the erection of temporary bonds allow the construction / staging out of foreign countries. Along SR 28, curbs and gutters installed to help direct the flow through the IPC, when the storm drain on income and interceptors are constructed directly by collecting runoff water collection tanks, vaults, and media filters that are updated and installed as part of the IPC. Sometimes proposed, and the filter media, border brown figure 2-2 are not connected to IPC. On the contrary, they are considered the water quality improvements, which will be implemented under the proposed WIP, which will further increase the treatment capacity of the water. Sometimes, the media and filters are installed under the Placer County roads (Coon Street and SECLIN Road / Brockway Vista Avenue) is located entirely outside the street. Construction activities, including staging equipment and parking should be completely online, and the erection of temporary bonds allow the construction / staging out of foreign countries. The ability of upstream facilities affected by the proposed action and the contact links in the proposed improvements WIP will be extended for the collection and transport of two upstream flows and stormwater flows generated by the road itself. Facilities should be designed and constructed to accommodate the storm water generated in the area and storm water entering the area from upstream. Improving drainage, collection, transportation and treatment are among those included in the WIP proposed to improve the water quality in Kings Beach area and in the range GB. Water rapidly absorbs both natural and man-made substances, generally making the water unsuitable for drinking without some form of treatment.

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Important categories of substances that can be considered undesirable in excess are: 1. Colour. This is due to the presence of dissolved organic matter from peaty soils, or the mineral salts of iron and manganese. 2. Suspended matter. This is ?ne mineral and plant material that is unable to settle out of solution under the prevailing conditions. 3. Turbidity. This is a measure of the clarity, or transparency, of the water. Cloudiness can be caused by numerous factors such as ?ne mineral particles in suspension, high bacteria concentrations, or even ?ne bubbles due to over-aeration of the water. 4. Pathogens. These can be viruses, bacteria, protozoa or other types of pathogenic organism that can adversely affect the health of the consumer. They can arise from animal or human wastes contaminating the water resource. 5. Hardness. Excessive and extremely low hardness are equally undesirable. Excessive hardness arises mainly from groundwater resources whereas very soft waters are characteristic of some upland catchments. 6. Taste and odour. Unpleasant tastes and odours are due to a variety of reasons such as contamination by wastewaters, excessive concentration of certain chemicals such as iron, manganese or aluminium, decaying vegetation, stagnant conditions due to a lack of oxygen in the water, or the presence of certain algae. 7. Harmful chemicals. There is a wide range of toxic and harmful organic and inorganic compounds that can occur in water resources. These are absorbed from the soil or occur due to contamination from sewage or industrial wastewaters. Water treatment and distribution is the process by which water is taken from water resources, made suitable for use and then transported to the consumer. This is the first half of the human or urban water cycle, before water is actually used by the consumer (Figure 1.2). The second half of the cycle is the collection, treatment and disposal of used water (sewage) (Gray, 2004). The

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objective of water treatment is to produce an adequate and continuous supply of water that is chemically, bacteriologically and aesthetically pleasing. More specifically, water treatment must produce water that is: 1. Palatable – that is, has no unpleasant taste; 2. Safe – it should not contain any pathogenic organism or chemical that could be harmful to the consumer; 3. Clear – be free from suspended matter and turbidity; 4. Colourless and odourless – be aesthetic to drink; 5. Reasonably soft – to allow consumers to wash clothes, dishes and themselves without excessive use of detergents or soaps; 6. Non-corrosive – water should not be corrosive to pipework or encourage leaching of metals from pipes or tanks; 7. Low in organic content – a high organic content will encourage unwanted biological growth in pipes or storage tanks, which can affect the quality of the water supplied. With the publication of drinking water standards such as the European Union Drinking Water Directive (98/83/EEC) (Appendix 1) and the Safe Drinking Water Act (1974) in the USA, which has given rise to the National Primary and Secondary Drinking Water Standards (Appendix 2), water must conform to the standards laid down for a large number of diverse parameters. In England and Wales, for example, the European Directive is enforced by the Water Supply

(Water Quality) Regulations (2000), which requires the water supply companies to deliver water to consumers that is wholesome and defines clearly what this term means. Consumers expect clear, wholesome water from their taps 24 hours a day, every day. Although water that is unaesthetic, for example due to colour or turbidity, may be perfectly safe to drink, the consumer will regard it as unpalatable and probably dangerous to health. Problems not only originate from the resources themselves, but during treatment, distribution and within the consumer's home (Chapter 3). Check your progress-1

1. Where does my water come from? 2. Why does my water appear milky or cloudy? 3. What are those white flakes in my faucet Aerator? 4. What causes odor in the hot water? 5. What causes the spots on my dishes?

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6. Should I buy a water softener? 4.4 LET US SUM UP

The model simulated the levels of water quality were used to identify water quality analysis of the sites that had the potential water quality problems. Analysis of water quality, limiting the sites were using the drains is the Fairview Creek downstream location, and then identify the areas of river basins, which contribute to the discharge point. By design, most of the waste stream / water quality sites are in line with the main roads in these areas. The analysis included main roads, which are the jurisdiction of Multnomah County (eg, Burnside Street, Stark Street, Glisan Street and Division Street). High concentrations were determined Oregon water quality standards or limit driving. The total contribution to the strain in kilograms of water quality testing of each site was calculated by multiplying the flow of concentration. According to the model, all sites were high quality water without pollutants modeled. However, in areas with existing development, or there is currently no plan for the water quality of care were considered problem areas. 4.5 SOME USEFUL BOOKS

Air pollution by M.N. Rao & H.V. Rao, Tata Mcgrawhill Publishing Company Environmental Engineering by Basak, TMH Principle of Environmental Science by Cunningham, Tata Mcgrawhill Publishing

Company Introduction to Environmental Engineering by Davis, TMH

4.6 ANSWER TO CHECK YOUR PROGRESS

Check your progress-1 1. Here in Volusia County our primary source of drinking water is the Floridan aquifer. The

Floridan aquifer is a lens of water located beneath the bedrock of northeast Florida. Currently all County of Volusia water treatment plants utilize wells to extract ground water from the aquifer.

2. A milky or cloudy appearance is usually caused by air bubbles in the water, which pose no health risk. If the water is allowed to sit, the air will dissipate and the water will clear. If the cloudiness does not disappear, please call Volusia County Water Resources and Utilities at 386-822-6465 so that we may investigate.

3. Most of the time white to greenish flakes are calcium deposits that build up in your hot water tank. The best way to control their formation is to flush your hot water tank once a year and keep the hot water temperature in the tank as low as you can.

4. The most common cause of odor in hot water is the water heater. If your cold water smells fine, check your water heater to ensure that the temperature setting is correct. Water heaters also need to be maintained (see manufacturer’s instructions). Please call Volusia County Water Resources and Utilities at 386-822-6465 if the odor persists or if it is present in both the hot and cold water.

5. Spots are caused by hard water, or minerals that remain after the water has evaporated. Spots can be eliminated through use of a dishwasher rinse agent.

6. The hardness of water varies with the water’s source. The choice to buy a softener is an

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aesthetic one, since hard water is not harmful to health. However, water softeners typically increase the sodium content of the water, a factor that should be considered by people on low-sodium diets.

4.7 GLOSSARY

Water Quality is a term used to describe the biological, chemical and physical characteristics of water and its general composition. These attributes affect water's ability to sustain life and its suitability for human consumption. Aquifer Water within the soil or rocks beneath the surface of the earth that supplies wells and springs, water in the zone of saturation where all openings in rocks and soil are filled with water, the upper surface of which forms the water table, the streams or pools of water that flow or collect under the surface of the land and not on the surface, these may be confined if there are layers of impermeable material both above and below and it is under pressure so that when the aquifer is penetrated by a well, the water will rise above the top of the aquifer, or unconfined when the upper water surface, the water table, is at atmospheric pressure, and is able to rise and fall,any geological formation containing or transmitting water, especially one that supplies the wate for wells and springs, use of the term may be restricted to those water-bearing formations capable of yielding water in sufficient quantity to constitute a usable supply,

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Block II – Introduction-Water Treatments

Water is a precious commodity. Most of the earth water is sea water. About 2.5% of the water is fresh water that does not contain significant levels of dissolved minerals or salt and two third of that is frozen in ice caps and glaciers. In total only 0.01% of the total water of the planet is accessible for consumption. Clean drinking water is a basic human need. Unfortunately, more than one in six people still lack reliable access to this precious resource in developing world. India accounts for 2.45% of land area and 4% of water resources of the world but represents 16% of the world population. With the present population growth-rate (1.9 per cent per year), the population is expected to cross the 1.5 billion mark by 2050. The Planning Commission, Government of India has estimated the water demand increase from 710 BCM (Billion Cubic Meters) in 2010 to almost 1180 BCM in 2050 with domestic and industrial water consumption expected to increase almost 2.5 times. The trend of urbanization in India is exerting stress on civic authorities to provide basic requirement such as safe drinking water, sanitation and infrastructure. The rapid growth of population has exerted the portable water demand, which requires exploration of raw water sources, developing treatment and distribution systems. The raw water quality available in India varies significantly, resulting in modifications to the conventional water treatment scheme consisting of aeration, chemical coagulation, flocculation, sedimentation, filtration and disinfection. The backwash water and sludge generation from water treatment plants are of environment concern in terms of disposal. Therefore, optimization of chemical dosing and filter runs carries importance to reduce the rejects from the water treatment plants. Also there is a need to study the water treatment plants for their operational status and to explore the best feasible mechanism to ensure proper drinking water production with least possible rejects and its management. With this backdrop, the Central Pollution Control Board (CPCB), studied water treatment plants located across the country, for prevailing raw water quality, water treatment technologies, operational practices, chemical consumption and rejects management. This document presents study findings and views for better management of water treatment plants.

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UNIT 1 LAYOUT OF TREATMENT PLANTS

Structure 1.0 Objective 1.1 Introduction 1.2 History 1.3 Layout of treatment plants 1.4 Let us sum up 1.5 Some Useful Books 1.6 Answer to Check your Progress 1.7 Glossary 1.0 OBJECTIVE

In this lesson we are going to discuss in detailed manner about : Wastewater from households and industry, commonly together with water runoff from

urban areas, is conveyed by the sewerage system to sewage treatment plants for safe and economic treatment of sewage, and treatment and disposal of the resulting sludge. This Information page describes the key processes involved.

1.1 INTRODUCTION

Wastewater treatment is a multi-stage process involving the separation of wastewater from solids. The process involves

screening grit removal

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clarification aeration digestion pressing final treatment of liquids with ultraviolet light final treatment of solids by processing into fertilizer

Screening Perforated plate screens and step screens catch large pieces of debris and other solids as wastewater enters the treatment plant. Material trapped by the screens is disposed of in a sanitary landfill. Grit Tanks Air diffusers are used to keep solids suspended in the wastewater allowing sand and grit to settle to the bottom. The sand and grit are removed from the tanks and taken to a sanitary landfill. Primary Clarifiers Tanks where heavier solids are allowed to sink to the bottom while automatic skimmers remove particulate matter and grease that floats to the top. The grease is pumped to a concentrator tank to remove excess water then to the digesters for anaerobic bacteria digestion. Aeration Basins and Secondary Clarifiers Basins that receive effluent (wastewater) from primary clarifiers where air is infused as a source of oxygen for aerobic bacteria. The bacteria consume and break down organic material and sink to the bottom. Some of the bacterial sludge and solids are sent to the centrifuges and the rest is reused in the secondary clarifiers. Fines (small particles) are also removed during secondary clarification. Liquids are sent to ultraviolet light disinfection. Digesters Solids sent to the digesters are reduced in volume by anaerobic bacteria and heat. During the process biogas (a mixture of methane and carbon dioxide) is produced and is used as fuel for gas fired boilers and in the fertilizer manufacturing process. Centrifuges Bacterial sludge from the digesters is dewatered by spinning in centrifuges. Liquids are sent back to the primary clarifiers and solids go to the fertilizer manufacturing facility. Fertilizer Manufacturing Facility Dewatered solids from the centrifuges are sent to an on-site manufacturing plant where they are further processed, dried, and bagged as SoundGRO, an EPA 'Exceptional Quality ' Class A pelletized fertilizer for residential and commercial use. Ultraviolet Light Disinfection After leaving the secondary clarifiers, wastewater receives final treatment by ultraviolet light to destroy any pathogens prior to discharge into Puget Sound. 1.2 HISTORY

This report provides the advice and recommendations of the Environmental Protection Authority (EPA) to the Minister for the Environment on the environmental factors relevant to the proposal by the Water Corporation to construct a new Wastewater Treatment Plant (WWTP) at Kemerton and woodlot for irrigation of the treated wastewater at Binningup. A definition report and an initial proposal was submitted to the Department of Environmental Protection (DEP) in September 2000, as a Notice of Referral (Kinhill, 2000). Following discussions with the DEP, Leschenault Inlet Management Authority (LIMA) and the Water and Rivers Commission (WRC), the proponent has subsequently provided a modified proposal, which presented additional information on options of wastewater management particularly in relation to nutrient management. The proponent has described the proposal, the management of environmental issues, provided a

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list of key stakeholders consulted and a table of the proponent’s commitments. 1.3 LAYOUT OF TREATMENT PLANTS

Purpose Three basic purpose of Water Treatment Plant are as follows: I. To produce water that is safe for human consumption II. To produce water that is appealing to the consumer III. To produce water - using facilities which can be constructed and operated at a reasonable cost Production of biologically and chemically safe water is the primary goal in the design of water treatment plants; anything less is unacceptable. A properly designed plant is not only a requirement to guarantee safe drinking water, but also skillful and alert plant operation and attention to the sanitary requirements of the source of supply and the distribution system are equally important. The second basic objective of water treatment is the production of water that is appealing to the consumer. Ideally, appealing water is one that is clear and colorless, pleasant to the taste, odorless, and cool. It is none staining, neither corrosive nor scale forming, and reasonably soft. The consumer is principally interested in the quality of water delivered at the tap, not the quality at the treatment plant. Therefore, water utility operations should be such that quality is not impaired during transmission, storage and distribution to the consumer. Storage and distribution system should be designed and operated to prevent biological growths, corrosion, and contamination by cross-connections. In the design and operation of both treatment plant and distribution system, the control point for the determination of water quality should be the customer’s tap. The third basic objective of water treatment is that water treatment may be accomplished using facilities with reasonable capital and operating costs. Various alternatives in plant design should be evaluated for production of cost effective quality water. Alternative plant designs developed should be based upon sound engineering principles and flexible to future conditions, emergency situations, operating personnel capabilities and future expansion. Surface Water Treatment System The sequence of water treatment units in a water treatment plant mostly remains same, as the principle objectives are to remove turbidity and disinfection to kill pathogens. The first treatment unit in a water treatment plant is aeration, where water is brought in contact with atmospheric air to fresh surface water and also oxidizes some of the compounds, if necessary. Many Water Treatment Plants do not have aeration system. The next unit is chemical addition or flash mixer where coagulant (mostly alum) is thoroughly mixed with raw water by way of which neutralization of charge of particles (coagulation) occurs.

In 1999, Metal Forming and Coining, Inc. decided to consolidate its various plants into one modern facility at its headquarters site in Maumee, Ohio. During that time the company took the opportunity to reassess its handling of plant wastewater.

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NEW WASTEWATER TREATMENT PLANT DESIGN

As the automotive industry is the company’s primary market, the layout of the new processing plant was geared towards increasing quality and environmental standards, qualities that are now demanded by the automotive manufacturers. As a consequence, the new layout included a new wastewater treatment system that helped lower operator time, chemical costs and the amount of sludge sent to landfill. The new automated phosphating lines also helped the company position itself to meet these increasing quality and environmental

standards from the automotive industry.

MF&C was also able to meet increased production demands, since the new barrel process was able to phosphate the 1.25in - 4in diameter parts in one hour instead of the eight hours it used to take with the older facilities. Phosphatizing waste requires a complex treatment process because of the secondary bi-products, such as acids, caustics, and soaps, as well as the phosphate compounds. The process needs to address various demands of the output, such as the amount of scale produced in the acid, or the TSS and O&G found in the zinc phosphate operation as a result of cleaning and other surface preparation procedures. The automation, equipment layout and appropriate chemistry therefore becomes critical to system optimisation and performance. Suppliers of the wastewater system, Beckart Environmental, tend to tailor all of its wastewater treatment systems to customer requirements, including the degree of automation required or appropriate. Systems equipped with programmable logic controllers (PLCs) provide an exceptionally user-friendly method of controlling system function; Beckart installed its custom software in the factory and configured it to make all necessary chemical and engineering decisions with minimal operator time requirements. The general options for automation are: Running Light Schematic - Provides overall view of the system status in an LED-illuminated diagram. PanelView Graphic Display - Operator interface with graphics capability that allows system data modification and manual motor/solenoid On/Off selection. Rapid Response Support System - A telecommunications module, which allows Beckart technicians to program, monitor, and control system operation via a telephone line.

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In Metal Forming and Coining’s case, engineers, Action Air and Hydraulics, Inc., installed the Beckart Environmental PLC-controlled sedimentation wastewater treatment system. To save on operator time, the system was installed with an Allen-Bradley programmable logic controller, data table access module and supporting running light schematic. The new plant layout was based on the design produced by SSOE, Inc., a Toledo, Ohio-based architectural and engineering firm, along with Metal Forming and Coining input. SSOE’s in-house staff of qualified engineers and technicians is dedicated to the design of facilities for the removal of contaminants found in wastewater. Due to a previous successful installation for the metal forming company, Beckart was also able to participate from the earliest design stages of the new plant. In planning the wastewater treatment system, the companies focused on lower operator time, decreased phosphate line chemical costs and minimizing waste output. The continuous settling wastewater treatment enables the company to reuse nearly 90% of the liquid recovered from the production line. WASTEWATER TREATMENT PROCESS Normal rinsewaters are automatically sent to a large equalization tank. Rather than hauling the spent zinc phosphates to a landfill, they are first segregated into a waste dump tank. Then, the upper liquid (80-89%) portion is recovered for reuse, while the lower settled solids are dewatered in a filter press. The acid, iron phosphate, and alkaline dumps are also transferred to separate holding tanks, and then pumped at brief, intermittent intervals by the PLC-controlled air-operated pumps to the equalization tank. The combined wastewaters can then proceed through the standard progression of treatment in the 800-gallon precipitation tank, 800-gallon pH-controlled neutralization tank, slant plate clarifier, sludge thickener tank, and filter press. Clear treated water from the top of the clarifier goes to the POTW sewer, while a PLC-controlled pump is used to pump settled floc from the bottom of the clarifier to the sludge thickener tank. A stroke-counting PLC-controlled pump then pumps the sludge to the filter press, and turns on a "Cycle Done" light. Filtrate from the filter press is re-circulated to the equalization tank, while the dewatered sludge ("bricks") is sent to a local landfill. The recovered zinc phosphate liquid is used back in the zinc phosphate tank. The new automated phosphating and related waste treatment system has allowed MF&C to increase production and meet the quality demands of its automotive customers. METAL FORMING AND COINING INC In operation since 1953, Metal Forming & Coining is a manufacturer of cold formed and impact extruded components for the automotive, commercial truck, off-highway, industrial and aerospace markets. It produces a variety of engine, automatic transmission, transfer case and driveline products. Check your progress-1

1. How deep down is the water intake? 2. Does the water smell when it comes to the treatment plant before treatment is started? If

so, describe the smell. 3. Is your reservoir treated with copper sulphate or some other chemical? If so, what is the

chemical and its purpose? 1.4 LET US SUM UP

With the rise in factories and industries, there is a greater amount of chemicals, waste, effluents flowing into the water resources thus dirty the natural resources and contributing to the cause of

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diseases to mankind. Hence, there is a need for pollution control related machinery and equipments. Few industries have already made a mark in this field and thus portion us save the water resources. The need of the hour is to treat water, protect natural water resources from getting depleted, recycling waste water or their treatment. This effluent treatment machinery aims astatine removing the contaminants from house hold sewage. It involves the treatment of water which is polluted with biological, physical and chemic contaminants. It treats the water in such a way that it not only prevents the contamination of the natural resources, saves the living creatures which feed on them but also make these contaminated water suitable for use. We don’t have to suffer due to water scarcity thanks to the sewage treatment machinery. Various treatments that these machineries can be used for are: -Raw water treatment -Sewage water treatment -Wastewater treatment -Effluent treatment etc. These are made suitable for discharge into the natural resources so that they don’t jeoparides the natural habitat and the living creatures. If not these chemical, biologic and physical contaminants will non only contaminate the water resources but also contribute to the growth of unwanted algae and other poisonous plants. Living creatures which feed on them ar susceptible. In turn, you can prevent a lot of unwanted happenings by treating waste water and sewage in the right way! 1.5 SOME USEFUL BOOKS

Council of the European Communities. Directive concerning urban wastewater treatment (91/271/EEC) 1991.

Foundation for Water Research. Review of Current Knowledge: Sewage Sludge. Foundation for Water Research, Marlow SL7 1FD. 2002.

Council of the European Communities. Directive on the protection of the environment, and in particular the soil, when sewage sludge is used in agriculture. (86/278/EEC). Official Journal of the European Communities. No.181/6. 4 July 1986.

The Safe Sludge Matrix - Guidelines for the Application of Sewage Sludge to Agricultural Land, 3rd Edition, April 2001. Guidance on the agreement made between Water UK representing the UK Water and Sewage Operators and the British Retail Consortium (BRC) representing the major retailers. This agreement affects all applications of sewage sludge to agricultural land and came into force on 31 December 1998.

1.6 ANSWER TO CHECK YOUR PROGRESS

Check your progress-1

1. If it is a shallow well (less than 30 m or 100 feet) then chances are that the quality of water is very different from a deep well (can sometimes be more than 100 m deep). The water from a shallow well can often have low levels of salt and other contaminants. With a shallow well the major concern is often if it is under the influence of surface water. This is called Groundwater Under the Influence of Surface Water abbreviated GUDI. The

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main concern with being a GUDI is the potential for contamination by disease-causing microorganisms.

2. If the answer to this question is yes then chances are high that there is very little oxygen in the water. When the oxygen disappears it is called anaerobic water. In anaerobic water different chemical processes start occurring. One of these processes is the formation of hydrogen sulphide, which dissolves in the water. When an egg goes rotten it is hydrogen sulphide that makes it smell. In addition to potentially high levels of hydrogen sulphide (which is toxic) the level of carbon dioxide increases. Both of these compounds will have to be removed before the water can be effectively treated. The simplest way of doing this is straight aeration. The addition of chlorine can also partially achieve this. Sometimes there are concerns about nitrates in groundwater. But, if there is no oxygen in the water then the nitrate (which has three oxygen atoms for every nitrogen atom) gets transformed to ammonium. While in regular testing it may look great to have no nitrate in the water, but if the nitrate has been transformed to ammonium then a whole new set of problems occur in the treatment plant. The biggest challenge for water with ammonium in it is disinfection. The water operator needs to add 15 times more chlorine than there is ammonium before the water starts to become properly disinfected. Residual Chlorine tests for the presence of ammonium may also give false positives. There are problems determining the chlorine residuals if there is ammonium in the water.

3. Copper sulphate is often used to control algal blooms, the pesticide Diquat (Reglon A), is used to control weed growth in the reservoir. If the Copper level in the drinking water is too high, it is more likely to result from copper distribution pipes, which can generate higher copper levels than correct additions of copper to treat a reservoir.

1.7 GLOSSARY

Waste Treatment Plant: A facility containing a series of tanks, screens, filters and other processes by which pollutants are removed from water. Waste Treatment Stream: The continuous movement of waste from generator to treater and disposer. WASTE WATER: Water that has been used. 1. (RO, ultrafiltration, electrodialysis) The stream of water (not product water) created as the result of processing water-the reject water or concentrate. 2. (ion exchange and filtration) The spent water used in the total backwash and/or regeneration cycle. 3. The used water and solids from a residence or a community (including used water from industrial processes) that flow to a septic system or a treatment plant. Storm water, surface water, and groundwater infiltration also may be included in the waste water that enters a waste water treatment plant. The term sewage usually refers to household wastes, but this word is being replaced by the term waste water

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UNIT 2 FILTRATION

Structure 2.0 Objective 2.1 Introduction 2.2 History 2.3 Filtration 2.4 Let us sum up 2.5 Some Useful Books 2.6 Answer to Check your Progress 2.7 Glossary 2.0 OBJECTIVE

In this lesson we are going to discuss in detailed manner about : The purpose of a water filter is to screen out harmful stuff and mechanical filtration is

currently the most common method of cleansing water. Filters use a mechanical process meaning the particles are trapped in a very fine porous element and prevented from coming out the clean water end. This is different from boiling and chemical treatment because those two methods do not remove particles, they just kill living critters in the water - you still ingest all the dead gunk.

Portable water filters are small, hand-held pumps that suck water in through a flexible tube dropped into the water source and then phyiscally strain out solid material. It's usually pretty fast and easy to pump and filter fresh water, but as filters get clogged they may become difficult and then unusable. Filters should eventually clog - it means it is doing its job. When the filter starts getting difficult to pump, don't force it or you might be forcing creepy crawlies into your water bottle. Cleaning a filter or replacing an element is a required maintenance task so make sure you follow the manufacturer's instructions.

2.1 INTRODUCTION

Drinking water, in many developed countries, has stringently controlled standards. Therefore, it is hard to imagine that water for human use delivered through taps, shower heads and other sources within buildings could contain harmful pathogens. However, water distribution systems are increasingly recognized as a source of infection, particularly in areas with immunocompromised patients. The main causes for bacterial growth in water systems within buildings are water stagnation, inappropriate water temperatures, and dead ends. These factors, plus the presence of particles and nutrients, contribute to the rapid formation of biofilm. Biofilm is extremely difficult to eradicate once established. Bacteria are released from the biofilm into the water stream, and reach users when taps or showers are opened. People with weakened immune defenses are particularly at risk. Pall Medical offers a broad product portfolio covering water system monitoring and environmental surveillance, and specialized filtration from the point of building entry through the point of use at taps, showers and other water sources.This portfolio assures the highest

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filtration efficiency for particles and waterborne pathogens in water networks and supports comprehensive water safety plans. 2.2 HISTORY

The history of water filters is indelibly tied to the history of water, itself. As human industry has grown and water has become more contaminated, water filters have emerged over the centuries in response to the growing recognition of the need for pure, clean water to drink and the realization that such water does not occur naturally. Water has greatly affected humanity and civilization for millennia. Because water is so absolutely vital to our body systems, we, as living beings, are entirely dependent upon water. In fact, this simple substance, more than any other factor, guided the formation of civilization. Early civilizations were clustered around water sources, and it was water that initiated the first substantial agriculture in the Fertile Crescent, leading to more complex and sedentary civilizations. For centuries, water availability guided the type of foodstuff that could be grown in an area. Water was also the impetus and guiding force behind the first cross-cultural interactions. Early trade was completely dependent upon water, for transportation of goods and sustenance of people and animals. Throughout the centuries, as technology developed, people have gradually gained more control of water. They have been able to transport water to arid lands, stop and redirect rivers, and even determine when, where, and how much rain will fall. Even with increased control of water resources, water still continues to dominate the political, economic, and social structure of all nations. This statement can be verified by looking at political struggles within the United States over water resources or throughout the Middle East over access to limited water. Concerning conflict in the Middle East, former World Bank Vice President Ismail Serageldin stated in 2000, "Many of the wars of this [20th] century were about oil, but the wars of the next century will be about water" (Smith, 2000). In modern times, concerns over water quality remain supreme. Over the years, scientists have discovered more and more contaminants in fresh water sources, and these same scientists have noted a strong correlation between drinking water contamination and many significant health problems. Due to the rampant impurity of water and the crucial, physiological need for clean, fresh drinking water, several treatment alternatives have emerged throughout the history of water treatment. Water filtration, one of the more viable and prominent of these treatment alternatives, has something of a remarkable past. Historians believe that the use of water filters began more than 4000 years ago! In the next several pages, the fascinating history of water filters will be addressed. Read on to learn more about this interesting history. 2.3 QUANTITY OF WATER

Water filters have a long history as a method of water purification, beginning as early as 2000 b.c.e. in ancient Egypt. Filtration has evolved from the simple Hippocratic sleeve of ancient Greece, made from cloth, to the complicated solid block carbon and multimedia water filters currently on the market. Water filtration is now the premier method of water purification, removing more water contaminants, more efficiently, than any other technique. The Process: The filtration process involves some type of filter media, over which water flows. This filter media blocks passage of contaminants through physical obstruction, chemical adsorption, or a

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combination of both processes. Material construction of the filter media varies widely, but the most effective medias are made from carbon or a combination of carbon with other elements. Modern filtration technology allows water filters to remove more and more contaminants through the chemical process of adsorption. In the adsorption process, contaminants are encouraged to break their bond with water molecules and chemically adhere to the filter media. Generally, water goes through several stages of filtration to ensure that each filter media will remove the ultimate number of contaminants. Water normally passes through a water filter at a relatively low speed, in order to ensure adequate contact time with the filter media. Once the water has passed through the required stages of filtration, it emerges as pure drinking water, free from contamination. Pros and Cons: Unlike reverse osmosis and distillation process, water filters are not limited in the type or size of contaminants they can remove. Thus, water filters are able to remove far more contaminants than any other purification method. Also, because they use the chemical adsorption process, water filters can selectively retain healthy trace minerals in drinking water. Filtration is the only one of the three water purification methods that is capable of removing chlorine, chlorine byproducts, and VOCs from drinking water. Chlorine and VOCs are the most dangerous and threatening contaminants of municipally treated drinking water. Besides the removal of these dangerous chemicals, water filters also extract from drinking water the chlorine-resistant protozoa giardia and cryptosporidium. These protozoa have plagued the water treatment industry for several decades and have caused a number of epidemics of severe gastrointestinal disease, contracted through drinking contaminated water. Water filters, because they do not require the costly energy sources of reverse osmosis and distillation, provide a source of relatively inexpensive, purified water. Also, water filters waste very little water, as compared to reverse osmosis and distillation systems. Depending upon the type of filter used, water filtration may be a less than ideal form of water purification. For example, granular filters do not utilize the chemical adsorption process, allowing several contaminants to pass through the filter media. Likewise, rapid water filters allot water inadequate contact time with the filter media, limiting the number of contaminants that may be removed. Solid block carbon filters solve both of these problems by using both adsorptive and slow filtration processes. Solid block carbon filters are absolutely the best and most effective water filters available. Check your progress-1

1. What types of fish pond filtration systems are available? 2. What is a mechanical filter? 3. How do I set up the pond filter?

2.4 LET US SUM UP

Methods of purifying unclean water for drinking purposes in emergencies. The three basic techniques include boiling the water and straining it through a cloth, adding 3 drops of tincture (alcoholic solution) of iodine per each quart of the water, and adding 10 drops of 1% chlorine bleach per each quart of water. When purifying chemicals are added, they should be thoroughly mixed with the water, and the mixture allowed to stand for 30 minutes. Also called emergency preparation of safe drinking water. 2.5 SOME USEFUL BOOKS

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Binnie, Chris, Kimber, Martin, & Smethurst, George. (2002). Basic water treatment (3rd ed.). London: Thomas Telford Ltd.

Holland, F. A., Siqueiros, J., Santoyo, S., Heard C. L., & Santoyo, E. R. (1999). Water purification using heat pumps. New York: Routledge.

Ramstorp, Matts. (2003). Contamination control in practice: Filtration and sterilization. Weinheim, Sweden: Wiley-VCH.

2.6 ANSWER TO CHECK YOUR PROGRESS

Check your progress-1 1. There are basically three main types of filter available for ponds.

Gravity return filters The set up in these requires a pump that feeds the water from the pond up to the filter and then the water is returned by means of gravity. The only drawback with these is the fact that the filter needs to be higher than the water level of the pond for it to work efficiently. Pressure filters These are ideal for the smaller ponds as the water is fed into the filter via a pump and leaves the filter under pressure as the filter is a sealed unit. These take up less space and can be positioned anywhere. Gravity fed filters The gravity fed filter is often used in large Koi ponds, the water is fed to the filter by means of drains in the bottom of the pond and then pumped back into the pond afterwards. These are very complex and usually fitted by experts.

2. A mechanical filter is purely used for removing particles and debris from the water. The filter will contain varying grades of sponges to perform this task. These are sometimes used in very small ponds and do not take up a lot of space.

3. With any bought pond filter there will be a pump that will feed the filter, this needs to be placed below the water surface at all times. By the means of piping this will be connected to the filter inlet. The filter box needs to be placed at the side of the pond; with some models they can be submerged in the ground to hide them. If the filter is a gravity return, remember it needs to be higher than the water level of the pond. The water is then returned to the pond by more piping.

Fish pond filters Fish pond and pond plants

Fish pond pump

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2.7 GLOSSARY

Filter Cake The debris collected on the filter element, block it, resist the water flow through the filter and increase the differential pressure. Filtration The process of removing solid particles from liquid or gas by forcing them through a porous medium Filtration Degree Size of pores in filtration medium (mm or microns) Filtration Element The active component of the filter, it determines the type of filter and the filtration level.

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UNIT 3 TREATMENT PROCESSES

Structure 3.0 Objective 3.1 Introduction 3.2 History 3.3 Treatment processes 3.4 Let us sum up 3.5 Some Useful Books 3.6 Answer to Check your Progress 3.7 Glossary 3.0 OBJECTIVE

In this lesson we will learn about the following concepts: The hydrologic cycle and how it is like nature's way of treating water An introduction to water treatment

3.1 INTRODUCTION

Now that you know how nature treats water, let's see how it's done in the water plant before we consume it in a glass of water. Water treatment in a typical water treatment plant is shown in the picture below. Based on the characteristics of the raw water and on other factors, this treatment process may vary considerably from place to place.

As water is pumped from the source (a well, spring, river, or lake) it is screened to remove debris. Then, at the water plant, various characteristics of the raw water are tested. The water may be prechlorinated to kill microorganisms, control odors and taste, and aid in coagulation and setttling. The water may also be aerated, which removes carbon dioxide (CO2) and raises pH, oxidizes iron (Fe) and manganese (Mn), removes hydrogen sulfide (H2S), and removes organic

contaminants. Potassium permanganate (KmnO4) may be added to the water in the collection

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tray of the aerator in order to remove iron and manganese from the water. Ozone may be added to the water to treat iron and manganese, remove algae, neutralize hydrogen sulfide (H2S), and aid in flocculation. Many of these are dependent upon the plant and the amount of water being distributed daily. In most cases, the water then enters a flash mix chamber. Here, various chemicals are added and are mixed into the water. Coagulants cause fine particles to clump together into larger particles. Alkali are added to adjust the pH as well as to oxidize iron and manganese. Hexametaphosphate may be added to prevent corrosion of pipes. After flowing out of the flash mix chamber, the water goes through a chamber which causes coagulation and flocculation to occur. Here, the fine particles of contaminants gather together into large clumps called floc. When the water flows into the sedimentation basin, some of the floc settles out of the water and is removed. Next, the water is passed through filters which remove particles too small to settle out in the sedimentation basin. Finally, chlorine is added to the water. The water may also be fluoridated to reduce tooth decay in the consumers. The water is left in the clear well for a period of time to allow the chlorine to kill bacteria in the water and to oxidize hydrogen sulfide. The water is now treated and ready to be distributed. That was a quick overview of the water treatment process and what happens to water as it goes through the plant step by step. We will get into greater detail in later lessons so that you will understand each step of the process, why it is done and how to make sure each step is being done efficiently. 3.2 HISTORY

In today’s modern society, it seems to be an assumption that city-supplied tap water, if not always the healthiest specimen of drinking water, has at least gone through some disinfection and purification processes prior to distribution. Most residents of the United States turn on their faucets feeling confident they can drink the water without contracting a waterborne disease or dying immediately. However, it is only a relatively new phenomenon for water consumers to receive treated water as an inherent right of municipal residence. For hundreds of years, as water treatment methods have evolved, the quality of municipal drinking water has developed from a relatively sketchy product to a strictly regulated commodity. Ancient Water Treatment The first documented attempts to treat drinking water are recorded in ancient Greek and Sanskrit writings that date back to 2000 B.C. At this time, people were aware that boiling water helped to purify it and that filtration and straining methods helped to reduce visible particles and turbidity in water. Because nothing was known about microorganisms or chemical contaminants (which would remain unseen in water until the seventeenth century), the motive for treating water was to make it smell and taste better. The Greek scientist Hippocrates, who invented the first cloth bag filter around 500 B.C, also believed that if water tasted and smelled clean, it must be healthful for the body. His invention, called the “Hippocratic sleeve,” was one of the first domestic water filters (Baker & Taras 1981). Discovery of Microorganisms

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After the first experimentations by early civilizations, advances in water treatment took a long hiatus during the Dark Ages. It would not be until 1627 that scientists would again take up the problem of purifying drinking water. In that year, Sir Robert Bacon began experimenting with a form of sand filtration to remove salt particles from seawater. His experiments proved largely unsuccessful, but his work sparked a revival of water treatment experimentation. Several decades later, Anton van Leeuwenhoek created the first microscope, which allowed scientists to view a whole new world of drinking water contamination. With his invention, Leeuwenhoek became the first person to discover microorganisms in water in 1676 (Baker & Taras 1981). Throughout the 1700s, as people began to understand more about the dangers of drinking water contaminants, domestic water filter units made from wool, sponge, and charcoal began to be used in individual homes. In the year 1804, the first large municipal water treatment plant was installed in Scotland in order to provide treated water to every resident (Baker & Taras 1981). This revolutionary installation prompted the idea that all people should have access to clean drinking water. However, it would be some time before this ambitious idea would be implemented widely throughout the world. Cholera and Chlorination In 1854, the British scientist John Snow found that the cholera disease was spread through contaminated water, a discovery that would greatly impact the future of water treatment and disinfection. While studying cholera epidemics in municipal areas of England, Snow noticed that regions that used slow sand filtration before distributing water tended toward fewer cholera cases. Eventually, he was able to trace the outbreaks of cholera to a particular water pump that had been contaminated by raw sewage. Snow used chlorine to kill the cholera bacteria in the water, leading to the rise of water chlorination as an effective disinfection process. His work also revolutionized the prevalent theory that good-tasting and odorless water naturally meant it was healthful and safe. Because the contaminated water had contained no detectable taste or odor, Snow surmised that water quality could not be established by that criteria alone. After his findings were published, several cities began to treat all water with sand filters and chlorine before distributing it to the public. In the late nineteenth century, municipal water treatment began to take hold in the United States. Technicians started experimenting with rapid, as opposed to slow, sand filtration and found the process to be much more efficient and effective. Also, the overall capacity and lifetime of the filter could be improved by cleaning it with a powerful steam jet, thus increasing the number of residents who could be served by one treatment plant. As a result of increased water treatment and chlorination within several U.S. cities and around the world, the outbreak of such waterborne diseases as cholera and typhoid rapidly decreased in the early twentieth century. Softening and Ion Exchange

By the early 1900s, water treatment experimentation had turned from the prevention of waterborne diseases to the creation of softer, less-mineralized water. Water softeners, which use sodium ions to replace water-hardening minerals in water, were first introduced into the water treatment market in 1903. The theory of ion exchange (in which a harmless or more desirable water ion is used to replace a harmful one) implemented by the softening systems would greatly impact the water treatment industry in later years -- the theory would

Using his microscope, Anton van Leeuwenhoek became the first person to discover microorganisms in water

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eventually be used to remove lead, mercury, and other insidious heavy metals from water. First Government Regulations As municipal water treatment eventually became a common practice in most U.S. cities, federal and state governments began to recognize the importance of drinking water standards for municipalities. While some limited drinking water standards would be implemented as early as 1914 (EPA 2000), it would not be until the 1940s that federal drinking water standards were widely applied. But the most comprehensive federal regulations and standards for the water treatment industry were implemented in the 1970s, in reaction to a huge increase in environmental concerns in the country. In 1972, the Clean Water Act passed through Congress and became law , requiring industrial plants to proactively improve their waste procedures in order to limit the effect of contaminants on freshwater sources. In 1974, the Safe Drinking Water Act was adopted by all 50 U.S. states for the regulation of public water systems within their jurisdictions. This law specified a number of contaminants that must be closely monitored in water and reported to residents should they exceed the maximum contaminant levels allowed by the federal government. Drinking water systems are now closely monitored by federal, state, and municipal governments for safety and compliance with existing regulations. Water Treatment Today The treatment of drinking water today continues to be largely based upon municipal filtration using chlorination or other means of disinfection (such as ozone and chloramines). While most municipal water treatment plants continue to use methods that have been in existence for hundreds of years, some newer types of treatment (such as activated carbon filtration and reverse osmosis) have been implemented in both public treatment plants and private homes. Water treatment methods will undoubtedly continue to evolve in coming years as newer, safer, and more efficient processes are developed. 3.3 TREATMENT PROCESSES

Public Water Systems Public Water Systems (PWSs) come in all shapes and sizes, and no two are exactly the same. They may be publicly or privately owned and maintained. While their design may vary, they all share the same goal - providing safe, reliable drinking water to the communities they serve. To do this, most water systems must treat their water. The types of treatment provided by a specific PWS vary depending on the size of the system, whether they use ground water or surface water, and the quality of the source water. Tapping a Source of Water Large-scale water supply systems tend to rely on surface water sources, while smaller systems tend to rely on ground water. Around 35 percent of the population served by community water systems (CWSs) drink water that originates as ground water. Ground water is usually pumped from wells ranging from shallow to deep (50 to 1,000 feet). The remaining 65 percent of the population served by CWSs receive water taken primarily from surface water sources like rivers, lakes, and reservoirs. Treating Raw Water The amount and type of treatment applied by a PWS varies with the source type and quality. Many ground water systems can satisfy all Federal requirements without applying

pitcher water filters have become a popular method of treating water at home

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any treatment, while others need to add chlorine or additional treatment. Because surface water systems are exposed to direct wet weather runoff and to the atmosphere and are therefore more easily contaminated, federal and state regulations require that these systems treat their water. Water suppliers use a variety of treatment processes to remove contaminants from drinking water. These individual processes may be arranged in a "treatment train" (a series of processes applied in sequence). The most commonly used processes include filtration, flocculation and sedimentation, and disinfection for surface water. Some treatment trains also include ion exchange and adsorption. Water utilities select a combination of treatment processes most appropriate to treat the contaminants found in the raw water used by the system. Types of Treatment Flocculation/Sedimentation Flocculation refers to water treatment processes that combine or coagulate small particles into larger particles, which settle out of the water as sediment. Alum and iron salts or synthetic organic polymers (used alone or in combination with metal salts) are generally used to promote coagulation. Settling or sedimentation occurs naturally as flocculated particles settle out of the water. Filtration Many water treatment facilities use filtration to remove all part icles from the water. Those particles include clays and silts, natural organic matter, precipitates from other treatment processes in the facility, iron and manganese, and microorganisms. Filtration clarifies water and enhances the effectiveness of disinfection. Ion Exchange Ion exchange processes are used to remove inorganic contaminants if they cannot be removed adequately by filtration or sedimentation. Ion exchange can be used to treat hard water. It can also be used to remove arsenic, chromium, excess fluoride, nitrates, radium, and uranium. Adsorption Organic contaminants, unwanted coloring, and taste-and-odor-causing compounds can stick to the surface of granular or powder activated carbon and are thus removed from the drinking water. Disinfection (chlorination/ozonation) Water is often disinfected before it enters the distribution system to ensure that potentially dangerous microbes are killed. Chlorine, chloramines, or chlorine dioxide are most often used because they are very effective disinfectants, not only at the treatment plant but also in the pipes that distribute water to our homes and businesses. Ozone is a powerful disinfectant, and ultraviolet radiation is an effective disinfectant and treatment for relatively clean source waters, but neither of these are effective in controlling biological contaminants in the distribution pipes. Monitoring Water Quality Water systems monitor for a wide variety of contaminants to verify that the water they provide to the public meets all federal and state standards. Currently, the nation's community water systems (CWSs) and nontransient non-community water systems (NTNCWSs) must monitor for more than 83 contaminants. The major classes of

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contaminants include volatile organic compounds (VOCs), synthetic organic compounds (SOCs), inorganic compounds (IOCs), radionuclides, and microbial organisms (including bacteria). Testing for these contaminants takes place on varying schedules and at different locations throughout the water system. Transient non-community water systems may monitor less frequently and for fewer contaminants than CWSs. Because these types of systems serve an ever-changing population, it is most important for them to monitor for contaminants such as microbiologicals and nitrate that can cause an immediate, acute public health effect. Water systems also monitor for a number of contaminants that are currently not regulated. This monitoring data provides the basis for identifying contaminants to be regulated in the future. Distribution to Customers An underground network of pipes typically delivers drinking water to the homes and businesses served by the water system. Small systems serving just a handful of households may be relatively simple. Large metropolitan water systems can be extremely complex - sometimes with thousands of miles of piping serving millions of people. Although water may be safe when leaving the water treatment plant it is important to ensure that this water does not become contaminated in the distribution system because of such things as water main breaks, pressure problems, or growth of microorganisms. The Water Cycle

Drinking water can come from both surface water and ground water. The water cycle begins with rainwater and snow melt that gathers in lakes and rivers which interact with ground water. Water Treatment Plant Follow a drop of water from the source through the treatment process. Water may be treated differently in different communities depending on the quality of the water

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which enters the plant. Groundwater is located underground and typically requiresless treatment than water from lakes, rivers, and streams.

Check your progress-1

1. Why isn’t my pond filter working properly? 2. Is my fountain acting as a filter? 3. What is a natural water filter in a pond? 4. If my water gets polluted how do I clear it? 5. How much water is rejected? 6. How do I dispose of reject water? 7. What types of membranes are there?

3.4 LET US SUM UP

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Nature treats water in its own way through the hydrologic cycle, though we still need to treat the water before we drink it due to all the pollution and bacteria in the environment. The hydrologic cycle provides the supply of water for us to use for consumption, continuously cycling through over and over. The five basic processes that make up the hydrologic cycle are condensation, precipitation, infiltration, runoff, and evapotranspiration. In the water treatment plant the water comes in from the source, is aerated and the addition of chemicals to aid in coagulation and flocculation occurs in the flash mix chamber, it is then allowed to go through coagulation and flocculation, and settle out in the sedimentation basin. The water will pass through a filtration system after the sedimentation basin, removing partilces that were too small to settle out. Chlorine is added as the final step and then the water is stored until it is distributed to the consumer 3.5 SOME USEFUL BOOKS

Baker, M.N. and Taras, Michael J. 1981. The Quest for Pure Water: A History of the Twentieth Century, Volume 1 and 2. Denver: AWWA.

Christman, Keith. 1998. The History of Chlorine. Waterworld, 14 (8), 66-67.

EPA. 2000. The History of Drinking Water Treatment. Environmental Protection Agesncy, Office of Water (4606), Fact Sheet EPA-816-F-00-006, United States.

3.6 ANSWER TO CHECK YOUR PROGRESS

Check your progress-1 1. Normally the filter will stop working when there is a blockage, this is normally inside the

filter as the sponges get clogged with debris. In the summer months when the filter is running 24/7 checks should be made on a regular basis to make sure the filter is working fine. If the sponges are blocked, rinse them out in old pond water- never use tap water to do this. Check the piping for a blockage, the use of stiff wires pushed down the pipes will move any debris that is jammed. If the filter is clear and the piping isn’t blocked then it has to be the pump that has broken down. There is only one action to take in this scenario, buy a replacement.

2. This depends on the fountain; certain models will have a small sponge filter built into them but not all models. The main uses for a fountain are for display reasons and to keep the water well oxygenated.

3. This is where a mini ecosystem is created in the pond and the balance of the pond is as near perfect as possible. This will take a lot longer to run properly and a lot harder to get right. Lots of plants are added to the pond; at least 2/3 of the pond will be planted. The plants will then act as the filter along with any bacteria in the water, soaking up any toxins in the pond that are produced by fish waste or rotting debris.

4. If the pond water is polluted from outside sources by chemicals or like wise, act quickly to remove it. Large water changes should be performed and add a commercial filter carbon into the filtration system to soak up any toxins. Once the toxins have been absorbed, remove the carbon and perform another water change.

5. This will vary with the configuration of the system. Up to 6 membranes can be connected

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in series and the theoretical capture rate is about 84% (rejecting 16%). We have use oversized systems and redirected the reject to the front of the system for a multiple pass system and have gotten recovery's of about 92% (half or the reject to drain, half to the system feed tank). This does require oversizing the pumps and system size to get the required flow rate.

6. Reject water is discharged directly to drain. Usually the TDS is less than 1500 PPM and there are no contaminants. If a system is used to recycle some water after a plating application, monitoring of the reject may be necessary.

7. There are two types of membrane materials in widespread use. These are thin film (TF) and Cellulose Triacetate (CTA) membranes. The thin film membrane is chlorine sensitive and requires carbon pretreatment to remove the chlorine. The CTA membranes don't. TF membranes have a little higher reject ratio and operate at a wider pH range than the CTA.

3.7 GLOSSARY

Water Treatment Processes illustrates the link between raw water quality and treatment process selection and performance. Individual chapters concentrate on specific water treatment processes, detailing the chemical and engineering principles behind the process, and further illustrating process implementation by the use of process flow diagrams, photographs and case studies. The final three chapters look specifically at the removal of organic and inorganic contaminants and at the treatment and disposal of sludge. With introductory chapters covering both UK/European legislation and WHO guidance, and a general introduction to process flow diagrams, Introduction to Potable Water Treatment Processes is essential reading for anyone operating or managing a water treatment process, or carrying out research on water treatment processes.

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UNIT 4 DISTRIBUTION SYSTEM

Structure 4.0 Objective 4.1 Introduction 4.2 History 4.3 Distribution system 4.4 Let us sum up 4.5 Some Useful Books 4.6 Answer to Check your Progress 4.7 Glossary 4.0 OBJECTIVE

In this lesson we are going to discuss in detailed manner about : To study the whole process of “Alternative Public Distribution System” initiated by DDS in eleven villages, we were guided by the following broad objectives:

To document the various processes involved in reclaiming fallows and setting up alternative public distribution system by the local communities.

To study the effects of reclamation of current fallow lands and alternative PDS on the livelihoods of the individual households as well as the community at large.

To study the economics of alternative PDS Scheme and its sustainability in future. To study lessons from the project implementation for its wider acceptance and

applicability across rain fed regions in the country. 4.1 INTRODUCTION

Over the decades the functioning of the Public Distribution System (PDS) in India has suffered due to inefficient management and lack of proper targeting to improve the food security of the poor. Although, India has achieved self-sufficiency in food grain production, and surplus food stocks are available in the FCI godowns across the country, the poor have little access to food as they lack purchasing power. This paradox of surplus food availability in the market and chronic hunger of the poor has brought into sharp focus, the lopsided policies of the government, with regard to food distribution in the country. The PDS evolved from a food rationing system introduced by the British in India during World War II. A fixed amount of food rations were distributed to the entitled families in specific towns/cities through The Department of Food created in 1942 under the Government of India. After the end of the war, the government abolished the rationing system only to reintroduce immediately after independence in 1950 due to inflationary pressures of the economy. Ever since, the Indian government has used the public distribution system as a deliberate policy instrument to overcome chronic food shortages, apart from using it for stabilizing food prices and consumption, in view of fluctuating food production in the country. In the present context of the failure of the PDS system to ensure the food security of the poor, it would be relevant to raise some important questions about the food security policies of the government as well as the need for alternative approaches/paradigms of food security. “The Alternative Public Distribution System (APDS) through the Community Grain Fund” conceived by Deccan Development Society is one such programme that breaks away from narrow framework of government PDS that is solely concerned with procurement and

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distribution of food grains to the target groups. The Deccan Development Society (DDS) conceived the APDS programme with an idea of local solutions for local problems. The programme integrates the goals of sustainable agricultural stratagies such as bio-diversity and natural resource management with community goals of rural livelihoods, food security and socio-economic empowerment of dalits and women, based on plural values, local customs, practices and indigenous knowledge. 4.2 HISTORY

Indoor plumbing was rare, especially in the countryside, and in cities it was inadequate at best. Tenements housing as many as 2,000 people typically had not one bathtub. Raw sewage was often dumped directly into streets and open gutters; untreated industrial waste went straight into rivers and lakes, many of which were sources of drinking water; attempts to purify water consistently fell short, and very few municipalities treated wastewater at all. As a result, waterborne diseases were rampant. Each year typhoid fever alone killed 25 of every 100,000 people (Wilbur Wright among them in 1912). Dysentery and diarrhea, the most common of the waterborne diseases, were the nation's third leading cause of death. Cholera outbreaks were a constant threat. These challenges of both quantity and quality—to make sure there was enough water conveniently supplied wherever it was wanted and to make sure that it was safe both before and after use—fell to the nation's civil engineers. The results of their efforts speak for themselves: a deadly handful of waterborne diseases virtually eliminated not only in the United States but throughout the developed world; water distribution systems pumping a clean supply into homes, apartments, businesses, and factories and meeting the needs of tens of millions of people in burgeoning new cities and communities; and the rich potential of western lands realized in acre upon acre of irrigated crops. All told, what 20th-century engineers did to improve the water supply wrought a host of stunning transformations—in public health, in living standards, and in both urban and agricultural development. As the century began, the most pressing task was to find better ways to make water clean. The impetus came from the discovery only a few years before the turn of the century that diseases such as typhoid and cholera were actually traced to microorganisms living in contaminated water. Treatment systems in place before then had focused on removing particulate matter suspended in water, typically by using various techniques that caused smaller particles to coagulate into heavier clumps that would settle out and by filtering the water through sand and other fine materials. Some harmful microorganisms were indeed removed in this way, but it wasn't good enough. One more step was necessary, and it involved the use of a chemical called chlorine. Known at the time for its bleaching power, chlorine also turned out to be a highly effective disinfectant, and it was just perfect for sterilizing water supplies: It killed a wide range of germs, persisted in residual amounts to provide ongoing protection, and left water free of disease and safe to drink. 4.3 DISTRIBUTION SYSTEM

THE ELECTRICAL DISTRIBUTION SYSTEM

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The generation and distribution of electricity is without question one of the greatest discoveries of the 19th century. It is the cornerstone of modern society and has transformed our standard of living. Computers, copy machines, printers, lighting, elevators, assembly lines, robotics, medical equipment and industrial equipment all rely on the generation and distribution of electricity. However, unlike nearly every invention of the 19th century, the distribution of electricity has not been upgraded to meet the needs of modern electrical equipment. There are two categories of distribution, utility and internal. Utility distribution delivers electricity from the generation site to homes and businesses, while internal distribution delivers electricity from the transformer throughout the building. Both were designed more than one hundred years ago, and have only been upgraded for safety. Ironically, one of those changes, the introduction of ground, has been misused so regularly that grounding is now a liability in most facilities.

Why is this important? Just 30 years ago the amount of computerization present in society was unimaginable. In 1977 the chairman of IBM, Ken Olson declared, "There is no reason for every individual to have a computer in his home." Now, society is completely dependent on computerization. However, the distribution system was never upgraded to handle this equipment. The introduction and proliferation of electronic equipment into the electrical environment forever changed the way electricity is used. In the past, equipment was resistive and linear, meaning the voltage and current waves reach their peak simultaneously. Now, nearly all equipment is nonlinear. These changes generate electromagnetic interference which pollutes the

electrical environment. EMI is responsible for generating: Transients/Surges High Frequency Skin Effect Proximity Effect Resistance /Heat Load Imbalance

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Eddy Currents Hysteresis Harmonics Voltage Flicker Ground Loops Power Factor These problems combine to corrupt power quality. Following flowchart explains the various EMI effects in any electrical distribution system

Consider that wire, in most facilities, is the largest singular load. It is also responsible for providing electrical power to all of your equipment. By upgrading the electrical distribution system you not only reduce the losses caused by poor power quality, you also improve the function and efficiency of all the equipment in your facility. Businesses are dependent on electrical equipment for every step of the business process: manufacturing, purchasing, accounting, shipping, receiving and even sales. Without electrical equipment, business and productivity would be severely handicapped. Removing EMI from the electrical distribution system should be the primary concern for all companies. AUTOMATION IN POWER DISTRIBUTION The demand for electrical energy is ever increasing. Today over 21% (theft apart!!) of the total electrical energy generated in India is lost in transmission (4-6%) and distribution (15-18%). The electrical power deficit in the country is currently about 18%. Clearly, reduction in distribution losses can reduce this deficit significantly. It is possible to bring down the distribution losses to a 6-8 % level in India with the help of newer technological options (including information

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technology) in the electrical power distribution sector which will enable better monitoring and control. How does Power reach us? Electric power is normally generated at 11-25kV in a power station. To transmit over long distances, it is then stepped-up to 400kV, 220kV or 132kV as necessary. Power is carried through a transmission network of high voltage lines. Usually, these lines run into hundreds of kilometres and deliver the power into a common power pool called the grid. The grid is connected to load centres (cities) through a sub-transmission network of normally 33kV (or sometimes 66kV) lines. These lines terminate into a 33kV (or 66kV) substation, where the voltage is stepped-down to 11kV for power distribution to load points through a distribution network of lines at 11kV and lower. The power network, which generally concerns the common man, is the distribution network of 11kV lines or feeders downstream of the 33kV substation. Each 11kV feeder which emanates from the 33kV substation branches further into several subsidiary 11kV feeders to carry power close to the load points (localities, industrial areas, villages, etc.,). At these load points, a transformer further reduces the voltage from 11kV to 415V to provide the last-mile connection through 415V feeders (also called as Low Tension (LT) feeders) to individual customers, either at 240V (as single-phase supply) or at 415V (as three-phase supply). A feeder could be either an overhead line or an underground cable. In urban areas, owing to the density of customers, the length of an 11kV feeder is generally up to 3 km. On the other hand, in rural areas, the feeder length is much larger (up to 20 km). A 415V feeder should normally be restricted to about 0.5-1.0 km. Unduly long feeders lead to low voltage at the consumer end. Bottlenecks in Ensuring Reliable Power Lack of information at the base station (33kV sub-station) on the loading and health status of the 11kV/415V transformer and associated feeders is one primary cause of inefficient power distribution. Due to absence of monitoring, overloading occurs, which results in low voltage at the customer end and increases the risk of frequent breakdowns of transformers and feeders. In fact, the transformer breakdown rate in India is as high as around 20%, in contrast to less than 2% in some advanced countries. In the absence of switches at different points in the distribution network, it is not possible to isolate certain loads for load shedding as and when required. The only option available in the present distribution network is the circuit breaker (one each for every main 11kV feeder) at the 33kV substation. However, these circuit breakers are actually provided as a means of protection to completely isolate the downstream network in the event of a fault. Using this as a tool for load management is not desirable, as it disconnects the power supply to a very large segment of consumers. Clearly, there is a need to put in place a system that can achieve a finer resolution in load management. In the event of a fault on any feeder section downstream, the circuit breaker at the 33kV substation trips (opens). As a result, there is a blackout over a large section of the distribution network. If the faulty feeder segment could be precisely identified, it would be possible to substantially reduce the blackout area, by re-routing the power to the healthy feeder segments through the operation of switches (of the same type as those for load management) placed at strategic locations in various feeder segments.

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Typical Power Transmission and Distribution Scenario with DA components The Technology Development Mission A Technology Development Mission on Communication, Networking and Intelligent Automation, was jointly taken up by IIT Kharagpur and IIT Kanpur. While the mission focus at IIT Kharagpur is to develop technology for industrial automation, IIT Kanpur embarked upon the development of an integrated technology for power distribution automation system. In a distribution automation (DA) system, the various quantities (e.g., voltage, current, switch status, temperature, and oil level) are recorded in the field at the distribution transformers and feeders, using a data acquisition device called Remote Terminal Units (RTU). These system quantities are transmitted on-line to the base station (33kV substation) through a variety of communication media. The media could be either wireless (e.g., radio, and pager) or wired (e.g., Dial-up telephone, RS-485 multi-drop, and Ethernet). The measured field data are processed at the base station for display of any operator selected system quantity through Graphic User Interface (GUI). In the event of a system quantity crossing a pre-defined threshold, an alarm is automatically generated for operator intervention. Any control action (for opening or closing of the switch or circuit breaker) is initiated by the operator and transmitted from the 33kV base station through the communication channel to the remote terminal unit associated with the corresponding switch or circuit breaker. The desired switching action then takes place and the action is acknowledged back to operator for information.

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DA systems are being adopted by utilities in some developed countries in a phased manner, primarily for reliability evaluation in a field environment. In India too, a small beginning has been made by a few state utilities (Andhra Pradesh, Assam, Kerala and Rajasthan), which are confining themselves initially to the automation of 33kV substations. Electronics Research and Development Centre, Trivandrum, and Computer Maintenance Corporation, Hyderabad, are involved in these early experiments, the main objective being the development of know-how and a better understanding of the issues involved in implementing DA systems indigenously. The utility environment in India is far different from that in most of the developed countries, because of the existing social scenario. Hence, technological solutions available for DA in developed countries cannot be directly implanted in India. Also, the cost of importing a DA system technology is prohibitive. The Mission Activities at IIT Kanpur IIT Kanpur has embarked on an effort to develop indigenous technology for an integrated power distribution automation system in collaboration with four industry partners (Secure Meters Limited, Udaipur; Indian Telephone Industries, Raebareli; DataPro Electronics Private Limited, Pune; and Danke Switchgears, Vadodara). This effort includes development of (a) communication and networking technology using wired and wireless media, (b) micro-controller based remote terminal unit (RTU), (c) remotely operable switch for 11kV and 415V feeders, (d) application Specific Integrated Circuit (ASIC) for electrical instrumentation, (e) DA software to enable remote monitoring, alarm generation and remote control, and (f) distribution network simulator (a scaled down model of a real-life distribution network) to provide a test bed for a comprehensive testing of the developed technology, components and software. Some of the developments noted above are being implemented in the IIT Kanpur distribution network as a pilot level installation for field reliability evaluation. Salient Contributions The technology development mission at the Institute has made the following contributions: Communication and Networking Technology This enables distributed data acquisition, monitoring and control system functions. Unlike traditional communication solutions, the approach here is to have a core communication controller in the base station that can support diverse choices of communication media (dial-up, RS485, Ethernet, and radio). This open approach facilitates cost effective implementation. The base station communication controller has cross-platform portability, supports functions for communications network management, and permits LAN, Internet, and Intranet connectivity through Ethernet. All command communication functions are invoked through GUI of automation software. Data transfer from/to RTUs supports industry standard data links. Remote Terminal Unit The micro-controller based pole-top RTU has 32 analog and 16 digital channels, and affords RS232 full duplex asynchronous communication. The acquired data (voltage and current) is processed for rms and power factor calculations. Some design goals focus at low cost, flexibility and expandability, modularity at signal conditioning level, and communication interface. Remotely Operable Switch A load break switch (LBS) for 11kV operation and a moulded case circuit breaker (MCCB) unit for 415V operation have been developed and tested as per available specifications. The three-pole 11kV LBS opens in 80 milliseconds at the rated current of 80 A. While this switch is

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primarily meant for breaking load current, it can sustain 16 kA of fault current for one second and can also close on fault. The remote operation is through a three-phase induction motor coupled with gear mechanism. The 415V MCCB unit, on the other hand, has an isolator on the incoming circuit and two MCCBs for two outgoing feeders. Flexibility exists to choose the MCCB of appropriate rating corresponding to the rated feeder current. The remote operation is through solenoid-plunger arrangement. Application Specific Integrated Circuit (ASIC) ASIC supports up to four-phase analog inputs (four voltage and four current) for applications such as tri-vectormetre, RTU, and single-phase meter. It has an option for frequency selection (50/60 Hz) and is of 0.2 class accuracy with 16 bit A/D converter. Sampling rate is 5000 samples per second per channel. It calculates quantities like rms values of voltage and current (both actual and fundamental), power, power factor, total harmonic distortion, frequency, and energy. The ASIC design is verified using Verilog HDL simulation. While the ASIC fabrication is being finalised, the ASIC-based metering applications have been validated using the hardware behavioural simulation of ASIC. DA software The DA software has the following components: (i) Distribution network software with attributes like graphical representation of network, cross-platform portability (Windows NT, Linux, Solaris), editing features, customizing, network validation, system topological information, component specification, and billboard printing; (ii) Set-up utilities for installation on different platforms; (iii) Automation software having real-time features, cross-platform portability, alarm generation (audio/video), system monitoring (of system quantities, equipment health and switch status), switch control commands, control interlocks and event log report; (iv) Database with real-time attributes that conforms to DNP3.0 library format, uses shared memory approach, provides SQL interface for backup in standard databases for all off-line applications, permits sharing of data in multiple processes, and has registry access for security and RTU identification; and (v) Application software which includes packages for network re-configuration, load shedding, volt-var control through capacitor switching, and fault detection and isolation. Distribution Network Simulator It is a scaled-down model of the actual IIT Kanpur distribution network, having suitably scaled-down versions of fourteen transformers, thirty 11 kV feeders, forty one circuit breakers represented by four-pole controllable relays (with selection for remote/local operation), LT loads which can be varied from 0-150% in steps of 25%, communication linkage (for Ethernet, dial-up, RS485 and radio), single generic RTU (96 digital and 128 analog channels) covering all transformers. The simulator applications include testing of various communication systems and protocols, testing of DA software, fine tuning of RTU and LBS control prior to field installation, and integration and testing of application software. As the simulator provides a feel of actual physical system, it can serve as a training tool for operators of DA system. Check your progress-1

1. What are the parameters of the induction motors and what are the tests to be performed on such machines to be able to obtain the values of these parameters?

2. How can the performance of an induction motor be analyzed?

4.4 LET US SUM UP

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Most of the developments undertaken as part of the mission have been completed over the last three years. Some of these developments have already been implemented in the 33kV substation of IIT Kanpur. Implementation at five 11kV substations in IIT Kanpur is currently in progress, and is expected to be completed by the end of 1999. Based on this field experience, the necessary fine tuning of the technology will be done for increased reliability. It is expected that the technology for DA system developed through this mission, will be marketed by the four industry partners, not just within India, but also in the other developing countries. and the other motor parameters (or the results of the tests), the following are calculated: the rotor current referred to stator (I2'), starting torque (Tst) and the power transferred by the rotating field to the rotor (Prot.f) for starting performance analysis. For the running performance: the slip(s), stator and rotor currents, the developed torque and power, the efficiency and the power transferred by rotating field at rated motor HP and at pull out conditions or states are calculated. 4.5 SOME USEFUL BOOKS

Outwater, Alice. 1996. Water: A Natural History. New York: Basic Books. Rona, Zolton P. and Martin, Jeanne Marie. (1995). Return to the Joy of Health.

Vancouver: Alive Books. Vigneswaran, S. & Visvanathan, C. (1995). Water treatment processes: Simple options.

Boca Raton, Florida: CRC Press. 4.6 ANSWER TO CHECK YOUR PROGRESS

Check your progress-1 1. The parameters of the induction motors are: the stator resistance per phase, stator leakage

reactance/phase, rotor resistance/phase, rotor leakage reactance/phase, main flux susceptance and conductance/phase. For motors under starting conditions the parameters are the same as above except the values of the rotor resistance and reactance (referred to the stator) are higher (due to skin effect) and lower (due to the skin effect & saturation), respectively. The tests to be performed on such machines to be able to calculate the parameters of the machine are the no load (open circuit) and locked rotor (short circuit) under full and reduced voltage. The reduced voltage test is run to get the unsaturated reactance values (for rotor & stator). The data to be collected from the no load test are: Primary voltage, the no load current and power at 75C (or 25 and corrected to 75); from the locked rotor: the voltage, current and power at 75C; from the locked rotor (reduced voltage): the voltage and current. For the first 2 tests, the nominal motor voltage is applied, if possible. Fig. 1 shows the equivalent circuit of a S.C.I.M.

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2. The performance of induction motors can be analyzed by studying the following points: heating of winding/iron, efficiency of motor, power factor of machine, pullout (maximum) torque, starting torque, starting currents and the effect of the parameters on such points. a) Heating of winding and iron: to reduce winding heating rotor and stator resistances have to be small. Though for a high starting torque, the rotor resistance has to be high. To reduce iron losses, the main flux has to be low. Note that the main flux and rotor current affect the torque. b) Efficiency: to have a high efficiency motor, the windings (copper) and iron losses have to be kept to the minimum possible. c) Power factor: to achieve a high power factor machine, the leakage reactances (stator and rotor) have to be low i.e. low reactive current. To have a high pullout torque, the flux has to be high. d) Maximum (pullout) torque: to have a high pullout torque in induction motors, primary (stator) and secondary (rotor) reactances should be kept to a minimum, the rotor resistance will only determine the slip of the maximum torque. e) Inrush Current: reactances (and for small motors, the resistances) of the rotor and stator windings have to be high to have a low inrush current. f) Starting torque: the rotor winding resistance has to be high to get a high starting torque, this contravenes the efficiency requirement. As can be seen from the above, the parameters of induction machines (i.e. their design) are a compromise to achieve the optimum starting, pullout and running performances required by the different applications. When a motor is existing and the following data are available: motor HP, terminal voltage, frequency, number of poles, stator resistance, windage losses, stray load losses

4.7 GLOSSARY

A system containing information about availability, prices, and related services for Airlines, Car Companies, Hotel Companies, Rail Companies, etc. and through which reservations can be made and tickets can be issued. A GDS also makes some or all of these functions available to subscribing travel agents, booking engines, and airlines. The GDS leaders are Amadeus, Apollo/Galileo/Worldspan, Sabre.

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Block III – Introduction-collections and conveyance of sewage

The Overall Sewage System. The STP itself is just one component of the overall sewage system which includes sewage collection and conveyance to the STP, effluent disposal or reuse, and sludge disposal. One of the most important considerations in purchasing an STP is that these other components of the system are compatible with the STP (and vice versa). Sewage Collection and Conveyance. There are two aspects of the collection and conveyance system that must be compatible with the STP: the flowrate to the STP, and the composition of the sewage with respect to grease, dissolved oxygen, and chemicals which might be harmful to the STP secondary treatment process. The flowrate to the STP will vary over the course of a day, and STP’s are designed to handle (and treat) higher than average flowrates. The highest flowrate to the STP, however, should not exceed the rating for the STP. The ratio of the highest flowrate to the average flowrate is called the peaking factor. For example, a peaking factor of 3 indicates the highest flowrate to the STP would be three times the average flowrate. Most smaller STP’s are designed for a peaking factor of about 3. When sewage is delivered to the STP by gravity, it is unlikely that the peaking factor would be exceeded. It is when sewage is delivered by a pump station that the peaking factor may be exceeded if the pumps are oversized. The pump stations pumping to the STP should be designed so as not to exceed the peaking factor for the STP. In cases where the collection and conveyance system is existing, and the peaking factor is exceeded, it may be necessary to construct a flow equalization pump station just ahead of the STP, to equalize the sewage flowrate to the STP. If there are excessive fats, oil, or grease in the influent sewage to the STP, it will decrease the treatment capability of the plant. Removal of the grease is best done at the source, ahead of the collection and conveyance systems, by installation of grease traps. Similarly, if there are substances in the sewage, such as cleaning or disinfecting solutions, which could kill the bacteria in the STP’s secondary treatment process, these should be prevented from ever entering the sewage collection and conveyance system.

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UNIT 1 DEFINITION OF TERMS

Structure 1.0 Objective 1.1 Introduction 1.2 History 1.3 Definition of terms 1.4 Let us sum up 1.5 Some Useful Books 1.6 Answer to Check your Progress 1.7 Glossary 1.0 OBJECTIVE

In this lesson we are going to discuss in detailed manner about : A sewage system may convey the wastewater by gravity to a sewage treatment plant. Where pipeline excavation is difficult because of rock or there is limited topographic

relief (i.e., due to flat terrain), gravity collection systems may not be practical and the sewage must be pumped through a pipeline to the treatment plant.

In low-lying communities, wastewater may be conveyed by vacuum. Pipelines range in size from pipes of six inches (150 mm) in diameter to concrete-lined

tunnels of up to thirty feet (10 m) in diameter. 1.1 INTRODUCTION

Consideration of benefits indicators is simplified by using common terms. These definitions distinguish clearly between four attributes of a natural resource systems including features, functions, services, and values. These terms are related to one another and, in some cases, may be used to represent one another. However, there are strong reasons why maintaining a clear distinction between them is important for purposes of assessing the benefits of conservation practices. Site and landscape factors strongly influence whether a given environmental feature (e.g., a riparian buffer) will provide a particular function (e.g., trap nutrients) and whether that function will generate a service (e.g., improved water quality, improved fishing) and how much economic value that service will have (e.g., willingness to pay for more fishing opportunities). This is important because the measurable outcome of conservation practices involve changes in environmental features (e.g., wetland acres restored or miles of forested buffer created).

1.2 HISTORY The historical focus of sewage treatment was on conveyance of raw sewage to a natural body of water, e.g. a river or ocean, where it would be satisfactorily diluted and dissipated. Early human habitations were often built next to water sources. Rivers could double as a crude form of natural sewage disposal. Ancient systems The first sanitation system has been found at the prehistoric Middle East, in south-east of Iran near Zabol In Burnt City (Shahre soukhteh) areas. The first time an inverted siphon system was used, along with glass covered clay pipes, was in the palaces of Crete, Greece. It is still in working condition, after about 3000 years.

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Higher population densities required more complex sewer collection and conveyance systems to maintain (somewhat) sanitary conditions in crowded cities. The ancient cities of Harappa and Mohenjo-daro of the Indus Valley civilization constructed complex networks of brick-lined sewage drains from around 2600 BC and also had outdoor flush toilets connected to this network. The urban areas of the Indus Valley civilization provided public and private baths, sewage was disposed through underground drains built with precisely laid bricks, and a sophisticated water management system with numerous reservoirs was established. In the drainage systems, drains from houses were connected to wider public drains Ancient Minoan civilization had stone sewers that were periodically flushed with clean water. Roman towns and garrisons in the United Kingdom between 46 BC and 400 AD had complex sewer networks sometimes constructed out of hollowed out Elm logs which were shaped so that they butted together with the down-stream pipe providing a socket for the upstream pipe. A significant development was the construction of a network of sewers to collect waste water, which began from the Indus Valley civilization. In some cities, including Rome, Istanbul (Constantinople) and Fustat, networked ancient sewer systems continue to function today as collection systems for those cities' modernized sewer systems. Instead of flowing to a river or the sea, the pipes have been re-routed to modern sewer treatment facilities. 16th century The system then remained with not much progress until the 16th century, where, in England, Sir John Harington invented a device for Queen Elizabeth (his godmother) that released wastes into cesspools. However, many cities had no sewers and relied on nearby rivers or occasional rain to wash away sewage. In some cities, waste water simply ran down the streets, which had stepping stones to keep pedestrians out of the muck, and eventually drained as runoff into the local watershed. This was enough in early cities with few occupants but the growth of cities quickly overpolluted streets and became a constant source of disease. Even as recently as the late 19th century sewerage systems in parts of the highly industrialised United Kingdom were so inadequate that water-borne diseases such as cholera and typhoid were still common. In Merthyr Tydfil, a large town in South Wales, most houses discharged their sewage to individual cess-pits which persistently overflowed causing the pavements to be awash with foul sewage. Industrial Revolution era As an outgrowth of the Industrial Revolution, many cities in Europe and North America grew in the 19th century, frequently leading to crowding and increasing concerns about public health. As part of a trend of municipal sanitation programs in the late 19th and 20th centuries, many cities constructed extensive sewer systems to help control outbreaks of disease. These developments dramatically reduced mortality in the United States. Approximately one third of the forty percent decline in mortality from 1900-1940 can be explained by such improvements. Initially these systems discharged sewage directly to surface waters without treatment. The first comprehensive sewer system was built in Hamburg, Germany in the mid-19th century. The first such systems in the United States were built in the late 1850s in Chicago and Brooklyn. As pollution of water bodies became a concern, cities attempted to treat the sewage before discharge. Early techniques involved land application of sewage on agricultural land. In the late 19th century some cities began to add chemical treatment and sedimentation systems to their sewers. In the United States, the first sewage treatment plant using chemical precipitation was built in Worcester, Massachusetts in 1890 1.3 DEFINITION OF TERMS

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Unless otherwise specified, for the purpose of this chapter the following words and terms shall have the following meanings unless the context clearly indicates otherwise: "Biosolids" means a sewage sludge that has received an established treatment for required pathogen control and is treated or managed to reduce vector attraction to a satisfactory level and contains limited levels of pollutants, such that it is acceptable for use by land application, marketing or distribution in accordance with the Biosolids Use Regulations (12 VAC 5-585-10 et seq.) of the Code of Virginia. "Board" means the State Board of Health. "Certificate" means either a permit issued by the State Water Control Board in accordance with permit regulations (9 VAC 25-31-10 et seq. and 9 VAC 25-32-10 et seq.), or a construction or operation permit issued in accordance with the provisions of this chapter . "Commissioner" means the State Health Commissioner. "Critical areas/waters" means areas/waters in proximity to shellfish waters, a public water supply, recreation or other waters where health or water quality concerns are identified by the Department or the State Water Control Board. "Conventional design" means the designs for unit operations (treatment system component) or specific equipment that has been in satisfactory operation for a period of one year or more, for which adequate operational information has been submitted to the division to verify that the unit operation or equipment is designed in substantial compliance with this chapter. Equipment or processes not considered to be conventional may be deemed as alternative or nonconventional. "Department" means the State Department of Health. "Discharge" means (when used without qualification) discharge of pollutant or any addition of any pollutant or combination of pollutants to state waters or waters of the contiguous zone or ocean other than discharge from a vessel or other floating craft when being used as a means of transportation. "Division" means the division of Wastewater Engineering of the Office of Environmental Health Services, the administrative unit responsible for implementing this chapter. "Effluent limitations" means any restrictions, or schedules of compliance, prohibitions or permit requirements established under State or Federal law for control of sewage discharges. "Exceptional quality biosolids" means biosolids that have received an established level of treatment for pathogen control and vector attraction reduction and contain known levels of pollutants, such that they may be marketed or distributed for public use in accordance with this chapter. "Field office" means the location of the Area Engineer through which the division implements its field operations. "Indirect discharger" means an industrial waste discharger introducing pollutants into treatment works. "Industrial wastes" means liquid or other wastes resulting from any process of industry, manufacture, trade or business, or from the development of any natural resources. "Land application" means the distribution of treated wastewater of acceptable quality, referred to as effluent, or supernatant from biosolids use facilities or stabilized sewage sludge of acceptable quality, referred to as biosolids, upon, or insertion into, the land with a uniform application rate for the purpose of assimilation, utilization, or pollutant removal. Bulk disposal of stabilized sludge in a confined area, such as in landfills, is not land application. "Licensee" means an individual holding a valid license issued by the Board for Waterworks and Wastewater Works Operators. "Licensed operator" means a licensee in the class of the treatment works who is an operator at the treatment works. "Manual" and "Manual of Practice" means Part III (12 VAC 5-581-370 et seq.) of the Sewage Collection and Treatment Regulations. "Operate"

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means the act of making a decision on one's own volition (i) to place into or take out of service a unit process or unit processes or (ii) to make or cause adjustments in the operation of a unit process or unit processes at a treatment works. "Operating staff" means individuals employed or appointed by any owner to work at a treatment works. Included in this definition are licensees whether or not their license is appropriate for the classification and category of the treatment works. "Operator" means any individual employed or appointed by any owner, and who is designated by such owner to be the person in responsible charge, such as a supervisor, a shift operator, or a substitute in charge, and whose duties include testing or evaluation to control treatment works operations. Not included in this definition are superintendents or directors of public works, city engineers, or other municipal or industrial officials whose duties do not include the actual operation or direct supervision of a treatment works. "Owner" means the Commonwealth or any of its political subdivisions, including sanitary districts, sanitation district commissions and authorities, federal agencies, any individual, any group of individuals acting individually or as a group, or any public or private institution, corporation, company, partnership, firm or association which owns or proposes to own a sewerage system or treatment works. "Permit" means an authorization granted by the commissioner to construct, or operate either, a sewage collection system, treatment works, or biosolids use facility. "Primary sludge" means sewage sludge removed from primary settling tanks designed in accordance with this chapter that is readily thickened by gravity thickeners designed in accordance with this chapter. "Point source" means any discernible, confined and discrete conveyance, including, but not limited to, any pipe, ditch, channel, tunnel, conduit, well, discrete fissure or container, from which pollutants are or may be discharged. "Pollutant" means any substance, radioactive material, or waste heat which causes or contributes to, or may cause or contribute to, pollution. "Pollution" means such alteration of the physical, chemical or biological properties of any state waters as will, or is likely to, create a nuisance or render such waters (i) harmful or detrimental or injurious to the public health, safety or welfare, or to the health of animals, fish or aquatic life; (ii) unsuitable with reasonable treatment for use as present or possible future sources of public water supply; or (iii) unsuitable for recreational, commercial, industrial, agricultural or for other reasonable uses; provided that: (a) an alteration of the physical, chemical or biological property of state waters, or either a discharge, or a deposit, of sewage, industrial wastes, or other wastes to state waters by any owner, which by itself is not sufficient to cause pollution, but which, in combination with such alteration of, or discharge, or deposit to state waters by other owners is sufficient to cause pollution; (b) the discharge of untreated sewage by any owner into state waters; and (c) contributing to the contravention of standards of water quality duly established by the State Water Control Board are "pollution" for the terms and purposes of this chapter. "Reliability" means a measure of the ability of a component or system to perform its designated function without failure or interruption of service. "Responsible charge" means designation by the owner of any individual to have the duty and authority to operate a treatment works. "Sewage" means the water-carried and nonwater-carried human excrement, kitchen, laundry, shower, bath or lavatory wastes, separately or together with such underground, surface, storm and other water and liquid industrial wastes as may be present from residences, buildings, vehicles, industrial establishments or other places. "Settled sewage" is effluent from a basin in which sewage is held or remains in quiescent

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conditions for 12 hours or more and the residual sewage sludge is not reintroduced to the effluent following the holding period. Sewage flows not in conformance with these conditions providing settled sewage shall be defined as nonsettled sewage. "Sewage sludge" or "sludge" means any solid, semisolid, or liquid residues which contain materials removed from municipal or domestic wastewater during treatment including primary and secondary residues. Other residuals or solid wastes consisting of materials collected and removed by sewage treatment, septage and portable toilet wastes are so included in this definition. Liquid sludge contains less than 15% dry residue by weight. Dewatered sludge contains 15% or more dry residue by weight. "Sewerage system" or "sewage collection system" means a sewage collection system consisting of pipelines or conduits, pumping stations and force mains and all other construction, devices and appliances appurtenant thereto, used for the collection and conveyance of sewage to a treatment works or point of ultimate disposal. "Shall" means a mandatory requirement. "Should" means a recommendation. "Sludge management" means the treatment, handling, transportation, use, distribution or disposal of sewage sludge. "State waters" means all water, on the surface and under the ground, wholly or partially within, or bordering the state or within its jurisdiction. "Substantial compliance" means designs that do not exactly conform to the guidelines set forth in Part III as contained in documents submitted pursuant to this chapter but whose construction will not substantially affect health considerations or performance of the sewerage system or treatment works. "Subsurface disposal" means a sewerage system involving the controlled distribution of treated sewage effluent below the ground surface in a manner that may provide additional treatment and assimilation of the effluent within the soil so as not to create a point source discharge or result in pollution of surface waters. "Surface waters" means: 1. All waters which are currently used, were used in the past, or may be susceptible to use in interstate or foreign commerce, including all waters which are subject to the ebb and flood of the tide; 2. All interstate waters, including interstate "wetlands;" 3. All other waters such as intrastate lakes, rivers, streams (including intermittent streams), mudflats, sandflats, "wetlands," sloughs, prairie potholes, wet meadows, playa lakes, or natural ponds the use, degradation, or destruction of which would affect or could affect interstate or foreign commerce including any such waters: a. That are or could be used by interstate or travelers for recreational or other purposes; b. From which fish or shellfish are or could be taken and sold in interstate or foreign commerce; or c. That are used or could be used for industrial purposes by industries in interstate commerce; 4. All impoundments of waters otherwise defined as waters of the United States under this definition; 5. Tributaries of waters identified in subdivisions 1 through 4 of this definition; 6. The territorial sea; and 7. "Wetlands" adjacent to waters (other than waters that are themselves wetlands) identified in subdivisions 1 through 6 of this definition. "Toxic pollutant" means any agent or material including, but not limited to, those listed under § 307(a) of the Clean Water Act which after discharge will, on the basis of available information, cause toxicity. Toxicity means the inherent potential or capacity of a material to cause adverse effects in a living organism, including acute or chronic effects to aquatic life, detrimental effects

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on human health or other adverse environmental effects. "Treatment works" means any device or system used in the storage, treatment, disposal or reclamation of sewage or combinations of sewage and industrial wastes, including but not limited to pumping, power and other equipment and their appurtenances, septic tanks and any works, including land, that are or will be (i) an integral part of the treatment process or (ii) used for ultimate disposal of residues or effluents resulting from such treatment. Treatment works does not mean either biosolids use facilities or land application of biosolids on private land, as permitted under the Biosolids Use Regulations (12 VAC 5-585-10 et seq.). "Variance" means any mechanism or provision which allows a conditional approval based on a waiver of specific regulations to a specific owner relative to a specific situation under documented conditions for a specified time period."Water quality standards" means the narrative statements for general requirements and numeric limits for specific requirements, that describe the water quality necessary to meet and maintain reasonable and beneficial uses. Such standards are established by the State Water Control Board under § 44.15(3a) of the Code of Virginia as the State Water Quality Standards (9 VAC 25-260-10 et seq.). 12 VAC 5-581-20. Terms. Generally used technical terms not defined in this chapter above shall be defined in accordance with "Glossary-Water and Wastewater Control Engineering" published by American Public Health Association (APHA), American Society of Civil Engineers (ASCE), American Water Works Association (AWWA), and Water Environment Federation (WEF). Check your progress-1

1. What kinds of facilities are included under category (i)? 2. What kinds of facilities are subject to storm water effluent guidelines? 3. What kinds of facilities are subject to '1oxic pollutant effluent standards"?

1.4 LET US SUM UP

A Decentralised Wastewater Treatment System (DWTS) provides an alternative to on-site wastewater treatment and disposal, especially for new subdivisions. Wastewater from multiple dwellings can be treated by a shared treatment and disposal system, often owned and operated by a Body Cooperate entity. The ARC promotes the use of DWTS over multiple onsite wastewater systems as a means of avoiding cumulative effects to the receiving environment. Benefits of choosing an appropriately designed DWTS include:

ability to select land most suitable for wastewater land disposal system thus avoiding potential for adverse effects to the receiving environment

improved treatment quality could be provided, better protecting ground and surface water quality

decreased risk of human contact with treated wastewater homeowners secure in knowledge that wastewater system will be well maintained and

managed. 1.5 SOME USEFUL BOOKS

Metcalf, Leonard; Eddy, Harrison P. (1922). Sewerage and Sewage Disposal: A Textbook. New York: McGraw-Hill.

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Staley, Cady; Pierson, George S. (1899). The Separate System of Sewerage, Its Theory and Construction. New York: Van Nostrand.

Rodda, J. C. and Ubertini, Lucio (2004). The Basis of Civilization - Water Science? pg 161. International Association of Hydrological Sciences (International Association of Hydrological Sciences Press 2004).

Steven J. Burian, Stephan J. Nix, Robert E. Pitt, and S. Rocky Durrans (2000). "Urban Wastewater Management in the United States: Past, Present, and Future." Journal of Urban Technology, Vol. 7, No. 3, pp. 33-62. doi:10.1080/713684134.

Cutler; Miller. The Role of Public Health Improvements in Health Advances. Metcalf, Leonard; Eddy, Harrison P. (1914). American Sewerage Practice. New York:

McGraw-Hill. Vol. I: Design of Sewers.

1.6 ANSWER TO CHECK YOUR PROGRESS

Check your progress-1 1. Category (i) includes facilities subject to storm water effluent limitations guidelines, new

source performance standards, or toxic pollutant effluent standards under Title 40 subchapter N of the Code of Federal Regulations (CFR) (except facilities with toxic pollutant effluent standards which are exempted under category (xi) of the definition of storm water discharge associated with industrial activity). The term "storm water" modifies only "effluent limitations guidelines." Facilities subject to subcategories with new source performance standards, toxic pollutant effluent standards, or storm water effluent limitation guidelines are required to submit a National Pollutant Discharge Elimination System (NPDES) permit application for storm water discharges associated with industrial activity.

2. The following categories of facilities have storm water effluent guidelines for at least one of their subcategories: cement manufacturing (40 CFR 411); feedlots (40 CFR 412); fertilizer manufacturing (40 CFR 418); petroleum refining (40 CFR 419); phosphate manufacturing (40 CFR 422); steam electric power generation (40 CFR 423); coal mining (40 CFR 434); mineral mining and processing (40 CFR 436); ore mining and dressing (40 CFR 440); and asphalt (40 CFR 443). A facility that falls into one of these general categories should examine the effluent guideline to determine if it is categorized in one of the subcategories that have storm water effluent guidelines. If a facility is classified as one of those subcategories, that facility is subject to the standards listed in the CFR for that category, and as such, is required to submit a storm water discharge permit application.

3. First, it is important to understand the term toxic pollutant. Toxic pollutants refers to the priority pollutants listed in Tables II and III of Appendix D to 40 CFR part 122 (not 40 CFR Part 129). If any of these toxic pollutants are limited in an effluent guideline to which the facility is subject (including pretreatment standards), then the facility must apply for a storm water permit. The following categories of facilities have toxic pollutant effluent standards for at least one subcategory: Textile mills (40 CFR 410) Electroplating (40 CFR 413) Organic chemicals, plastics, and synthetic fibers (40 CFR 414) Inorganic chemicals (40 CFR 415)

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Petroleum refining (40 CFR 419) Iron and steel manufacturing (40 CFR 420) Nonferrous metals manufacturing (40 CFR 421) Steam electric power generating (40 CFR 423) Ferroalloy manufacturing (40 CFR 424) Leather tanning and finishing (40 CFR 425) Glass manufacturing (40 CFR 426) Rubber manufacturing (40 CFR 428) Timber products processing (40 CFR 429) Pulp, paper, and paperboard (40 CFR 430) Metal finishing (40 CFR 433) Pharmaceutical manufacturing (40 CFR 439) Ore mining and dressing (40 CFR 440) Pesticide chemicals (40 CFR 455) Photographic processing (40 CFR 459) Battery manufacturing (40 CFR 461) Metal molding and casting (40 CFR 464) Coil coating (40 CFR 465) Porcelain enameling (40 CFR 466) Aluminum forming (40 CFR 467) Copper forming (40 CFR 468) Electrical and electronic components (40 CFR 469) Nonferrous metals forming and metal powders (40 CFR 471)

4.7 GLOSSARY

Features-site-specific characteristics of a natural resource system (e.g., soil, ground cover, hydrology) that establish its capacity to support various ecosystem functions. A farm is one form of a natural resource system that provides agricultural output in addition to ecosystem services. Onsite farm features are the target of conservation practices. ‘ Functions-the biophysical processes that take place within an ecosystem. These can be characterized apart from any human context (e.g., fish and waterfowl habitat, cycling carbon, trapping nutrients). The level of function depends on the capacity of the ecosystem (onsite features) and certain aspects of its landscape context (e.g., connectedness to other natural/human features, accessibility to birds, fish).

Services-the beneficial outcomes that result from ecosystem functions (e.g., better fishing and hunting, cleaner water, better views, reduced human health and ecosystem risks). These require some interaction with, or at least some appreciation by, humans, but can be measured in physical terms (e.g., catch rates, water quality, property damage avoided). These depend on ecosystem functions and certain aspects of landscape context (e.g., proximity to floodwaters, people, and property; accessibility to hunters, birders, fishermen).

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UNIT 2 PHYSICAL AND CHEMICAL BACTERIOLOGICAL BOD,COD

Structure 2.0 Objective 2.1 Introduction 2.2 History 2.3 Physical and chemical bacteriological BOD, COD 2.4 Let us sum up 2.5 Some Useful Books 2.6 Answer to Check your Progress 2.7 Glossary 2.0 OBJECTIVE

In this lesson we will discuss the concepts of physical and chemical bacteriological. After studying this lesson you will be able to: (i) define BOD. (ii) describeCOD. 2.1 INTRODUCTION

BOD Characteristics of wastewater in general can be broadly divided into four categories: Physical Inorganic Chemicals Organic Chemicals and Toxicity The physical characteristics such as quantities of dissolved solids and suspended solid, temperature, color and quantities of inorganic chemicals such as iron and ammonia present are all readily measured by various standard techniques. However, the measurement of organic pollution is less straightforward and it is usually based on the oxygen demand of the sample. An important effect of leachates or wastewater entering a river can be the removal of oxygen from that river by bacteria, as they break down the organic compounds they have. In severe organic pollution the river may be completely denuded of oxygen with drastic effects on aquatic life. Thus the measurement of oxygen demand of a leachate or wastewater can give an estimate of the organic pollution potential. Techniques for measuring the oxygen demand of wastewaters can be devided into three categories: Biochemical Chemical Instrumental Biochemical techniques use bacteria to oxidize the organic material and the loss of oxygen due to bacterial activity can be measured as in the biochemical oxygen demand test, BOD. The BOD is often adopted as the standard test for measuring oxygen demand. It is expressed as the milligrams of oxygen required by the microorganisms due to oxidation of organic matter in a liter of water. In the standard test, a sample of the leachate or a dilution of it is incubated at 20Oc for five days (BOD5). A blank sample shows how much the dissolved oxygen in the diluting water decreases with time. The dilution waster is seeded with bacteria, typically by adding a few

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mililiters of sewage works effluent, and some inorganic nutrients. Precaution must be taken to ensure that the bacterial seed is appropriate for the sample, otherwise the bacteria must be acclimatized to the sample. The oxidation of ammonia to nitrite and nitrate by bacteria may occur during the test. If the oxygen used by this process is not to be included in the BOD test, then a small quantity of allyl thiourea (ATU) can be added and this will inhibit the nitrifying bacteria. Although the BOD test is often adopted as the standard test for measuring oxygen demand it has several major disadvantages. These include an accuracy of less than plus/minus 10%, a five day wait for completion of the test, and the fact that the results can be seriously affected by chemicals that inhibit bacterial activity COD, TOC, LD50 The chemical techniques use chemical agents to oxidize the organic material, and the difference between the original concentration of oxidizing agents and that which remains after a given contact time with the sample is a measure of the oxygen demand of the sample. The most common chemical technique is the chemical oxygen demand, COD. The COD of a natural water or wastewater is measured by adding the sample to a mixture of concentrated sulphuric acid and potassium dichromate, K2Cr2O7, together with silver sulphate. Mercuric sulphate is also added to combine with chlorides which otherwise would precipitate the silver catalyst as silver chloride. The mixture is boiled for two hours, much more convenient than the five days of the BOD test. The COD value is normally higher than the BOD value because more organic matter can be oxidized in these chemicals than are biodegradable in the BOD test. A low BOD5/COD ratio (e.g. 0.1) for a leachate may indicate the presence either of organic matter that are hard to biodegrade or of toxic material inhibiting the BOD results. Instrumental techniques use thermal oxidation of the organic material with subsequent measurement of the gases produced. The total organic carbon, TOC, is an instrumental method in which a small quantity of the liquid sample or a dilution of it is injected into a stream of air into the instrument. The water is vaporized and the organic matter oxidized to carbon dioxide, CO2. The concentration of carbon dioxide in the gas stream is measured by n infra-red device. Alternatively, the carbon dioxide may be reduced in a catalytic column to methane, CH4. The methane concentration can then be measured. This technique is more complex but may be more accurate at low concentrations of organic matter. The BOD, COD and TOC may all give different values for some sample and an understanding of the relevance of these measurements can give an insight into the nature of the leachate sample. Another important area of pollution measurement is that of toxicity. Toxicity of a chemical is usually expressed as the concentration of chemical required to kill 50% of the test organism in a given period of time (e.g. 48 to 96 hours). The value is known as the 50 lethal dose, LD50, or median tolerance limit, TLm. The test organisms are often fish such as trout, minnows, sticklebacks. The test is dependent on the species of test organism, pH, temperature and presence of other antagonistic chemicals in the water. 2.2 HISTORY

Biological oxygen demand (BOD) is a measure of the amount of oxygen that is consumed by bacteria during the decomposition of organic matter. Having a safe BOD level in wastewater is essential to producing quality effluent. If the BOD level is too high then the water could be at risk for further contamination, interfering with the treatment process and affecting the end

product.

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There are several factors that can contribute to high BOD levels: nitrates and phosphates present in the wastewater, water temperature, and others. Each factor affects the plant life in the water, such as algae, and in turn also has an effect on the organisms that help decompose water contaminants in the wastewater treatment process. The best quality wastewater treatment will occur in an environment that supports the life of these bacteria while maintaining a controlled population of them so as to not encourage rapid bacterial decomposition, which would create higher BOD levels. Similar to BOD is chemical oxygen demand (COD). COD measures the amount of oxygen that is consumed by the water in the decomposition and oxidation processes, specifically the decomposition of organic matter and oxidation of inorganic matter, or chemicals. COD is an application that is usually used in industrial settings; however, municipalities treating wastewater with chemical pollutants may use it. 2.3 PHYSICAL AND CHEMICAL BACTERIOLOGICAL BOD,COD

Uttarakhand is bounded by Himalayas in the north, Shivalik hills in south, Ganga in the east and Yamuna in the west. It has a moderate climate. Maximum temperature in summers is oaround 36 C while the minimum temperatureomay fall to 5 C in winters. Summers last fromApril to July while winter lasts from November to February.With the rapid development in agriculture, mining, urbanization, and industrialization activities, the river water contamination with hazardous waste and wastewater is becoming a common phenomenon. The water quality and human health are closely related. The domestic waste from each building along with the effluent of small scale industries is disposed off into the open drains and gutters which ultimately enter into the rivers. The quality of water is mainly deteriorated by human activities. Nowadays, many industries have developed in Uttarakhand state viz. pharmaceutical, textiles, toy making, colouring etc. They use dispose the waste directly or indirectly into the river water, which affects the BOD, COD, turbidity and also causes the physico-chemical changes. Rivers are getting contaminated due to waste disposing into them. Waste comprises liquid waste discharged by domestic residences, commercial properties, industry or agriculture and can encompass a wide range of potential contaminants and con-centrations (APHA 1998). In the most common usage, it refers to the municipal wastewater that contains a broad spectrum of contaminants resulting from the mixing of wastewater from different sources. Sewage is created by residences, institutions, hospitals and commercial and industrial establishments (APHA 1998). Raw influent includes household waste liquid from toilets, baths, showers, kitchens, sinks, and so forth that is disposed of via sewers. In many areas, sewage also includes liquid waste from industry and commerce. As rainfall runs over the surface of roofs and the ground, it may pick up various contaminants including soil particles and other sediment, heavy metals, organic compounds animal waste and oil and grease (FWPCA 1998). Consequently, the problem was taken up when effluents of these industries go into the water system and change the physicochemical quality of water and make it unfit for drinking and other uses. Since all natural waterways contain bacteria and nutrients, almost any waste compounds introduced into such waterways will initiate biochemical reactions. These biochemical reactions are measured as BOD and COD in laboratory (Tchobanoglous et al. 2003). Both the BOD and COD tests are a measure of the relative oxygen-depletion effect of a waste contaminant. Both have been widely adopted as a measure of pollution effect. The BOD test measures the oxygen demand of biodegradable pollutants whereas the COD test measures the oxygen demand of oxidizable pollutants. Disposal of wastewaters from an industrial plant is

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a difficult and costly problem (Clair 2003). Most petroleum refineries, chemical and petrochemical plants have onsite facilities to treat their wastewaters so that the pollutant concentrations in the treated wastewater comply with the local or national regulations regarding disposal of wastewaters into community treatment plants or into rivers, lakes or oceans (Tchobanoglous et al. 2003). Physically, wastewater is usually characterized by grey colour, musty odour, 0.1% solid content and 99.9% water content (Massoud and Ahmad 2005). The solids can be suspended 30% as well as dissolved solids which are about 70%. Dissolved solids can be precipitated by chemical and biological processes. From a physical point of view, the suspended solids can lead to the development of sludge deposits and anaerobic conditions when discharged into the receiving environment(Maiti 2004). Chemically, wastewater is com-posed of organic and inorganic compounds as well as various gases. Organic components may consist of carbohydrates, proteins, fats and greases, surfactants, oils, pesticides, phenols etc. (Tchobanoglous et al. 2003; Maiti 2004). Drinking water treatment efforts can become weighed down when water resources are heavily polluted by wastewater microorganism species. Pathogenic viruses, bacteria, protozoa and helminthes and other wastewater microorganism species, may be present in raw municipal wastewater and will survive in the environment longer periods (Mane et al. 2005). Sewage pathogens may be present in wastewater at much lower levels than the coliform group of bacteria, which are much easy to identify and enumerate as number of total Coliforms per 100 ml (Feng and Weagant 2002). Various wastewater microorganism species have an adverse impact on human health. Some illnesses from wastewater-related sources are relatively common (WHO 1999). The objective of this study was to check the physical and chemical parameters of the river samples and to find the degree of pollution in them. METHODS Water samples were collected from five rivers of Uttarakhand from various regions. The places from where the samples were collected include Devprayag, Gangotri. Haridwar, Rudra-prayag, Dakpathar and Yamunotri. The rivers for this study were: Alaknanda (A), Bhagirathi (B), Ganga (G), Mandakini (M) and Yamuna (Y). Water samples were collected once every month during April- June from two sites-middle of the river stretch and discharge point at nine monitoring stations viz. Har ki Pauri and Brahma Kund (Haridwar) river Ganga, Rudrapryag river Alaknanda and Mandakini, Devprayag river Alaknanda and Bhagirathi, Dakpathar and Yamunotri river Yamuna and Gangotri river Bhagirathi and samples coded as AR, AD, BD, BG, GH, GB, MR, YD and YY. The water samples were collected in prerinsed clean one liter polythene bottle having double stopper facility to its full capacity without entrapping air bubbles inside it. When the water samples from all the monitoring stations were received, systematic analysis of the water samples was undertaken. For analysis of samples, methods followed were of APHA 1998. Temperature, pH and turbidity were measured by thermometer, digital pH meter (NIG 333) and UV-VIS Spectrophotometer. Total alkalinity, total hardness, DO, BOD and COD was measured by titration method. Microbial analysis was done. After growing in mix culture, they were inoculated in selective media viz. EMB agar, Brain Heart infusion agar, Mac Conkey agar, Mannitiol Salt agar, and Nutrient agar for isolation of different microorganisms in the rivers’ water samples. The various morphological characteristics of recovered isolates viz., colony morphological (Colour, Shape, Arrangement and Gram staining) and the biochemical tests carried out for identification of isolates (Holt et al. 1994). The most common physical assessment of water quality is the measurement of temperature. Temperature impacts both the chemical and biological characteristics of surface water. All rivers

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of study had normal pH range, the pH values were 7.59 and 7.53 at Har ki Pauri and Brahma Kund in river Ganga Haridwar, 7.35 and 7.66 at Rudrapryag in river Alaknanda and Mandakini repectively, 7.6 and 7.82 at Devprayag in river Alaknanda and Bhagirathi, 8.16 and 7.03 at Dakpathar and Yamunotri in river Yamuna and 7.02 at Gangotri in river Bhagirathi (Table 1). The pH is measure of the intensity of acidity or alkalinity and the concentration of hydrogen ion in water. pH has no direct adverse effects on health, however, higher values of pH hasten the scale formation in water heating apparatus and also reduce germicidal potential of chloride. High pH induces the formation of trihalomethanes which are toxic (Kumar et al. 2010). pH affects the dissolved oxygen level in the water, photosynthesis of aquatic plants, metabolic rates of aquatic organisms and the sensitivity of these organisms to pollution, parasites and disease (FWPCA 1968). Most rivers have a neutral to slightly basic pH of 6.5 to 8.5. If stream water has a pH less than 5.5, it may be too acidic for fish to survive in, while stream water with a pH greater than 8.6 may be too basic. A change in stream water pH can also affect aquatic life indirectly by altering other aspects of water chemistry e.g. low pH levels can increase the solubility of certain heavy metals. This allows the metals to be more easily absorbed by aquatic organisms (Schlesinger 1991). Turbidity of all nine monitoring stations was isted in table 1. The water of river Ganga at Brahma Kund Haridwar was most turbid as turbidity measured 15 NTU, whereas at other places t was range from 1 – 7 NTU. Turbidity, measure of water clarity, tells the degree to which light entering a column of water is scattered by suspended solids. Suspended solids include hings such as mud, algae, detritus, and fecal material. Factors contributing to water turbidity nclude soil erosion, elevated nutrient inputs that stimulate algal blooms, waste discharge, and an abundance of bottom feeders that stir up sediments (Schlesinger 1991). As water becomes more turbid, less sunlight is able to penetrate ts surface, therefore the amount of photosynhesis that can decrease. This results in a decreasen the amount of oxygen produced by aquatic plants. In addition, suspended materials absorb heat from sunlight and raise the water temperature. This also limits the amount of dissolved oxygen water can hold (Merritts 1998). The values of alkalinity listed in table 1. It was in normal and in permissible limit, ranges from 32-118 mg/l. Alkalinity is measured to determine the ability of a stream to resist changes in pH. That is to say alkalinity allows

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scientists to determine a stream’s buffering capacity (FWPCA 1968). Alkalinity values of 20-200 ppm are common in freshwater ecosystems. Alkalinity levels below 10 ppm indicate poorly buffered streams. These streams are the least capable of resisting changes in pH; therefore they are most susceptible to problems which occur as a result of acidic pollutants (Merritts 1998). Alkalinity results from the dissolution of calcium carbonate (CaCO ) from limestone bedrock which is eroded during the natural processes of weathering. The carbon dioxide (CO ) released from the calcium carbonate into the stream water undergoes several equilibrium reactions (Schlesinger1991).Total hardness of river water ranged 42-194mg/l (Table 1), which showed the desirable limitas per Indian standard (ICMR 1996). Calciumcarbonate and magnesium carbonate were in range from 32-98 and 10-94 mg/l respectively. Total hardness of water is due to the presence of bicarbonate, sulphates, chloride, and nitrates of Ca and Mg (Kumar et al. 2010). Maximum permissible limit for total hardness is 600 mg/l as per Indian standards. Total hardness recorded for waste water is ranged between 50-200 mg/ L. Hardness has got no adverse effect on human health. Water with hardness above 200 mg/l may cause scale deposition in the water distribution system and more soap consumption. BOD or biochemical oxygen demand repre-sents the amount of oxygen that microbes need to stabilize biologically oxidizable matter. BOD range varies from 1.4 - 4.5 mg/l (Table 1) in river samples. Desirable limit for BOD is 4.0 mg/land permissible limit is 6.0 mg/l according to Indian standards. BOD demand below 3 mg/lor less is required for the best use. The chemical oxygen demand (COD) ranged from 2.9 – 34.2 mg/l (Table 1). The test is commonly used to indirectly measure the amount of organic compounds in water. Most applications of COD determine the amount of organic pollutants found in surface water, making COD a useful measure of water quality. It is expressed in milligrams per liter (mg/l), which indicates the mass of oxygen consumed per liter of solution (Clair 2003). Bacteriological analysis showed the four mic-robes in river water samples. All samples had E. coli, as indicator of fecal pollution (Table 2). Staphylococcus aureus was found in six samples (GH, GB, AR, AD, BD and YY). Bacillus cereus was present in four samples (GB, AR, AD and YD) and Pseudomonas spp in three samples viz. GH, GB and MR (Table 2). Escherichia coli are the most widely adopted indicator of fecal pollution and they can also be isolated and identified simply, with their numbers usually being given in the form of fecal Coliforms (FC)/100 ml of wastewater (De Boer 2000). Outbreaks of these diseases can occur as a result of, drinking water from wells polluted by a combination of different wastewater microorganism species, eating contaminated fish, or indulging in recreational activities in polluted water bodies containing water borne pathogen. E. coli cause urinary tract infection and diarrhea and Bacillus can cause the anthrax. Pseudomonas aeruginosa is a common bacterium which can cause disease in animals and humans (Balcht 1994). Pseudomonas can, in rare circumstances, cause community-acquired pneumonias as well as ventilator-associated pneumonias, being one of the most common agents isolated in several studies (Fine et al. 1996). Staphylococcus aureus is the most common cause of staph infections. It is a spherical bacterium, frequently found in the nose and skin of a person. S. aureus can cause a range of illnesses from minor skin infections, such as pimples, impetigo, boils, cellulitis folliculitis, furuncles, carbuncles, scalded skin syndrome and abscesses, to life-threatening diseases such as pneumonia, meningitis, osteomyelitis, endocarditis, toxic shock syndrome, and septicemia. Its incidence is from skin, soft tissue, respiratory, bone, joint, endovascular to wound infections (Fine et al. 1996).

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Check your progress-1

1. What is the difference between BOD vs. CBOD? 2. Where did BOD5 come from?

2.4 LET US SUM UP

The present investigations conclude that the quality of water samples subjected to study was acceptable from physico-chemical parameters, while E. coli, an indicator of fecal pollution was found in all samples. The river Ganga at Brahma Kund in Haridwar was most polluted despite being a quite popular tourist place in Haridwar. 2.5 SOME USEFUL BOOKS

American Concrete Institute. (2000). Service-Life Prediction: State- of-the-Art Report. American Concrete Institute: Framington Hills, MI.

American Water Works Association Research Foundation (AwwaRF). (2005). Risk Management of Large-Diameter Water Transmission Mains. AwwaRF Project No. 2883. AwwaRF: Denver, CO.

Fleury, M.A. and Warner, J. (2007). Arizona’s Largest Condition Assessment. Proceedings of WEF Collection Systems Specialty Conference, May 13-16, Portland, OR.

2.6 ANSWER TO CHECK YOUR PROGRESS

Check your progress-1 1. BOD5 measures the oxidation of carbons and possibly nitrogenous compounds

present in a water sample. CBOD only measures oxidation of carbons. 2. The BOD test Originated in the United Kingdom due to pollution in the Thames

River. Legend has it that the 5-day BOD (Biological or Biochemical Oxygen Demand) test was developed in England. Sewage was dumped in a river and it took five days for it to reach the ocean, hence the five-day incubation requirement in the BOD method. It is rumored that a ferry tipped over and that many of the people who fell in the river got sick or died. This was not due to drowning, but due to the effects of the pollution in the river. The Royal Commission on Sewage Disposal recommended and adopted the BOD5 test in 1908. The duration of the test is normally 5 days. The Average temperature is = 20 degrees C. 300 ml are usually used. Dark Incubation is needed to restrict the growth of algae. The final measurement is usually expressed as O2 mg/l. BOD measures all biodegradable

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organic carbons, and under certain conditions, oxidizable nitrogen present in the waste. The biochemical oxygen demand (BOD) test tries to closely model an aerobic wastewater treatment system and the natural aquatic ecosystem. It measures oxygen taken up by the bacteria during the oxidation of organic matter. The test usually runs for a five-day period, but can run 7 or 10 days as well, depending on specific sample circumstances.

2.7 GLOSSARY

Biological oxygen demand (BOD): The amount of oxygen consumed by biota in water. It is a measure of the portion of organic carbon that is relatively easily oxidised by micro-organisms. It is used as an indicator of dissolved organic carbon, often in conjunction with chemical oxygen demand (COD). Total organic carbon (TOC) = BOD + COD. Alternative:The chemical oxidation (adding of oxygen) to certain chemical components by bacteria in order for them to obtain energy (ammonium nitrogen can, for example, be oxidized to nitric acid by nitrifying bacteria). Chemical Oxygen Demand (COD): COD is used as a measure of the oxygen equivalent of the organic matter content of the sample. Only the organic matter that is susceptible to oxidation by strong chemical oxidant. COD is typically used when there are industrial wastewater sources, comparing biological to chemical oxidation in the selection of treatment process and performances, or depending on the waste stream it can provide insight into the concentration of reduced inorganic metal inorganic, such as ferrous iron, sulfide, and manganese. Chromium (Cr): The MCL is 0.05 mg/L. The impact of chromium is not clearly defined, but it is known to adversely impact aquatic organisms.

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UNIT 3 ESTIMATION OF QUANTITY OF SEWAGE-PROBLEMS

Structure 3.0 Objective 3.1 Introduction 3.2 History 3.3 Estimation of quantity of sewage – problems 3.4 Let us sum up 3.5 Some Useful Books 3.6 Answer to Check your Progress 3.7 Glossary 3.0 OBJECTIVE

In this lesson we are going to discuss in detailed manner about : A combined sewer is a type of sewer system that collects sanitary sewage and

stormwater runoff in a single pipe system. Combined sewers can cause serious water pollution problems due to combined sewer overflows, which are caused by large variations in flow between dry and wet weather. This type of sewer design is no longer used in building new communities, but many older cities continue to operate combined sewers.

3.1 INTRODUCTION

One pollutant in the ocean is sewage. Human sewage largely consists of excrement from toilet-flushing; wastewater from bathing, laundry, and dishwashing; and animal and vegetable matter from food preparation that is disposed through an in-sink garbage disposal. Because coasts are densely populated, the amount of sewage reaching seas and oceans is of particular concern because some substances it contains can harm ecosystems and pose a significant public health threat. In addition to the nutrients which can cause overenrichment of receiving waterbodies, sewage carries an array of potentially disease-causing microbes known as pathogens. 3.2 HISTORY

The earliest covered sewers uncovered by archaeologists are in the regularly planned cities of the Indus Valley Civilization. In ancient Rome, the Cloaca Maxima, considered a marvel of engineering, disgorged into the Tiber. In ancient China, sewers existed in various cities such as Linzi. In medieval European cities, small natural waterways used for carrying off wastewater were eventually covered over and functioned as sewers. London's River Fleet is such a system. Open drains along the center of some streets were known as 'kennels' (= canals, channels). The nineteenth century brick-vaulted sewer system of Paris (The Paris sewers) offers tours for tourists. Most of these early sewers received significant amounts of draft animal dung in street runoff; but handling of human waste varied with location. Public latrines were built over the Cloaca Maxima,but chamber pot contents were prohibited from Paris sewers as recently as 1880. People wealthy enough to enjoy 19th century flush toilets often had the political power to allow them to

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drain into public sewers; and the practice became the norm as indoor plumbing became more common. Many cities that installed sewage collection systems in the early 20th century, or earlier, used single-pipe systems that collect both sewage and urban runoff from streets and roofs. This type of collection system is referred to as a combined sewer system or a CSS. The cities' rationale when these systems were built was that it would be cheaper to build just a single system. Most cities at that time did not have sewage treatment plants, so there was no perceived public health advantage in constructing a separate storm sewer system. Combined sewer systems are found throughout the United States, but are most heavily concentrated in the Northeast and Great Lakes regions. State and local authorities have generally not allowed the construction of new CSSs since the first half of the 20th century. When constructed, combined sewer systems were typically sized to carry three to five times the average dry weather flows. As cities added sewage treatment plants, relief structures were installed in the collection system so that the flow could be discharged into a river or stream during large storm events when the capacity of the pipe exceeded the capacity of the wastewater treatment plant. By using these devices, called regulators, to discharge the excessive flow into a nearby water body, sewer backups in homes and streets are prevented. In the UK, sewerage provision regulators (agencies) categorise all sewerage derived flooding as being one of two types: those due to hydraulic overloading and those due to all other causes. Although the media tends to focus on the former, 84% of sewerage derived flooding incidents (~26,000 per year) in England and Wales fall into the latter of these categories and ~90% of these are due to blockages. Considering the role of blockages is therefore a key research challenge; across the world they are probably the number one cause of losses in sewer serviceability (and hence flooding) in either dry or wet weather flow conditions 3.3 ESTIMATION OF QUANTITY OF SEWAGE-PROBLEMS

Costs Associated with Constructed Facilities The costs of a constructed facility to the owner include both the initial capital cost and the subsequent operation and maintenance costs. Each of these major cost categories consists of a number of cost components. The capital cost for a construction project includes the expenses related to the inital establishment of the facility:

Land acquisition, including assembly, holding and improvement Planning and feasibility studies Architectural and engineering design Construction, including materials, equipment and labor Field supervision of construction Construction financing Insurance and taxes during construction Owner's general office overhead Equipment and furnishings not included in construction Inspection and testing

The operation and maintenance cost in subsequent years over the project life cycle includes the following expenses:

Land rent, if applicable

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Operating staff Labor and material for maintenance and repairs Periodic renovations Insurance and taxes Financing costs Utilities Owner's other expenses

The magnitude of each of these cost components depends on the nature, size and location of the project as well as the management organization, among many considerations. The owner is interested in achieving the lowest possible overall project cost that is consistent with its investment objectives. It is important for design professionals and construction managers to realize that while the construction cost may be the single largest component of the capital cost, other cost components are not insignificant. For example, land acquisition costs are a major expenditure for building construction in high-density urban areas, and construction financing costs can reach the same order of magnitude as the construction cost in large projects such as the construction of nuclear power plants. From the owner's perspective, it is equally important to estimate the corresponding operation and maintenance cost of each alternative for a proposed facility in order to analyze the life cycle costs. The large expenditures needed for facility maintenance, especially for publicly owned infrastructure, are reminders of the neglect in the past to consider fully the implications of operation and maintenance cost in the design stage. In most construction budgets, there is an allowance for contingencies or unexpected costs occuring during construction. This contingency amount may be included within each cost item or be included in a single category of construction contingency. The amount of contingency is based on historical experience and the expected difficulty of a particular construction project. For example, one construction firm makes estimates of the expected cost in five different areas:

Design development changes, Schedule adjustments, General administration changes (such as wage rates), Differing site conditions for those expected, and Third party requirements imposed during construction, such as new permits.

Contingent amounts not spent for construction can be released near the end of construction to the owner or to add additional project elements. In this chapter, we shall focus on the estimation of construction cost, with only occasional reference to other cost components. In Chapter 6, we shall deal with the economic evaluation of a constructed facility on the basis of both the capital cost and the operation and maintenance cost in the life cycle of the facility. It is at this stage that tradeoffs between operating and capital costs can be analyzed. Example: Energy project resource demands The resources demands for three types of major energy projects investigated during the energy crisis in the 1970's are shown in Table 5-1. These projects are: (1) an oil shale project with a capacity of 50,000 barrels of oil product per day; (2) a coal gasification project that makes gas with a heating value of 320 billions of British thermal units per day, or equivalent to about 50,000 barrels of oil product per day; and (3) a tar sand project with a capacity of 150,000 barrels of oil product per day.

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For each project, the cost in billions of dollars, the engineering manpower requirement for basic design in thousands of hours, the engineering manpower requirement for detailed engineering in millions of hours, the skilled labor requirement for construction in millions of hours and the material requirement in billions of dollars are shown in Table 5-1. To build several projects of such an order of magnitude concurrently could drive up the costs and strain the availability of all resources required to complete the projects. Consequently, cost estimation often represents an exercise in professional judgment instead of merely compiling a bill of quantities and collecting cost data to reach a total estimate mechanically.

TABLE 5-1 Resource Requirements of Some Major Energy Projects

Oil shale (50,000 barrels/day)

Coal gasification (320 billions BTU/day)

Tar Sands (150,000 barrels/day)

Cost ($ billion) 2.5 4 8 to 10

Basic design (Thousands of hours)

80 200 100

Detailed engineering (Millions of hours)

3 to 4 4 to 5 6 to 8

Construction (Millions of hours)

20 30 40

Materials ($ billion) 1 2 2.5

Source: Exxon Research and Engineering Company, Florham Park, NJ Approaches to Cost Estimation Cost estimating is one of the most important steps in project management. A cost estimate establishes the base line of the project cost at different stages of development of the project. A cost estimate at a given stage of project development represents a prediction provided by the cost engineer or estimator on the basis of available data. According to the American Association of Cost Engineers, cost engineering is defined as that area of engineering practice where engineering judgment and experience are utilized in the application of scientific principles and techniques to the problem of cost estimation, cost control and profitability. Virtually all cost estimation is performed according to one or some combination of the following basic approaches: Production function. In microeconomics, the relationship between the output of a process and the necessary resources is referred to as the production function. In construction, the production function may be expressed by the relationship between the volume of construction and a factor of production such as labor or capital. A production function relates the amount or volume of output to the various inputs of labor, material and equipment. For example, the amount of output Q may be derived as a function of various input factors x1, x2, ..., xn by means of mathematical

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and/or statistical methods. Thus, for a specified level of output, we may attempt to find a set of values for the input factors so as to minimize the production cost. The relationship between the size of a building project (expressed in square feet) to the input labor (expressed in labor hours per square foot) is an example of a production function for construction. Several such production functions are shown in Figure 3-3 of Chapter 3. Empirical cost inference. Empirical estimation of cost functions requires statistical techniques which relate the cost of constructing or operating a facility to a few important characteristics or attributes of the system. The role of statistical inference is to estimate the best parameter values or constants in an assumed cost function. Usually, this is accomplished by means of regression analysis techniques. Unit costs for bill of quantities. A unit cost is assigned to each of the facility components or tasks as represented by the bill of quantities. The total cost is the summation of the products of the quantities multiplied by the corresponding unit costs. The unit cost method is straightforward in principle but quite laborious in application. The initial step is to break down or disaggregate a process into a number of tasks. Collectively, these tasks must be completed for the construction of a facility. Once these tasks are defined and quantities representing these tasks are assessed, a unit cost is assigned to each and then the total cost is determined by summing the costs incurred in each task. The level of detail in decomposing into tasks will vary considerably from one estimate to another. Allocation of joint costs. Allocations of cost from existing accounts may be used to develop a cost function of an operation. The basic idea in this method is that each expenditure item can be assigned to particular characteristics of the operation. Ideally, the allocation of joint costs should be causally related to the category of basic costs in an allocation process. In many instances, however, a causal relationship between the allocation factor and the cost item cannot be identified or may not exist. For example, in construction projects, the accounts for basic costs may be classified according to (1) labor, (2) material, (3) construction equipment, (4) construction supervision, and (5) general office overhead. These basic costs may then be allocated proportionally to various tasks which are subdivisions of a project. Types of Construction Cost Estimates Construction cost constitutes only a fraction, though a substantial fraction, of the total project cost. However, it is the part of the cost under the control of the construction project manager. The required levels of accuracy of construction cost estimates vary at different stages of project development, ranging from ball park figures in the early stage to fairly reliable figures for budget control prior to construction. Since design decisions made at the beginning stage of a project life cycle are more tentative than those made at a later stage, the cost estimates made at the earlier stage are expected to be less accurate. Generally, the accuracy of a cost estimate will reflect the information available at the time of estimation. Construction cost estimates may be viewed from different perspectives because of different institutional requirements. In spite of the many types of cost estimates used at different stages of a project, cost estimates can best be classified into three major categories according to their functions. A construction cost estimate serves one of the three basic functions: design, bid and control. For establishing the financing of a project, either a design estimate or a bid estimate is used.

1. Design Estimates. For the owner or its designated design professionals, the types of cost estimates encountered run parallel with the planning and design as follows:

Screening estimates (or order of magnitude estimates)

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Preliminary estimates (or conceptual estimates) Detailed estimates (or definitive estimates) Engineer's estimates based on plans and specifications

For each of these different estimates, the amount of design information available typically increases.

2. Bid Estimates. For the contractor, a bid estimate submitted to the owner either for competitive bidding or negotiation consists of direct construction cost including field supervision, plus a markup to cover general overhead and profits. The direct cost of construction for bid estimates is usually derived from a combination of the following approaches.

Subcontractor quotations Quantity takeoffs Construction procedures.

3. Control Estimates. For monitoring the project during construction, a control estimate is derived from available information to establish:

Budget estimate for financing Budgeted cost after contracting but prior to construction Estimated cost to completion during the progress of construction.

Design Estimates In the planning and design stages of a project, various design estimates reflect the progress of the design. At the very early stage, the screening estimate or order of magnitude estimate is usually made before the facility is designed, and must therefore rely on the cost data of similar facilities built in the past. A preliminary estimate or conceptual estimate is based on the conceptual design of the facility at the state when the basic technologies for the design are known. The detailed estimate or definitive estimate is made when the scope of work is clearly defined and the detailed design is in progress so that the essential features of the facility are identifiable. The engineer's estimate is based on the completed plans and specifications when they are ready for the owner to solicit bids from construction contractors. In preparing these estimates, the design professional will include expected amounts for contractors' overhead and profits. The costs associated with a facility may be decomposed into a hierarchy of levels that are appropriate for the purpose of cost estimation. The level of detail in decomposing the facility into tasks depends on the type of cost estimate to be prepared. For conceptual estimates, for example, the level of detail in defining tasks is quite coarse; for detailed estimates, the level of detail can be quite fine. As an example, consider the cost estimates for a proposed bridge across a river. A screening estimate is made for each of the potential alternatives, such as a tied arch bridge or a cantilever truss bridge. As the bridge type is selected, e.g. the technology is chosen to be a tied arch bridge instead of some new bridge form, a preliminary estimate is made on the basis of the layout of the selected bridge form on the basis of the preliminary or conceptual design. When the detailed design has progressed to a point when the essential details are known, a detailed estimate is made on the basis of the well defined scope of the project. When the detailed plans and specifications are completed, an engineer's estimate can be made on the basis of items and quantities of work. Bid Estimates The contractor's bid estimates often reflect the desire of the contractor to secure the job as well as the estimating tools at its disposal. Some contractors have well established cost estimating procedures while others do not. Since only the lowest bidder will be the winner of the contract in

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most bidding contests, any effort devoted to cost estimating is a loss to the contractor who is not a successful bidder. Consequently, the contractor may put in the least amount of possible effort for making a cost estimate if it believes that its chance of success is not high. If a general contractor intends to use subcontractors in the construction of a facility, it may solicit price quotations for various tasks to be subcontracted to specialty subcontractors. Thus, the general subcontractor will shift the burden of cost estimating to subcontractors. If all or part of the construction is to be undertaken by the general contractor, a bid estimate may be prepared on the basis of the quantity takeoffs from the plans provided by the owner or on the basis of the construction procedures devised by the contractor for implementing the project. For example, the cost of a footing of a certain type and size may be found in commercial publications on cost data which can be used to facilitate cost estimates from quantity takeoffs. However, the contractor may want to assess the actual cost of construction by considering the actual construction procedures to be used and the associated costs if the project is deemed to be different from typical designs. Hence, items such as labor, material and equipment needed to perform various tasks may be used as parameters for the cost estimates. Control Estimates Both the owner and the contractor must adopt some base line for cost control during the construction. For the owner, a budget estimate must be adopted early enough for planning long term financing of the facility. Consequently, the detailed estimate is often used as the budget estimate since it is sufficient definitive to reflect the project scope and is available long before the engineer's estimate. As the work progresses, the budgeted cost must be revised periodically to reflect the estimated cost to completion. A revised estimated cost is necessary either because of change orders initiated by the owner or due to unexpected cost overruns or savings. For the contractor, the bid estimate is usually regarded as the budget estimate, which will be used for control purposes as well as for planning construction financing. The budgeted cost should also be updated periodically to reflect the estimated cost to completion as well as to insure adequate cash flows for the completion of the project. Example: Screening estimate of a grouting seal beneath a landfill One of the methods of isolating a landfill from groundwater is to create a bowl-shaped bottom seal beneath the site as shown in Figure 5-0. The seal is constructed by pumping or pressure-injecting grout under the existing landfill. Holes are bored at regular intervals throughout the landfill for this purpose and the grout tubes are extended from the surface to the bottom of the landfill. A layer of soil at a minimum of 5 ft. thick is left between the grouted material and the landfill contents to allow for irregularities in the bottom of the landfill. The grout liner can be between 4 and 6 feet thick. A typical material would be Portland cement grout pumped under pressure through tubes to fill voids in the soil. This grout would then harden into a permanent, impermeable liner.

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Figure: Grout Bottom Seal Liner at a Landfill The work items in this project include (1) drilling exploratory bore holes at 50 ft intervals for grout tubes, and (2) pumping grout into the voids of a soil layer between 4 and 6 ft thick. The quantities for these two items are estimated on the basis of the landfill area: 8 acres = (8)(43,560 ft2/acre) = 348,480 ft2 (As an approximation, use 360,000 ft2 to account for the bowl shape) The number of bore holes in a 50 ft by 50 ft grid pattern covering 360,000 ft2 is given by:

The average depth of the bore holes is estimated to be 20 ft. Hence, the total amount of drilling is (144)(20) = 2,880 ft. The volume of the soil layer for grouting is estimated to be: for a 4 ft layer, volume = (4 ft)(360,000 ft2) = 1,440,000 ft3 for a 6 ft layer, volume = (6 ft)(360,000 ft2) = 2,160,000 ft3 It is estimated from soil tests that the voids in the soil layer are between 20% and 30% of the total volume. Thus, for a 4 ft soil layer: grouting in 20% voids = (20%)(1,440,000) = 288,000 ft3 grouting in 30 % voids = (30%)(1,440,000) = 432,000 ft3 and for a 6 ft soil layer: grouting in 20% voids = (20%)(2,160,000) = 432,000 ft3

grouting in 30% voids = (30%)(2,160,000) = 648,000 ft3 The unit cost for drilling exploratory bore holes is estimated to be between $3 and $10 per foot (in 1978 dollars) including all expenses. Thus, the total cost of boring will be between (2,880)(3) = $ 8,640 and (2,880)(10) = $28,800. The unit cost of Portland cement grout pumped into place is between $4 and $10 per cubic foot including overhead and profit. In addition to the variation in the unit cost, the total cost of the bottom seal will depend upon the thickness of the soil layer grouted and the proportion of voids in the soil. That is:

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for a 4 ft layer with 20% voids, grouting cost = $1,152,000 to $2,880,000 for a 4 ft layer with 30% voids, grouting cost = $1,728,000 to $4,320,000 for a 6 ft layer with 20% voids, grouting cost = $1,728,000 to $4,320,000 for a 6 ft layer with 30% voids, grouting cost = $2,592,000 to $6,480,000 The total cost of drilling bore holes is so small in comparison with the cost of grouting that the former can be omitted in the screening estimate. Furthermore, the range of unit cost varies greatly with soil characteristics, and the engineer must exercise judgment in narrowing the range of the total cost. Alternatively, additional soil tests can be used to better estimate the unit cost of pumping grout and the proportion of voids in the soil. Suppose that, in addition to ignoring the cost of bore holes, an average value of a 5 ft soil layer with 25% voids is used together with a unit cost of $ 7 per cubic foot of Portland cement grouting. In this case, the total project cost is estimated to be: (5 ft)(360,000 ft2)(25%)($7/ft3) = $3,150,000 An important point to note is that this screening estimate is based to a large degree on engineering judgment of the soil characteristics, and the range of the actual cost may vary from $ 1,152,000 to $ 6,480,000 even though the probabilities of having actual costs at the extremes are not very high. Example: Example of engineer's estimate and contractors' bids The engineer's estimate for a project involving 14 miles of Interstate 70 roadway in Utah was $20,950,859. Bids were submitted on March 10, 1987, for completing the project within 320 working days. The three low bidders were: 1. Ball, Ball & Brosame, Inc., Danville CA $14,129,798 2. National Projects, Inc., Phoenix, AR $15,381,789 3. Kiewit Western Co., Murray, Utah $18,146,714 It was astounding that the winning bid was 32% below the engineer's estimate. Even the third lowest bidder was 13% below the engineer's estimate for this project. The disparity in pricing can be attributed either to the very conservative estimate of the engineer in the Utah Department of Transportation or to area contractors who are hungrier than usual to win jobs. The unit prices for different items of work submitted for this project by (1) Ball, Ball & Brosame, Inc. and (2) National Projects, Inc. are shown in Table 5-2. The similarity of their unit prices for some items and the disparity in others submitted by the two contractors can be noted.

TABLE 5-2: Unit Prices in Two Contractors' Bids for Roadway Construction

Items Unit Quantity Unit price 1 2

Mobilization ls 1 115,000 569,554 Removal, berm lf 8,020 1.00 1.50 Finish subgrade sy 1,207,500 0.50 0.30 Surface ditches lf 525 2.00 1.00 Excavation structures cy 7,000 3.00 5.00 Base course, untreated, 3/4'' ton 362,200 4.50 5.00

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TABLE 5-2: Unit Prices in Two Contractors' Bids for Roadway Construction Items Unit Quantity Unit price Lean concrete, 4'' thick sy 820,310 3.10 3.00 PCC, pavement, 10'' thick sy 76,010 10.90 12.00 Concrete, ci AA (AE) ls 1 200,000 190,000 Small structure cy 50 500 475 Barrier, precast lf 7,920 15.00 16.00 Flatwork, 4'' thick sy 7,410 10.00 8.00 10'' thick sy 4,241 20.00 27.00 Slope protection sy 2,104 25.00 30.00 Metal, end section, 15'' ea 39 100 125 18'' ea 3 150 200 Post, right-of-way, modification lf 4,700 3.00 2.50 Salvage and relay pipe lf 1,680 5.00 12.00 Loose riprap cy 32 40.00 30.00 Braced posts ea 54 100 110 Delineators, type I lb 1,330 12.00 12.00 type II ea 140 15.00 12.00 Constructive signs fixed sf 52,600 0.10 0.40 Barricades, type III lf 29,500 0.20 0.20 Warning lights day 6,300 0.10 0.50 Pavement marking, epoxy material Black gal 475 90.00 100 Yellow gal 740 90.00 80.00 White gal 985 90.00 70.00 Plowable, one-way white ea 342 50.00 20.00 Topsoil, contractor furnished cy 260 10.00 6.00 Seedling, method A acr 103 150 200 Excelsior blanket sy 500 2.00 2.00 Corrugated, metal pipe, 18'' lf 580 20.00 18.00 Polyethylene pipe, 12'' lf 2,250 15.00 13.00 Catch basin grate and frame ea 35 350 280 Equal opportunity training hr 18,000 0.80 0.80 Granular backfill borrow cy 274 10.00 16.00

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TABLE 5-2: Unit Prices in Two Contractors' Bids for Roadway Construction Items Unit Quantity Unit price Drill caisson, 2'x6'' lf 722 100 80.00 Flagging hr 20,000 8.25 12.50 Prestressed concrete member type IV, 141'x4'' ea 7 12,000 16.00 132'x4'' ea 6 11,000 14.00 Reinforced steel lb 6,300 0.60 0.50 Epoxy coated lb 122,241 0.55 0.50 Structural steel ls 1 5,000 1,600 Sign, covering sf 16 10.00 4.00 type C-2 wood post sf 98 15.00 17.00 24'' ea 3 100 400 30'' ea 2 100 160 48'' ea 11 200 300 Auxiliary sf 61 15.00 12.00 Steel post, 48''x60'' ea 11 500 700 type 3, wood post sf 669 15.00 19.00 24'' ea 23 100 125 30'' ea 1 100 150 36'' ea 12 150 180 42''x60'' ea 8 150 220 48'' ea 7 200 270 Auxiliary sf 135 15.00 13.00 Steel post sf 1,610 40.00 35.00 12''x36'' ea 28 100 150 Foundation, concrete ea 60 300 650 Barricade, 48''x42'' ea 40 100 100 Wood post, road closed lf 100 30.00 36.00

Effects of Scale on Construction Cost Screening cost estimates are often based on a single variable representing the capacity or some physical measure of the design such as floor area in buildings, length of highways, volume of storage bins and production volumes of processing plants. Costs do not always vary linearly with respect to different facility sizes. Typically, scale economies or diseconomies exist. If the average cost per unit of capacity is declining, then scale economies exist. Conversely, scale

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diseconomies exist if average costs increase with greater size. Empirical data are sought to establish the economies of scale for various types of facility, if they exist, in order to take advantage of lower costs per unit of capacity. Let x be a variable representing the facility capacity, and y be the resulting construction cost. Then, a linear cost relationship can be expressed in the form:

(5.1)

where a and b are positive constants to be determined on the basis of historical data. Note that in Equation (5.1), a fixed cost of y = a at x = 0 is implied as shown in Figure 5-2. In general, this relationship is applicable only in a certain range of the variable x, such as between x = c and x = d. If the values of y corresponding to x = c and x = d are known, then the cost of a facility corresponding to any x within the specified range may be obtained by linear interpolation. For example, the construction cost of a school building can be estimated on the basis of a linear relationship between cost and floor area if the unit cost per square foot of floor area is known for school buildings within certain limits of size.

Figure: Linear Cost Relationship with Economies of Scale A nonlinear cost relationship between the facility capacity x and construction cost y can often be represented in the form:

(5.2)

where a and b are positive constants to be determined on the basis of historical data. For 0 < b < 1, Equation (5.2) represents the case of increasing returns to scale, and for b ;gt 1, the relationship becomes the case of decreasing returns to scale, as shown in Figure 5-3. Taking the logarithm of both sides this equation, a linear relationship can be obtained as follows:

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Figure: Nonlinear Cost Relationship with increasing or Decreasing Economies of Scale

(5.3)

Although no fixed cost is implied in Eq.(5.2), the equation is usually applicable only for a certain range of x. The same limitation applies to Eq.(5.3). A nonlinear cost relationship often used in estimating the cost of a new industrial processing plant from the known cost of an existing facility of a different size is known as the exponential rule. Let yn be the known cost of an existing facility with capacity Qn, and y be the estimated cost of the new facility which has a capacity Q. Then, from the empirical data, it can be assumed that:

(5.4)

where m usually varies from 0.5 to 0.9, depending on a specific type of facility. A value of m = 0.6 is often used for chemical processing plants. The exponential rule can be reduced to a linear relationship if the logarithm of Equation (5.4) is used:

(5.5)

or

(5.6)

The exponential rule can be applied to estimate the total cost of a complete facility or the cost of some particular component of a facility. Example: Determination of m for the exponential rule

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Figure: Log-Log Scale Graph of Exponential Rule Example The empirical cost data from a number of sewage treatment plants are plotted on a log-log scale for ln(Q/Qn) and ln(y/yn) and a linear relationship between these logarithmic ratios is shown in Figure 5-4. For (Q/Qn) = 1 or ln(Q/Qn) = 0, ln(y/yn) = 0; and for Q/Qn = 2 or ln(Q/Qn) = 0.301, ln(y/yn) = 0.1765. Since m is the slope of the line in the figure, it can be determined from the geometric relation as follows:

For ln(y/yn) = 0.1765, y/yn = 1.5, while the corresponding value of Q/Qn is 2. In words, for m = 0.585, the cost of a plant increases only 1.5 times when the capacity is doubled. Example: Cost exponents for water and wastewater treatment plants The magnitude of the cost exponent m in the exponential rule provides a simple measure of the economy of scale associated with building extra capacity for future growth and system reliability for the present in the design of treatment plants. When m is small, there is considerable incentive to provide extra capacity since scale economies exist as illustrated in Figure 5-3. When m is close to 1, the cost is directly proportional to the design capacity. The value of m tends to increase as the number of duplicate units in a system increases. The values of m for several types of treatment plants with different plant components derived from statistical correlation of actual construction costs are shown in Table 5-3. TABLE 5-3 Estimated Values of Cost Exponents for Water Treatment Plants

Treatment plant type

Exponent m

Capacity range (millions of gallons per day)

1. Water treatment 0.67 1-100 2. Waste treatment Primary with digestion (small) 0.55 0.1-10 Primary with digestion (large) 0.75 0.7-100 Trickling filter 0.60 0.1-20 Activated sludge 0.77 0.1-100

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Stabilization ponds 0.57 0.1-100

Source: Data are collected from various sources by P.M. Berthouex. See the references in his article for the primary sources. Example: Some Historical Cost Data for the Exponential Rule The exponential rule as represented by Equation (5.4) can be expressed in a different form as:

where

If m and K are known for a given type of facility, then the cost y for a proposed new facility of specified capacity Q can be readily computed. TABLE 5-4 Cost Factors of Processing Units for Treatment Plants

Processing unit

Unit of capacity

K Value (1968 $)

m value

1. Liquid processing Oil separation mgd 58,000 0.84 Hydroclone degritter mgd 3,820 0.35 Primary sedimentation ft2 399 0.60 Furial clarifier ft2 700 0.57 Sludge aeration basin mil. gal. 170,000 0.50 Tickling filter ft2 21,000 0.71 Aerated lagoon basin mil. gal. 46,000 0.67 Equalization mil. gal. 72,000 0.52 Neutralization mgd 60,000 0.70

2. Sludge handling Digestion ft3 67,500 0.59 Vacuum filter ft2 9,360 0.84

Centrifuge lb dry solids/hr 318 0.81

Source: Data are collected from various sources by P.M. Berthouex. See the references in his article for the primary sources. The estimated values of K and m for various water and sewage treatment plant components are shown in Table 5-4. The K values are based on 1968 dollars. The range of data from which the K and m values are derived in the primary sources should be observed in order to use them in making cost estimates.

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As an example, take K = $399 and m = 0.60 for a primary sedimentation component in Table 5-4. For a proposed new plant with the primary sedimentation process having a capacity of 15,000 sq. ft., the estimated cost (in 1968 dollars) is: y = ($399)(15,000)0.60 = $128,000. Unit Cost Method of Estimation If the design technology for a facility has been specified, the project can be decomposed into elements at various levels of detail for the purpose of cost estimation. The unit cost for each element in the bill of quantities must be assessed in order to compute the total construction cost. This concept is applicable to both design estimates and bid estimates, although different elements may be selected in the decomposition. For design estimates, the unit cost method is commonly used when the project is decomposed into elements at various levels of a hierarchy as follows:

1. Preliminary Estimates. The project is decomposed into major structural systems or production equipment items, e.g. the entire floor of a building or a cooling system for a processing plant.

2. Detailed Estimates. The project is decomposed into components of various major systems, i.e., a single floor panel for a building or a heat exchanger for a cooling system.

3. Engineer's Estimates. The project is decomposed into detailed items of various components as warranted by the available cost data. Examples of detailed items are slabs and beams in a floor panel, or the piping and connections for a heat exchanger.

For bid estimates, the unit cost method can also be applied even though the contractor may choose to decompose the project into different levels in a hierarchy as follows:

1. Subcontractor Quotations. The decomposition of a project into subcontractor items for quotation involves a minimum amount of work for the general contractor. However, the accuracy of the resulting estimate depends on the reliability of the subcontractors since the general contractor selects one among several contractor quotations submitted for each item of subcontracted work.

2. Quantity Takeoffs. The decomposition of a project into items of quantities that are measured (or taken off) from the engineer's plan will result in a procedure similar to that adopted for a detailed estimate or an engineer's estimate by the design professional. The levels of detail may vary according to the desire of the general contractor and the availability of cost data.

3. Construction Procedures. If the construction procedure of a proposed project is used as the basis of a cost estimate, the project may be decomposed into items such as labor, material and equipment needed to perform various tasks in the projects.

Simple Unit Cost Formula Suppose that a project is decomposed into n elements for cost estimation. Let Qi be the quantity of the ith element and ui be the corresponding unit cost. Then, the total cost of the project is given by:

(5.7)

where n is the number of units. Based on characteristics of the construction site, the technology employed, or the management of the construction process, the estimated unit cost, ui for each element may be adjusted.

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Factored Estimate Formula A special application of the unit cost method is the "factored estimate" commonly used in process industries. Usually, an industrial process requires several major equipment components such as furnaces, towers drums and pump in a chemical processing plant, plus ancillary items such as piping, valves and electrical elements. The total cost of a project is dominated by the costs of purchasing and installing the major equipment components and their ancillary items. Let Ci be the purchase cost of a major equipment component i and fi be a factor accounting for the cost of ancillary items needed for the installation of this equipment component i. Then, the total cost of a project is estimated by:

(5.8)

where n is the number of major equipment components included in the project. The factored method is essentially based on the principle of computing the cost of ancillary items such as piping and valves as a fraction or a multiple of the costs of the major equipment items. The value of Ci may be obtained by applying the exponential rule so the use of Equation (5.8) may involve a combination of cost estimation methods. Formula Based on Labor, Material and Equipment Consider the simple case for which costs of labor, material and equipment are assigned to all tasks. Suppose that a project is decomposed into n tasks. Let Qi be the quantity of work for task i, Mi be the unit material cost of task i, Ei be the unit equipment rate for task i, Li be the units of labor required per unit of Qi, and Wi be the wage rate associated with Li. In this case, the total cost y is:

(5.9)

Note that WiLi yields the labor cost per unit of Qi, or the labor unit cost of task i. Consequently, the units for all terms in Equation (5.9) are consistent. Example 5-7: Decomposition of a building foundation into design and construction elements. The concept of decomposition is illustrated by the example of estimating the costs of a building foundation excluding excavation as shown in Table 5-5 in which the decomposed design elements are shown on horizontal lines and the decomposed contract elements are shown in vertical columns. For a design estimate, the decomposition of the project into footings, foundation walls and elevator pit is preferred since the designer can easily keep track of these design elements; however, for a bid estimate, the decomposition of the project into formwork, reinforcing bars and concrete may be preferred since the contractor can get quotations of such contract items more conveniently from specialty subcontractors.

TABLE 5-5 Illustrative Decomposition of Building Foundation Costs

Design Contract elements

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elements Formwork Rebars Concrete Total cost

Footings $5,000 $10,000 $13,000 $28,000 Foundation walls 15,000 18,000 28,000 61,000 Elevator pit 9,000 15,000 16,000 40,000 Total cost $29,000 $43,000 $57,000 $129,000

Example: Cost estimate using labor, material and equipment rates. For the given quantities of work Qi for the concrete foundation of a building and the labor, material and equipment rates in Table 5-6, the cost estimate is computed on the basis of Equation (5.9). The result is tabulated in the last column of the same table.

TABLE 5-6 Illustrative Cost Estimate Using Labor, Material and Equipment Rates

Description Quantity Qi

Material unit cost Mi

Equipment unit cost Ei

Wage rate Wi

Labor input Li

Labor unit cost WiLi

Direct cost Yi

Formwork 12,000 ft2 $0.4/ft2 $0.8/ft2 $15/hr 0.2 hr/ft2 $3.0/ft2 $50,400 Rebars 4,000 lb 0.2/lb 0.3/lb 15/hr 0.04 hr/lb 0.6/lb 4,440 Concrete 500 yd3 5.0/yd3 50/yd3 15/hr 0.8 hr/yd3 12.0/yd3 33,500 Total $88,300

Methods for Allocation of Joint Costs The principle of allocating joint costs to various elements in a project is often used in cost estimating. Because of the difficulty in establishing casual relationship between each element and its associated cost, the joint costs are often prorated in proportion to the basic costs for various elements. One common application is found in the allocation of field supervision cost among the basic costs of various elements based on labor, material and equipment costs, and the allocation of the general overhead cost to various elements according to the basic and field supervision cost. Suppose that a project is decomposed into n tasks. Let y be the total basic cost for the project and yi be the total basic cost for task i. If F is the total field supervision cost and Fi is the proration of that cost to task i, then a typical proportional allocation is:

(5.10)

Similarly, let z be the total direct field cost which includes the total basic cost and the field supervision cost of the project, and zi be the direct field cost for task i. If G is the general office overhead for proration to all tasks, and Gi is the share for task i, then

(5.11)

Finally, let w be the grand total cost of the project which includes the direct field cost and the general office overhead cost charged to the project and wi be that attributable task i. Then,

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(5.12)

and

(5.13)

Example: Prorated costs for field supervision and office overhead If the field supervision cost is $13,245 for the project in Table 5-6 (Example 5-8) with a total direct cost of $88,300, find the prorated field supervision costs for various elements of the project. Furthermore, if the general office overhead charged to the project is 4% of the direct field cost which is the sum of basic costs and field supervision cost, find the prorated general office overhead costs for various elements of the project. For the project, y = $88,300 and F = $13,245. Hence: z = 13,245 + 88,300 = $101,545 G = (0.04)(101,545) = $4,062 w = 101,545 + 4,062 = $105,607 The results of the proration of costs to various elements are shown in Table 5-7.

TABLE 5-7 Proration of Field Supervision and Office Overhead Costs

Description Basic cost yi

Allocated field supervision cost Fi

Total field cost zi

Allocated overhead cost Gi

Total cost Li

Formwork $50,400 $7,560 $57,960 $2,319 $60,279 Rebars 4,400 660 5,060 202 5,262 Concrete 33,500 5,025 38,525 1,541 40,066 Total $88,300 $13,245 $101,545 $4,062 $105,607

Example: A standard cost report for allocating overhead The reliance on labor expenses as a means of allocating overhead burdens in typical management accounting systems can be illustrated by the example of a particular product's standard cost sheet. Table 5-8 is an actual product's standard cost sheet of a company following the procedure of using overhead burden rates assessed per direct labor hour. The material and labor costs for manufacturing a type of valve were estimated from engineering studies and from current material and labor prices. These amounts are summarized in Columns 2 and 3 of Table 5-8. The overhead costs shown in Column 4 of Table 5-8 were obtained by allocating the expenses of several departments to the various products manufactured in these departments in proportion to the labor cost. As shown in the last line of the table, the material cost represents 29% of the total cost, while labor costs are 11% of the total cost. The allocated overhead cost constitutes 60% of the total cost. Even though material costs exceed labor costs, only the labor costs are used in allocating overhead. Although this type of allocation method is common in industry, the arbitrary allocation of joint costs introduces unintended cross subsidies among products and may produce

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adverse consequences on sales and profits. For example, a particular type of part may incur few overhead expenses in practice, but this phenomenon would not be reflected in the standard cost report.

TABLE 5-8 Standard Cost Report for a Type of Valve

(1) Material cost

(2) Labor cost

(3) Overhead cost

(4) Total cost

Purchased part $1.1980 $1.1980 Operation Drill, face, tap (2) $0.0438 $0.2404 $0.2842 Degrease 0.0031 0.0337 0.0368 Remove burs 0.0577 0.3241 0.3818 Total cost, this item 1.1980 0.1046 0.5982 1.9008 Other subassemblies 0.3523 0.2994 1.8519 2.4766 Total cost, subassemblies 1.5233 0.4040 2.4501 4.3773

Assemble and test 0.1469 0.4987 0.6456 Pack without paper 0.0234 0.1349 0.1583 Total cost, this item $1.5233 $0.5743 $3.0837 $5.1813 Cost component, % 29% 11% 60% 100%

Source: H. T. Johnson and R. S. Kaplan, Relevance lost: The Rise and Fall of Management Accounting, Harvard Business School Press, Boston. Reprinted with permission.

Historical Cost Data Preparing cost estimates normally requires the use of historical data on construction costs. Historical cost data will be useful for cost estimation only if they are collected and organized in a way that is compatible with future applications. Organizations which are engaged in cost estimation continually should keep a file for their own use. The information must be updated with respect to changes that will inevitably occur. The format of cost data, such as unit costs for various items, should be organized according to the current standard of usage in the organization. Construction cost data are published in various forms by a number of organizations. These publications are useful as references for comparison. Basically, the following types of information are available:

Catalogs of vendors' data on important features and specifications relating to their products for which cost quotations are either published or can be obtained. A major source of vendors' information for building products is Sweets' Catalog published by McGraw-Hill Information Systems Company.

Periodicals containing construction cost data and indices. One source of such information is ENR, the McGraw-Hill Construction Weekly, which contains extensive cost data including quarterly cost reports. Cost Engineering, a journal of the American Society of Cost Engineers, also publishes useful cost data periodically.

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Commercial cost reference manuals for estimating guides. An example is the Building Construction Cost Data published annually by R.S. Means Company, Inc., which contains unit prices on building construction items. Dodge Manual for Building Construction, published by McGraw-Hill, provides similar information.

Digests of actual project costs. The Dodge Digest of Building Costs and Specifications provides descriptions of design features and costs of actual projects by building type. Once a week, ENR publishes the bid prices of a project chosen from all types of construction projects.

Historical cost data must be used cautiously. Changes in relative prices may have substantial impacts on construction costs which have increased in relative price. Unfortunately, systematic changes over a long period of time for such factors are difficult to predict. Errors in analysis also serve to introduce uncertainty into cost estimates. It is difficult, of course, to foresee all the problems which may occur in construction and operation of facilities. There is some evidence that estimates of construction and operating costs have tended to persistently understate the actual costs. This is due to the effects of greater than anticipated increases in costs, changes in design during the construction process, or overoptimism. Since the future prices of constructed facilities are influenced by many uncertain factors, it is important to recognize that this risk must be borne to some degree by all parties involved, i.e., the owner, the design professionals, the construction contractors, and the financing institution. It is to the best interest of all parties that the risk sharing scheme implicit in the design/construct process adopted by the owner is fully understood by all. When inflation adjustment provisions have very different risk implications to various parties, the price level changes will also be treated differently for various situations. Cost Indices Since historical cost data are often used in making cost estimates, it is important to note the price level changes over time. Trends in price changes can also serve as a basis for forecasting future costs. The input price indices of labor and/or material reflect the price level changes of such input components of construction; the output price indices, where available, reflect the price level changes of the completed facilities, thus to some degree also measuring the productivity of construction. A price index is a weighted aggregate measure of constant quantities of goods and services selected for the package. The price index at a subsequent year represents a proportionate change in the same weighted aggregate measure because of changes in prices. Let lt be the price index in year t, and lt+1 be the price index in the following year t+1. Then, the percent change in price index for year t+1 is:

(5.14)

or

(5.15)

If the price index at the base year t=0 is set at a value of 100, then the price indices l1, l2...ln for the subsequent years t=1,2...n can be computed successively from changes in the total price charged for the package of goods measured in the index.

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The best-known indicators of general price changes are the Gross Domestic Product (GDP) deflators compiled periodically by the U.S. Department of Commerce, and the consumer price index (CPI) compiled periodically by the U.S. Department of Labor. They are widely used as broad gauges of the changes in production costs and in consumer prices for essential goods and services. Special price indices related to construction are also collected by industry sources since some input factors for construction and the outputs from construction may disproportionately outpace or fall behind the general price indices. Examples of special price indices for construction input factors are the wholesale Building Material Price and Building Trades Union Wages, both compiled by the U.S. Department of Labor. In addition, the construction cost index and the building cost index are reported periodically in the Engineering News-Record (ENR). Both ENR cost indices measure the effects of wage rate and material price trends, but they are not adjusted for productivity, efficiency, competitive conditions, or technology changes. Consequently, all these indices measure only the price changes of respective construction input factors as represented by constant quantities of material and/or labor. On the other hand, the price indices of various types of completed facilities reflect the price changes of construction output including all pertinent factors in the construction process. The building construction output indices compiled by Turner Construction Company and Handy-Whitman Utilities are compiled in the U.S. Statistical Abstracts published each year. Figure 5-7 and Table 5-9 show a variety of United States indices, including the Gross Domestic Product (GDP) price deflator, the ENR building index, and the Turner Construction Company Building Cost Index from 1996 to 2007, using 2000 as the base year with an index of 100. TABLE 5-9 Summary of Input and Output Price Indices, 1996-2007 Year 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 Turner Construction - Buildings 84.9 88.2 92.3 95.8 100.0 103.0 104.0 104.4 110.1 120.5 133.3 143.5 ENR - Buildings 90.5 95.0 95.8 97.6 100.0 101.0 102.4 104.4 112.6 118.8 123.5 126.7 GDP Deflator 94.0 95.6 96.8 98.0 100.0 102.3 104.2 105.9 107.2 108.6 110.2 112.0

Note: Index = 100 in base year of 2000. Figure 5-7 Trends for US price indices.

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Figure 5-8 Price and cost indices for construction. Since construction costs vary in different regions of the United States and in all parts of the world, locational indices showing the construction cost at a specific location relative to the national trend are useful for cost estimation. ENR publishes periodically the indices of local construction costs at the major cities in different regions of the United States as percentages of local to national costs. When the inflation rate is relatively small, i.e., less than 10%, it is convenient to select a single price index to measure the inflationary conditions in construction and thus to deal only with a single set of price change rates in forecasting. Let jt be the price change rate in year t+1 over the price in year t. If the base year is denoted as year 0 (t=0), then the price change rates at years 1,2,...t are j1,j2,...jt, respectively. Let At be the cost in year t expressed in base-year dollars and At' be the cost in year t expressed in then-current dollars. Then:

(5.16)

Conversely

(5.17)

If the prices of certain key items affecting the estimates of future benefits and costs are expected to escalate faster than the general price levels, it may become necessary to consider the differential price changes over and above the general inflation rate. For example, during the period between 1973 through 1979, it was customary to assume that fuel costs would escalate faster than the general price levels. With hindsight in 1983, the assumption for estimating costs over many years would have been different. Because of the uncertainty in the future, the use of differential inflation rates for special items should be judicious. Future forecasts of costs will be uncertain: the actual expenses may be much lower or much higher than those forecasted. This uncertainty arises from technological changes, changes in relative prices, inaccurate forecasts of underlying socioeconomic conditions, analytical errors,

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and other factors. For the purpose of forecasting, it is often sufficient to project the trend of future prices by using a constant rate j for price changes in each year over a period of t years, then

(5.18)

and

(5.19)

Estimation of the future rate increase j is not at all straightforward. A simple expedient is to assume that future inflation will continue at the rate of the previous period:

(5.20)

A longer term perspective might use the average increase over a horizon of n past periods:

(5.21)

More sophisticated forecasting models to predict future cost increases include corrections for items such as economic cycles and technology changes. Example: Changes in highway and building costs Figure 5-9 shows the change of standard highway costs from 1992 to 2002, and Table 5-10 shows the change of residential building costs from 1970 to 1990. In each case, the rate of cost increase was substantially above the rate of inflation in the decade of the 1970s.. Indeed, the real cost increase between 1970 and 1980 was in excess of three percent per year in both cases. However, these data also show some cause for optimism. For the case of the standard highway, real cost decreases took place in the period from l970 to l990. Unfortunately, comparable indices of outputs are not being compiled on a nationwide basis for other types of construction.

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Figure 5-9 Producer Prices of Highway and Street Construction (Producer Price Index: Highways and Streets-monthly data). TABLE 5-10 Comparison of Residential Building Costs, 1970-1990

year

Standard residence cost (1972=100)

Price deflator (1972=100)

Standard residence real cost (1972=100)

Percentage change per year

1970 77 92 74 1980 203 179 99 +3.4% 1990 287 247 116 +1.7%

Source: Statistical Abstract of the United States. GNP deflator is used for the price deflator index. Applications of Cost Indices to Estimating In the screening estimate of a new facility, a single parameter is often used to describe a cost function. For example, the cost of a power plant is a function of electricity generating capacity expressed in megawatts, or the cost of a sewage treatment plant as a function of waste flow expressed in million gallons per day. The general conditions for the application of the single parameter cost function for screening estimates are:

1. Exclude special local conditions in historical data 2. Determine new facility cost on basis of specified size or capacity (using the methods

described in Sections 5.3 to 5.6) 3. Adjust for inflation index 4. Adjust for local index of construction costs 5. Adjust for different regulatory constraints 6. Adjust for local factors for the new facility

Some of these adjustments may be done using compiled indices, whereas others may require field investigation and considerable professional judgment to reflect differences between a given project and standard projects performed in the past. Example 5-13: Screening estimate for a refinery The total construction cost of a refinery with a production capacity of 200,000 bbl/day in Gary, Indiana, completed in 2001 was $100 million. It is proposed that a similar refinery with a production capacity of 300,000 bbl/day be built in Los Angeles, California, for completion in 2003. For the additional information given below, make an order of magnitude estimate of the cost of the proposed plant.

1. In the total construction cost for the Gary, Indiana, plant, there was an item of $5 million for site preparation which is not typical for other plants.

2. The variation of sizes of the refineries can be approximated by the exponential rule, Equation (5.4), with m = 0.6.

3. The inflation rate is expected to be 8% per year from 1999 to 2003. 4. The location index was 0.92 for Gary, Indiana and 1.14 for Los Angeles in 1999. These

indices are deemed to be appropriate for adjusting the costs between these two cities. 5. New air pollution equipment for the LA plant costs $7 million in 2003 dollars (not

required in the Gary plant).

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6. The contingency cost due to inclement weather delay will be reduced by the amount of 1% of total construction cost because of the favorable climate in LA (compared to Gary).

On the basis of the above conditions, the estimate for the new project may be obtained as follows:

1. Typical cost excluding special item at Gary, IN is $100 million - $5 million = $ 95 million

2. Adjustment for capacity based on the exponential law yields ($95)(300,000/200,000)0.6 = (95)(1.5)0.6 = $121.2 million

3. Adjustment for inflation leads to the cost in 2003 dollars as ($121.2)(1.08)4 = $164.6 million

4. Adjustment for location index gives ($164.6)(1.14/0.92) = $204.6 million

5. Adjustment for new pollution equipment at the LA plant gives $204.6 + $7 = $211.6 million

6. Reduction in contingency cost yields ($211.6)(1-0.01) = $209.5 million

Since there is no adjustment for the cost of construction financing, the order of magnitude estimate for the new project is $209.5 million. Example: Conceptual estimate for a chemical processing plant In making a preliminary estimate of a chemical processing plant, several major types of equipment are the most significant parameters in affecting the installation cost. The cost of piping and other ancillary items for each type of equipment can often be expressed as a percentage of that type of equipment for a given capacity. The standard costs for the major equipment types for two plants with different daily production capacities are as shown in Table 5-11. It has been established that the installation cost of all equipment for a plant with daily production capacity between 100,000 bbl and 400,000 bbl can best be estimated by using linear interpolation of the standard data.

TABLE 5-11 Cost Data for Equipment and Ancillary Items

Equipment type

Equipment Cost ($1000) Cost of ancillary items as % of equipment cost ($1000)

100,000 bbl 400,000 bbl 100,000 bbl 400,000 bbl Furnace 3,000 10,000 40% 30% Tower 2,000 6,000 45% 35% Drum 1,500 5,000 50% 40% Pump, etc. 1,000 4,000 60% 50%

A new chemical processing plant with a daily production capacity of 200,000 bbl is to be constructed in Memphis, TN in four years. Determine the total preliminary cost estimate of the plant including the building and the equipment on the following basis:

1. The installation cost for equipment was based on linear interpolation from Table 5-11, and adjusted for inflation for the intervening four years. We expect inflation in the four years to be similar to the period 1990-1994 and we will use the GNP Deflator index.

2. The location index for equipment installation is 0.95 for Memphis, TN, in comparison with the standard cost.

3. An additional cost of $500,000 was required for the local conditions in Memphis, TN.

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The solution of this problem can be carried out according to the steps as outlined in the problem statement:

1. The costs of the equipment and ancillary items for a plant with a capacity of 200,000 bbl can be estimated by linear interpolation of the data in Table 5-11 and the results are shown in Table 5-12.

TABLE 5-12 Results of Linear Interpolation for an Estimation Example Equipment type

Equipment Cost (in $1,000)

Percentage for ancillary items

Furnace $3,000 + (1/3)($10,000-$3,000) = $5,333 40% - (1/3)(40%-30%) = 37% Tower $2,000 + (1/3)($6,000-$2,000) = $3,333 45% - (1/3)(45%-35%) = 42% Drum $1,500 + (1/3)($5,000-$1,500) = $2,667 50% - (1/3)(50%-40%) = 47% Pumps, etc. $1,000 + (1/3)($4,000-$1,000) = $2,000 60% - (1/3)(60%-50%) = 57%

2. Hence, the total project cost in thousands of current dollars is given by Equation (5.8) as: 3. ($5,333)(1.37) + ($3,333)(1.42) +($2,667)(1.47) + ($2,000)(1.57) =

= $2,307 + $4,733 + $3,920 + $3,140 = $ 19,000 4. The corresponding cost in thousands of four year in the future dollars using Equation

(5.16) and Table 5-9 is: ($19,100)(105/94) = $21,335

5. The total cost of the project after adjustment for location is (0.95)($21,335,000) + $500,000 $20,800,000

Estimate Based on Engineer's List of Quantities The engineer's estimate is based on a list of items and the associated quantities from which the total construction cost is derived. This same list is also made available to the bidders if unit prices of the items on the list are also solicited from the bidders. Thus, the itemized costs submitted by the winning contractor may be used as the starting point for budget control. In general, the progress payments to the contractor are based on the units of work completed and the corresponding unit prices of the work items on the list. Hence, the estimate based on the engineers' list of quanitities for various work items essentially defines the level of detail to which subsequent measures of progress for the project will be made. Example: Bid estimate based on engineer's list of quantities Using the unit prices in the bid of contractor 1 for the quantitites specified by the engineer in Table 5-2 (Example 5-3), we can compute the total bid price of contractor 1 for the roadway project. The itemized costs for various work items as well as the total bid price are shown in Table 5-13.

TABLE 5-13: Bid Price of Contractor 1 in a Highway Project Items Unit Quantity Unit price Item cost Mobilization ls 1 115,000 115,000 Removal, berm lf 8,020 1.00 8.020 Finish subgrade sy 1,207,500 0.50 603,750 Surface ditches lf 525 2.00 1,050 Excavation structures cy 7,000 3.00 21,000

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TABLE 5-13: Bid Price of Contractor 1 in a Highway Project Items Unit Quantity Unit price Item cost Base course, untreated, 3/4'' ton 362,200 4.50 1,629,900 Lean concrete, 4'' thick sy 820,310 3.10 2,542,961 PCC, pavement, 10'' thick sy 76,010 10.90 7,695,509 Concrete, ci AA (AE) ls 1 200,000 200,000 Small structure cy 50 500 25,000 Barrier, precast lf 7,920 15.00 118,800 Flatwork, 4'' thick sy 7,410 10.00 74,100 10'' thick sy 4,241 20.00 84,820 Slope protection sy 2,104 25.00 52,600 Metal, end section, 15'' ea 39 100 3,900 18'' ea 3 150 450 Post, right-of-way, modification lf 4,700 3.00 14,100 Salvage and relay pipe lf 1,680 5.00 8,400 Loose riprap cy 32 40.00 1,280 Braced posts ea 54 100 5,400 Delineators, type I lb 1,330 12.00 15,960 type II ea 140 15.00 2,100 Constructive signs fixed sf 52,600 0.10 5,260 Barricades, type III lf 29,500 0.20 5,900 Warning lights day 6,300 0.10 630 Pavement marking, epoxy material Black gal 475 90.00 42,750 Yellow gal 740 90.00 66,600 White gal 985 90.00 88,650 Plowable, one-way white ea 342 50.00 17,100 Topsoil, contractor furnished cy 260 10.00 2,600 Seedling, method A acr 103 150 15,450 Excelsior blanket sy 500 2.00 1,000 Corrugated, metal pipe, 18'' lf 580 20.00 11,600 Polyethylene pipe, 12'' lf 2,250 15.00 33,750 Catch basin grate and frame ea 35 350 12,250 Equal opportunity training hr 18,000 0.80 14,400

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TABLE 5-13: Bid Price of Contractor 1 in a Highway Project Items Unit Quantity Unit price Item cost Granular backfill borrow cy 274 10.00 2,740 Drill caisson, 2'x6'' lf 722 100 72,200 Flagging hr 20,000 8.25 165,000 Prestressed concrete member type IV, 141'x4'' ea 7 12,000 84,000 132'x4'' ea 6 11,000 66,000 Reinforced steel lb 6,300 0.60 3,780 Epoxy coated lb 122,241 0.55 67,232.55 Structural steel ls 1 5,000 5,000 Sign, covering sf 16 10.00 160 type C-2 wood post sf 98 15.00 1,470 24'' ea 3 100 300 30'' ea 2 100 200 48'' ea 11 200 2,200 Auxiliary sf 61 15.00 915 Steel post, 48''x60'' ea 11 500 5,500 type 3, wood post sf 669 15.00 10,035 24'' ea 23 100 2,300 30'' ea 1 100 100 36'' ea 12 150 1,800 42''x60'' ea 8 150 1,200 48'' ea 7 200 1,400 Auxiliary sf 135 15.00 2,025 Steel post sf 1,610 40.00 64,400 12''x36'' ea 28 100 2,800 Foundation, concrete ea 60 300 18,000 Barricade, 48''x42'' ea 40 100 4,000 Wood post, road closed lf 100 30.00 3,000 Total $14,129,797.55

5.11 Allocation of Construction Costs Over Time Since construction costs are incurred over the entire construction phase of a project, it is often necessary to determine the amounts to be spent in various periods to derive the cash flow profile,

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especially for large projects with long durations. Consequently, it is important to examine the percentage of work expected to be completed at various time periods to which the costs would be charged. More accurate estimates may be accomplished once the project is scheduled as described in Chapter 10, but some rough estimate of the cash flow may be required prior to this time. Consider the basic problem in determining the percentage of work completed during construction. One common method of estimating percentage of completion is based on the amount of money spent relative to the total amount budgeted for the entire project. This method has the obvious drawback in assuming that the amount of money spent has been used efficiently for production. A more reliable method is based on the concept of value of work completed which is defined as the product of the budgeted labor hours per unit of production and the actual number of production units completed, and is expressed in budgeted labor hours for the work completed. Then, the percentage of completion at any stage is the ratio of the value of work completed to date and the value of work to be completed for the entire project. Regardless of the method of measurement, it is informative to understand the trend of work progress during construction for evaluation and control. In general, the work on a construction project progresses gradually from the time of mobilization until it reaches a plateau; then the work slows down gradually and finally stops at the time of completion. The rate of work done during various time periods (expressed in the percentage of project cost per unit time) is shown schematically in Figure 5-10 in which ten time periods have been assumed. The solid line A represents the case in which the rate of work is zero at time t = 0 and increases linearly to 12.5% of project cost at t = 2, while the rate begins to decrease from 12.5% at t = 8 to 0% at t = 10. The dotted line B represents the case of rapid mobilization by reaching 12.5% of project cost at t = 1 while beginning to decrease from 12.5% at t = 7 to 0% at t = 10. The dash line C represents the case of slow mobilization by reaching 12.5% of project cost at t = 3 while beginning to decrease from 12.5% at t = 9 to 0% at t = 10.

Figure 5-10: Rate of Work Progress over Project Time The value of work completed at a given time (expressed as a cumulative percentage of project cost) is shown schematically in Figure 5-11. In each case (A, B or C), the value of work completed can be represented by an "S-shaped" curve. The effects of rapid mobilization and slow mobilization are indicated by the positions of curves B and C relative to curve A, respectively.

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Figure 5-11: Value of Work Completed over Project Time While the curves shown in Figures 5-10 and 5-11 represent highly idealized cases, they do suggest the latitude for adjusting the schedules for various activities in a project. While the rate of work progress may be changed quite drastically within a single period, such as the change from rapid mobilization to a slow mobilization in periods 1, 2 and 3 in Figure 5-10, the effect on the value of work completed over time will diminish in significance as indicated by the cumulative percentages for later periods in Figure 5-11. Thus, adjustment of the scheduling of some activities may improve the utilization of labor, material and equipment, and any delay caused by such adjustments for individual activities is not likely to cause problems for the eventual progress toward the completion of a project. In addition to the speed of resource mobilization, another important consideration is the overall duration of a project and the amount of resources applied. Various strategies may be applied to shorten the overall duration of a project such as overlapping design and construction activities (as described in Chapter 2) or increasing the peak amounts of labor and equipment working on a site. However, spatial, managerial and technical factors will typically place a minimum limit on the project duration or cause costs to escalate with shorter durations. Example: Calculation of Value of Work Completed From the area of work progress in Figure 5-10, the value of work completed at any point in Figure 5-11 can be derived by noting the area under the curve up to that point in Figure 5-10. The result for t = 0 through t = 10 is shown in Table 5-14 and plotted in Figure 5-11.

TABLE 5-14 Calculation of Value of Work Completed

Time Case A Case B Case C

0 0 0 0 1 3.1% 6.2% 2.1% 2 12.5 18.7 8.3 3 25.0 31.2 18.8 4 37.5 43.7 31.3

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5 50.0 56.2 43.8 6 62.5 68.7 56.3 7 75.0 81.2 68.8 8 87.5 91.7 81.9 9 96.9 97.9 93.8 10 100.0 100.0 100.0

Computer Aided Cost Estimation Numerous computer aided cost estimation software systems are now available. These range in sophistication from simple spreadsheet calculation software to integrated systems involving design and price negotiation over the Internet. While this software involves costs for purchase, maintenance, training and computer hardware, some significant efficiencies often result. In particular, cost estimates may be prepared more rapidly and with less effort. Some of the common features of computer aided cost estimation software include:

Databases for unit cost items such as worker wage rates, equipment rental or material prices. These databases can be used for any cost estimate required. If these rates change, cost estimates can be rapidly re-computed after the databases are updated.

Databases of expected productivity for different components types, equiptment and construction processes.

Import utilities from computer aided design software for automatic quantity-take-off of components. Alternatively, special user interfaces may exist to enter geometric descriptions of components to allow automatic quantity-take-off.

Export utilities to send estimates to cost control and scheduling software. This is very helpful to begin the management of costs during construction.

Version control to allow simulation of different construction processes or design changes for the purpose of tracking changes in expected costs.

Provisions for manual review, over-ride and editing of any cost element resulting from the cost estimation system

Flexible reporting formats, including provisions for electronic reporting rather than simply printing cost estimates on paper.

Archives of past projects to allow rapid cost-estimate updating or modification for similar designs.

A typical process for developing a cost estimate using one of these systems would include: 1. If a similar design has already been estimated or exists in the company archive, the old

project information is retreived. 2. A cost engineer modifies, add or deletes components in the project information set. If a

similar project exists, many of the components may have few or no updates, thereby saving time.

3. A cost estimate is calculated using the unit cost method of estimation. Productivities and unit prices are retrieved from the system databases. Thus, the latest price information is used for the cost estimate.

4. The cost estimation is summarized and reviewed for any errors. Estimation of Operating Costs In order to analyze the life cycle costs of a proposed facility, it is necessary to estimate the

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operation and maintenance costs over time after the start up of the facility. The stream of operating costs over the life of the facility depends upon subsequent maintenance policies and facility use. In particular, the magnitude of routine maintenance costs will be reduced if the facility undergoes periodic repairs and rehabilitation at periodic intervals. Since the tradeoff between the capital cost and the operating cost is an essential part of the economic evaluation of a facility, the operating cost is viewed not as a separate entity, but as a part of the larger parcel of life cycle cost at the planning and design stage. The techniques of estimating life cycle costs are similar to those used for estimating capital costs, including empirical cost functions and the unit cost method of estimating the labor, material and equipment costs. However, it is the interaction of the operating and capital costs which deserve special attention. As suggested earlier in the discussion of the exponential rule for estimating, the value of the cost exponent may influence the decision whether extra capacity should be built to accommodate future growth. Similarly, the economy of scale may also influence the decision on rehabilitation at a given time. As the rehabilitation work becomes extensive, it becomes a capital project with all the implications of its own life cycle. Hence, the cost estimation of a rehabilitation project may also involve capital and operating costs. While deferring the discussion of the economic evaluation of constructed facilities to Chapter 6, it is sufficient to point out that the stream of operating costs over time represents a series of costs at different time periods which have different values with respect to the present. Consequently, the cost data at different time periods must be converted to a common base line if meaningful comparison is desired. Example: Maintenance cost on a roadway Maintenance costs for constructed roadways tend to increase with both age and use of the facility. As an example, the following empirical model was estimated for maintenance expenditures on sections of the Ohio Turnpike: C = 596 + 0.0019 V + 21.7 A where C is the annual cost of routine maintenance per lane-mile (in 1967 dollars), V is the volume of traffic on the roadway (measured in equivalent standard axle loads, ESAL, so that a heavy truck is represented as equivalent to many automobiles), and A is the age of the pavement in years since the last resurfacing. According to this model, routine maintenance costs will increase each year as the pavement service deteriorates. In addition, maintenance costs increase with additional pavement stress due to increased traffic or to heavier axle loads, as reflected in the variable V. For example, for V = 500,300 ESAL and A = 5 years, the annual cost of routine maintenance per lane-mile is estimated to be: C = 596 + (0.0019)(500,300) + (21.7)(5) = 596 + 950.5 + 108.5 = 1,655 (in 1967 dollars) Example: Time stream of costs over the life of a roadway The time stream of costs over the life of a roadway depends upon the intervals at which rehabilitation is carried out. If the rehabilitation strategy and the traffic are known, the time stream of costs can be estimated. Using a life cycle model which predicts the economic life of highway pavement on the basis of the effects of traffic and other factors, an optimal schedule for rehabilitation can be developed. For example, a time stream of costs and resurfacing projects for one pavement section is shown in Figure 5-11. As described in the previous example, the routine maintenance costs increase as

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the pavement ages, but decline after each new resurfacing. As the pavement continues to age, resurfacing becomes more frequent until the roadway is completely reconstructed at the end of 35 years.

Figure 5-11: Time Stream of Costs over the Life of a Highway Pavement Problems

1. Suppose that the grouting method described in Example 5-2 is used to provide a grouting seal beneath another landfill of 12 acres. The grout line is expected to be between 4.5 and 5.5 feet thickness. The voids in the soil layer are between 25% to 35%. Using the same unit cost data (in 1978 dollars), find the range of costs in a screening estimate for the grouting project.

2. To avoid submerging part of U.S. Route 40 south and east of Salt Lake City due to the construction of the Jardinal Dam and Reservoir, 22 miles of highway were relocated to the west around the site of the future reservoir. Three separate contracts were let, including one covering 10 miles of the work which had an engineer's estimate of $34,095,545. The bids were submitted on July 21, 1987 and the completion date of the project under the contract was August 15, 1989. (See ENR, October 8, 1987, p. 34). The three lowest bids were: 1) W.W. Clyde & Co., Springville, Utah 2) Sletten Construction company, Great Falls, Montana 3) Gilbert Western Corporation, Salt Lake city, Utah

$21,384,919 $26,701,018 $30,896,203

3. Find the percentage of each of these bidders below the engineer's cost estimate. 4. In making a screening estimate of an industrial plant for the production of batteries, an

empirical formula based on data of a similar buildings completed before 1987 was proposed: C = (16,000)(Q + 50,000)1/2 where Q is the daily production capacity of batteries and C is the cost of the building in 1987 dollars. If a similar plant is planned for a daily production capacity of 200,000 batteries, find the screening estimate of the building in 1987 dollars.

5. For the cost factor K = $46,000 (in 1968 dollars) and m = 0.67 for an aerated lagoon basin of a water treatment plant in Table 5-4 (Example 5-6), find the estimated cost of a proposed new plant with a similar treatment process having a capacity of 480 million

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gallons (in 1968 dollars). If another new plant was estimated to cost $160,000 by using the same exponential rule, what would be the proposed capacity of that plant?

6. Using the cost data in Figure 5-5 (Example 5-11), find the total cost including overhead and profit of excavating 90,000 cu.yd. of bulk material using a backhoe of 1.5 cu.yd. capacity for a detailed estimate. Assume that the excavated material will be loaded onto trucks for disposal.

7. The basic costs (labor, material and equipment) for various elements of a construction project are given as follows: Excavation Subgrade Base course Concrete pavement Total

$240,000 $100,000 $420,000 $640,000 $1,400,000

8. Assuming that field supervision cost is 10% of the basic cost, and the general office overhead is 5% of the direct costs (sum of the basic costs and field supervision cost), find the prorated field supervision costs, general office overhead costs and total costs for the various elements of the project.

9. In making a preliminary estimate of a chemical processing plant, several major types of equipment are the most significant components in affecting the installation cost. The cost of piping and other ancillary items for each type of equipment can often be expressed as a percentage of that type of equipment for a given capacity. The standard costs for the major equipment types for two plants with different daily production capacities are as shown in Table 5-15. It has been established that the installation cost of all equipment for a plant with daily production capacity between 150,000 bbl and 600,000 bbl can best be estimated by using liner interpolation of the standard data. A new chemical processing plant with a daily production capacity of 400,000 bbl is being planned. Assuming that all other factors remain the same, estimate the cost of the new plant.

Table 5-15

Equipment type Equipment cost ($1,000) Factor for ancillary items 150,000 bbl 600,000 bbl 150,000 bbl 600,000 bbl

Furnace Tower Drum Pumps, etc.

$3,000 2,000 1,500 1,000

$10,000 6,000 5,000 4,000

0.32 0.42 0.42 0.54

0.24 0.36 0.32 0.42

10. The total construction cost of a refinery with a production capacity of 100,000 bbl/day in Caracas, Venezuela, completed in 1977 was $40 million. It was proposed that a similar refinery with a production capacity of $160,000 bbl/day be built in New Orleans, LA for completion in 1980. For the additional information given below, make a screening estimate of the cost of the proposed plant.

1. In the total construction cost for the Caracus, Venezuela plant, there was an item of $2 million for site preparation and travel which is not typical for similar plants.

2. The variation of sizes of the refineries can be approximated by the exponential law with m = 0.6.

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3. The inflation rate in U.S. dollars was approximately 9% per year from 1977 to 1980.

4. An adjustment factor of 1.40 was suggested for the project to account for the increase of labor cost from Caracas, Venezuela to New Orleans, LA.

5. New air pollution equipment for the New Orleans, LA plant cost $4 million in 1980 dollars (not required for the Caracas plant).

6. The site condition at New Orleans required special piling foundation which cost $2 million in 1980 dollars.

11. The total cost of a sewage treatment plant with a capacity of 50 million gallons per day completed 1981 for a new town in Colorado was $4.5 million. It was proposed that a similar treatment plant with a capacity of 80 million gallons per day be built in another town in New Jersey for completion in 1985. For additional information given below, make a screening estimate of the cost of the proposed plant.

1. In the total construction cost in Colorado, an item of $300,000 for site preparation is not typical for similar plants.

2. The variation of sizes for this type of treatment plants can be approximated by the exponential law with m = 0.5.

3. The inflation rate was approximately 5% per year from 1981 to 1985. 4. The locational indices of Colorado and New Jersey areas are 0.95 and 1.10,

respectively, against the national average of 1.00. 5. The installation of a special equipment to satisfy the new environmental standard

cost an extra $200,000 in 1985 dollar for the New Jersey plant. 6. The site condition in New Jersey required special foundation which cost $500,00

in 1985 dollars. 12. Using the ENR building cost index, estimate the 1985 cost of the grouting seal on a

landfill described in Example 5-2, including the most likely estimate and the range of possible cost.

13. Using the unit prices in the bid of contractor 2 for the quantitites specified by the engineer in Table 5-2 (Example 5-3), compute the total bid price of contractor 2 for the roadway project including the expenditure on each item of work.

14. The rate of work progress in percent of completion per period of a construction project is shown in Figure 5-13 in which 13 time periods have been assumed. The cases A, B and C represent the normal mobilization time, rapid mobilization and slow mobilization for the project, respectively. Calculate the value of work completed in cumulative percentage for periods 1 through 13 for each of the cases A, B and C. Also plot the volume of work completed versus time for these cases.

Figure 5-13

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15. The rate of work progress in percent of completion per period of a construction project is shown in Figure 5-14 in which 10 time periods have been assumed. The cases A, B and C represent the rapid mobilization time, normal mobilization and slow mobilization for the project, respectively. Calculate the value of work completed in cumulative percentage for periods 1 through 10 for each of the cases A, B and C. Also plot the volume of work completed versus time for these cases.

Figure 5-14

16. Suppose that the empirical model for estimating annual cost of routine maintenance in Example 5-17 is applicable to sections of the Pennsylvania Turnpike in 1985 if the ENR building cost index is applied to inflate the 1967 dollars. Estimate the annual cost of maintenance per lane-mile of the tunrpike for which the traffic volume on the roadway is 750,000 ESAL and the age of the pavement is 4 years in 1985.

17. The initial construction cost for a electric rower line is known to be a function of the cross-sectional area A (in cm2) and the length L (in kilometers). Let C1 be the unit cost of construction (in dollars per cm3). Then, the initial construction cost P (in dollars) is given by P = C1AL(105) The annual operating cost of the power line is assumed to be measured by the power loss. The power loss S (in kwh) is known to be

where J is the electric current in amperes, R is the resistivity in ohm-centimeters. Let C2 be the unit operating cost (in dollars per kwh). Then, the annual operating cost U (in dollars) is given by

Suppose that the power line is expected to last n years and the life cycle cost T of the power line is equal to: T = P + UK where K is a discount factor depending on the useful life cycle n and the discount rate i (to be explained in Chapter 6). In designing the power line, all quantitites are assumed to be known except A which is to be determined. If the owner wants to minimize the life cycle cost, find the best cross-sectional area A in terms of the known quantities.

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Check your progress-1 1. What is "Sewage Sludge?" 2. How Do We Handle Resolve the Sewage Sludge Pollution Problem?

3.4 LET US SUM UP

oday, the United States is the richest and most powerful nation in the world. Across T the globe, government leaders and concerned citizens look to this country as a model of technological advancement and effective infrastructure management. Letís hope theyíre not looking too closely at our sewage collection system. These pipes, some as much as 200 years old, carry enough raw sewage to fill the Great Lakes about every four months. Laid end to end, the pipes that carry raw sewage from Americaís homes, businesses, institutions, and industries would stretch to the moon and backótwice. But in too many communities across the land, pipes are broken or leaking, systems are overloaded, and treatment is sometimes bypassed. The result is that in this most technologically advanced nation on the face of the planet, raw sewage backs up into peopleís homes with disturbing frequency, and is routinely permitted to flow into bodies of water that are sources of drinking water. Theoretically (and by law), all this raw sewage, with its cargo of infectious bacteria, viruses, parasites, and a growing legion of potentially toxic chemicals, gets treated in wastewater treatment plants. But in reality, this aging, often neglected, and sometimes insufficient network of pipes releases untreated or only partly treated sewage directly into 3 the environment. The average age of collection system components is about 33 years, 4,5 but some pipes still in use are almost 200 years old. Ironically, the nation at the forefront of the information age has about as clear a view of the quantity of raw sewage that leaks, spills, and backs up each year as we do of the sewage pipes buried beneath our feet. In the face of woefully inadequate data on the fre quency and volume of sewage overflows, the Environmental Protection Agencyís best guess is that every year, for every county in the United States, enough untreated sewage 6 overflows to fill both the Empire State Building and Madison Square Garden. These raw sewage overflows, occurring primarily during wet weather, spill into our recreational and drinking water, into groundwater, and directly onto private property, often in the form of basement backups. Health experts in government, academia, and the private sector voice concern over lack of information and potential health impacts, particularly for the most vulnerable in our society (young children, the elderly, the immuno-suppressed, etc.) who are more susceptible when exposed to the mix of infectious organisms and toxic chemicals in untreated sewage. The problem is compounded by the rise of antibiotic-resistant ìsuperbugs,î emerging infectious organisms (such as SARS) that can be transmitted through sewage, and increases in the release of myriad toxic industrial chemicals into sewage collection systems. While thereís disagreement over whether the numbers of people made sick every year from waterborne diseases in the United States are in the hundred thousands or millions, there is wide greement that not enough information is being collected to protect public health. This problem is bound to worsen as: (1) population growth puts added pressure on sewage collection and treatment systems already operating at or above design capacity; (2) urban sprawl creates more land area impervious to stormwater, further aggravating insufficiencies and weaknesses in the collection system during wet weather; (3) climate change increases the frequency and severity of storms in some areas; and (4) proposed changes to existing laws expose more people to untreated sewage. 3.5 SOME USEFUL BOOKS

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Marlow, D., Heart, S., Burn, S., Urquhart, A., Gould, S., Anderson, M., Cook, S., Ambrose, M., Madin, B., and Fitzgerald, A. (2007). Condition Assessment Strategies and Protocols for Water and Wastewater Utility Assets. Water Environment Research Foundation (WERF): Alexandria, VA and IWA Publishing: London, United Kingdom.

McDonald, S.E. and Zhao, J.Q. 2001. Condition Assessment and Rehabilitation of Large Sewers. Report No. NRCC-44696. Institute for Research in Construction, National Research Council Canada: Ottawa, Canada

Merrill, M.S., Lukas, A., Palmer, R.N., and Hahn, M.A. (2004). Development of a Tool to Prioritize Sewer Inspections. WERF: Alexandria, VA.

National Association of Sewer Service Companies (NAASCO). (2001). Pipeline Assessment And Certificate Program (PACP),v. 3.0. NASSCO: Owings Mills, MD.

3.6 ANSWER TO CHECK YOUR PROGRESS

Check your progress-1

1. Some would have the public believe that sewage sludge, also known as "biosolids," is recycled "domestic waste." The latest is the E.P.A. is allowing "sewage sludge" to be renamed "compost" in an effort to fool the public about the toxic nature of sewage sludge. The fact is, sewage sludge is defined by Harper-Collins Dictionary of Environmental Science as "a semi-solid mixture of bacteria, virus-laden organic matter, toxic metals, synthetic organic chemicals, and settled solids removed from domestic and industrial waste at sewage treatment plants." It gets worse, current federal regulations allow every business to dump 33 pounds of hazardous waste into public sewers every month without reporting or scrutiny. No wonder that the Federal Clean Water Act classifies sewage sludge as a pollutant. The EPA is charged with protecting the environment, but when it comes to sewage sludge, the E.P.A. seems to be making exceptions to its' own laws and regulations, and looks the other way.

2. Certainly NOT by placing on our agricultural lands where our food is grown! We believe the best way to handle the sewage sludge pollution problem is through the "waste to energy" solution of Biomass Gasification!

3.7 GLOSSARY

Sewerage refers to the collection, treatment and disposal of liquid waste. Sewage systems include all the physical structures required for collection, treatment and disposal of the wastes. In other words, discharged waste water's that are collected in large sewerage networks, transporting the waste from the site of production to the site of treatment comprise Sewage treatment networks (Sewerage system). • SEWAGE: Sewage consists of liquid wastes produced in residences, commercial establishments and institutions; Liquid Wastes discharged from industries; and any subsurface, surface or storm-water which enters the sewer. Hence basically sewage contains three components:

1. Sanitary or domestic sewage 2. Industrial wastes

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3. Infiltration, Inflow and storm-water. • SEWER: A Sewer is a pipe or conduit, normally closed, flowing full or partially full, which carries sewage. Classification based on use of Sewers or Sewage systems can be done as follows

1. Sanitary Sewers: These sewers transport domestic sewage, industrial wastes to the treatment plant. Storm-water does not normally enter these sewers except through joints, manhole covers and defaults in the system.

2. Storm sewers: These carry the surface and storm-water passing through or generated in the area that they usually serve.

3. Combined Sewers: These sewers carry all types of wastes - domestic sewage, industrial wastes and storm water in the same conduit.

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UNIT 4 LAYING OF SEWERS LINES & SEWAGE PUMPS

Structure 4.0 Objective 4.1 Introduction 4.2 History 4.3 Laying of sewers lines & Sewage pumps 4.4 Let us sum up 4.5 Some Useful Books 4.6 Answer to Check your Progress 4.7 Glossary 4.0 OBJECTIVE

In this lesson we will discuss the concepts of laying of sewers links & sewage pumps. After studying this lesson you will be able to: (i) define laying of sewers links. (ii) describe sewage pumps. 4.1 INTRODUCTION

1. Collection chambers and vacuum valve units 2.Vacuum sewer lines 3.Central vacuum station Vacuum technology is based on differential air pressure. Rotary vane vacuum pumps generate an operation pressure of -0.4 to -0.6 bar at the vacuum station, which is also the only element of the vacuum sewerage system that must be supplied with electricity. Interface valves that are installed inside the collection chambers work pneumatically. Any sewage flows by means of gravity into each house’s collection sump. After a certain fill level inside this sump is reached, the interface valve will open. The impulse to open the valve is usually transferred by a pneumatically (pneumatic pressure created by fill level) controlled controller unit. No electricity is needed to open or close the valve. The according energy is provided by the vacuum itself. While the valve is open, the resulting differential pressure between atmosphere and vacuum becomes the driving force and transports the wastewater towards the vacuum station. Besides these collection chambers, no other manholes, neither for changes in direction, nor for inspection or connection of branch lines, are necessary. High flow rates keep the system free of any blockages or sedimentation. Vacuum sewer systems are considered to be free of ex- and infiltration which allows the usage even in water protection areas. For this reason, vacuum sewer lines may even be laid in the same trench as potable water lines (depending on local guidelines). The system supplier should certify his product to be used in that way. To achieve the condition of an infiltration-free system and therefore allowing to reduce the waste water amounts that need to be treated, water tight (PE material or similar) collection chambers should be used. Valve and collection sump (waste water) preferably should be physically separated (different chambers) in order to protect service personal against direct contact with waste water and to ensure longer life cycles (waste water is considered to be corrosive). In order to ensure reliable transport, the vacuum sewer line is laid in a saw-tooth (length-) profile, which will be referred to more precisely afterwards. The whole vacuum sewers are filled with air at a pressure of -0.4 to -0.6 bar. The most important aspect for a reliable operation is the

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air-to-liquid ratio. When a system is well designed, the sewers contain only very small amounts of sewage. The air-to-liquid ratio is usually maintained by "intelligent" controller units or valves that adjust their opening times according to the pressure in the system. Considering that the vacuum idea relies on external energy for the transport of fluids, sewers can be laid in flat terrain and up to certain limits may also be counter-sloped. The saw-tooth profile keeps sewer lines shallow, lifts minimise trench depth (approx. 1.0 – 1.2 m). In this depth, expensive trenching, as it is the case for gravity sewers with the necessity to install continuously falling slopes of at least 0.5 - 1.0%, is avoided. Lifting stations are not required. Once arrived in the vacuum collection tank at the vacuum station, the wastewater is pumped to the discharge point, which could be a gravity sewer or the treatment station directly. As the dwell time of the watewater inside the system is very short and the wastewater is continuously mixed with air, the sewage is kept fresh and any fouling inside the system is avoided (less H2S). 4.2 HISTORY

A vacuum sewer system uses the differential pressure between atmospheric pressure and a partial vacuum maintained in the piping network and vacuum station collection vessel. This differential pressure allows a central vacuum station to collect the wastewater of several thousand individual homes, depending on terrain and the local situation. Vacuum sewers take advantage of available natural slope in the terrain and are most economical in flat sandy soils with high ground water. Vacuum sewers were first installed in Europe in 1882 but until the last 30 years it had been relegated to a niche market. The first who has applied the negative pressure drainage (so called vacuum sewerage) was the Dutch engineer Liernur in the second half of the 19th century. It was only used on ships, trains and airplanes for a long time. Technical implementations of vacuum sewerage systems were started after 1959 in Sweden by Joel Liljendahl and afterwards brought onto the market by Electrolux. Nowadays several system suppliers offer a wide range of products for many applications. 4.3 LAYING OF SEWERS LINES & SEWAGE PUMPS

Installing sewer lines entails laying a main line. Branch or drain lines run from various fixtures, including sinks, showers and toilets that connect to the main line. The main sewer line connects the house's plumbing system to either a septic tank that treats the waste or a public system. The public system leads to a waste water treatment facility. Pipes and Fittings Generally, sewer pipe and fittings for residential installations consist of Polyvinyl Chloride (PVC) or cast iron. The main residential sewer pipe diameters vary from 4 to 6 inches. Branch lines must be 1-1/4 to 2 inches in diameter. Pipes and fittings must meet or exceed specific standards, such as those outlined by ASTM International, which establishes voluntary standards for materials systems and services. Many codes require the pipe manufacturer to mark materials with the manufacturer's name or trademark and production code. Permit and Buried Lines Typically, the plumbing contractor must obtain a work permit before proceeding with the project. The contractor must also erect guards, rails, lights or other equipment, when excavating, to protect workers and the public when excavating to lay pipe. Most municipalities require the contractor to contact the city before excavating in order to locate and identify water,steam, gas, utility or other buried lines.

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Service Check Valve Installation Most codes require a service check valve installed in the sewer line. The service check valve allows waste water to flow toward the main sewage line but prevents waste water from reversing back toward the building. The valve must have certain components that permit access to parts of the valve. The valve has to meet other requirements as specified by building codes and ASTM International. Excavation and Installation When excavating, remove only as much soil as necessary to stay ahead of the workers laying the pipe. This provides protection against having an open trench in case of rain or a delay in the project. Dig the trench manually or use a backhoe. Start digging from the foundation wall of the house. Make the width of the trench about 24 inches. This ensures enough room to work when laying the sewer pipe. Follow the local building code rules to prepare the soil surface. Lay the pipe on a solid bed to prevent the soil from settling and causing the pipe to move. Make connections according to the guidelines for the material selected. PVC pipe and fittings usually require special PVC cement to make the connections. Keep the pipes as straight as possible for better waste water flow. In addition, local rules require a specific slope for sewer pipe, such as a 1/4-inch slope for each foot of pipe installed. Connection to Public System or Septic Tank When connecting to a public system, the municipality usually requires the work to take place under the direct supervision of a plumbing supervisor from the building inspection department. The main sewer lines are about 10 feet below the street surface. The house sewer line usually connects to the main sewer at a 45-degree angle located at a point above the main line. Follow the manufacturer's instructions for connecting the pipe to a septic tank; have the sewer pipes and connections inspected and approved by the building code inspector before fully covering the line. Check your progress-1

1. Why is the City taking steps to reduce sump pump discharges into the sanitary sewer? 2. Besides sump pumps, what other sources contribute to high wet weather flows in the

sanitary sewer, and what is the City doing about those? 3. What if my sump pump discharge pipe freezes up in winter or creates a safety problem

for me or my neighbors? 4. If I am issued a permit for winter discharge into the sanitary sewer do I still need to have

my sump pump plumbed to the outside of my home or business? 5. I currently have a sump pump discharging into the sanitary sewer. Do I need a permit to

leave it connected? 6. Will the City inspect my plumbing to check that my sump pump does not discharge into

the sanitary sewer after March 15? 7. What happens if I do not let the sump pump inspector into my home? 8. Do I need a permit to correct my sump pump discharge? 9. Where can I run the sump pump hose? What type of hose works best? 10. How can I prevent or reduce water problems in my basement?

4.4 LET US SUM UP

Highly estimated operation costs and fear of malfunction have been the main prejudices and obstacles in the past against an expanded use of vacuum sewers. For an unprejudiced choice of a sewerage concept, it is necessary not to overestimate operational costs of alternative wastewater

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collection systems. Further, more difficult conditions during construction have to be considered for conventional gravity sewerage! When a vacuum sewerage system is well designed, operational reliability will be guaranteed. Vacuum sewerage seems to become more and more important as capital costs could be reduced remarkably. Good references from communities seem to show satisfaction. Especially in cases of sparse population density, flat terrain, and high specific costs of pipe-laying, alternative sewerage systems could become much more economic, also in the long run. It is significant not to over-estimate the operation costs of alternative wastewater collection systems, in comparison with the costs of a conventional gravity system (which constitutes work under more difficult conditions). When a vacuum sewerage system is duly designed and built, its operational reliability is guaranteed. As engineers and municipal officials become acquainted with the advantages of vacuum sewers, the use of this technology will probably expand more and more worldwide. It is hoped that the use of alternative sewerage concepts will allow designers and regulators to find ways of keeping project costs at a minimum. Frequently, a combination of different alternative systems together as well as conventional sections will become the most feasible and the most reliable solution for the collection of wastewater. 4.5 SOME USEFUL BOOKS

CEN : European Standard DIN EN 1091 “Vacuum Sewerage outside buildings”, (1992) ATV Arbeitsblatt A 116 : “Besondere Entwässerungsverfahren, Unterdruckentwässerung

– Druckentwässerung”, Hennef (1992) ATV Arbeitsgruppe 1.1.2 : “Fragen des Betriebs und der Nutzungsdauer von Druck- und

Unterdrucksystemen”, Korrespondenz Abwasser (1997), P. 921-922 ATV-Handbuch : “Bau und Betrieb der Kanalisation”, (1995)

4.6 ANSWER TO CHECK YOUR PROGRESS

Check your progress-1

1. Basement backups, sewage bypasses to the river, and higher pumping costs are the result of large increases in flows experienced by the City’s sanitary sewer system within half an hour of the onset of rainstorms and during the following several days. As a recent example, in the weeks leading up to the rainstorm of June 2, 2007, the City’s sewage lift stations were pumping about 0.8 million gallons per day (MGD). On June 2 the sewer system was overwhelmed with rain-induced inflow and infiltration and a total of 3.2 MGD was pumped that day. Over the next several days flows in the system gradually decreased to about 1.0 MGD on June 5. Approximately 150 homes and business suffered damages from basement backups on June 2. Sump pump discharges to the sanitary sewer have been demonstrated to be significant sources of extraneous wet weather flows throughout the country, and experience indicates the same problem exists in Wahpeton.

2. Storm water can enter the sanitary sewer through manhole covers or cracks in the pavement around manhole covers, through joints or cracks in manhole walls, through

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cross connections with the storm sewer, or through pipe joints or cracks. 1.) The City is installing sealed manhole covers to replace covers that have exposed lifting holes or are vented style and is repairing pavement around manholes to prevent surface water from entering the sewer. For 2008 $20,000 has been budgeted for manhole cover replacements and repairs, and similar amounts will be budgeted for the next several years. 2.) In 2007 the City completed the 2nd year of an ongoing program to repair deteriorated manholes, having increased its budget for manhole repairs from $2,000 in 2005 to $30,000 in 2008. Approximately 30 manholes have been reconstructed to be water-tight, preventing storm water infiltration, and to be structurally sound. 3.) The City smoke tested approximately 15% of the sanitary sewer collection system in the older areas of the City, including Dakota Avenue, to identify sources of storm water inflow, and will test the remainder of the system over the next 2 years. Results from the 2007 smoke testing showed no cross connections with the storm sewer system, with one minor exception, since repaired, and no rain gutters directly connected to the sanitary sewers.

3. You may apply for a Winter Discharge Permit that will allow you to discharge your sump pump into the sanitary sewer from November 15 to March 15 for a fee of $15/month.

4. Yes, all sump pumps, with or without a winter discharge permit, must be plumbed to discharge outside the building. Permitted connections to the sanitary sewer need to include piping and valves to direct discharges outside the building between March 15 and November 15.

5. No, until March 15, 2008 an existing connection to the sanitary sewer may remain in place without a permit. However, all sump pump discharges need to be removed from the sanitary sewer after March 15, and any new sump pump connections will require a Winter Discharge Permit.

6. Yes, after March 15 the City will begin random sump pump inspections of as many homes and businesses as time allows.

7. A fee of $75 per month will be added to your utility bill until your home/business sump pump is inspected.

8. No, a City permit is not needed to reroute your sump pump discharge outside the building, unless you plan to connect directly into an existing City storm sewer.

9. You should run your sump pump hose at least 8 - 10’ away from your house to avoid it “recycling” back into the house. It is acceptable to run it on your front or back yard, or to the street. You should not run the hose through the curb and gutter. Try also to avoid running the water directly onto your neighbor’s property. The City receives numerous complaints from neighbors about wet yards and streets, but this will be difficult to avoid. Most people use the flexible, black hose that can be moved around easily; however, this pipe’s capacity can be greatly reduced if it is rolled up or extremely curvy, and many people have problems when it is not properly located or unfolded during a storm. It also is not recommended to use this type of hose in the winter. The smooth, white PVC pipe (1 1/2” diameter) has more capacity, is less susceptible to freezing and works better in situations where you do not need to move the hose around.

10. 1. Install rains gutters on your house and direct the downspouts away from your home. If you already have rain gutters, make sure that they are installed correctly and are cleaned out regularly, and that the downspouts are draining at least 3-5 feet away from your

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foundation. 2. Shape any landscaping to grade away at least 5 feet from your home’s foundation. Soils around a house tend to compact and drop after construction, creating a situation in which yard drainage may be directed up next to the house, increasing the potential for water intrusion. Many people fill in this area with landscaping rock, which may hide the actual soil slope under them, and has the potential to create an area next to the house where water can build up. You may need to remove the rock, add clay soil to grade away from the house and then reinstall the rock or other landscaping. Look for any obstructions in your yard that may prohibit surface water from flowing away from your home, or through your yard. This often happens when a storage shed is built too close to your home or is blocking drainage in the back of your lot. Often drainage swales in rear yards or between home are blocked during landscaping. Also it is common to see sand boxes, gardens or other items that may block drainage. It is important that the water can run out to a curb line or storm sewer drain without being blocked.

4.7 GLOSSARY

Agitation: Process of stirring a pesticide solution to keep formulations in suspension. Anti-Siphoning Device: A mechanism used to prevent the flow of a pesticide solution from a mix tank to a water source. Back-Flow Preventer: see “Anti-Siphoning Device.” Building Sewer: That portion of a sewer system that lies between the building foundation and the collector sewer. Also called a lateral sewer. Bypass pumping: The process of temporarily re-routing wastewater flows around a given section of sewer. Calibration: The process of adjusting application equipment so that pesticides are applied at the proper rate. Also, the process of determining the rate at which a given piece of application equipment discharges pesticides. Carrier: An inert ingredient used to dilute a mixture of pesticides, or to transport a pesticide to target. CHEMTREC: The Chemical Transportation Emergency Center. This organization operates a 24-hour information hot-line (1-800-424-9300) for pesticide spills, fires, and accidents. Chronic Toxicity: The long-term effects of exposure to a pesticide.

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Block IV – Introduction-Treatments and disposal The sludge which is found in the bottom of a sedimentation tank in water treatment plant is primarily composed of water. The solids in the sludge are mainly flocs, excess coagulant, such as alum. Alum sludge has a solids concentration of only about 1 % when automatically removed from the basin, or about 2% if manually removed. Many options exist for disposal of sedimentation sludge such as disposal in streams, lagoons and landfills. In the past, sludge and backwash water was typically released into streams and other bodies of water. However, this practice is becoming much less common and is now well regulated. Most of the other alternatives require transporting sludge away from the treatment plant. Sludge is typically dried before it is trucked away since the greater volume of wet sludge makes it much more expensive to transport. This drying process is known as dewatering or thickening. Alum sludge is difficult to thicken, but a variety of devices have been developed to thicken the sludge. Treating the sludge to aid in thickening is known as conditioning the sludge,_Once the sludge has been conditioned, it may be dewatered in a lagoon, drying bed, or one of several other devices. Other processes used to dewater sludge include filter presses, belt filter presses, centrifuges, and vacuum filters. These processes result in sludge with a solids content ranging from 30 to 50 %. DESIGN CRITERIA

Surface Loading Rate The terminal velocity has great significance in the design of settling tanks. It is called design overflow rate or surface loading rate or hydraulic loading (m3 / m2/d). It shall be used for designing the surface area of the sedimentation basin.

Detention Time When the surface loading rate is selected for an acceptable settling water quality, the required side water depth is often considered based on detention time, which is another important design parameter. The performance in the actual settling basins is affected by the dead spaces in the basins, eddy currents, wind currents and thermal currents. In the ideal settling basin all of the fluid elements pass through the basin at equal time to the theoretical detention time, t, which is equal to V/Q. Actual basins, however, have most of the fluids passing at a time shorter than the theoretical detention time. Dead spaces and eddy currents have rotational flow and do very little sedimentation since the inflow and outflow from these spaces is very small. As a result, the net volume available for settling is reduced and the mean flow-through time for the fluid element is decreased. Wind and thermal. currents also create flows that pass directly from the inlet to the outlet of the basin, which decreases the mean flow-through time. If there are dead spaces, the following relationship occurs: Mean t / Theoretical t < 1 If there are no dead spaces, the relationship is: Mean t / Theoretical t = 1 If short circuiting is occurring, the time relationship is: Median t / Mean t < 1 If there is no short circuiting: Mean t = Median t The most common use of type I or discrete settling is plain sedimentation basins, which are generally adopted prior to slow sand filter to remove sand, gravel and other discrete particles from raw water sources such as river supply and to reduce the turbidity level to less than 40

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NTU. A surface loading rate of 15 to 30 m3/ m2/ d and water depth of 3 to 5 m are used for the design of plain sedimentation basins.

Weir Loading Rate Weir loading, also known as weir overflow rate, is the number of cubic metres of water passing over a metre length of weir per day. The standard weir overflow rate is 170 to 600 m3/ day/metre. Longer weirs allow more water to flow out of the sedimentation basin without exceeding the recommended water velocity; Design criteria for Rectangular Sedimentation Tank Detention time = 2 to 3 hours Dept of the tank = 2.5 to 5.0 m Velocity of flow through basin= 30 cm/min Width of the tank = 12m Maximum length of tank = 30m Length to breath ratio = 3 to5.1 Surface loading rate: Granular solids = 15 to 30 m3 / day / m2 Floor slope towards sludge hopper = 1% to 4% Sludge hopper slope = 1.2 to 2V : 1H Scrapper velocity = 0.5 to 1.0 cm/ s Outlet weir loading: Normal = 300m3 / day / m-length of weir Velocity of flow in the launder= 0.2 to 0.3 m /s Head loss = 1.7 times velocity head Design criteria for Circular Sedimentation Tank Detention time = 1.5 to 3 hours Dept of the tank = 2.5 to 5.0m Velocity of flow <= 30 cm/min Maximum diameter of tank = 60m (preferable max:30m) Surface loading rate: Granular solids = 15 to 30m3 / day / m2 Amorphous flow = 30 to 40m3 / day / m2 Flocculent materials = 40 to50m3 / day / m2 Floor slope= 8% Sludge hopper = 1.2 to 2V:1H Scrapper velocity = 0.5 to 1.0 cm/s Outlet weir loading: Preferable maximum = 600m3/day/m-length 0f weir Normal = 300m3/day/m-length of weir Velocity of flow = 0.2 to 0.3 m/s Head loss = 1.7 times velocity head

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UNIT 1 TREATMENT OF SEWAGE

Structure 1.0 Objective 1.1 Introduction 1.2 History 1.3 Treatment of sewage 1.4 Let us sum up 1.5 Some Useful Books 1.6 Answer to Check your Progress 1.7 Glossary 1.0 OBJECTIVE

MTB offer a full service for Bulk Liquid Treatment and Disposal of various Hazardous and Non Hazardous waste streams such as:

Oil water emulsions Acidic solutions Alkaline solutions Neutral effluents Pumpable sludges

We are able to provide a site survey and sampling service through to the most cost effective routing and disposal of your Bulk Liquid. We operate a nationwide collection service for collections up to 6000 Gallons. 1.1 INTRODUCTION

Disposing of medical waste presents several unique problems: The risk of infection is the foremost among the challenges posed by medical waste

disposal. Certain types of infectious waste pose additional risk factors: Pathological wastes (infectious wastes that contain animal/human tissue) may

harbor particularly dangerous or communicable infectious agents. Laboratory cultures may contain high concentrations of infectious agents. "Sharps" (objects sharp enough to pierce the skin) can deliver infectious agents

directly into the bloodstream. Classification as a "hazardous waste". Some medical wastes contain certain highly

toxic compounds, such as those used in chemotherapy, that can cause the waste to fall under the "hazardous waste" classification. These materials are subject to special regulation under the federal Resource Conservation and Recovery Act, as well as additional rules in many states. Wastes which are regulated both as medical wastes and as hazardous wastes can be particularly difficult to deal with, since most service providers that handle treatment and disposal of medical wastes are not willing to accept hazardous wastes, and vice versa.

Other RMW waste types posing special problems include: Fluids pose a potential containment problem during shipment.

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Most states require that medical waste be treated before disposal to reduce the risk to acceptable levels. But different states have different requirements that apply to the various types of waste listed above. This page reviews commonly available treatment technology options, outlines specific waste management challenges posed by the different types of medical waste, available waste treatment and disposal options, and indicates which options are particularly suitable for each waste type, from both a technical and a regulatory standpoint. 1.2 HISTORY

The use of sewers is not new. In the Mesopotamian empire (3500 to 2500 BC) some homes were connected to a stormwater drain system to carry away wastes. In Babylon there were latrines which were connected to 18 inch (450 mm) diameter vertical shafts lined with perforated clay pipes leading to cesspools. However most people in Babylon threw debris including garbage and excrement on to the unpaved streets. The streets were periodically covered with clay, eventually raising the street levels to the extent that stairs had to be built down into houses. In the Indus city of Mohenjo-daro (located in Pakistan) the wealthy as well as some of the peasants used latrines and cesspools. These were connected to drainage systems in the streets from whence the liquid flowed to cesspools or through drains to the nearest river. In some cases terracotta pipes were used to connect second-floor bathrooms to street sewers. Archaeologists have found four separate drainage systems at King Minos’ Royal Palace at Knossos (Crete), which dates from 1700 BC. The wastewater drained through terracotta pipes which were joined with cement into stone sewers. Rainwater-fed cisterns and stone aqueducts tapped available water sources to deliver a continuous flow of water through the bathrooms and latrines which eventually discharged to the Kairatos River. From 2000 BC the island of Crete had a drainage system made up of terracotta pipes with bell and spigot joints sealed with cement. The system conveyed mainly stormwater but also some human waste. Water stored in large jars was used to fill the system periodically. Wolfe (1999) states that many of the drains are still in use today. There was a recent discovery of a stone lavatory with running water in a royal tomb from the Western Han dynasty (206 BC to AD 24) in the central province of Henan, China (Rennie 2000). The Ancient Greeks (300 BC to 500 AD) tackled the problem of waste in a different way. They had public latrines which drained into sewers which conveyed the sewage and stormwater to a collection basin outside the city. From there brick-lined conduits took the wastewater to agricultural fields which used the wastewater for irrigation and to fertilise crops and orchards. The sewers were periodically flushed with wastewater. A good review of the very earliest uses of sewers and waste disposal is given by Wolfe (1999) in the special issue of World of Water 2000. The reader is referred to that review for more detailed information. 1.3 TREATMENT OF SEWAGE

Origins of sewage Sewage is created by residential, institutional, and commercial and industrial establishments. It includes household waste liquid from toilets, baths, showers, kitchens, sinks and so forth that is disposed of via sewers. In many areas, sewage also includes liquid waste from industry and

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commerce. The separation and draining of household waste into greywater and blackwater is becoming more common in the developed world, with greywater being permitted to be used for watering plants or recycled for flushing toilets. Sewage may include stormwater runoff. Sewerage systems capable of handling stormwater are known as combined systems. Combined sewer systems are usually avoided now because precipitation causes widely varying flows reducing sewage treatment plant efficiency. Combined sewers require much larger and more expensive treatment facilities than sanitary sewers. Heavy storm runoff may overwhelm the sewage treatment system, causing a spill or overflow. Sanitary sewers are typically much smaller than combined sewers, and they are not designed to transport stormwater. Backups of raw sewage can occur if excessive Infiltration/Inflow is allowed into a sanitary sewer system. Modern sewered developments tend to be provided with separate storm drain systems for rainwater. As rainfall travels over roofs and the ground, it may pick up various contaminants including soil particles and other sediment, heavy metals, organic compounds, animal waste, and oil and grease. (See urban runoff.) Some jurisdictions require stormwater to receive some level of treatment before being discharged directly into waterways. Examples of treatment processes used for stormwater include retention basins, wetlands, buried vaults with various kinds of media filters, and vortex separators (to remove coarse solids). Process overview Sewage can be treated close to where it is created, a decentralised system, (in septic tanks, biofilters or aerobic treatment systems), or be collected and transported via a network of pipes and pump stations to a municipal treatment plant, a centralised system, (see sewerage and pipes and infrastructure). Sewage collection and treatment is typically subject to local, state and federal regulations and standards. Industrial sources of wastewater often require specialized treatment processes (see Industrial wastewater treatment). Sewage treatment generally involves three stages, called primary, secondary and tertiary treatment.

Primary treatment consists of temporarily holding the sewage in a quiescent basin where heavy solids can settle to the bottom while oil, grease and lighter solids float to the surface. The settled and floating materials are removed and the remaining liquid may be discharged or subjected to secondary treatment. Secondary treatment removes dissolved and suspended biological matter. Secondary treatment is typically performed by indigenous, water-borne micro-organisms in a managed habitat. Secondary treatment may require a separation process to remove the micro-organisms from the treated water prior to discharge or tertiary treatment. Tertiary treatment is sometimes defined as anything more than primary and secondary treatment in order to allow rejection into a highly sensitive or fragile ecosystem (estuaries, low-flow rivers, coral reefs,...). Treated water is sometimes disinfected chemically or physically (for example, by lagoons and microfiltration) prior to discharge into a stream, river, bay, lagoon or wetland, or it can be used for the irrigation of a golf course, green way or park. If it is sufficiently clean, it can also be used for groundwater recharge or agricultural purposes.

Process Flow Diagram for a typical large-scale treatment plant

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Process Flow Diagram for a typical treatment plant via Subsurface Flow Constructed Wetlands (SFCW)

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Pre-treatment Pre-treatment removes materials that can be easily collected from the raw waste water before they damage or clog the pumps and skimmers of primary treatment clarifiers (trash, tree limbs, leaves, etc.). Screening The influent sewage water is screened to remove all large objects like cans, rags, sticks, plastic packets etc. carried in the sewage stream. This is most commonly done with an automated mechanically raked bar screen in modern plants serving large populations, whilst in smaller or less modern plants a manually cleaned screen may be used. The raking action of a mechanical bar screen is typically paced according to the accumulation on the bar screens and/or flow rate. The solids are collected and later disposed in a landfill or incinerated. Bar screens or mesh screens of varying sizes may be used to optimize solids removal. If gross solids are not removed they become entrained in pipes and moving parts of the treatment plant and can cause substantial damage and inefficiency in the process. Grit removal Pre-treatment may include a sand or grit channel or chamber where the velocity of the incoming wastewater is adjusted to allow the settlement of sand, grit, stones, and broken glass. These particles are removed because they may damage pumps and other equipment. For small sanitary sewer systems, the grit chambers may not be necessary, but grit removal is desirable at larger plants.

An empty sedimentation tank at the treatment plant in Merchtem, Belgium. Flow equalization Clarifiers and mechanized secondary treatment are more efficient under uniform flow conditions. Equalization basins may be used for temporary storage of diurnal or wet-weather flow peaks. Basins provide a place to temporarily hold incoming sewage during plant maintenance and a means of diluting and distributing batch discharges of toxic or high-strength waste which might otherwise inhibit

biological secondary treatment (including portable toilet waste, vehicle holding tanks, and septic tank pumpers). Flow equalization basins require variable discharge control, typically include provisions for bypass and cleaning, and may also include aerators. Cleaning may be easier if the basin is downstream of screening and grit removal. Fat and grease removal In some larger plants, fat and grease is removed by passing the sewage through a small tank where skimmers collect the fat floating on the surface. Air blowers in the base of the tank may also be used to help recover the fat as a froth. Many plants, however, use primary clarifiers with mechanical surface skimmers for fat and grease removal. Primary treatment In the primary sedimentation stage, sewage flows through large tanks, commonly called "primary clarifiers" or "primary sedimentation tanks." The tanks are used to settle sludge while

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grease and oils rise to the surface and are skimmed off. Primary settling tanks are usually equipped with mechanically driven scrapers that continually drive the collected sludge towards a hopper in the base of the tank where it is pumped to sludge treatment facilities. Grease and oil from the floating material can sometimes be recovered for saponification. The dimensions of the tank should be designed to effect removal of a high percentage of the floatables and sludge. A typical sedimentation tank may remove from 50 to 70 percent of suspended solids, and from 30 to 35 percent of biochemical oxygen demand (BOD) from the sewage. Secondary treatment Secondary treatment is designed to substantially degrade the biological content of the sewage which are derived from human waste, food waste, soaps and detergent. The majority of municipal plants treat the settled sewage liquor using aerobic biological processes. To be effective, the biota require both oxygen and food to live. The bacteria and protozoa consume biodegradable soluble organic contaminants (e.g. sugars, fats, organic short-chain carbon molecules, etc.) and bind much of the less soluble fractions into floc. Secondary treatment systems are classified as fixed-film or suspended-growth systems.

Fixed-film or attached growth systems include trickling filters, Moving Bed Biofilm Reactors (MBBR), and rotating biological contactors, where the biomass grows on media and the sewage passes over its surface. Suspended-growth systems include activated sludge, where the biomass is mixed with the sewage and can be operated in a smaller space than fixed-film systems that treat the same amount of water. However, fixed-film systems are more able to cope with drastic changes in the amount of biological material and can provide higher removal rates for organic material and suspended solids than suspended growth systems Roughing filters are intended to treat particularly strong or variable organic loads, typically industrial, to allow them to then be treated by conventional secondary treatment processes. Characteristics include filters filled with media to which wastewater is applied. They are designed to allow high hydraulic loading and a high level of aeration. On larger installations, air is forced through the media using blowers. The resultant wastewater is usually within the normal range for conventional treatment processes.

A generalized, schematic diagram of an activated sludge process. A filter removes a small percentage of the suspended organic matter, while the majority of the organic matter undergoes a change of character, only due to the biological oxidation and nitrification taking place in the filter. With this aerobic oxidation and nitrification, the organic solids are converted into coagulated suspended mass, which is heavier and bulkier, and can settle to the bottom of a tank. The effluent of the filter is therefore passed through

a sedimentation tank, called a secondary clarifier, secondary settling tank or humus tank. Activated sludge Main article: Activated sludge

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In general, activated sludge plants encompass a variety of mechanisms and processes that use dissolved oxygen to promote the growth of biological floc that substantially removes organic material. The process traps particulate material and can, under ideal conditions, convert ammonia to nitrite and nitrate ultimately to nitrogen gas. (See also denitrification).

A Typical Surface-Aerated Basin (using motor-driven floating aerators) Surface-aerated basins (Lagoons) Many small municipal sewage systems in the United States (1 million gal./day or less) use aerated lagoons. Most biological oxidation processes for treating industrial wastewaters have in common the use of oxygen (or air) and microbial action. Surface-aerated basins achieve 80 to 90 percent removal of BOD with retention times of 1 to 10 days. The

basins may range in depth from 1.5 to 5.0 metres and use motor-driven aerators floating on the surface of the wastewater. In an aerated basin system, the aerators provide two functions: they transfer air into the basins required by the biological oxidation reactions, and they provide the mixing required for dispersing the air and for contacting the reactants (that is, oxygen, wastewater and microbes). Typically, the floating surface aerators are rated to deliver the amount of air equivalent to 1.8 to 2.7 kg O2/kW·h. However, they do not provide as good mixing as is normally achieved in activated sludge systems and therefore aerated basins do not achieve the same performance level as activated sludge units. Biological oxidation processes are sensitive to temperature and, between 0 °C and 40 °C, the rate of biological reactions increase with temperature. Most surface aerated vessels operate at between 4 °C and 32 °C. Constructed wetlands Constructed wetlands (can either be surface flow or subsurface flow, horizontal or vertical flow), include engineered reedbeds and belong to the family of phytorestoration and ecotechnologies; they provide a high degree of biological improvement and depending on design, act as a primary, secondary and sometimes tertiary treatment, also see phytoremediation. One example is a small reedbed used to clean the drainage from the elephants' enclosure at Chester Zoo in England; numerous CWs are used to recycle the water of the city of Honfleur in France and numerous other towns in Europe, the US, Asia and Australia. They are known to be highly productive systems as they copy natural wetlands, called the "Kidneys of the earth" for their fundamental recycling capacity of the hydrological cycle in the biosphere. Robust and reliable, their treatment capacities improve as time go by, at the opposite of conventional treatment plants whose machinery age with time. They are being increasingly used, although adequate and experienced design are more fundamental than for other systems and space limitation may impede their use. Filter beds (oxidizing beds) In older plants and those receiving variable loadings, trickling filter beds are used where the settled sewage liquor is spread onto the surface of a bed made up of coke (carbonized coal),

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limestone chips or specially fabricated plastic media. Such media must have large surface areas to support the biofilms that form. The liquor is typically distributed through perforated spray arms. The distributed liquor trickles through the bed and is collected in drains at the base. These drains also provide a source of air which percolates up through the bed, keeping it aerobic. Biological films of bacteria, protozoa and fungi form on the media’s surfaces and eat or otherwise reduce the organic content. This biofilm is often grazed by insect larvae, snails, and worms which help maintain an optimal thickness. Overloading of beds increases the thickness of the film leading to clogging of the filter media and ponding on the surface. Recent advances in media and process micro-biology design overcome many issues with Trickling filter designs. Soil Bio-Technology A new process called Soil Bio-Technology (SBT) developed at IIT Bombay has shown tremendous improvements in process efficiency enabling total water reuse, due to extremely low operating power requirements of less than 50 joules per kg of treated water. Typically SBT systems can achieve chemical oxygen demand (COD) levels less than 10 mg/L from sewage input of COD 400 mg/L. SBT plants exhibit high reductions in COD values and bacterial counts as a result of the very high microbial densities available in the media. Unlike conventional treatment plants, SBT plants produce insignificant amounts of sludge, precluding the need for sludge disposal areas that are required by other technologies. In the Indian context, conventional sewage treatment plants fall into systemic disrepair due to 1) high operating costs, 2) equipment corrosion due to methanogenesis and hydrogen sulphide, 3) non-reusability of treated water due to high COD (>30 mg/L) and high fecal coliform (>3000 NFU) counts, 4) lack of skilled operating personnel and 5) equipment replacement issues. Examples of such systemic failures has been documented by Sankat Mochan Foundation at the Ganges basin after a massive cleanup effort by the Indian government in 1986 by setting up sewage treatment plants under the Ganga Action Plan failed to improve river water quality. Biological aerated filters Biological Aerated (or Anoxic) Filter (BAF) or Biofilters combine filtration with biological carbon reduction, nitrification or denitrification. BAF usually includes a reactor filled with a filter media. The media is either in suspension or supported by a gravel layer at the foot of the filter. The dual purpose of this media is to support highly active biomass that is attached to it and to filter suspended solids. Carbon reduction and ammonia conversion occurs in aerobic mode and sometime achieved in a single reactor while nitrate conversion occurs in anoxic mode. BAF is operated either in upflow or downflow configuration depending on design specified by manufacturer.

Schematic diagram of a typical rotating biological contactor (RBC). The treated effluent clarifier/settler is not included in the diagram. Rotating biological contactors Rotating biological contactors (RBCs) are mechanical secondary treatment systems, which are robust and capable of withstanding surges in organic load. RBCs were first installed in Germany in 1960 and have since been developed and

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refined into a reliable operating unit. The rotating disks support the growth of bacteria and micro-organisms present in the sewage, which break down and stabilise organic pollutants. To be successful, micro-organisms need both oxygen to live and food to grow. Oxygen is obtained from the atmosphere as the disks rotate. As the micro-organisms grow, they build up on the media until they are sloughed off due to shear forces provided by the rotating discs in the sewage. Effluent from the RBC is then passed through final clarifiers where the micro-organisms in suspension settle as a sludge. The sludge is withdrawn from the clarifier for further treatment. A functionally similar biological filtering system has become popular as part of home aquarium filtration and purification. The aquarium water is drawn up out of the tank and then cascaded over a freely spinning corrugated fiber-mesh wheel before passing through a media filter and back into the aquarium. The spinning mesh wheel develops a biofilm coating of microorganisms that feed on the suspended wastes in the aquarium water and are also exposed to the atmosphere as the wheel rotates. This is especially good at removing waste urea and ammonia urinated into the aquarium water by the fish and other animals. Membrane bioreactors Membrane bioreactors (MBR) combine activated sludge treatment with a membrane liquid-solid separation process. The membrane component uses low pressure microfiltration or ultrafiltration membranes and eliminates the need for clarification and tertiary filtration. The membranes are typically immersed in the aeration tank; however, some applications utilize a separate membrane tank. One of the key benefits of an MBR system is that it effectively overcomes the limitations associated with poor settling of sludge in conventional activated sludge (CAS) processes. The technology permits bioreactor operation with considerably higher mixed liquor suspended solids (MLSS) concentration than CAS systems, which are limited by sludge settling. The process is typically operated at MLSS in the range of 8,000–12,000 mg/L, while CAS are operated in the range of 2,000–3,000 mg/L. The elevated biomass concentration in the MBR process allows for very effective removal of both soluble and particulate biodegradable materials at higher loading rates. Thus increased sludge retention times, usually exceeding 15 days, ensure complete nitrification even in extremely cold weather. The cost of building and operating an MBR is usually higher than conventional wastewater treatment. Membrane filters can be blinded with grease or abraded by suspended grit and lack a clarifier's flexibility to pass peak flows. The technology has become increasingly popular for reliably pretreated waste streams and has gained wider acceptance where infiltration and inflow have been controlled, however, and the life-cycle costs have been steadily decreasing. The small footprint of MBR systems, and the high quality effluent produced, make them particularly useful for water reuse applications. Secondary sedimentation

Secondary Sedimentation tank at a rural treatment plant. The final step in the secondary treatment stage is to settle out the biological floc or filter material through a secondary clarifier and to produce sewage water containing low levels of organic material and suspended matter. Tertiary treatment The purpose of tertiary treatment is to provide a final treatment stage to

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raise the effluent quality before it is discharged to the receiving environment (sea, river, lake, ground, etc.). More than one tertiary treatment process may be used at any treatment plant. If disinfection is practiced, it is always the final process. It is also called "effluent polishing." Filtration Sand filtration removes much of the residual suspended matter. Filtration over activated carbon, also called carbon adsorption, removes residual toxins. Lagooning

A sewage treatment plant and lagoon in Everett, Washington, United States. Lagooning provides settlement and further biological improvement through storage in large man-made ponds or lagoons. These lagoons are highly aerobic and colonization by native macrophytes, especially reeds, is often encouraged. Small filter feeding invertebrates such as Daphnia and species of Rotifera greatly assist in treatment by removing fine particulates.

Nutrient removal Wastewater may contain high levels of the nutrients nitrogen and phosphorus. Excessive release to the environment can lead to a build up of nutrients, called eutrophication, which can in turn encourage the overgrowth of weeds, algae, and cyanobacteria (blue-green algae). This may cause an algal bloom, a rapid growth in the population of algae. The algae numbers are unsustainable and eventually most of them die. The decomposition of the algae by bacteria uses up so much of oxygen in the water that most or all of the animals die, which creates more organic matter for the bacteria to decompose. In addition to causing deoxygenation, some algal species produce toxins that contaminate drinking water supplies. Different treatment processes are required to remove nitrogen and phosphorus. Nitrogen removal The removal of nitrogen is effected through the biological oxidation of nitrogen from ammonia to nitrate (nitrification), followed by denitrification, the reduction of nitrate to nitrogen gas. Nitrogen gas is released to the atmosphere and thus removed from the water. Nitrification itself is a two-step aerobic process, each step facilitated by a different type of bacteria. The oxidation of ammonia (NH3) to nitrite (NO2

−) is most often facilitated by Nitrosomonas spp. (nitroso referring to the formation of a nitroso functional group). Nitrite oxidation to nitrate (NO3

−), though traditionally believed to be facilitated by Nitrobacter spp. (nitro referring the formation of a nitro functional group), is now known to be facilitated in the environment almost exclusively by Nitrospira spp. Denitrification requires anoxic conditions to encourage the appropriate biological communities to form. It is facilitated by a wide diversity of bacteria. Sand filters, lagooning and reed beds can all be used to reduce nitrogen, but the activated sludge process (if designed well) can do the job the most easily. Since denitrification is the reduction of nitrate to dinitrogen gas, an electron donor is needed. This can be, depending on the wastewater, organic matter (from faeces), sulfide, or an added donor like methanol. The sludge in the anoxic tanks (denitrification tanks) must be mixed well (mixture of recirculated mixed liquor, return activated sludge [RAS], and raw influent) e.g. by using submersible mixers in order to achieve the desired denitrification. Sometimes the conversion of toxic ammonia to nitrate alone is referred to as tertiary treatment.

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Many sewage treatment plants use axial flow pumps to transfer the nitrified mixed liquor from the aeration zone to the anoxic zone for denitrification. These pumps are often referred to as Internal Mixed Liquor Recycle (IMLR) pumps. Phosphorus removal Each person excretes between 200 and 1000 grams of phosphorus annually. Studies of United States sewage in the late 1960s estimated mean per capita contributions of 500 grams in urine and feces, 1000 grams in synthetic detergents, and lesser variable amounts used as corrosion and scale control chemicals in water supplies. source control via alternative detergent formulations has subsequently reduced the largest contribution, but the content of urine and feces will remain unchanged. Phosphorus removal is important as it is a limiting nutrient for algae growth in many fresh water systems. (For a description of the negative effects of algae, see Nutrient removal). It is also particularly important for water reuse systems where high phosphorus concentrations may lead to fouling of downstream equipment such as reverse osmosis. Phosphorus can be removed biologically in a process called enhanced biological phosphorus removal. In this process, specific bacteria, called polyphosphate accumulating organisms (PAOs), are selectively enriched and accumulate large quantities of phosphorus within their cells (up to 20 percent of their mass). When the biomass enriched in these bacteria is separated from the treated water, these biosolids have a high fertilizer value. Phosphorus removal can also be achieved by chemical precipitation, usually with salts of iron (e.g. ferric chloride), aluminum (e.g. alum), or lime. This may lead to excessive sludge production as hydroxides precipitates and the added chemicals can be expensive. Chemical phosphorus removal requires significantly smaller equipment footprint than biological removal, is easier to operate and is often more reliable than biological phosphorus removal. Another method for phosphorus removal is to use granular laterite. Once removed, phosphorus, in the form of a phosphate-rich sludge, may be stored in a land fill or resold for use in fertilizer. Disinfection The purpose of disinfection in the treatment of waste water is to substantially reduce the number of microorganisms in the water to be discharged back into the environment for the later use of drinking, bathing, irrigation, etc. The effectiveness of disinfection depends on the quality of the water being treated (e.g., cloudiness, pH, etc.), the type of disinfection being used, the disinfectant dosage (concentration and time), and other environmental variables. Cloudy water will be treated less successfully, since solid matter can shield organisms, especially from ultraviolet light or if contact times are low. Generally, short contact times, low doses and high flows all militate against effective disinfection. Common methods of disinfection include ozone, chlorine, ultraviolet light, or sodium hypochlorite. Chloramine, which is used for drinking water, is not used in waste water treatment because of its persistence. After multiple steps of disinfection, the treated water is ready to be released back into the water cycle by means of the nearest body of water or agriculture. Afterwards, the water can be transferred to reserves for everyday human uses. Chlorination remains the most common form of waste water disinfection in North America due to its low cost and long-term history of effectiveness. One disadvantage is that chlorination of residual organic material can generate chlorinated-organic compounds that may be carcinogenic or harmful to the environment. Residual chlorine or chloramines may also be capable of chlorinating organic material in the natural aquatic environment. Further, because residual

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chlorine is toxic to aquatic species, the treated effluent must also be chemically dechlorinated, adding to the complexity and cost of treatment. Ultraviolet (UV) light can be used instead of chlorine, iodine, or other chemicals. Because no chemicals are used, the treated water has no adverse effect on organisms that later consume it, as may be the case with other methods. UV radiation causes damage to the genetic structure of bacteria, viruses, and other pathogens, making them incapable of reproduction. The key disadvantages of UV disinfection are the need for frequent lamp maintenance and replacement and the need for a highly treated effluent to ensure that the target microorganisms are not shielded from the UV radiation (i.e., any solids present in the treated effluent may protect microorganisms from the UV light). In the United Kingdom, UV light is becoming the most common means of disinfection because of the concerns about the impacts of chlorine in chlorinating residual organics in the wastewater and in chlorinating organics in the receiving water. Some sewage treatment systems in Canada and the US also use UV light for their effluent water disinfection. Ozone (O3) is generated by passing oxygen (O2) through a high voltage potential resulting in a third oxygen atom becoming attached and forming O3. Ozone is very unstable and reactive and oxidizes most organic material it comes in contact with, thereby destroying many pathogenic microorganisms. Ozone is considered to be safer than chlorine because, unlike chlorine which has to be stored on site (highly poisonous in the event of an accidental release), ozone is generated onsite as needed. Ozonation also produces fewer disinfection by-products than chlorination. A disadvantage of ozone disinfection is the high cost of the ozone generation equipment and the requirements for special operators. Odour Control Odours emitted by sewage treatment are typically an indication of an anaerobic or "septic" condition. Early stages of processing will tend to produce foul smelling gases, with hydrogen sulfide being most common in generating complaints. Large process plants in urban areas will often treat the odours with carbon reactors, a contact media with bio-slimes, small doses of chlorine, or circulating fluids to biologically capture and metabolize the obnoxious gases. Other methods of odour control exist, including addition of iron salts, hydrogen peroxide, calcium nitrate, etc. to manage hydrogen sulfide levels. Package plants and batch reactors To use less space, treat difficult waste and intermittent flows, a number of designs of hybrid treatment plants have been produced. Such plants often combine at least two stages of the three main treatment stages into one combined stage. In the UK, where a large number of wastewater treatment plants serve small populations, package plants are a viable alternative to building a large structure for each process stage. In the US, package plants are typically used in rural areas, highway rest stops and trailer parks. One type of system that combines secondary treatment and settlement is the sequencing batch reactor (SBR). Typically, activated sludge is mixed with raw incoming sewage, and then mixed and aerated. The settled sludge is run off and re-aerated before a proportion is returned to the headworks SBR plants are now being deployed in many parts of the world. The disadvantage of the SBR process is that it requires a precise control of timing, mixing and aeration. This precision is typically achieved with computer controls linked to sensors. Such a complex, fragile system is unsuited to places where controls may be unreliable, poorly maintained, or where the power supply may be intermittent. Extended aeration package plants use separate basins for aeration and settling, and are somewhat larger than SBR plants with reduced timing sensitivity. Package plants may be referred to as high charged or low charged.

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This refers to the way the biological load is processed. In high charged systems, the biological stage is presented with a high organic load and the combined floc and organic material is then oxygenated for a few hours before being charged again with a new load. In the low charged system the biological stage contains a low organic load and is combined with flocculate for longer times. Sludge treatment and disposal The sludges accumulated in a wastewater treatment process must be treated and disposed of in a safe and effective manner. The purpose of digestion is to reduce the amount of organic matter and the number of disease-causing microorganisms present in the solids. The most common treatment options include anaerobic digestion, aerobic digestion, and composting. Incineration is also used albeit to a much lesser degree. Sludge treatment depends on the amount of solids generated and other site-specific conditions. Composting is most often applied to small-scale plants with aerobic digestion for mid sized operations, and anaerobic digestion for the larger-scale operations. Anaerobic digestion Anaerobic digestion is a bacterial process that is carried out in the absence of oxygen. The process can either be thermophilic digestion, in which sludge is fermented in tanks at a temperature of 55°C, or mesophilic, at a temperature of around 36°C. Though allowing shorter retention time (and thus smaller tanks), thermophilic digestion is more expensive in terms of energy consumption for heating the sludge. Anaerobic digestion is the most common (mesophilic) treatment of domestic sewage in septic tanks, which normally retain the sewage from one day to two days, reducing the BOD by about 35 to 40 percent. This reduction can be increased with a combination of anaerobic and aerobic treatment by installing Aerobic Treatment Units (ATUs) in the septic tank. One major feature of anaerobic digestion is the production of biogas (with the most useful component being methane), which can be used in generators for electricity production and/or in boilers for heating purposes. Aerobic digestion Aerobic digestion is a bacterial process occurring in the presence of oxygen. Under aerobic conditions, bacteria rapidly consume organic matter and convert it into carbon dioxide. The operating costs used to be characteristically much greater for aerobic digestion because of the energy used by the blowers, pumps and motors needed to add oxygen to the process. Aerobic digestion can also be achieved by using diffuser systems or jet aerators to oxidize the sludge. Fine bubble diffusers are typically the more cost-efficient diffusion method, however, plugging is typically a problem due to sediment settling into the smaller air holes. Coarse bubble diffusers are more commonly used in activated sludge tanks (generally a side process in waste water management) or in the flocculation stages. A key component for selecting diffuser type is to ensure it will produce the required oxygen transfer rate. Composting Composting is also an aerobic process that involves mixing the sludge with sources of carbon such as sawdust, straw or wood chips. In the presence of oxygen, bacteria digest both the wastewater solids and the added carbon source and, in doing so, produce a large amount of heat. Incineration Incineration of sludge is less common because of air emissions concerns and the supplemental fuel (typically natural gases or fuel oil) required to burn the low calorific value sludge and vaporize residual water. Stepped multiple hearth incinerators with high residence time and

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fluidized bed incinerators are the most common systems used to combust wastewater sludge. Co-firing in municipal waste-to-energy plants is occasionally done, this option being less expensive assuming the facilities already exist for solid waste and there is no need for auxiliary fuel Sludge disposal When a liquid sludge is produced, further treatment may be required to make it suitable for final disposal. Typically, sludges are thickened (dewatered) to reduce the volumes transported off-site for disposal. There is no process which completely eliminates the need to dispose of biosolids. There is, however, an additional step some cities are taking to superheat sludge and convert it into small pelletized granules that are high in nitrogen and other organic materials. In New York City, for example, several sewage treatment plants have dewatering facilities that use large centrifuges along with the addition of chemicals such as polymer to further remove liquid from the sludge. The removed fluid, called centrate, is typically reintroduced into the wastewater process. The product which is left is called "cake" and that is picked up by companies which turn it into fertilizer pellets. This product is then sold to local farmers and turf farms as a soil amendment or fertilizer, reducing the amount of space required to dispose of sludge in landfills. Much sludge originating from commercial or industrial areas is contaminated with toxic materials that are released into the sewers from the industrial processes. Elevated concentrations of such materials may make the sludge unsuitable for agricultural use and it may then have to be incinerated or disposed of to landfill. Treatment in the receiving environment

The outlet of the Karlsruhe sewage treatment plant flows into the Alb. Many processes in a wastewater treatment plant are designed to mimic the natural treatment processes that occur in the environment, whether that environment is a natural water body or the ground. If not overloaded, bacteria in the environment will consume organic contaminants, although this will reduce the levels of oxygen in the water and may significantly change the overall ecology of the receiving

water. Native bacterial populations feed on the organic contaminants, and the numbers of disease-causing microorganisms are reduced by natural environmental conditions such as predation or exposure to ultraviolet radiation. Consequently, in cases where the receiving environment provides a high level of dilution, a high degree of wastewater treatment may not be required. However, recent evidence has demonstrated that very low levels of specific contaminants in wastewater, including hormones (from animal husbandry and residue from human hormonal contraception methods) and synthetic materials such as phthalates that mimic hormones in their action, can have an unpredictable adverse impact on the natural biota and potentially on humans if the water is re-used for drinking water. In the US and EU, uncontrolled discharges of wastewater to the environment are not permitted under law, and strict water quality requirements are to be met, as clean drinking water is essential. (For requirements in the US, see Clean Water Act.) A significant threat in the coming decades will be the increasing uncontrolled discharges of wastewater within rapidly developing countries. Effects on Biology Sewage treatment plants can have multiple effects on nutrient levels in the water that the treated sewage flows into. These effects on nutrients can have large effects on the biological life in the

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water in contact with the effluent. Stabilization ponds (or treatment ponds) can include any of the following: Oxidation ponds, which are aerobic bodies of water usually 1–2 meters in depth that

receive effluent from sedimentation tanks or other forms of primary treatment. Dominated by algae

Polishing ponds are similar to oxidation ponds but receive effluent from an oxidation pond or from a plant with an extended mechanical treatment. Dominated by zooplankton Facultative lagoons, raw sewage lagoons, or sewage lagoons are ponds where

sewage is added with no primary treatment other than coarse screening. These ponds provide effective treatment when the surface remains aerobic; although anaerobic conditions may develop near the layer of settled sludge on the bottom of the pond. Anaerobic lagoons are heavily loaded ponds.

Dominated by bacteria Sludge lagoons are aerobic ponds, usually 2–5 meters in depth, that receive

anaerobically digested primary sludge, or activated secondary sludge under water.

Upper layers are dominated by algae Phosphorus limitation is a possible result from sewage treatment and results in flagellate-dominated plankton, particularly in summer and fall. At the same time a different study found high nutrient concentrations linked to sewage effluents. High nutrient concentration leads to high chlorophyll a concentrations, which is a proxy for primary production in marine environments. High primary production means high phytoplankton populations and most likely high zooplankton populations because zooplankton feed on phytoplankton. However, effluent released into marine systems also leads to greater population instability A study done in Britain found that the quality of effluent affected the planktonic life in the water in direct contact with the wastewater effluent. Turbid, low-quality effluents either did not contain ciliated protozoa or contained only a few species in small numbers. On the other hand, high-quality effluents contained a wide variety of ciliated protozoa in large numbers. Due to these findings, it seems unlikely that any particular component of the industrial effluent has, by itself, any harmful effects on the protozoan populations of activated sludge plants. The planktonic trends of high populations close to input of treated sewage is contrasted by the bacterial trend. In a study of Aeromonas spp. in increasing distance from a wastewater source, greater change in seasonal cycles was found the furthest from the effluent. This trend is so strong that the furthest location studied actually had an inversion of the Aeromonas spp. cycle in comparison to that of fecal coliforms. Since there is a main pattern in the cycles that occurred simultaneously at all stations it indicates seasonal factors (temperature, solar radiation, phytoplankton) control of the bacterial population. The effluent dominant species changes from Aeromonas caviae in winter to Aeromonas sobria in the spring and fall while the inflow dominant species is Aeromonas caviae, which is constant throughout the seasons.

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Sewage treatment in developing countries Few reliable figures on the share of the wastewater collected in sewers that is being treated in the world exist. In many developing countries the bulk of domestic and industrial wastewater is discharged without any treatment or after primary treatment only. In Latin America about 15% of collected wastewater passes through treatment plants (with varying levels of actual treatment). In Venezuela, a below average country in South America with respect to wastewater treatment, 97 percent of the country’s sewage is discharged raw into the environment. n a relatively developed Middle Eastern country such as Iran, the majority of Tehran's population has totally untreated sewage injected to the city’s groundwater. However now the construction of major parts of the sewage system, collection and treatment, in Tehran is almost complete, and under development, due to be fully completed by the end of 2012. In Israel, about 50 percent of agricultural water usage (total use was 1 billion cubic metres in 2008) is provided through reclaimed sewer water. Future plans call for increased use of treated sewer water as well as more desalination plants. Most of sub-Saharan Africa is without wastewater treatment.

Check your progress-1 1. What is the difference between a septic tank and a sewage treatment plant? 2. Do plants have to comply with EN/CE Regulations? 3. Is approval required to install a Sewage Treatment plant? 4. Do sewage treatment plants or septic tanks smell?

1.4 LET US SUM UP

The purpose of disinfection in the treatment of wastewater is to substantially reduce the number of living organisms in the water to be discharged back into the environment. The effectiveness of disinfection depends on the quality of the water being treated (e.g., TSS, pH, etc.), the type of disinfection being used, the disinfectant dosage (concentration and time), and other environmental variables. Turbid water will be treated less successfully since solid matter can shield organisms, especially from ultraviolet light or if contact time is low. Generally, short contact times, low doses and high flows are against effective disinfection. Common methods of disinfection include use of ozone, chlorine, or UV light. Chloramine, which is used for drinking water, is not used in waste water treatment because of its persistence. Disinfection follows secondary clarification in most treatment plants or after tertiary treatment when the wastewater reclamation and reuse is contemplated. Disinfection is normally accomplished with chlorine. Due to the potential environmental impact of chlorine, most plants now dechlorinate wastewater effluents before discharge 1.5 SOME USEFUL BOOKS

Ciaponi, C.: Fognature Nere in depressione”, Sistemi di Fognatura, (Centro Studi Deflussi Urbani), Milano (1997)

Ciaponi, C.: Un’Esperienza di applicazione del sistema di Fognatura Nera con funzionamento in depressione, Università di Pavia (1986)

Garnier, C., Brémond, B. : “Assainissement sous-vide, étude technique-économique”, CEMAGREF, Groupement de Bordeaux, Division Hydraulique Agricole (1986)

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Ghetti, A.: “Prove Idrauliche e technologiche relative alla fognatura di Venezia”, Padova (1970)

1.6 ANSWER TO CHECK YOUR PROGRESS

Check your progress-1

1. A septic tank receives untreated wastewater from a property and allows the heavier solids to settle at the bottom whilst the effluent rises to the top. Self forming bacteria help the system digest the solids or sludge and the remaining liquids flow out of the tank into a drainage field. The effluent from a septic tank still contains about 70% of the polluted matter in the sewage, and further treatment is necessary. Alternatively, a sewage treatment plant gives aerobic digestion of the wastewater contaminants, and treats to a much higher standard than a septic tank. Treatment plant effluent has the appearance of clear water and can be discharged into a water course or ditch (with Environment Agency approval) or to a conventional soakaway. Treatment plants also vary, some have internal moving parts and others do not. The WPL Diamond plant has no internal moving parts and as a result requires minimal maintenance.

2. Yes, all small treatment plants up to 50 persons must, by law, be fully type tested and certified with the CE Mark accordance with EN12566-3. All manufacturers should be able to produce their certificate on request, ours is available here. It is also important it complies with Environment Agency consent standards and is designed in accordance with British Water Codes of Practice Flows and Loads, to ensure correct sizing of all tanks. The full Diamond DMS and DMC Domestic Sewage Treatment Plants Range is fully type tested and certified in accordance with all these regulations.

3. All sewage treatment plants need to be registered with the Environment Agency (EA) as they may require an environmental permit, or they will need to register for an exemption from this permit if they meet certain requirements. The environmental permit was formerly referred to as a ‘consent to discharge’ as it is an application to discharge treated water to surface water e.g. a stream or estuary, or to ground water via an infiltration system. EPP2 (Environmental Permitting Programme): If the sewage treatment plant is eligible (certificated and CE Marked EN12566-3), it can be registered for a free exemption from the need to have a permit under the Environmental Permitting (England and Wales) Regulations 2010. There are certain conditions associated with registering for this exemption concerning the design, installation and maintenance of the sewage treatment plant. If the treated water is being discharged from an approved domestic sewage treatment plant to a soakaway, the plant will usually be eligible to register for an exemption. All of the plants within the WPL Domestic Diamond sewage treatment range will be eligible to apply for an exemption to the permit. The EA will inform applicants if they are not eligible for a registration and therefore that they require a permit.

4. If a sewage treatment plant has a holding area or primary settlement tank then smells may occur, as is often the case with septic tanks. However, plants which use a continuous aeration process with no primary settlement and no septicity, such as the WPL Diamond Plant, should not emit odours. Therefore the treatment process for the Diamond plant is odour free.

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1.7 GLOSSARY

Third stage treatment is referred to as tertiary treatment or advanced treatment. More commonly used advanced systems are adsorption to activated carbon, filtration through sand and other media, ion exchange, various membrane processes, nitrification-denitrification, coagulation-flocculation, and micro-screening. UNIT 2 SEDIMENTATION

Structure 2.0 Objective 2.1 Introduction 2.2 History 2.3 Sedimentation 2.4 Let us sum up 2.5 Some Useful Books 2.6 Answer to Check your Progress 2.7 Glossary 2.0 OBJECTIVE

Suspended solids (or SS), is the mass of dry solids retained by a filter of a given porosity related to the volume of the water sample. This includes particles of a size not lower than 10 μm. Colloids are particles of a size between 0.001 µm and 1 µm depending on the method of quantification. Due to electrostatic forces balancing the gravity, they are not likely to settle naturally. The limit sedimentation velocity of a particle is its theoretical descending speed in clear and still water. In settling process theory, a particle will settle only if:

1. In a vertical ascending flow, the ascending water velocity is lower than the limit sedimentation velocity.

2. In a longitudinal flow, the ratio of the length of the tank to the height of the tank is higher than the ratio of the water velocity to the limit sedimentation velocity.

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There are four types of sedimentation processes: Type 1 - Dilutes, non-flocculent, free-settling. (Every particle settles independently.) Type 2 - Dilute, flocculent. (Particles can flocculate as they settle.) Type 3 - Concentrated Suspensions, Zone Settling (Sludge Thickening). Type 4 - Concentrated Suspensions, Compression (Sludge Thickening).

2.1 INTRODUCTION

Sedimentation, or clarification, is the process of letting suspended material settle by gravity. Suspended material may be particles, such as clay or silts, originally present in the source water. More commonly, suspended material or floc is created from material in the water and the chemical used in coagulation or in other treatment processes, such as lime softening. (see Coagulation and Flocculation chapter) Sedimentation is accomplished by decreasing the velocity of the water being treated to a point below which the particles will no longer remain in suspension. When the velocity no longer supports the transport of the particles, gravity will remove them from the flow. 2.2 HISTORY

The sedimentation history in the Spring Creek Arm and in Keswick Reservoir can be divided into three phases: (1) prior to the closing of Keswick Dam in January 1950, (2) between January 1950 and the construction of the Spring Creek Debris Dam in 1963 (Prokopovich, 1991), and (3) after 1963. Prior to the construction of Keswick Dam, the Spring Creek watershed drained the Spring Creek Arm and the Iron Mountain region, joining the Sacramento River, which flowed freely through a narrow channel in the vicinity of the town of Keswick. Pre-mining sediments were locally derived and largely composed of granitic boulders and cobbles in a sandy matrix, as found in test borings prior to construction of the Spring Creek Debris Dam. Most of the sediments entering lower Spring Creek were flushed into the Sacramento River during major winter storms and then entered into the normal Sacramento River sedimentary system. These sediments included mining wastes and smelter slag, some of which still lines the banks of the Spring Creek Arm of Keswick Reservoir. The closure of Keswick Dam in 1950 flooded the lower Spring Creek area. This event led to the rapid construction of a delta in lower Spring Creek between 1950 and 1963 that was composed of alluvium, smelter wastes, and mining-related debris flushed down Spring Creek into the reservoir. By 1960, the length of the subaerial delta was about 850 m, ranging from 0.1 to 8.6 m in thickness, and averaging 4.2 m (Prokopovich, 1991). The shallowest part of the Spring Creek Delta was excavated during construction of the tailrace channel for the Spring Creek Power Plant; at least some of the excavated material was used in the construction of the Spring Creek Debris Dam (Prokopovich, 1991). After completion of the Spring Creek Debris Dam in 1963, sedimentation into the lower Spring Creek Arm of Keswick Reservoir was largely derived from metals precipitated out of the acid-mine drainage waters entering the reservoir via Spring Creek. The resulting reddish-brown mud comprises most of the sediment sampled from the present sediment accumulations in the arm. Within these muds are occasional layers of sandy to silty sediment, probably derived during times of high flow or overflow from the Spring Creek Debris Dam. The sediments that now

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occupy the arm consist largely of chemically precipitated materials of distinctly fine-grain size; these were the focus of the 1993 surveying effort by the USGS. 2.3 SEDIMENTATION

FACTORS AFFECTING SEDIMENTATION Several factors affect the separation of settleable solids from water. Some of the more common types of factors to consider are: PARTICLE SIZE The size and type of particles to be removed have a significant effect on the operation of the sedimentation tank. Because of their density, sand or silt can be removed very easily. The velocity of the water-flow channel can be slowed to less than one foot per second, and most of the gravel and grit will be removed by simple gravitational forces. In contrast, colloidal material, small particles that stay in suspension and make the water seem cloudy, will not settle until the material is coagulated and flocculated by the addition of a chemical, such as an iron salt or aluminum sulfate. The shape of the particle also affects its settling characteristics. A round particle, for example, will settle much more readily than a particle that has ragged or irregular edges. All particles tend to have a slight electrical charge. Particles with the same charge tend to repel each other. This repelling action keeps the particles from congregating into flocs and settling. WATER TEMPERATURE Another factor to consider in the operation of a sedimentation basin is the temperature of the water being treated. When the temperature decreases, the rate of settling becomes slower. The result is that as the water cools, the detention time in the sedimentation tanks must increase. As the temperature decreases, the operator must make changes to the coagulant dosage to compensate for the decreased settling rate. In most cases temperature does not have a significant effect on treatment. A water treatment plant has the highest flow demand in the summer when the temperatures are the highest and the settling rates the best. When the water is colder, the flow in the plant is at its lowest and, in most cases, the detention time in the plant is increased so the floc has time to settle out in the sedimentation basins. CURRENTS Several types of water currents may occur in the sedimentation basin: Density currents caused by the weight of the solids in the tank, the concentration of solids and temperature of the water in the tank. Eddy currents produced by the flow of the water coming into the tank and leaving the tank. The currents can be beneficial in that they promote flocculation of the particles. However, water currents also tend to distribute the floc unevenly throughout the tank; as a result, it does not settle out at an even rate. Some of the water current problems can be reduced by the proper design of the tank. Installation of baffles helps prevent currents from short circuiting the tank. SEDIMENTATION BASIN ZONES Under ideal conditions, the sedimentation tank would be filled with the water that has been

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coagulated, and the floc would be allowed to settle before any additional water is added. That is not possible for most types of water treatment plants. Most sedimentation tanks are divided into these separate zones: Inlet zone The inlet or influent zone should provide a smooth transition from the flocculation zone and should distribute the flow uniformly across the inlet to the tank. The normal design includes baffles that gently spread the flow across the total inlet of the tank and prevent short circuiting in the tank. (Short circuiting is the term used for a situation in which part of the influent water exits the tank too quickly, sometimes by flowing across the top or along the bottom of the tank.) The baffle could include a wall across the inlet, perforated with holes across the width of the tank. Settling Zone The settling zone is the largest portion of the sedimentation basin. This zone provides the calm area necessary for the suspended particles to settle. Sludge Zone The sludge zone, located at the bottom of the tank, provides a storage area for the sludge before it is removed for additional treatment or disposal. Basin inlets should be designed to minimize high flow velocities near the bottom of the tank. If high flow velocities are allowed to enter the sludge zone, the sludge could be swept up and out of the tank. Sludge is removed for further treatment from the sludge zone by scraper or vacuum devices which move along the bottom. Outlet Zone The basin outlet zone or launder should provide a smooth transition from the sedimentation zone to the outlet from the tank. This area of the tank also controls the depth of water in the basin. Weirs set at the end of the tank control the overflow rate and prevent the solids from rising to the weirs and leaving the tank before they settle out. The tank needs enough weir length to control the overflow rate, which should not exceed 20,000 gallons per day per foot of weir.

SELECTION OF BASIN There are many sedimentation basin shapes. They can be rectangular, circular, and square.

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Rectangular Basins

Rectangular basins are commonly found in large-scale water treatment plants. Rectangular tanks are popular as they tend to have:

High tolerance to shock overload Predictable performance Cost effectiveness due to lower construction cost

Lower maintenance Minimal short circuiting

Circular and Square Basins Circular basins are frequently referred to as clarifiers. These basins share some of the performance advantages of the rectangular basins, but are generally more prone to short circuiting and particle removal problems. For square tanks the design engineer must be certain that some type of sludge removal equipment for the corners is installed.

HIGH RATE SETTLERS High rate tube settlers are designed to improve the characteristics of the rectangular basin and to increase flow through the tank. The tube settlers consist of a series of tubes that are installed at a

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60 degree angle to the surface of the tank. The flow is directed up through the settlers. Particle have a tendency to flow at a angle different than the water and to contact the tube at some point before reaching the top of the tube. After particles have been removed from the flow and collected on the tubes, they tend to slide down the tube and back into the sludge zone.

SOLIDS CONTACT UNITS A solids contact unit combines the coagulation, flocculation, and sedimentation basin in one unit. These units are also called upflow clarifiers or sludge-blanket clarifiers. The solids contact unit is used primarily in the lime-soda ash process to settle out the floc formed during water softening. Flow is usually in an upward direction through a sludge blanket or slurry of flocculated suspended solids.

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Check your progress-1

1. Why does the cataweb county erosion control program cost more than the state’s program?

2. Who do I call if I see mud in the street near a construction site? 3. What’s in the county soil erosion and sedimentation control ordinance?

2.4 LET US SUM UP

In conclusion, approximately 1,800,000 yd3 (or about 2,400,000 tons) of sandy overbank deposits are stored along the margins of Halfway Creek through the upper and lower marsh and in alluvial fan deposits where Sand Lake Coulee previously entered or currently enters the lower marsh. The historical overbank deposits affect the modern fluvial processes of Halfway Creek and marsh/wetland fluvial dynamics. The fluvial system through the marsh accepts the additional sediment and adjusts within the physical laws that constrain it. System-wide adjustments to historical sediment loading of this magnitude will probably continue for decades and centuries, manifested during extreme floods and moderate flows, continually flushing legacy sediment from channel margins downstream into the lower marsh and eventually to Lake Onalaska and to the Mississippi River. The history of human activities, magnitude of overbank sediment loading, and continued fluvial adjustments to the loading in Halfway Creek Marsh are typical for the numerous small tributaries that flow into critical backwater marsh habitats along the Upper Mississippi River National Wildlife and Fish Refuge and along the Upper Mississippi River System. Due to the high probability of remobilization of stored historical sediment and associated nutrients, and their long-term effects on lowland vegetation and fish and wildlife habitat, it is important to improve understanding of how human activities have influenced patterns and rates of sedimentation in riparian environments. In addition, the legacy of past

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erosion and sedimentation will continue to influence current and future water quality, sediment loads, nutrient loads, and water-related resources. 2.5 SOME USEFUL BOOKS

Anderson, R.F., Schiff, S.L., and Hesslein, R.H., 1987, Determining sediment accumulations and mixing rates using 210Pb, 137Cs, and other tracers—Problems due to postdepositional mobility or coring artifacts: Canadian Journal of Fisheries and Aquatic Science, v. 44 (Supplement 1), p. 231–240.

Birkland, P.W., 1984, Soils and geomorphology: New York, Oxford University Press, 372 p.

Brown, W.N., Inc., 1931. Upper Mississippi River—Hastings, Minnesota to Grafton, Illinois, Survey 1929 to 1930: Washington, D.C., Williams and Heintz Co.

Butterfield, C.W., 1881, History of Wisconsin, in History of La Crosse County, Wisconsin: Chicago, Western Historical Company, p. 19–308.

2.6 ANSWER TO CHECK YOUR PROGRESS

Check your progress-1

1. The County’s Soil Erosion and Sedimentation Control Program forms a true partnership between the regulatory body and developer/property owner. County staff will respond to complaints and concerns within 1 (one) working day. Plans are reviewed in 10 (ten) days or less with Express Plan Review options. NC DENR (North Carolina Department of Natural Resources) is only in Catawba County 3 (three) days per week; County staff are present every workday and are active partners in all land disturbing activities to ensure water quality and erosion control compliance. The Catawba County Erosion Control program is completely self-supported by users of the program. No tax money or general fund money is used to support the erosion control program.

2. A county inspector will assess the matter within 1 (one) working day. If a violation is found and documented, a Notice of Violation (NOV) will be imposed on the site. If a construction site is out of compliance, and receives a Notice of Violation, the project may not have any activity, i.e. building inspections, until the NOV re-inspection fine is paid to the Catawba County Finance Department, located on the second floor of the Government Center in Newton. Fines and re-inspection fees may NOT be charged; they must be paid by cash or check.

3. The law in North Carolina is that if you disturb any earth at all you need to “take all reasonable measures” to make sure the sediment doesn’t damage adjacent properties. In the case of the Catawba County Ordinance, disturbance of one acre or more requires a formal plan submittal and review. However, just because a construction site is not required to submit a plan does NOT mean that site is exempt from sedimentation control laws. You must take all reasonable measures to keep your soil on your own property, off of roads and adjacent land and out of creeks and waterways.

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2.7 GLOSSARY Only long-term, prevailing currents can deposit homogeneous sediments (like the Coconino) across the face of a continent in a global flood scenario. In response, YEC's propose that large-scale, regional currents were responsible for depositing extensive, tabular beds of sandstone, shale, and limestone. But such currents cannot account for the heterogeneity found in the layers of the Bright Angel Shale, Supai Group, and other formations. Consequently, YEC's must also argue that repeated transgression, regression, and periods of 'stand-still' occurred amid the flood, wherein sediments of differing clast size and composition could be deposited between larger waves. But if continuous, prevailing currents are not sufficient even to carry the sediment required even for the 150–500 foot-thick Coconino Sandstone within a full year, how can Flood geologists explain the remaining miles of sediment in the Colorado Plateau? The challenge grows immensely when one examines the microscale heterogeneity in sedimentary rocks (carbonates in particular). Catastrophic, sediment-choked currents would have had zero time to slow down, change directions, or stop completely. Therefore, Flood geology cannot satisfactorily explain the range of geological data as a unified theory. But unfortunately, Flood geologists continue to mislead amateur readers by explaining various phenomena in isolation from the relevant data. The result is a confused populace, seeking only to reconcile their faith with the facts of nature. Such misplaced trust is unhealthy, in my opinion, for the future of public/private education, the scientific community, and especially for the church.

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UNIT 3 SEPTIC TANKS

Structure 3.0 Objective 3.1 Introduction 3.2 History 3.3 Septic tanks 3.4 Let us sum up 3.5 Some Useful Books 3.6 Answer to Check your Progress 3.7 Glossary 3.0 OBJECTIVE

In this lesson we are going to discuss in detailed manner about : A septic tank is an underground watertight chamber made of brick work, concrete,

fibreglass, PVC or plastic that receives both blackwater from cistern or pour-flush toilets and greywater through a pipe from inside a building.

Settling and anaerobic digestion reduce solids and organics. Septic tanks are primary treatment methods, and the only moderately treated effluent is infiltrated into the ground or transported via a sewer. Accumulating faecal sludge needs to be dug out the chamber and correctly disposed regularly.

3.1 INTRODUCTION

These septic system articles explain how to buy, inspect, install, test, diagnose maintain and repair septic tanks and all other components of all types of septic systems. We discuss how septic systems work, and how to provide septic system care to avoid replacing the septic system unnecessarily. We provide septic cleaning and septic maintenance procedures, septic inspection methods, septic repair guides, and septic system design information. 3.2 HISTORY

For many years, in fact 1000's of years sanitation (in this context the disposal of raw sewage) was not a pleasant, responsible or healthy one. In England up until the victorian era people would generally go outside to do their business. In isolated country places this worked fine, but in villages and towns this posed a real problem. People would literally poo and wee everywhere indiscriminately. Whether it be in the streets, in rooms, in houses in pubs or even in the Kings court! The terrible extent to how bad this became peaked in Henry VIII's time. Things got so bad that he passed a law that no one was allowed to randomly poo and wee in his court any more. The problem became especially dire in London. Although cesspits were starting to be built and used, raw sewage was still everywhere. This led to the contamination of water sources especially wells. The result was cholera and 1000's of people died because of it. 3.3 SEPTIC TANKS

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The septic tank is the most common small-scale decentralised treatment unit for greywater and blackwater from cistern or pour-flush toilets. It is basically a sedimentation tank (physical treatment) in which settled sludge (solids and organics) is stabilised by anaerobic digestion (biological treatment). Dissolved and suspended (unsettleable) matter leaves the tank more or less untreated. Its shape can be rectangular or cylindrical. Septic tanks are used for wastewater with a high content of settleable solids, typically for effluent from domestic sources, but they are also suitable for other wastewater of similar properties (SASSE 1998). Typical basic systems including septic tanks at household or school level are pour flush toilets, followed by two-chamber septic tanks and a soak pit, a leach field, or an evapo-transpiration mound (www.schoolsanitation.org). In densely populated areas, on-site infiltration should not be used because the saturation of the soil with the only moderately treated effluent can cause a serious health risk. In these cases, septic tanks should be connected to a simplified sewer or solids-free sewer to transport the effluents to a secondary treatment (e.g. surface flow, horizontal or vertical flow constructed wetlands). When septic tanks are used as a primary settling treatment in DEWATS systems, they are generally followed by anaerobic filters, anaerobic baffled reactors (ABRs), constructed wetlands (planted gravel filters) and maturation ponds. In any case, water is needed to pour and bring the wastes to the septic tank (5 to 40 L of water per day per person, DFID 2003).

Overview scheme of a septic tank. Solids settle out and undergo anaerobic digestion, the effluent with suspended and dissolved pollutants flows through. A venting pipe can evacuate the biogas formed during anaerobic digestion. Source: adapted from TILLEY et al. (2008). Treatment Process and Basic Design Principles A septic tank consists at minimum of 2 compartments made out of concrete or bricks. Pre-fabricated concrete rings, PVC or fibreglass septic tanks are also available and may be less expensive in some contexts (WSP 2008). The first compartment occupies at least the half the total volume, because most of the sludge accumulates here (SASSE 1998), while scum (oil and fat) floats to the top. When there are only two chambers, the first one should be 2/3 of the total length (TILLEY et al. 2008). The following chamber(s) are provided to calm the turbulent liquid.

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The baffle, or the separation between the chambers, is to prevent scum and solids from escaping with the effluent (TILLEY et al. 2008). A T-shaped outlet pipe, the lower arm of which dives 30 cm below water level (SASSE 1998), will further reduce the scum and solids that are discharged.

Normally, the chambers are all of the same depth (between 1.5 to 2.5 m), but sometimes the first chamber is made deeper as the others. Over time, anaerobic bacteria and microorganisms start to digest the settled sludge anaerobically, transforming it into CO2 and CH4 (biogas) and some heat. Optimal physical treatment by sedimentation

takes place when the flow is smooth and undisturbed. Biological treatment by anaerobic digestion is optimised by a quick and intensive contact between the new inflow and old sludge, particularly when the flow is turbulent. Depending on the way the new influent flows through the tank, different treatment effect predominate. With a turbulent flow, the degradation of suspended and dissolved solids starts more quickly; however, more suspended solids are discharged with the effluent. This leads to bad odours, as active solids that are not completely fermented leave the tank (SASSE 1998). The contact and hence degradation is slower when the flow is less turbulent, but also less suspended solids leave the tank. The gases produced during anaerobic digestion must be allowed to escape. If the drainage system of the house or other building has a ventilation pipe at the upper end, gases can escape from the septic tank along the drains. If the drainage system is not ventilated, a screened vent pipe should be provided from the septic tank itself (WHO 1992). A septic tank as primary treatment, followed by a leach field. Source: U.S. EPA (n.y.) The size of the first chamber is calculated to be at least twice the accumulating sludge volume. The sludge volume depends on different factors: the number of users; the portion of settleable solids of the influent; the amount of water used per capita; the average annual temperature and on de-sludging intervals (SASSE 1998). Approximately 80 to 100 L should be provided per domestic user (SASSE 1998), but most countries provide a national standard for tank volume per domestic user. The retention time should be designed for 48 hours to achieve at least a moderate treatment (TILLEY et al. 2008). For help on dimensioning of septic tank, an exercise is given in Eawag/Sandec (2008, Sanitation Systems and Technologies. Exercise Septic Tank) and Excel

spreadsheets are available in SASSE (1998). Septic tank receiving black- and greywater from a housing (left) and a septic tank collecting wastewater from several housing as a primary treatment before a small bore sewer system (right). Sources: http-

//cfpub.epa.gov/owm/septic/septic.cfm?page_id=265 (left) and SANIMAS (2005) (right).

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A septic tank will remove 30 to 50% of BOD (Biological Oxygen Demand), 40 to 60% of TSS (Total Suspended Solids) (UNEP 2004) and result in an abatement of 1 log units E. coli (a faecal indicator bacteria) (TILLEY et al. 2008) although efficiencies vary greatly depending on the influent concentrations and climatic conditions. Hydraulic Retention Times (HRT) are generally 24 hours (MOREL & DIENER 2006).

Aqua privy Toilet with aqua privy and soak pit. Source: WAaF (2002) The aqua privy is a variation of the septic tank and consists of a simple storage and settling tank immediately under the latrine floor. Excreta drop directly into the tank through a pipe. The bottom of the pipe is submerged in a liquid in the tank, forming a water seal to prevent escape of flies, mosquitoes and smell (WHO 1992). The tank functions like a septic tank.

The effluent usually infiltrates into the ground through a soak pit and accumulated solids (sludge) must be removed frequently (WHO 1992). In any case, the accumulating sludge must be treated. Costs considerations Construction costs of septic tank are relatively low compared to other water based systems. However, they are much more expensive than for dry or composting toilets and unlikely to be affordable by poorer people in society. They also require sufficient piped water to flush all the wastes through the drains and manual or mechanical (vacuum or gulper) de-sludging needs to be done periodically. Engineers must prepare design and layout, while unskilled labourers can carry out construction if a mason supervises the work. Operation and Maintenance To start up a septic tank it should be "seeded" with sludge from a tank that has been operating for some time to ensure that the necessary microorganisms responsible for anaerobic digestion are present (WHO 1992). Routine inspection is necessary to remove floating debris such as coarse materials and grease, to ensure that there are no blockages at the inlet or outlet and to check whether de-sludging is needed. De-sludging is needed when 1/2 to 2/3 of the total depth between the water level and the bottom of the tank are occupied by sludge and scum (WHO 1992). One of the difficulties with septic tanks is that when the tank is almost full of solids, the inflow scours a channel through the sludge and pass through the tank in a matter of minutes rather than remaining in the tank for the required retention time (SASSE 1998). The most satisfactory method of sludge removal is by vacuum tanker. If a vacuum tanker is not available, the sludge must be bailed out manually using buckets or a gulper. This is an unpleasant work and care must be taken to ensure that sludge is not spilled around the tank during emptying, as the removed sludge from a septic tank includes fresh excrete and presents a risk of transmission of diseases of faecal origin (TILLEY et al. 2008). The faecal sludge needs to be correctly disposed and further treated (e.g. small or large scale composting , anaerobic digestion). Before that, the faecal sludge

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can also be further separated from the liquid in drying beds or settling. The separated effluents from these systems should be treated in waste stabilisation ponds (WSP) or constructed wetlands (surface flow, horizontal or vertical flow). Generally, septic tanks should be emptied every 1 to 5 years. A small amount of sludge should be left in the tank to ensure continuing rapid digestion. When opening the tank, gas produced in anaerobic digestion could escape and therefore, open fire should be avoided when opening the septic tank. Regular de-sludging activities require well-organised community or public/private service provider (TILLEY et al. 2008). Because of the delicate ecology, care should also be taken not to discharge harsh chemicals into the septic tank (TILLEY et al. 2008). Health Aspects Since the effluent from septic tanks is anaerobic, it is likely to contain large numbers of pathogens, which can be a potential source of infection (WHO 1992). Many of the problems with septic tank systems arise because no adequate consideration is given to the disposal of the tank effluent. However, the entire tank is below the surface so direct contact of users with any wastewater is avoided (TILLEY et al. 2008). But because of the microbial health risk which arises from both the effluent and the faecal sludge care should be taken during inspections and emptying. Mechanical emptying in a vacuum truck or a manual technology like a sludge gulper can decrease the health risks (TILLEY et al. 2008). At a Glance

Working Principle

Basically a sedimentation tank (physical treatment) in which settled sludge is stabilised by anaerobic digestion (biological treatment). Dissolved and suspended matter leaves the tank more or less untreated.

Capacity/Adequacy

Household and community level; Primary treatment for domestic grey- and blackwater. Depending on the following treatment, septic tanks can also be used for industrial wastewater. Not adapted for areas with high groundwater table or prone to flooding.

Performance BOD: 30 to 50%; TSS: 40 to 60 %; E. coli: 1 log units HRT: about 1 day

Costs Low-cost, depending on availability of materials and frequency of de-sludging.

Self-help Compatibility Requires expert design, but can be constructed with locally available material.

O&M

Should be checked for water tightness, scum and sludge levels regularly. Sludge needs to be dug out every 1 to 5 years and discharged properly (e.g. in composting or drying bed). Needs to be vented.

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Reliability When not regularly emptied, wastewater flows through without being treated. Generally good resistance to shock loading.

Main strength Simple to construct and to operate.

Main weakness Effluent and sludge require further treatment. Long start-up phase.

Applicability Septic tanks can be installed in every type of climate, although the efficiency will be affected in colder climates (TILLEY et al. 2008). Septic tanks are used for wastewater with a high percentage of settleable solids, typically for effluent from domestic sources (SASSE 1998). They can be introduced as a decentralized, on-site treatment system at household, block or school level (UNEP 2004). Effluents still contain pathogens and should therefore not be used for crop irrigation nor should it be discharged to canals or surface water drains (WHO 1992). Effluents form septic tanks can be soil infiltrated in soak pits, a leach field or mounds. In more dense areas, the effluents should not be infiltrated but the septic tank may be integrated as individual pre-treatment units for a community into a small bore sewer system transporting the wastewaters to a secondary treatment. Even though the septic tank is watertight, it should not be constructed in areas with high groundwater tables or where there is frequent flooding (TILLEY et al. 2008). Aqua privies can be built indoors and above ground and are appropriate for rocky or flood prone areas where pits or other technologies would not be appropriate, but they require frequent emptying and constant maintenance (TILLEY et al. 2008). Advantages

Can be built and repaired with locally available materials No real problems with flies or odours if used correctly Long service life Little space required due to underground construction Low investment costs, low operation and maintenance costs depending on the availability

of water and the requirement for emptying No energy required

Disadvantages High cost compared to dry or composting toilet systems Constant and sufficient amounts of piped water required to bring the waste to the

treatment unit Low reduction in pathogens, solids and organics: Secondary treatment for both effluent

and faecal sludge required De-sludging required: Manual de-sludging is hazardous to health and mechanical de-

sludging (vacuum trucks) requires the infrastructure and may be rather costly Only suitable for low-density housing in areas with low water table and not prone to

flooding Manual cleaning of the tank is highly hazardous and an inhumane task, while mechanical

cleansing (vacuum trucks) requires sophisticated instruments Check your progress-1

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1. How can I inspect my septic tank myself? 2. I have an alternating drain field system. How often should I alternate my leach lines? 3. How can I locate my septic tank? 4. Can I install a drywell for my graywater?

3.4 LET US SUM UP

septic tank, underground sedimentation tank in which sewage is retained for a short period while it is decomposed and purified by bacterial action. The organic matter in the sewage settles to the bottom of the tank, a film forms excluding atmospheric oxygen, and anaerobic bacteria attack the solid matter, causing it to disintegrate, liquefy, and give off gases. The gases are discharged from a vent and the liquids overflow through an outlet into a disposal field where they can leach into the soil. Here aerobic bacteria purify the liquid. The Imhoff septic tank, an improvement over the ordinary septic tank, is still used in the United States; it is a two-story structure with the upper compartment used for settling the sewage, the lower one for the anaerobic disintegration of sludge. A sloping floor enables solid material to slide to the lower compartment, where, since the sludge is separated from the material in the sedimentation compartment, the action is more rapid. A cesspool is a simpler underground structure that allows the liquids to leach directly into the soil while retaining the solids. The solids are not as efficiently decomposed as in a septic tank and more frequent cleaning is necessary. Also, as the effluent is likely to contain more coliform bacteria than that of a septic tank, cesspools pose a greater threat to water supplies. Septic tanks and cesspools are usually used in rural areas. For urban sewage-disposal systems 3.5 SOME USEFUL BOOKS

Evans, T.J., 2003, Geology of La Crosse County, Wisconsin: Wisconsin Geological and Natural History Survey, Bulletin 101, 33 p.

Fitzpatrick, F.A., Knox, J.C., and Whitman, H.E., 1999, Effects of historical land-cover changes on flooding and sedimentation, North Fish Creek, Wisconsin: U.S. Geological Survey Water-Resources Investigations Report 99–4083, 12 p.

Fitzpatrick, F.A., 2005, Trends in streamflow, sedimentation, and sediment chemistry for the Wolf River, Menominee Indian Reservation, Wisconsin, 1850–1999: U.S. Geological Survey Scientific Investigations Report 2005–5030, 47 p.

Happ, S.C., Rittenhouse, G., and Dobson, G.C., 1940, Some principles of accelerated stream and valley sedimentation: U.S. Department of Agriculture Technical Bulletin 695.

3.6 ANSWER TO CHECK YOUR PROGRESS

1. The easiest way to gain information on the condition of the tank is to hire a professional experienced with septic systems. To inspect the tank, remove the manhole cover at the inlet end. It is most thorough to check both the scum and sludge levels, but checking only the scum layer will give you a good idea if the tank needs pumping or not. Usually these tanks have a 6-foot liquid depth. Use caution to avoid falling in the tank. Do not

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light a match near an open tank or inhale significant amounts of noxious fumes liberated. Standing on the tank or surrounding soil, use a shovel and push the scum layer away from the side of the tank so that you can estimate its thickness. If the thickness of the scum layer is a foot or more, arrange to have your tank pumped immediately. Replace the manhole cover and thoroughly wash the shovel and hands. The disease-causing bacteria found in the septic tank can be hazardous to your health if ingested. Good person hygiene after this type of contact is critical. If your system has inspection pipes at the end of the leach lines, theycan be checked for pooling of liquid. Accumulation of water in the leach line is an early indication of problems.

2. Every 6 to 12 months. This gives the unused leach lines a time to “rest”, thereby increasing the life of the system. Be sure to rotate the valve back again after the 6 to 12 month resting period.

3. Some simple methods are to probe for the tank with a metal rod, follow the pipeline from the house or by listening for the noise a plumber’s snake makes when it hits the tank. Dig to uncover the manholes on the top of the tank. Your local Environmental Health Division is available to assist with questions or concerns. If you suspect or detect failure of your system, or plan to repair a system, contact the Environmental Health Division. All new construction or repair work on septic system must be done under permit from the Health Department.

4. A drywell is a shallow pit filled with stone or perforated well tile that holds a volume of water within the well and allows it to trickle out through the sides of the pit. When used to dispose of wastewater a drywell is also known as a cesspool or seepage pit. This type of system cannot be legally installed in Maine because the wastewater does not receive adequate treatment and may pollute the groundwater. Separated laundry disposal systems may be used if designed by a licensed site evaluator. The requirements for a separated laundry system are the same as for any other wastewater disposal system except that a septic tank is not required before the leachfield. Because there is no preliminary treatment in a tank, this type of system is susceptible to plugging due to lint. A separated laundry system may be an economical alternative to replacing the entire leachfield when the performance of the septic system is sluggish, but site conditions may prevent this from being a satisfactory alternative.

3.7 GLOSSARY

A single-story, watertight, on-site treatment system for domestic sewage, consisting of one or more compartments, in which the sanitary flow is detained to permit concurrent sedimentation and sludge digestion. The septic tank is constructed of materials not subject to decay, corrosion, or decomposition, such as precast concrete, reinforced concrete, concrete block, or reinforced resin and fiberglass. The tank must be structurally capable of supporting imposed soil and liquid loads. Septic tanks are used primarily for individual residences, isolated institutions, and commercial complexes such as schools, prisons, malls, fairgrounds, summer theaters, parks, or recreational facilities. Septic tanks have limited use in urban areas where sewers and municipal treatment plants exist. See Concrete, Reinforced concrete, Structural materials Septic tanks do not treat sewage; they merely remove some solids and condition the sanitary flow so that it can be safely disposed of to a subsurface facility such as a tile field, leaching pools, or buried sand filter. The organic solids retained in the tank undergo a process of liquefaction and anaerobic decomposition by bacterial organisms. The clarified septic tank

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effluent is highly odorous, contains finely divided solids, and may contain enteric pathogenic organisms. The small amounts of gases produced by the anaerobic bacterial action are usually vented and dispersed to the atmosphere without noticeable odor or ill effects. See Sewage, Sewage treatment

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UNIT 4 DISPOSAL OF SEPTIC TANK EFFLUENT

Structure 4.0 Objective 4.1 Introduction 4.2 History 4.3 Disposal of Septic Tank effluent 4.4 Let us sum up 4.5 Some Useful Books 4.6 Answer to Check your Progress 4.7 Glossary 4.0 OBJECTIVE

In this lesson we will discuss the concepts of disposal of septic tank effluent. After studying this lesson you will be able to: (i) define dispocal tank. (ii) describe septic tank effluent.. 4.1 INTRODUCTION

A septic tank generally consists of a tank (or sometimes more than one tank) of between 4000 and 7500 litres (1,000 and 2,000 gallons) in size connected to an inlet wastewater pipe at one end and a septic drain field at the other. In general, these pipe connections are made via a T pipe, which allows liquid entry and exit without disturbing any crust on the surface. Today, the design of the tank usually incorporates two chambers (each of which is equipped with a manhole cover), which are separated by means of a dividing wall that has openings located about midway between the floor and roof of the tank. Wastewater enters the first chamber of the tank, allowing solids to settle and scum to float. The settled solids are anaerobically digested, reducing the volume of solids. The liquid component flows through the dividing wall into the second chamber, where further settlement takes place, with the excess liquid then draining in a relatively clear condition from the outlet into the leach field, also referred to as a drain field or seepage field, depending upon locality. The remaining impurities are trapped and eliminated in the soil, with the excess water eliminated through percolation into the soil (eventually returning to the groundwater), through evaporation, and by uptake through the root system of plants and eventual transpiration. A piping network, often laid in a stone-filled trench (see weeping tile), distributes the wastewater throughout the field with multiple drainage holes in the network. The size of the leach field is proportional to the volume of wastewater and inversely proportional to the porosity of the drainage field. The entire septic system can operate by gravity alone or, where topographic considerations require, with inclusion of a lift pump. Certain septic tank designs include siphons or other methods of increasing the volume and velocity of outflow to the drainage field. This helps to load all portions of the drainage pipe more evenly and extends the drainage field life by preventing premature clogging. An Imhoff tank is a two-stage septic system where the sludge is digested in a separate tank. This avoids mixing digested sludge with incoming sewage. Also, some septic tank designs have a

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second stage where the effluent from the anaerobic first stage is aerated before it drains into the seepage field. Waste that is not decomposed by the anaerobic digestion eventually has to be removed from the septic tank, or else the septic tank fills up and undecomposed wastewater discharges directly to the drainage field. Not only is this bad for the environment but, if the sludge overflows the septic tank into the leach field, it may clog the leach field piping or decrease the soil porosity itself, requiring expensive repairs. How often the septic tank has to be emptied depends on the volume of the tank relative to the input of solids, the amount of indigestible solids, and the ambient temperature (as anaerobic digestion occurs more efficiently at higher temperatures). The required frequency varies greatly depending on jurisdiction, usage, and system characteristics. Some health authorities require tanks to be emptied at prescribed intervals, while others leave it up to the determination of the inspector. Some systems require pumping every few years or sooner, while others may be able to go 10–20 years between pumpings. Contrary to what many believe, there is no "rule of thumb" for how often tanks should be emptied. An older system with an undersize tank that is being used by a large family will require much more frequent pumping than a new system used by only a few people. Anaerobic decomposition is rapidly re-started when the tank re-fills. A properly designed and normally operating septic system is odor-free and, besides periodic inspection and pumping of the septic tank, should last for decades with no maintenance 4.2 HISTORY

State Government involvement in STEDS – a brief history It has been asserted that there is not a clear, ntegrated policy position on STEDS by the State Government, even though there are a number of agencies with an interest either in terms of development or regulation of schemes. A brief outline of the history of the development of sewerage infrastructure and services is helpful in gaining an understanding of the current policy. The Sewerage Act 1929 is the legislation providing for the State Government to construct and operate deep drainage sewerage treatment schemes in South Australia. Section 18 of that Act enables areas of the State to be proclaimed as drainage areas in the metropolitan area and country drainage areas, typically in the larger provincial cities. It is self evident that in the proclaimed drainage areas, the State Government through the then Engineering and Water Supply Department (E&WS) was responsible for the construction, operation and funding of the sewerage systems. Outside of the proclaimed drainage areas, pressure developed progressively for communal effluent drainage solutions for areas where septic tank effluent was causing problems in country towns or on the metropolitan fringe. Initially the demand for STEDS in these locations was managed solely by councils, and reflecting this fact, the Parliament introduced ‘enabling provisions’ to the Local Government Act 1934 in 1963 and 1965 clarifying councils’ powers to construct and manage STEDS and to levy user charges. However, by 1972 the high demand for STEDS and increasing costs of installation led to State Government involvement through provision of funds to assist in the installation of new schemes. The policy and funding administration responsibility for STEDS in the State Government was transferred several times between 1972 and 1994 from E&WS, the SA Health Commission and ultimately the then Department of Local Government, prior to its abolition in 1990. Consistent with the thinking of the time, the administrative responsibility for STEDS was transferred to the LGA as part of the State / Local Government Reform Fund negotiations, as it was considered that the State Government funding contribution could be efficiently and effectively managed by the Local Government sector through the LGA.

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These arrangements were confirmed in a Memorandum of Understanding in 1994 and with an extension in 2000. In summary, for the whole period of the history of the development of STEDS in this State, the STEDS program has struggled to find a natural ‘home’ in the State Government agency framework. State legislation guides the installation, licensing and operation of STEDS schemes; namely the Public and Environment Health Act 1987 and the Environment Protection Act 1993 (with further statutory requirements under the Environment Protection (Water Quality) Policy). There also appears to have been at least a de facto recognition that the State Government shared some responsibility for STEDS (as the ‘equivalent’ service to E&WS sewerage systems) through ongoing State Government funding. However, the primary responsibility for STEDS has remained with the Local Government sector. 4.3 DISPOSAL OF SEPTIC TANK EFFLUENT

We assess applications for on-site effluent disposal systems within the City. This includes both combined effluent disposal systems at premises where sewer is not available, and also greywater re-use systems which may be installed in either sewered or unsewered areas. The City of Cockburn will only consider applications for installation of an on-site effluent disposal system where that system has been approved for use in Western Australia by the Department of Health. The type of system required at a property depends on a number of factors. The On-site Effluent Disposal Systems brochure has further information on such systems in the City.

Conventional septic system Nutrient retentive effluent disposal systems Greywater Re-use Systems Application to install an effluent disposal system - forms

and charges Water Corporations infill sewage program Decommissioning of septic tanks

Conventional Septic System Conventional effluent disposal systems incorporate two septic tanks and two leach drains or four soak wells. Septic tanks digest the solid and liquid waste into an effluent, which is discharged into the ground via the leach drains or soak wells. Please check the list of approved plastic septic tanks for plastic tanks that are approved to be used. Please check the Yellow Pages for suppliers of concrete septic tanks. More information can be found by reading the Understanding Septic Tank Systems brochure. There are a number of requirements associated with the installation of an effluent disposal system, including setbacks and environmental factors. The Standard Systems brochure has further information. Maintenance of Systems DO DO NOT Pump out the tanks regularly:

average 4 person household approximately every 4 years.

2 person household approximately 8-9 years.

Dispose of materials that do not break down readily (e.g. plastic bags, kitchen sponges, sanitary napkins, tampons, disposable nappies). Dispose of old medicines, large amounts of

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Alternate your leach drains each year. All domestic systems approved from 1990 and onwards have two leach drains and an alternating device to allow systems to rest.

disinfectant or other strong chemicals down the pipes leading to the septic tank. (Bleaches and detergents are acceptable if used in moderation).

Please be advised that only licensed liquid waste contractors can pump out septic tanks. A list of contractors can be obtained from the Yellow Pages under Septic Tank Cleaning Services. Nutrient Retentive Systems Nutrient retentive onsite effluent disposal systems are an alternative to conventional septic systems. They can be installed in areas which are environmentally sensitive, or where untreated effluent would pose a public health risk, due to their ability to produce "cleaner" effluent. Nutrient retentive systems are required in a number of areas within the resource zone due to high ground water levels and their close proximity to the Peel-Harvey Catchment Area. Nutrient retentive onsite effluent disposal system are categorised into one of two types:

1. Aerobic Treatment Units (ATU) incorporate aeration systems to aid in the breakdown of the waste to an effluent. The effluent is then further treated and disposed of either by surface irrigation, sub-soil dripper or leach drain system. Surface irrigation is not a preferred method of disposal within the City.

2. Nutrient Removing Effluent Disposal Systems utilise septic tanks to process the solid and liquid wastes, however the effluent is discharged through an amended soil, which strips the effluent of nutrients.

Please check the list of approved aerobic treatment units and nutrient removing systems for apparatus that are approved by the Department of Health for use. It is recommended that you contact the manufacturers of ATU's and nutrient retentive leaching systems to obtain further details on approved systems. Greywater re-use systems Greywater systems allow house holders to conserve water by re-using wastewater from bathrooms and laundries (greywater) on gardens and lawns on their property. The Department of Health approves the design of greywater systems under the current legislation. These systems provide some treatment or filtration of greywater before disposal of the effluent through a sub-surface reticulation system. A list of Approved Greywater Systems is available for your information. All greywater system installations must be approved by the City's Health Services. Please complete the Application to Construct or Install an Apparatus For the Treatment of Sewage. The City of Cockburn does not charge a fee for this approval. Further information on greywater systems can be obtained here, or from the Wastewater Management Section of the Department of Health on 9388 4932. The Water Corporation promotes the use of approved greywater systems for water conservation under the Waterwise Rebate Program. Rebates are only available subject to the terms and conditions of the program. Visit the Department of Water website for further information on the rebates available. Installation of Effuent Disposal Systems All onsite effluent disposal systems installed within the City of Cockburn must be assessed and approved by Health Services.

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Please complete the Application to Construct or Install an Apparatus For the Treatment of Sewage. Applications must be submitted with the prescribed fee. This fee is made up of two charges, these being a fee for an "Approval to Construct an Apparatus" and a fee for a "Permit to Use" an apparatus once it is installed. Applications for multiple dwellings and premises that produce more than 540 litres of sewage per day must be approved by the Department of Health. Additional fees apply in these cases. Please note that it is illegal to use an onsite effluent disposal system unless it has been approved for use by an Environmental Health Officer and a "Permit to Use" has been issued. Copies of the layout of onsite effluent disposal systems within the City can be obtained from Council Administration. Plans will only be released to the property owner, or the owner's agent. Water Corporations Infill Sewage Program A number of residential areas within the City of Cockburn are in the process of being connected to mains sewage. The Water Corporation drives the infill sewage program with Western Australia. Decommissioning of Septic Tanks When a property is connected to mains sewer, the property owner is required to decommission the existing septic tank and effluent disposal system when the following circumstances arise:

There is a change of ownership of the property (accordingly the new owner has 60 days to decommission the septic tank apparatus).

There is a material change in the use of the premises (accordingly the owner has 60 days to decommission the septic tank apparatus).

If the foundations for a building on the premises are to be built closer than 1.2m to the septic tank apparatus or a building is to be constructed above the septic tank apparatus or closer than 1.8m to any leach drain or soakwell (accordingly the owner shall decommission the septic tank apparatus before the building work commences).

Decommissioning means that: All septic tanks, soakwells and/or leach drains are pumped empty by a licensed

Liquid Waste Contractor. All empty septic tanks, soakwells and/or leach drains must be either removed or

have their lids and bases broken and filled with clean sand. Check your progress-1

1. What is Onsite Septic Effluent Disposal, Graywater Disposal, or Wastewater Disposal? 2. What is Onsite Septic Effluent Treatment?

4.4 LET US SUM UP

SYSTEM SIZING Water Usage: The amount of wastewater that is anticipated will be discharged into the system each day. For residential dwellings it is assumed that each occupant will discharge an average of 50 gallons per day (GPD). Under normal circumstances not more than two people would occupy any bedroom; therefore, a maximum of 100 GPD usage has been set for each bedroom for sizing the system per code. For other uses, such as, office / retail, restaurant, industrial, etc., the water usage would be determined on a case by case basis. Number of Bedrooms: The number of potential bedrooms in a home determine the maximum occupancy for that home. This, in turn, will determine the size of the leaching system based on

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this maximum occupancy assumption. It is not possible for anyone to foresee future utilization of a home over and above the present occupants. It is for that reason that reductions in leaching system size are not allowed even though the present owners may not be using all the potential bedrooms as bedrooms (they may be using rooms as studies, or sewing rooms, or computer rooms, etc.) or occupying each room with two people. 4.5 SOME USEFUL BOOKS

Hughes, M.L., McDowell, P.F., and Marcus, W.A., 2006, Accuracy assessment of georectified aerial photographs—Implications for measuring lateral channel movement in a GIS: Geomorphology, v. 74, p. 1–16.

Johnson, L.C., 1991, Soil conservation in Wisconsin—Birth to rebirth: Madison, Wis., University of Wisconsin Dept. of Soil Science, 332 p.

Knox, J.C., 1985, Holocene geomorphic history of the Sand Lake Site, La Crosse County, Wisconsin: Madison, Wis., University of Wisconsin Unpublished Final Report of Investigations, Contract Reference No. LAX-58.

Knox, J.C., 1987, Historical valley floor sedimentation in the Upper Mississippi River Valley: Annals of the Association of American Geographers, v. 77, no. 2, p. 224–244.

Knox, J.C., 1999, Long-term episodic changes in magnitudes and frequencies of floods in the Upper Mississippi River Valley, in Brown, A.G., and Quine, T.A., eds., Fluvial processes and environmental change: Chichester, U.K., John Wiley and Sons, Ltd., chap. 14, p. 255–282.

4.6 ANSWER TO CHECK YOUR PROGRESS

Check your progress-1

1. Wastewater is disposed-of on-site. We "get rid of" the liquid. This means that the liquid portion of waste piped from a building is released into the soil, typically at a drainfield or soakaway bed or leachfield (these are synonyms). There most of the water eventually joins groundwater in the soils around or passing through the property. A portion of effluent or wastewater is also released through evaporation, or transpiration. Moisture moves naturally upwards through soil to the more dry air above. Preserving transpiration or evaporative transpiration is one of the reasons that we don't want to pave over a drainfield nor cover it by plastic or insulation or anything that blocks moisture movement out of the soil into the air.

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2. Septic effluent that leaves a septic tank is treated by various processes so that when it is released to the environment the wastewater is sufficiently sanitary. A properly functioning septic system should not carry pathogens, chemicals, or other contaminants to the environment. Septic effluent is the liquid portion of sewage waste that passes out of a septic tank into a disposal system such as a drainfield or leach field. Sewage is partially treated in the septic tank (the level of treatment varies depending on the type of septic system and septic tank). In the septic tank effluent is separated from most solids. Solids remain in the tank and effluent passes out of the septic tank to the soil absorption system: the drainfield. In the drain field, septic effluent is further treated by soil filtration and bacterial action in the drainfield. However there can also be treatment failures. Effluent may not back up or appear on the surface, but if insufficiently treated effluent reaches a private well or any stream or waterway, the environment is being contaminated -- this is an unacceptable condition.

4.7 GLOSSARY

SEPTIC TANK Purpose of Septic Tank: The septic tank's function is to slow down discharges from the building's plumbing fixtures so that solid material can fall to the bottom of the tank and greases and scum can rise to the top. (See drawing.) A stable biological system within the tank promotes the conversion of organic solids to soluble organic chemicals and gases. The result is a relatively uniform quality septage that will proceed to the leaching fields. There is no need to introduce any commercial additives to the tank to promote biological growth. Pump-Out Frequency: It is recommended that septic tanks be cleaned every 2 to 5 years. The frequency should be based on the occupancy of the home and how quickly solid material builds up in the tank. It should be noted that the use of a garbage disposal significantly increases solid material and greases to a tank and therefore, should result in more frequent pumping. Volume of Tank: the Public Health Code requires a minimum 1,000 gallon septic tank for all new buildings. For residential buildings an additional 250 gallons of capacity shall be added for each bedroom over three (3). Therefore, a four (4) bedroom home would require a 1,250 gallon tank, a five (5) bedroom home a 1,500 gallon tank, etc. If an older house has a septic tank which falls below the present sizing requirements, it does not have to be replaced (unless physically damaged in some way), but may have to be cleaned more often. Inlet and Outlet Baffles / Compartment Wall: In order to further reduce the flow of septage through the tank, baffles are placed on the inlet and outlet piping to and from the tank. In most cases, the baffles consist of "tee" connections of 4" PVC piping. The piping is submerged into septic liquid a minimum of 8" at the inlet and 10" at the outlet. On all new tanks a compartment

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wall is installed in order to separate the liquid in the tank into 2/3, 1/3 volumes. The septage in the tank passes from the first compartment to the second through a mid-depth opening. Outlet Effluent Filter: As of July 1, 2000, all newly installed septic tanks shall have an effluent filter placed at the outlet in place of the outlet baffle. The purpose of the filter is to trap suspended solids that are not heavy enough nor have had time enough to sink to the bottom of the tank (as in a tank that hasn't been pumped in a timely manner and has significant amounts of material that reduces its effective volume). Filters must be periodically cleaned so that they do not plug and back septage back into the house. The cleaning interval should correspond to the recommended pump-out frequency. If the filter plugs at a higher frequency the options would be to change the type of filter presently being utilized (increasing the flow through surface area) or, add additional filters in series to increase the time interval between cleanings.

Block V – Introduction-environmental pollution and control Complex environmental problems are often reduced to an inappropriate level of simplicity. While this book does not seek to present a comprehensive scientific and technical coverage of all

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aspects of the subject matter, it makes the issues, ideas, and language of environmental engineering accessible and understandable to the nontechnical reader. Improvements introduced in the fourth edition include a complete rewrite of the chapters dealing with risk assessment and ethics, the introduction of new theories of radiation damage, inclusion of environmental disasters like Chernobyl and Bhopal, and general updating of all the content, specifically that on radioactive waste. Since this book was first published in 1972, several generations of students have become environmentally aware and conscious of their responsibilities to the planet earth. Many of these environmental pioneers are now teaching in colleges and universities, and have in their classes students with the same sense of dedication and resolve that they themselves brought to the discipline. In those days, it was sometimes difficult to explain what indeed environmental science or engineering was, and why the development of these fields was so important to the future of the earth and to human civilization. Today there is no question that the human species has the capability of destroying its collective home, and that we have indeed taken major steps toward doing exactly that. And yet, while, a lot has changed in a generation, much has not. We still have air pollution; we still contaminate our water supplies; we still dispose of hazardous materials improperly; we still destroy natural habitats as if no other species mattered. And worst of all, we still continue to populate the earth at an alarming rate. There is still a need for this book, and for the college and university courses that use it as a text, and perhaps this need is more acute now than it was several decades ago. Although the battle to preserve the environment is still raging, some of the rules have changed. We now must take into account risk to humans, and be able to manipulate concepts of risk management. With increasing population, and fewer alternatives to waste disposal, this problem is intensified. Environmental laws have changed, and will no doubt continue to evolve. Attitudes toward the environment are often couched in what has become known as the environmental ethic. Finally, the environmental movement has become powerful politically, and environmentalism can be made to serve a political agenda. In revising this book, we have attempted to incorporate the evolving nature of environmental sciences and engineering by adding chapters as necessary and eliminating material that is less germane to today's students. We have nevertheless maintained the essential feature of this book -- to package the more important aspects of environmental engineering science and technology in an organized manner and present this mainly technical material to a nonengineering audience. This book has been used as a text in courses which require no prerequisites, although a high school knowledge of chemistry is important. A knowledge of college level algebra is also useful, but calculus is not required for the understanding of the technical and scientific concepts. We do not intend for this book to be scientifically and technically complete. In fact, many complex environmental problems have been simplified to the threshold of pain for many engineers and scientists. Our objective, however, is not to impress nontechnical students with the rigors and complexities of pollution control technology but rather to make some of the language and ideas of environmental engineering and science more understandable. PAV JJP RFW UNIT 1 INDUSTRIAL WASTE

Structure 1.0 Objective

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1.1 Introduction 1.2 History 1.3 Industrial waste 1.4 Let us sum up 1.5 Some Useful Books 1.6 Answer to Check your Progress 1.7 Glossary 1.0 OBJECTIVE

Waste management is the handling of discarded materials. Recycling and composting, which transform waste into useful products, are forms of waste management. The management of waste also includes disposal, such as landfilling. Waste can be almost anything, including food, leaves, newspapers, bottles, construction debris, chemicals from a factory, candy wrappers, disposable diapers, old cars, or radioactive materials. People have always produced waste, but as industry and technology have evolved and the human population has grown, waste management has become increasingly complex. A primary objective of waste management today is to protect the public and the environment from potentially harmful effects of waste. Some waste materials are normally safe, but can become hazardous if not managed properly. For example, 1 gal (3.75 l) of used motor oil can potentially contaminate one million gallons (3,790,000 l) of drinking water. Every individual, business or organization must make decisions and take some responsibility regarding the management of their waste. On a larger scale, government agencies at the local, state, and federal levels enact and enforce regulations governing waste management. These agencies also educate the public about proper waste management. In addition, local government agencies may provide disposal or recycling services, or they may hire or authorize private companies to perform those functions. 1.1 INTRODUCTION

Civilization also produces waste products. Disposal issue of the waste products is a challenge. Some of these materials are not biodegradable and often leads to waste disposal crisis and environmental pollution. The present article seeks the possibilities of whether some of these waste products can be utilized as highway construction materials. Traditionally soil, stone aggregates, sand, bitumen, cement etc. are used for road construction. Natural materials being exhaustible in nature, its quantity is declining gradually. Also, cost of extracting good quality of natural material is increasing. Concerned about this, the scientists are looking for alternative materials for highway construction, and industrial waste product is one such category. If these materials can be suitably utilized in highway construction, the pollution and disposal problems may be partly reduced. The following table presents a partial list of industrial waste materials that may be used in highway construction:

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1.2 HISTORY

Throughout history, there have been four basic methods of managing waste: dumping it; burning it; finding another use for it (reuse and recycling); and not creating the waste in the first place (waste prevention). How those four methods are utilized depends on the wastes being managed. Municipal solid waste is different than industrial, agricultural, or mining waste. Hazardous waste is a category that should be handled separately, although it sometimes is generated with the other types. The rapid increase in government regulation since about the early 1970s is a phenomenon that has had an enormous impact on all forms of waste management. This has been especially true in the United States, but it has also occurred in many other countries. 1.3 INDUSTRIAL WASTE

Material acceptability criteria Roads are typically constructed from layers of compacted materials, and generally its strength decreases downwards. For conventional materials, a number of tests are conducted and their acceptability is decided based on the test results and the specifications. This ensures the desirable level of performance of the chosen material, in terms of its permeability, volume stability, strength, hardness, toughness, fatigue, durability, shape, viscosity, specific gravity, purity, safety, temperature susceptibility etc., whichever are applicable. There are a large number tests suggested by various guidelines/ specifications; presently the performance based tests are being emphasized, rather than the tests which estimate the individual physical properties.

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The tests and specifications, which are applicable for conventional materials, may be inappropriate for evaluation of non-conventional materials, such as industrial wastes. This is because the material properties, for example, particle sizes, grading and chemical structure, may differ substantially from those of the conventional materials. Thus for an appropriate assessment of these materials, new tests are to be devised and new acceptability criteria are to be formed. However, with the advent of performance based tests, it is expected that the performances of the conventional as well as new materials can be tested on a same set-up and be compared. Figure-1 presents a flow chart to evaluate the suitability of industrial waste for potential usage in highway construction. Health and safety considerations should be given due importance handing industrial waste materials [1, 9]. Suitability of industrial wastes as highway material Limited information is available on suitability of individual industrial wastes for its utilization in highway construction. The following table (Table-2) summarizes the advantages and disadvantages of using specific industrial wastes in highway construction.

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The Importance of Industrial Waste Management

It takes a lot of valuable energy and materials to create and manufacture products and the resulting industrial waste can be difficult to manage. Many cities and countries have put new laws into place to heavily tax companies that produce excess amounts of waste or create potentially harmful effects on the air and ecosystem. The extra taxes help to offset the environment damage by going toward environmental restoration, protection and spreading information to increase knowledge on these issues. People and companies need to educate themselves about the

environment. Smog alerts in many cases result from not only harmful transportation emissions but also from the output of factories into the air we breathe. Companies need to be responsible with their industrial waste management and specifically their hazardous waste. Many local governments provide counseling, consulting and recommendations to organizations on what they can do to better manage their waste and plan for a more environmentally friendly production processes. More than ever, there need to be consequences to companies that do not take waste management seriously. Part of this includes reducing harmful emissions into the environment

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over a period of time and correctly disposing of waste materials Countries have terms and conditions about what is acceptable in terms of waste management. Today, more than ever, industries know their impact of manufacturing on smog levels and the escalating cost of managing their waste. More industrial leaders are showing their accountability for the environment. Citizens need to support companies whose business

practices include environmentally conscious and responsible conditions. Using energy more efficiently, reducing the hazardous waste they output into the air and to the landfills and practicing composting and recycling are key factors in improving the way waste is managed.

Companies who have no choice but to continue creating hazardous industrial waste due to the nature of their business need to ensure that they properly dispose of that material and are upfront an honest about the contents of their vehicles, their facilities and management of the waste. Environmental protection acts encourage and reward companies who do their part to more effectively manage waste and work with environmental

agencies to maximize efforts to minimize the impact on the environment. Industrial waste producers need to pay for the disposal of their materials and in particular, need to take caution in the way they dispose of hazardous materials. There have been cases documented of companies mislabeling goods and of irresponsible practices leading to contamination of local watersheds. The more that citizens and government push for reform, the more companies will realize that they are accountable for their industrial waste Check your progress-1

1. What does the extension of the deadline mean to the other mixing pits still operating? Will they also be granted an extension?

2. How many mixing pits were affected by the closure decision? 3. Who operates them and where are they?

1.4 LET US SUM UP

It appears that some of the industrial waste materials may find a suitable usage in highway construction. However, environmental consequences of reuse of such materials needs to be thoroughly investigated. 1.5 SOME USEFUL BOOKS

Knox, J.C., 2001, Agricultural influence on landscape sensitivity in the Upper Mississippi River Valley: Catena, v. 42, p. 193–224.

Knox, J.C., 2006, Floodplain sedimentation in the Upper Mississippi Valley—Natural versus human accelerated. Geomorphology, v. 79, p. 286–310.

Krishnaswami, S., and Lal, D., 1978, Radionuclide limnochronology, in Lerman, A., ed., Lakes—Chemistry, geology, physics: New York, Springer-Verlag, p. 153–177.

Mason, J.A., and Knox, J.C., 1997, Age of colluvium indicates accelerated Late Wisconsin hillslope erosion in the Upper Mississippi Valley: Geology, v. 25, p. 267–270.

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Milfred, C.J., Olson, G.W., and Hole, F.D., 1967, Soil resources and forest ecology of Menominee County, Wisconsin: Madison, Wis., University of Wisconsin, Geological and Natural History Survey, Soil Survey Division, Bulletin 85, Soil Series No. 60, 203 p., 3 pl.

1.6 ANSWER TO CHECK YOUR PROGRESS

Check your progress-1

1. Yes. All mixing pit operators, including Castle, were required to cease use of their pits by 30 June 2008. Mixing pits are the lowest cost option for mixing or treating hazardous wastes. In the interests of ensuring that other operators are not financially disadvantaged, we will allow the other mixing pits to operate until this date.

2. Originally there were nine but 2 have already closed. 3. The sites still in operation are Augean Treatment Ltd, Cannock, Castle Waste Services,

Ilkeston, Collier Industrial Waste, Manchester, CSG Lanstar (Cadishead), Manchester, Red Industries Ltd, Burslem, Veolia ES Onyx Ltd, Bootle, Waste Recycling Ltd, Sheffield.

1.7 GLOSSARY

Industrial waste is waste produced by industrial activity, for example in factories, mills and mines, and is non-recyclable (solids and liquids). Final WasteWaste, whether or not derived from waste treatment, which can no longer be treated under present-day technical and economic conditions, in particular extracting of the recoverable part or reducing its pollutant or hazardous character. This definition was laid down by the Circular of April 28, 1998 issued by the Ministry of the Environment concerning the reorientation of departmental plans for the elimination of household and similar waste. Final waste is waste from which the recoverable part has been extracted, including any pollutants, e.g. batteries, accumulators, etc. It is the result of objectives defined in cooperation with plan designers. This definition hinges on the place and time. Article L.541-1 of the French Environmental Code and the Circular of April 28, 1998 concern the implementation and development of Departmental plans for eliminating household and similar waste.

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UNIT 2 TREATMENT PROCESS

Structure 2.0 Objective 2.1 Introduction 2.2 History 2.3 Treatment Processes 2.4 Let us sum up 2.5 Some Useful Books 2.6 Answer to Check your Progress 2.7 Glossary 2.0 OBJECTIVE

Upon completion of the course, the participants will be able to: critically analyse water quality data and to select the most attractive raw water

resource; design and engineer a surface water intake and a water treatment plant; execute plant performance studies and proposing improvements in order to

rehabilitate the malfunctioning parts of the plant; show professional know-how for operating (process & quality control, trouble

shooting) and maintaining of manually and semi-automated water treatment plants.

2.1 INTRODUCTION

Glaser (1980) noted that assessing treatment and treatment processes had not been a high priority in the alcohol treatment field. Subsequent to his observation, however, a surge of interest in treatment assessment has taken place among administrators, researchers, and clinicians. Indeed, a recent issue of Substance Use & Misuse (Magura 2000) contained several articles on substance abuse treatment assessment. That interest has been spurred by several developments. One is an expanding focus on systems analysis and between–program differences, prompted by efforts toward health care reform. In order to describe programs and examine interrelationships among program characteristics and quality of care indices, policymakers, administrators, and researchers recognized the need for instruments to assess program–level variables. A second reason for rising interest in treatment assessment has been increasing recognition of the complex nature of predominantly psychosocial interventions, such as those often used to treat alcohol use disorders even when pharmacologic agents also are provided. One example of this complexity is “therapist effects” in the delivery of treatment (Najavits and Weiss 1994; Najavits et al. 2000), that is, the way in which the “same” treatment can be delivered quite differently by different therapists. Treatment researchers have become aware of the need to not only facilitate the provision of standardized treatment through the use of therapist training, supervision, and treatment manuals (e.g., K.M. Carroll 1997) but also to assess the implementation of the complex, multifaceted treatments they are studying. For example, it is important to document that distinctive treatments have been applied in comparative evaluations, especially in studies of patient–treatment matching, and to conduct treatment process analyses to identify “active ingredients of treatment” and “mechanisms of change.”

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On the clinical side, treatment providers need instruments with which to assess the quality of treatment provision, as well as the progress of their clients during treatment. Their motivation is the same as that among researchers: Such instruments are seen as essential elements in the effort to improve clinical care. This chapter first presents a broad, multilevel model of the treatment processes. Then, measures of the different domains of treatment variables addressed by the model are reviewed. The predominantly recent interest in the assessment of treatment continues to be reflected in the availability of only a few established measures. A number of promising instruments are reviewed, however. When multiple measures assess a particular domain, descriptive and psychometric data for them are presented in tabular form. The final section considers additional work needed to develop high–quality measures of treatment and treatment processes. 2.2 HISTORY

Discusses the widely differing influences on the development of aerobic treatment such as water supply, toxic trade effluents, microscopy and population growth in urban areas. It covers the historical development of sewage treatment and the emergence of aerobic biological treatment from the early nineteenth century to the present day. The importance of water supply is examined and the influence this had on the water-carriage system, and the consequent discharge of sewage into rivers. The factors which govern process selection and process development are discussed. There is a continued impetus to reduce land area, capital costs, running costs, and to optimise performance and process control. The discovery of the activated sludge process is detailed including the development, in the early 1900s, of many forms of this process. Industrial wastes were discharged to biological treatment systems and the impact of such pollutants is reviewed. The work of Royal Commissions, River Boards and the National Rivers Authority is summarised, and the advances in chemical analysis and “on-line” measurement of chemical quality characteristics. Later developments such as reed beds and the use of hybrid treatment systems are covered. Examples are included such as the “fixed film” activated sludge process which has found application for small communities in package form, and also for large-scale municipal treatment plants. Aerobic Wastewater Treatment Processes: History and Development is valuable reading for students of the following courses on CIWEM Dip examination, WITA and B Tech and Environmental Science and Civil Engineering. 2.3 TREATMENT PROCESSES

Wastewater treatment is closely related to the standards and/or expectations set for the effluent quality. Wastewater treatment processes are designed to achieve improvements in the quality of

the wastewater. The various treatment processes may reduce: 1. Suspended solids (physical particles that can clog rivers

or channels as they settle under gravity) Biodegradable organics (e.g. BOD) which can serve as “food” for microorganisms in the receiving body. Microorganisms combine this matter with oxygen from the water to yield the energy they need to thrive and multiply; unfortunately, this oxygen is also needed by fish and other organisms in the

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river. Heavy organic pollution can lead to “dead zones” where no fish can be found; sudden releases of heavy organic loads can lead to dramatic “fishkills”. 2. Pathogenic bacteria and other disease causing organisms These are most relevant where

the receiving water is used for drinking, or where people would otherwise be in close contact with it; and

3. Nutrients, including nitrates and phosphates. These nutrients can lead to high concentrations of unwanted algae, which can themselves become heavy loads of biodegradable organic load Treatment processes may also neutralize or removing industrial wastes and toxic chemicals. This type of treatment should ideally take place at the industrial plant itself, before discharge of their effluent in municipal sewers or water courses.

Widely used terminology refers to three levels of wastewater treatment: primary, secondary, and tertiary (or advanced). Primary (mechanical) treatment is designed to remove gross, suspended and floating solids from raw sewage. It includes screening to trap solid objects and sedimentation by gravity to remove suspended solids. This level is sometimes referred to as “mechanical treatment”, although chemicals are often used to accelerate the sedimentation process. Primary treatment can reduce the BOD of the incoming wastewater by 20-30% and the total suspended solids by some 50-60%. Primary treatment is usually the first stage of wastewater treatment. Many advanced wastewater treatment plants in industrialized countries have started with primary treatment, and have then added other treatment stages as wastewater load has grown, as the need for treatment has increased, and as resources have become available. Secondary (biological) treatment removes the dissolved organic matter that escapes primary treatment. This is achieved by microbes consuming the organic matter as food, and converting it to carbon dioxide, water, and energy for their own growth and reproduction. The biological process is then followed by additional settling tanks (“secondary sedimentation", see photo) to remove more of the suspended solids. About 85% of the suspended solids and BOD can be removed by a well running plant with secondary treatment. Secondary treatment technologies include the basic activated sludge process, the variants of pond and constructed wetland systems, trickling filters and other forms of treatment which use biological activity to break down organic matter. Tertiary treatment is simply additional treatment beyond secondary! Tertiary treatment can remove more than 99 percent of all the impurities from sewage, producing an effluent of almost drinking-water quality. The related technology can be very expensive, requiring a high level of technical know-how and well trained treatment plant operators, a steady energy supply, and chemicals and specific equipment which may not be readily available. An example of a typical tertiary treatment process is the modification of a conventional secondary treatment plant to remove additional phosphorus and nitrogen. Disinfection, typically with chlorine, can be the final step before discharge of the effluent. However, some environmental authorities are concerned that chlorine residuals in the effluent can be a problem in their own right, and have moved away from this process. Disinfection is frequently built into treatment plant design, but not effectively practiced, because of the high cost of chlorine, or the reduced effectiveness of ultraviolet radiation where the water is not sufficiently clear or free of particles. Conventional systems and treatment options

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The three primary components of a conventional system (figure 4-1) are the soil, the subsurface wastewater infiltration system (SWIS; also called a leach field or infiltration trench), and the septic tank. The SWIS is the interface between the engineered system components and the receiving ground water environment. It is important to note that the performance of conventional systems relies primarily on treatment of the wastewater effluent in the soil horizon(s) below the dispersal and infiltration components of the SWIS. Information on SWIS siting, hydraulic and mass loadings, design and geometry, distribution methods, and construction considerations is included in this chapter. The other major component of a conventional system, the septic tank, is characterized by describing its many functions in an OWTS. Figure 4-1 Conventional subsurface wastewater infiltration system

Treatment options include physical, chemical, and biological processes. Use of these options is determined by site-specific needs. Table 4-1 lists common onsite treatment processes and methods that may be used alone or in combination to assemble a treatment train capable of meeting established performance requirements. Special issues that might need to be addressed in OWTS design include treatment of high-strength wastes (e.g., biochemical oxygen demand and grease from schools and restaurants), mitigation of impacts from home water softeners and garbage disposals, management of holding tanks, and additives (see related fact sheets). Table 4-1. Commonly used treatment processes and optional treatment methods

Treatment objective Treatment process Treatment methods

Suspended solids removal

Sedimentation

Septic tank Free water surface constructed wetland Vegetated submerged bed

Filtration

Septic tank effluent screens Packed-bed media filters (incl. dosed systems) Granular (sand,

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gravel, glass, bottom ash) Peat, textile Mechanical disk filters Soil Infiltration

Soluble carbonaceous BOD and ammonium removal

Aerobic, suspended-growth reactors

Extended aeration Fixed-film activated sludge Sequencing batch reactors (SBFs)

Fixed-film aerobic bioreactor

Soil infiltration Packed-bed media filters (incl. dosed systems) Granular (sand, gravel, glass) Peat, textile, foam Trickling filter Fixed-film activated sludge Rotating biological contractors

Lagoons

Facultative and aerobic lagoons Free water surface constructed wetlands

Nitrogen transformation

Biological Nitrification (N) Denitrification (D)

Activated sludge (N) Sequencing batch reactors (N) Fixed film bio-reactor (N) Recirculating media filter (N, D) Fixed-film activated sludge (N) Anaerobic upflow filter (N) Anaerobic

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submerged media reactor (D) Submerged vegetated bed (D) Free-water surface constructed wetland (N, D)

Ion exchange

Cation exchange (ammonium removal) Anion exchange (nitrate removal)

Phosphorus removal Physical/Chemical

Infiltration by soil and other media Chemical flocculation and settling Iron-rich packed-bed media filter

Biological Sequencing batch reactors

Pathogen removal (bacteria, viruses, parasites)

Filtration/Predation/Inactivation

Soil infiltration Packed-bed media filters Granular (sand, gravel, glass bottom ash) Peat, textile

Disinfection Hypochlorite feed Ultraviolet light

Grease removal Flotation Grease trap

Septic tank

Adsorption Mechanical skimmer

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Aerobic biological treatment (incidental removal will occur; overloading is possible)

Aerobic biological system

Check your progress-1

1. What is the Systematic Treatment Enhancement Program for Bipolar Disorder (STEP-BD) Study?

2. How is the STEP-BD study different from other treatment studies of bipolar disorder? 3. What treatments did each participant receive in the STEP-BD program? 4. How were placebos used in STEP-BD?

2.4 LET US SUM UP

This review is not exhaustive. For example, it does not address general group processes in alcoholism treatment (for a review of instruments, see Beutler et al. 1993; see also Moos 1986a; Moos et al. 1993), instruments to assess the quality of work environments for treatment staff (e.g., Moos 1986b), or treatment costs. Nevertheless, the review points to a few established and a number of promising instruments for assessing treatment and treatment processes in the alcohol field. Overall, many of the measures reviewed have only minimal psychometric data available and have been used in only a limited number of studies (in some cases, only one). Additional research is needed to more accurately gauge their reliability and validity. For the proximal outcome variable measures that were reviewed, more research is needed to establish their responsiveness to different treatment approaches and their linkage to ultimate outcome variables. New measures of treatment and treatment processes also should be developed. Better conceptualization of treatment processes should be a precursor to the development of those instruments, so that variables of the greatest relevance are focused upon. For example, disulfiram implants, although not used in the United States, are a treatment modality with more evidence of effectiveness than oral disulfiram (Holder et al. 1991; Finney and Monahan 1996). Disulfiram implants have proved effective even though it has been shown repeatedly in serum assays that an “active ingredient” is not present and they do not produce an effective dosage level (Johnsen et al. 1987). However, the most relevant proximal outcome variable in disulfiram treatment, as well as other antidipsotropics, is a psychological “mechanism of change”—anticipation or expectancy of a negative reaction if alcohol is consumed. Such expectancies (in addition to assays) should be examined to evaluate the full implementation of disulfiram treatment and to explore the process through which disulfiram may exert its effects. Treatment researchers and providers can use various “conceptual heuristics” (McClintock 1990) to develop better models of the treatment processes they are assessing or attempting to influence. Additional efforts to improve the assessment of alcohol treatment and treatment processes would be well placed. They can help improve the provision and monitoring of patient care, as well as enhance the ability of research to identify more effective forms of treatment, how they work, and for whom particular types of treatment are indicated. 2.5 SOME USEFUL BOOKS

Munsell Color, 1975, Munsell soil color charts: Baltimore, Munsell Color Division of Kollmorgen Corp. [variously paginated].

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Ogle, G.A., 1906, Standard atlas of La Crosse County, Wisconsin: Chicago, Geo. A. Ogle & Co., p. 7.

Olson, C., 1962, Holmen area centennial 1862–1962: Holmen, Wis., pamphlet. Renggly, J.A., and others, 1881, History of La Crosse County, in History of La Crosse

County, Wisconsin: Chicago, Western Historical Company, p. 309–731. Railway and Locomotive Historical Society, Inc., 1937, The railroads of Wisconsin

1827–1937: Boston, Mass., 73 p.

2.6 ANSWER TO CHECK YOUR PROGRESS

Check your progress-1 1. STEP-BD is the largest, federally-funded treatment study ever conducted for bipolar

disorder1. It is a long-term outpatient study that enrolled 4,360 participants from 22 sites over seven years (1998 to 2005). STEP-BD was designed to find out which treatments, or combinations of treatments, are most effective for treating episodes of depression and mania and for preventing recurrent episodes in people with bipolar disorder. STEP-BD is different from typical clinical trials that test one potential new treatment. It is a broad research program that includes several different studies, each aimed at a different aspect of treatment for the illness. Multiple treatments, including medications and psychotherapies, currently are available for people with bipolar disorder, but doctors are often uncertain which of these treatments actually work best for specific aspects of the illness. STEP-BD’s size, scope and broad criteria for inclusion of participants will make its findings relevant to all patients seeking the most effective care for the disorder, and provide much needed information to help doctors choose treatments for the everyday care of those with the disorder.

2. STEP-BD differs from traditional bipolar disorder clinical trials in several important ways. Because the main goal of STEP-BD is to improve treatment and outcomes for all people with bipolar disorder, it was designed as a large-scale, public health study that included real-world patients contending with multiple mental and/or physical illnesses who are seeking care in their own communities. Most other clinical research studies exclude people with co-existing disorders, thus limiting those studies’ real-world applicability. In addition, STEP-BD was long-term. In most clinical trials, individuals are usually asked to participate for a relatively short period of time (e.g., 8-12 weeks), and receive only one of a few treatments being studied. In contrast, STEP-BD offered participants long-term continuity of care. Once enrolled, participants could receive care for as long as they were in the program — up to five years — and were monitored systematically, even when they were feeling well. STEP-BD also assessed participants’ “clinical status” every three to six months at a minimum for as long as they were in the program, a different process from other bipolar illness clinical studies in which a treatment’s success may be measured with only a single measurement at one point in time. At each follow-up, participants were determined to be recovered, recovering, continuing to have residual symptoms, or in a full mood episode (depression, mania, hypomania, or mixed). Finally, unlike other trials, doctors participating in STEP-BD were extensively trained in the use of evidence-based treatments to become “STEP

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certified.” STEP-BD’s rigorous treatment and measurement process, known as the Best Practice Pathway, allowed clinicians to evaluate their patients’ full range of symptoms and monitor the course of the illness. If participants experienced a change in clinical status, such as a depressive episode, they could choose to enter a STEP-BD “randomized controlled clinical trial.” The randomized controlled clinical trials of STEP-BD were designed to answer a specific treatment question using traditional clinical trials methodology. Regardless of the outcome of care within the randomized controlled trials, participants could remain in STEP-BD and under the care of their STEP-BD clinician.

3. STEP-BD aimed to determine which treatments or combination of treatments are most effective for treating episodes of depression and mania and for preventing recurrent episodes. STEP-BD assessed the outcomes of many of the most established treatments used for bipolar disorder, including; mood-stabilizing medications; antidepressants; atypical antipsychotic medications; and standardized psychosocial interventions that included family-focused treatment, interpersonal and social rhythm therapy, and cognitive behavioral therapy, all of which were compared to a brief psychosocial control treatment. All psychotherapy treatments were geared toward helping participants and their families better understand the disorder, develop coping strategies and stick to treatment plans, and were always given in conjunction with medication treatment. Medication and dosing recommendations were derived from published, evidence-based treatment guidelines.

4. Best Practice Pathway participants, all of whom were age 15 and older, received individualized care based on their symptoms, past history, medical conditions, and other factors. Most received mood-stabilizing (anti-manic) medication and, where necessary, additional medications as indicated by best practices guidelines. Participants and their doctors worked together to decide on the best treatment plan, and changed these plans if needed. Those wishing to stay on their current treatment plan upon entering STEP-BD could also do so in this pathway.

2.7 GLOSSARY

Textile chemical processing today, particularly the pre-treatment processes require a highly sophisticated technology and engineering to achieve the well known concepts of "Right first time, Right everytime and Right on time" processing and production. Chemical pre-treatment may be broadly defined as a procedure mainly concerned with the removal of natural as well as added impurities in fabric to a level necessary for good whiteness and absorbency by utilising minimum time, energy and chemicals as well as water. This book discusses the fundamental aspects of chemistry, chemical technology and machineries involved in the various pre-treatment process of textiles before subsequent dyeing, printing and finishing. With the introduction of newer fibres, specialty chemicals, improved technology and sophisticated machineries developed during the last decade, this book fills a gap in this area of technology. However, its real strength is its clear perception of ample background description, which will enable readers to understand most current journals, thus staying abreast of the latest advances in the field.

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UNIT 3 WATER POLLUTION

Structure 3.0 Objective 3.1 Introduction 3.2 History 3.3 Water pollution 3.4 Let us sum up 3.5 Some Useful Books 3.6 Answer to Check your Progress 3.7 Glossary 3.0 OBJECTIVE

When toxic substances enter lakes, streams, rivers, oceans, and other water bodies, they get dissolved or lie suspended in water or get deposited on the bed. This results in the pollution of water whereby the quality of the water deteriorates, affecting aquatic ecosystems. Pollutants can also seep down and affect the groundwater deposits. Water pollution has many sources. The most polluting of them are the city sewage and industrial waste discharged into the rivers. The facilities to treat waste water are not adequate in any city in India. Presently, only about 10% of the waste water generated is treated; the rest is discharged as it is into our water bodies. Due to this, pollutants enter groundwater, rivers, and other water bodies. Such water, which ultimately ends up in our households, is often highly contaminated and carries disease-causing microbes. Agricultural run-off, or the water from the fields that drains into rivers, is another major water pollutant as it contains fertilizers and pesticides. Domestic sewage refers to waste water that is discarded from households. Also referred to as sanitary sewage, such water contains a wide variety of dissolved and suspended impurities. 3.1 INTRODUCTION Water pollution occurs when a body of water is adversely affected due to the addition of large amounts of materials to the water. The sources of water pollution are categorized as being a point source or a non-source point of pollution. Point sources of pollution occur when the polluting substance is emitted directly into the waterway. A pipe spewing toxic chemicals directly into a river is an example. A non-point source occurs when there is runoff of pollutants into a waterway, for instance when fertilizer from a field is carried into a stream by surface runoff. 3.2 HISTORY Pollution is not a new phenomenon. In fact, it is older than most people realize. Archeologists digging through sites of Upper Paleolithic settlements (settlements of the first modern humans, between forty thousand and ten thousand years ago) routinely find piles of discarded stone tools, and the litter from the making of these tools. One could even argue that the first use of wood-burning fire ushered in the era of air pollution. Lead pollution from Roman smelters can be traced all across Europe. Yet all this early pollution was limited in its effects on the environment. As humans moved from nomadic to settled societies, however, pollution increased in magnitude, becoming a real problem for the environment and its human and nonhuman inhabitants. Although pollution of major proportions has been a problem since the centuries preceding the Middle Ages, it is worth noting that after World War II, the type of pollution involved changed

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significantly. Industries began manufacturing and using synthetic materials such as plastics, polychlorinated biphenyls (PCBs), and inorganic pesticides like dichlorodiphenyl trichloroethane (DDT). These materials are not only toxic, they also accumulate in the environment—they are not biodegradable. Thus, increased rates of cancers, physical birth defects, and mental retardation, among other health problems, are now being observed. A worrisome loss of biodiversity

The Exxon Valdez leaking oil; the slick is visible along side of ship. ( Courtesy of Richard Stapleton. Reproduced by permission. ) exists in the environment—animal and plant species become extinct at an alarming rate. There is an increased risk of catastrophic industrial accidents, such as the one that occurred in Bhopal, India. The tremendous cleanup costs of hazardous waste dumps, and the difficulty in disposing of these chemicals safely, assure that water, land, and air pollution will continue to be a problem for generations to come. Throughout history and to this day, pollution touches all parts of the environment—the water, the air, and the land. 3.3 WATER POLLUTION Types of Water Pollution Toxic Substance -- A toxic substance is a chemical pollutant that is not a naturally occurring substance in aquatic ecosystems. The greatest contributors to toxic pollution are herbicides, pesticides and industrial compounds. Organic Substance -- Organic pollution occurs when an excess of organic matter, such as manure or sewage, enters the water. When organic matter increases in a pond, the number of decomposers will increase. These decomposers grow rapidly and use a great deal of oxygen during their growth. This leads to a depletion of oxygen as the decomposition process occurs. A lack of oxygen can kill aquatic organisms. As the aquatic organisms die, they are broken down by decomposers which leads to further depletion of the oxygen levels.

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A type of organic pollution can occur when inorganic pollutants such as nitrogen and phosphates accumulate in aquatic ecosystems. High levels of these nutrients cause an overgrowth of plants and algae. As the plants and algae die, they become organic material in the water. The enormous decay of this plant matter, in turn, lowers the oxygen level. The process of rapid plant growth followed by increased activity by decomposers and a depletion of the oxygen level is called eutrophication. Thermal Pollution -- Thermal pollution can occur when water is used as a coolant near a power or industrial plant and then is returned to the aquatic environment at a higher temperature than it was originally. Thermal pollution can lead to a decrease in the dissolved oxygen level in the water while also increasing the biological demand of aquatic organisms for oxygen. Ecological Pollution -- Ecological pollution takes place when chemical pollution, organic pollution or thermal pollution are caused by nature rather than by human activity. An example of ecological pollution would be an increased rate of siltation of a waterway after a landslide which would increase the amount of sediments in runoff water. Another example would be when a large animal, such as a deer, drowns in a flood and a large amount of organic material is added to the water as a result. Major geological events such as a volcano eruption might also be sources of ecological pollution. Specific Sources of Water Pollution Farming:

Farms often use large amounts of herbicides and pesticides, both of which are toxic pollutants. These substances are particularly dangerous to life in rivers, streams and lakes, where toxic substances can build up over a period of time.

Farms also frequently use large amounts of chemical fertilizers that are washed into the waterways and damage the water supply and the life within it. Fertilizers can increase the amounts of nitrates and phosphates in the water, which can lead to the process of eutrophication.

Allowing livestock to graze near water sources often results in organic waste products being washed into the waterways. This sudden introduction of organic material increaces the amount of nitrogen in the water, and can also lead to eutrophication.

Four hundred million tons of soil are carried by the Mississippi River to the Gulf of Mexico each year. A great deal of this siltation is due to runoff from the exposed soil of agricultural fields. Excessive amounts of sediment in waterways can block sunlight, preventing aquatic plants from photosynthesizing, and can suffocate fish by clogging their gills.

Business: Clearing of land can lead to erosion of soil into the river. Waste and sewage generated by industry can get into the water supply, introducing large

organic pollutants into the ecosystem. Many industrial and power plants use rivers, streams and lakes to despose of waste heat.

The resulting hot water can cause thermal pollution. Thermal pollution can have a disasterous effect on life in an aquatic ecosystem as temperature increaces decreace the amount of oxygen in the water, thereby reducing the number of animals that can survive there.

Water can become contaminated with toxic or radioactive materials from industry, mine sites and abandoned hazardous waste sites.

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Acid precipitation is caused when the burning of fossil fuels emits sulfur dioxide into the atmosphere. The sulfur dioxide reacts with the water in the atmosphere, creating rainfall which contains sulfuric acid. As acid precipitation falls into lakes, streams and ponds it can lower the overall pH of the waterway, killing vital plant life, thereby affecting the whole food chain. It can also leach heavy metals from the soil into the water, killing fish and other aquatic organisms. Because of this, air pollution is potentially one of the most threatening forms of pollution to aquatic ecosystems.

Homes: Sewage generated by houses or runoff from septic tanks into nearby waterways,

introduce organic pollutants that can cause eutrophication. Fertilizers, herbicides and pesticides used for lawn care can runoff and contaminate the

waterway. As with agriculteral fertilizers, home fertilizers can lead to the eutrophication of lakes and rivers.

Improper disposal of hazardous chemicals down the drain itroduce toxic materials into to the ecosystem, contaminating the water supplies in a way that can harm aquatic organisms.

Leaks of oil and antifreeze from a car on a driveway can be washed off by the rain into nearby waterways, polluting it.

Check your progress-1 1. What is water pollution? 2. What are the major water pollutants? 3. Where does water pollution come from? 4. How do we detect water pollution? 5. What is heat pollution, what causes it and what are the dangers?

3.4 LET US SUM UP

Water covers over 70% of the Earth’s surface and is a very important resource for people and the environment. Water pollution affects drinking water, rivers, lakes and oceans all over the world. This consequently harms human health and the natural environment. Here you can find out more about water pollution and what you can do to prevent it.

3.5 SOME USEFUL BOOKS

Reese, H.M., Lillesand, T., Nagel, D.E., Stewart, J.S., Goldmann, R.A., Simmons, T.E., Chipman, J.W., and Tessar, P.A., 2002, Statewide land cover derived from multiseasonal Landsat TM—A retrospective of the WISCLAND project: Remote Sensing of the Environment, v. 82, p. 224–237.

Retallick, G., 1985, Laboratory exercises in paleopedology: Eugene, Oreg., University of Oregon, course handout, 74 p.

Schelske, C.L., Peplow, A., Brenner, M., and Spencer, C.N., 1994, Low-background gamma counting–Applications for 210Pb dating of sediments: Journal of Paleolimnology, v. 10, p. 115–128.

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Snyder, Van Vechten & Co., 1878, Historical atlas of Wisconsin: Milwaukee, Snyder, Van Vechten & Co., p. 64.

3.6 ANSWER TO CHECK YOUR PROGRESS

Check your progress-1 1. Water pollution is any chemical, physical or biological change in the quality of water that

has a harmful effect on any living thing that drinks or uses or lives (in) it. When humans drink polluted water it often has serious effects on their health. Water pollution can also make water unsuited for the desired use.

2. There are several classes of water pollutants. The first are disease-causing agents. These are bacteria, viruses, protozoa and parasitic worms that enter sewage systems and untreated waste. A second category of water pollutants is oxygen-demanding wastes; wastes that can be decomposed by oxygen-requiring bacteria. When large populations of decomposing bacteria are converting these wastes it can deplete oxygen levels in the water. This causes other organisms in the water, such as fish, to die. A third class of water pollutants is water-soluble inorganic pollutants, such as acids, salts and toxic metals. Large quantities of these compounds will make water unfit to drink and will cause the death of aquatic life. Another class of water pollutants are nutrients; they are water-soluble nitrates and phosphates that cause excessive growth of algae and other water plants, which deplete the water's oxygen supply. This kills fish and, when found in drinking water, can kill young children. Water can also be polluted by a number of organic compounds such as oil, plastics and pesticides, which are harmful to humans and all plants and animals in the water. A very dangerous category is suspended sediment, because it causes depletion in the water's light absorption and the particles spread dangerous compounds such as pesticides through the water. Finally, water-soluble radioactive compounds can cause cancer, birth defects and genetic damage and are thus very dangerous water pollutants.

3. Water pollution is usually caused by human activities. Different human sources add to the pollution of water. There are two sorts of sources, point and nonpoint sources. Point sources discharge pollutants at specific locations through pipelines or sewers into the surface water. Nonpoint sources are sources that cannot be traced to a single site of discharge. Examples of point sources are: factories, sewage treatment plants, underground mines, oil wells, oil tankers and agriculture.Examples of nonpoint sources are: acid deposition from the air, traffic, pollutants that are spread through rivers and pollutants that enter the water through groundwater. Nonpoint pollution is hard to control because the perpetrators cannot be traced.

4. Water pollution is detected in laboratories, where small samples of water are analysed for different contaminants. Living organisms such as fish can also be used for the detection of water pollution. Changes in their behaviour or growth show us, that the water they live in is polluted. Specific properties of these organisms can give information on the sort of pollution in their environment. Laboratories also use computer models to determine what dangers there can be in certain waters. They import the data they own on the water into the computer, and the computer then determines if the water has any impurities.

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5. In most manufacturing processes a lot of heat originates that must be released into the

environment, because it is waste heat. The cheapest way to do this is to withdraw nearby surface water, pass it through the plant, and return the heated water to the body of surface water. The heat that is released in the water has negative effects on all life in the receiving surface water. This is the kind of pollution that is commonly known as heat pollution or thermal pollution. The warmer water decreases the solubility of oxygen in the water and it also causes water organisms to breathe faster. Many water organisms will then die from oxygen shortages, or they become more susceptible to diseases.

3.7 GLOSSARY

Water pollution Degradation of a body of water by a substance or condition to such a degree that the water fails to meet specified standards or cannot be used for a specific purpose.

Water purveyor a public utility, mutual water company, county water district, or municipality that delivers drinking water to customers.

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UNIT 4 LAND POLLUTION

Structure 4.0 Objective 4.1 Introduction 4.2 History 4.3 Land pollution 4.4 Let us sum up 4.5 Some Useful Books 4.6 Answer to Check your Progress 4.7 Glossary 4.0 OBJECTIVE

People should be educated and made aware about the harmful effects of littering Items used for domestic purposes ought to be reused or recycled Personal litter should be disposed properly Organic waste matter should be disposed in areas that are far away from residential

places Inorganic matter such as paper, plastic, glass and metals should be reclaimed and then

recycled 4.1 INTRODUCTION

Land pollution basically is about contaminating the land surface of the Earth through dumping urban waste matter indiscriminately, dumping of industrial waste, mineral exploitation, and misusing the soil by harmful agricultural practices. Land pollution includes visible litter and waste along with the soil itself being polluted. The soil gets polluted by the chemicals in pesticides and herbicides used for agricultural purposes along with waste matter being littered in urban areas such as roads, parks, and streets 4.2 HISTORY

Land use history report A land use history report may be useful if you are planning to develop a site that has a known previous use. Our scientific team can provide you with a summary report containing:

historic land use information from the 1860s onwards an aerial photograph of the site

The sources of this information are as follows: a review of Kelly's and other local trade directories (1860-1975) on a five-year interval scrutiny of the 1:1250, 1:2500 and 1:10000 Ordnance Survey maps available for the

Cambridge area from 1880 onwards review of aerial photography for 1940, 1944 and 2002 a review of information held within our archives since 1990 - this contains much

information on remedial work carried out on newly developed sites A land use history report is available for £136.

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4.3 LAND POLLUTION

Land Pollution At the beginning of the twentieth century, William T. Love imagined a model community in New York, on the edge of Niagara Falls. Love dug a canal to supply water power to what he envisioned would be a combination of industrial and residential areas in his community. Love was unable to complete his project. During the 1920s the canal he dug was turned into a landfill operated by the Hooker Chemical Company. In 1953 Hooker sold the site to the Niagara Falls Board of Education for $1, with the disclaimer ". . .that the premises above described have been filled . . . to the present grade level thereof with waste products resulting from the manufacturing of chemicals. . . ." The city built an elementary school on the site. Houses were later added. Over the years, the underground containers filled with approximately 21,000 tons of chemical waste corroded. In 1977 a record rainfall brought about a tragic consequence: The waste began to leach into people's homes, backyards, and playgrounds. Love Canal has been officially associated with high rates of birth defects, miscarriages, and other severe illness resulting from land contamination. The tragedy of Love Canal is perhaps the most famous incident of chemical waste dumps harming people, but it is definitely not the only one. Health effects range from cancer to birth defects. The practice of chemical dumping persisted for years in the early twentieth century, in many places, without a thought to the possible risks or consequences of these actions. When Love Canal leached its deadly contents, the United States took notice. In 1980 Congress enacted the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA), the first U.S. federal law to address toxic waste dumps. CERCLA, also known as Superfund, is the emergency fund to clean toxic waste dumps when the owners of the dumps are unknown or unable to pay for a necessary cleanup. While Superfund is helping clean up many hazardous sites, litigation over liability led to delay and costly legal battles over who pays for cleanups. Another criticism is that Superfund lacks clear standards as to what constitutes a "clean" site. Across the globe, developing countries have been buying hazardous waste from developed nations, where disposal is more expensive. Historically, there has been little or no regulation of hazardous waste disposal in developing nations; as the world becomes more of a global community, however, this problem will no doubt haunt future generations. Chemical Pollution In 1984, 30 tons of lethal methyl isocyanate gas were released into the air in Bhopal, India, from a Union Carbide plant. Thousands of people (estimates range from 2,500 to well over 8,000) died immediately. Deaths and disabilities continued to plague the populace for years following what was termed, at the time, "the worst industrial accident in history." A year later, in Institute, West Virginia, another Union Carbide plant released toxic gas into the atmosphere, resulting in illnesses among town residents. Deeply concerned about the possibility of a Bhopal-like disaster in the United States, Congress acted swiftly to enact the Emergency Planning and Community Right-to-Know Act (EPCRA). The law requires companies that handle hazardous waste to furnish complete disclosure of their annual polluting activities, storage and handling facilities, any accidental release of hazardous material into the environment in a quantity above an established safe limit, and all material necessary for local authorities to respond to an accident involving the hazardous material(s) on site. Since the law was enacted, a substantial reduction in toxic releases was reported by companies who are required to participate in EPCRA disclosures.

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Oil pollutes land and water sources, the most tragic example of which is the Exxon Valdez. While not one of the largest spills in the world, it is considered the worst in terms of the damage to the environment. On the night of March 24, 1989, the oil tanker ran aground at Bligh Reef, Alaska, spilling eleven million gallons of oil into the fragile environment of Prince William Sound. A lack of containment and cleanup equipment compounded the problem, and even fifteen years after the spill the Prince William Sound environment was still struggling to recover from the massive damage. One response to the Valdez disaster was the passage of the 1990 Oil Pollution Act, which, among other things, required oil tankers to be double-hulled, and gave states more say in their spill-prevention standards. The spill-response equipment and safeguards procedures at Prince William

Residents of Bhopal, India, standing outside the gate of the Union Carbide factory where a chemical leak killed thousands and blinded many others. ( ©Bettmann/Corbis. Reproduced by permission .) Sound, loading terminal for the major tanker route on the Trans-Alaska Pipeline System, have been brought up to date. Nuclear power is one of the most controversial issues of our time. For many people, the benefits it brings are dwarfed by the immense dangers inherent in the nature of its fuel. Release of radioactivity into the air and the atmosphere occurred over the years, but accidents like Chernobyl and Three Mile Island terrify people, and with good reason. On March 28, 1979, a partial meltdown of the reactor in Three Mile Island, Pennsylvania, released radioactivity into the atmosphere. The release itself was small, according to authorities. But inside the containment building a hydrogen bubble was growing, threatening to blow the building and spew radioactivity into an area inhabited by some 300,000 people. The effects such

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an explosion would have had on the population were only theorized until 1986, when the nuclear reactor in Chernobyl, Ukraine, did explode. Though the immediate loss of life was small according to official figures, within several months the death toll was growing. Cancer rates, especially in children, have soared in the Ukraine and Belarus. And while the blown reactor is buried in concrete, evidence show the cover is deteriorating. The Three Mile Island accident led to the establishment of the Institute of Nuclear Power Operations (INPO). INPO is tasked with promoting safety in commercial nuclear plants in the United States, and cooperates with similar international organizations. While safety regulations and oversight bodies were upgraded and tightened as a result of the two accidents above, nuclear waste, both civilian and military, presents a huge problem of disposal. The decay of some nuclear waste can take thousands of years. Disposal of the short-lived waste is easy compared to finding a place that can safely store highly radioactive materials for thousands of years. Moreover, many communities oppose the transportation and/or burial of such waste in their area. Environmental pollution is not new, but its scope, type, and complexity have worsened since World War II. The good news is that nations across the globe now have an awareness of the consequences of pollution, and the dangers they pose to our very existence. Both governments and nongovernmental organizations are working on the many facets of pollution. Among the answers they seek are alternative, nonpolluting energy sources, a way to control harmful emissions and toxic discharges into the air and water, and methods for cleaning up damaged ecosystems and bringing species back from the brink of extinction. Coincident with this work is the growing understanding that a safe and protected environment must begin with social healing, that both poverty and affluence perpetuate environmental degradation. Poor societies must concentrate on immediate survival before they can spare the time or energy to worry about environmental health. Rich societies must understand that their comfortable lifestyle comes at the high price of increased pollution—from sources such as factories, car engines, and power plants. The challenges that face the global community as it tries to combat an ecological crisis involve creating social conditions that allow all members of the community to be equally committed to, and equally capable of, healing the place we all call home. Check your progress-1

1. Where did the new diffuse pollution regulations come from? 2. Why are these requirements neccessary? 3. What do the new regulations cover?

4.4 LET US SUM UP

After finishing this webquest, you have learnt know what air pollution is, what the major air pollutants are, where they come from and what harmful effects they have on human's health and on the environment. Furthermore, you have learnt what we can do to minimize air pollution. Everyone has to pay effort to successfully solve the problem of air pollution, including you and me. However, air pollution is not the only human activity that harm the environment and ourselves, there are other type of pollution such as land pollution and water pollution. Try to learn more about these pollution from the internet, and see what we should do to protect ourselves and the environment.

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4.5 SOME USEFUL BOOKS

Soil Survey Staff, 1951, Soil survey manual: U.S. Department of Agriculture, Agricultural Handbook 18, 503 p.

U.S. Department of Agriculture, 2005, Wisconsin digital aerial photography, National Agriculture Imagery Program, 1-m pixel resolution, accessed March 5, 2007,

U.S. Fish and Wildlife Service, 2000, Upper Halfway Creek Marsh Project, final report, December 2000: La Crosse, Wis., U.S. Fish and Wildlife Service, unpublished report, 19 p.

Vanoni, V.A., ed., 2006, Sedimentation engineering–Chapter III, Sediment measurement techniques: American Society of Civil Engineers Manuals and Reports on Engineering Practice, no. 54, p. 227–233.

4.6 ANSWER TO CHECK YOUR PROGRESS

Check your progress-1

1. The Scottish Government published The Water Environment (Diffuse Pollution) (Scotland) Regulations 2008. This new legislation is based on widely accepted standards in codes of good practice such as the Prevention of Environmental Pollution from Agricultural Activity (PEPFAA) , the Forests and Water Guidelines and the 4 Point Plan These regulations, in the form of General Binding Rules (GBRs) came into force in April 2008 and the resulting seven additional GBRs have now been incorporated into the Water Environment (Controlled Activities) (Scotland) Regulations 2011 (CAR). In addition, a provision in the Control of Pollution (Silage, Slurry and Agricultural Fuel Oil) Regulations 2003 (SSAFO) has been amended to permit lightly contaminated water from farm yards to be drained to constructed farm wetlands.

2. Diffuse pollution from land use activities has a significant impact on water quality. To achieve the objectives of the Water Framework Directive (WFD), we need to maintain and improve water quality. Rural diffuse pollution arises from land use activities such as livestock grazing, cultivation of land to grow crops and from forestry operations. Such activities can give rise to a release of potential pollutants which individually may not have an impact but together, at the scale of a river catchment, can impact on water quality. The pressures and impacts from diffuse pollution are described in the Significant Water Management Issues consultation document and include eutrophication, loss of biodiversity, silting of fish spawning grounds, and impacts on human health through drinking water or bathing water pollution. The pollutants of concern include the nutrients nitrogen and phosphorus, sediment, pesticides, biodegradable substances, ammonia and micro-organisms.

3. The following activities require some form of authorisation from SEPA under the Controlled Activities Regulations (CAR):

Storage and application of fertilisers; Keeping of livestock; Cultivation of land;

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Discharge of surface water run-off; Construction and maintenance of waterbound roads and tracks; Application of pesticide; Operation of sheep dipping facilities.

4.7 GLOSSARY

Poultry Production (broilers and layers) Resource Risks (-) and opportunities (+) Underlying factors Land (-) Toxic levels of nutrients in soils · Poor management of animal wastes

(-) Chemical pollution of soils · Poor management of chemical inputs (-) soil pollution with heavy metals (Zinc and Cadmium)

· Poor management of animal wastes

(-) destruction of vegetation by acid rain · Ammonia emissions from animal wastes (+) improved soil fertility · Balanced application to the land of

poultry manure will lead to improved soil fertility

Water (-) pollution of surface and ground water

· Poor management of animal wastes

· Poor management of chemical inputs (-) depletion of fresh water resources · Increased use of fresh water

Air (-) global warming: emissions of Carbon Dioxide, Methane and Nitrous Oxide

· Increased Greenhouse Gas Emission

Biodiversity (-) loss of genetic diversity · Loss of local breeds (-) increased susceptibility to diseases · Loss of disease resistance

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UNIT 5 CONTROL OF AIR POLLUTION

Structure 5.0 Objective 5.1 Introduction 5.2 History 5.3 Control of Air Pollution 5.4 Let us sum up 5.5 Some Useful Books 5.6 Answer to Check your Progress 5.7 Glossary 5.0 OBJECTIVE

Concerns about global air pollution levels are increasing, and for business owners feeling the pressure, the growing area of air pollution control can be pretty cloudy itself. Enviro News explores the day-to-day methods available to modern industries to help minimise air pollution using practicable systems. 5.1 INTRODUCTION

The legal authority for federal programs regarding air pollution control is based on the 1990 Clean Air Act Amendments (1990 CAAA). These are the latest in a series of amendments made to the Clean Air Act (CAA). This legislation modified and extended federal legal authority provided by the earlier Clean Air Acts of 1963 and 1970. The Air Pollution Control Act of 1955 was the first federal legislation involving air pollution. This Act provided funds for federal research in air pollution. The Clean Air Act of 1963 was the first federal legislation regarding air pollution control. It established a federal program within the U.S. Public Health Service and authorized research into techniques for monitoring and controlling air pollution. In 1967, the Air Quality Act was enacted in order to expand federal government activities. In accordance with this law, enforcement proceedings were initiated in areas subject to interstate air pollution transport. As part of these proceedings, the federal government for the first time conducted extensive ambient monitoring studies and stationary source inspections. 5.2 HISTORY

The Air Pollution Control Act of 1955 First federal air pollution legislation Funded research for scope and sources of air pollution

Clean Air Act of 1963 Authorized the development of a national program to address air pollution related

environmental problems Authorized research into techniques to minimize air pollution

Air Quality Act of 1967 Authorized enforcement procedures for air pollution problems involving interstate

transport of pollutants

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Authorized expanded research activities Clean Air Act 1970

Authorized the establishment of National Ambient Air Quality Standards Established requirements for State Implementation Plans to achieve the National Ambient

Air Quality Standards Authorized the establishment of New Source Performance Standards for new and

modified stationary sources Authorized the establishment of National Emission Standards for Hazardous Air

Pollutants Increased enforcement authority Authorized requirements for control of motor vehicle emissions

1977 Amendments to the Clean Air Act of 1970 Authorized provisions related to the Prevention of Significant Deterioration Authorized provisions relating to areas which are non-attainment with respect to the

National Ambient Air Quality Standards 1990 Amendments to the Clean Air Act of 1970

Authorized programs for Acid Deposition Control Authorized a program to control 189 toxic pollutants, including those previously

regulated by the National Emission Standards for Hazardous Air Pollutants Established permit program requirements Expanded and modified provisions concerning the attainment of National Ambient Air

Quality Standards Expanded and modified enforcement authority Established a program to phase out the use of chemicals that deplete the ozone layer.

5.3 CONTROL OF AIR POLLUTION

Air Pollution The growth of population centers coupled with the switch from wood-burning to coal-burning fires created clouds of smoke over cities as early as the eleventh century. Air pollution regulations first appeared in England in 1273, but for the next several centuries, attempts at controlling the burning of coal met with notable failure. The problem was not confined to London, nor was it confined to England. As the Industrial Revolution swept across countries, and as coal became common in private residences, smoke and industrial pollution claimed more and more lives. In the United States, Donora, Pennsylvania, became famous for a tragedy that symbolized the dangers of industrial air pollution. On October 26, 1948, a thick, malodorous fog enveloped the small industrial town. Unlike usual fogs, it did not burn off as the day progressed. Instead, it stayed on the ground for five days. Twenty people died in Donora and 7,000 were hospitalized with respiratory problems. The cause was a weather anomaly that trapped toxic waste emissions from the town's zinc smelting plant close to the ground. The Donora disaster brought air pollution into focus in the United States, and paved the way for the Clean Air Act, enacted in 1963 and strengthened in 1970. Between December 5 and 9, 1952, 4,000 people died in London as a result of smog trapped in a thermal inversion (a condition where the air close to the ground is colder than the layer above it, and is therefore unable to rise above it). This incident brought about England's Clean Air Act in 1956.

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Smoke from coal-fired power plants creates the related problem of acid rain. Gases (sulfur dioxide and nitrogen oxides) released by burning fossil fuels make the rain more acidic and therefore corrosive. Acid rain kills plants and trees and damages structures. It also accumulates in rivers and streams, and has resulted in lakes that are already devoid of life in large parts of eastern North America and Scandinavia. All around the world, the advent of the internal combustion engine-powered vehicles compounded air pollution, adding particulate and gaseous contaminate to the air people breath. The use of leaded gasoline raised lead levels in populations around the world. Leaded gasoline was phased out in the U.S. starting in 1976, but is still in use in many parts of the world In 1987, scientists discovered a hole in the ozone layer and recognized a serious threat to the layer that protects the earth from the sun's ultraviolet radiation. The Montréal Protocol, drafted in 1987, addressed the damage caused to the ozone layer by a chemical group known as CFCs, which were common in aerosol spray containers and air conditioners. The Montréal Protocol set as a goal the elimination of CFCs in consumer and industrial products. The global climate change accord signed in Rio de Janeiro, Brazil, in 1992 addressed the so-called "green-house gases," gases which trap heat in the atmosphere and lead to a global warming trend. The Rio Accord, and the Kyoto Protocol (1997) call for a reduction in greenhouse gases emissions but little progress has been made as the United States, a major generator of greenhouse gases, never signed the treaty and President George W. Bush has rejected the Kyoto Protocol outright.

Check your progress-1

1. What causes acidic deposition? 2. What is acid rain? 3. What are the local regulations for agricultural burning in my area?

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4. What are the effects of agricultural burning? 5. Where can I get a burn permit?

5.4 LET US SUM UP There are many factors which regulate the air pollution. It states that there should always be a distance between the industrial and residential area. The chimneys must be tall in size so that the emissions must be released higher up in the environment. The filters and precipitators must be used in the chimneys. The scrubber or spray collector must be used to remove the poisonous gases. The ash production must be reduced by the high temperature incinerators. The sulphur must be removed after the combustion. The non combustive sources of energy are the nuclear power, geothermal power, solar, tidal and wind power. The gasoline must have anti knocking agents. The railway track must be electrified. The mining area must be rich in trees. The gas fuel must be used instead of the coal fuel. The emission control system must be present in the automobiles. The wastes must be removed and recycled in the industrial plants and refineries. The automobiles must be pollution free by making the fuel alcohol based and using the battery power. There are certain plants which have the ability to fix the carbon monoxide. These should be grown in the larger numbers. It includes the ficus and coleus. There are certain plants which have the ability to metabolize the nitrogen oxides and other pollutants. It includes the pinus and ribes. 5.5 SOME USEFUL BOOKS

Vierbicher Associates, Inc., 1995, Final report, Hydraulic and sedimentation study, Town of Onalaska, WI: Reedsburg, Wis., Vierbicher Associates, Inc., Economic Development Administration Project no. 06–06–61061, accessed January 17, 2008,

Wang, L., Lyons, J., Kanehl, P., and Gatti, R., 1997, Influences of watershed land use on habitat quality and biotic integrity in Wisconsin streams: Fisheries, v. 22, no. 6, p. 6–12.

Warren, G.K., 1867, Survey of the Upper Mississippi River: Washington, D.C., U.S. House of Representatives Executive Document 58, 39th Congress, 2nd Session, p. 5–38.

Wingate, R.G., 1975, Settlement patterns of La Crosse County, Wisconsin, 1850–1875: University of Minnesota, Ph.D. dissertation.

5.6 ANSWER TO CHECK YOUR PROGRESS

Check your progress-1 1. Acid deposition - commonly called acid rain - is caused by emissions of sulphur dioxide

and nitrogen oxides. Although natural sources of sulphur oxides and nitrogen oxides do exist, more than 90% of the sulphur and 95% of the nitrogen emissions occurring in eastern North America are of human origin. These primary air pollutants arise from the use of coal in the production of electricity, from base-metal smelting, and from fuel combustion in vehicles. Once released into the atmosphere, they can be converted chemically into such secondary pollutants as nitric acid and sulfuric acid, both of which dissolve easily in water. The resulting acidic water droplets can be carried long distances

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by prevailing winds, returning to Earth as acid rain, snow, or fog. 2. "Acid rain" is a broad term used to describe several ways that acids fall out of the

atmosphere. A more precise term is acid deposition, which has two parts: wet (rain, fog, and snow) and dry (particles and gases). Acid rain's effects include: harming fish and other organisms living in lakes and streams harming to a variety of plants and animals on land damaging human health reducing how clearly we see through the air damaging to materials like those found in statues and buildings. The specific effects and their severity depends on several factors, including soil and surface water chemistry, the amount of air pollution that creates acid rain, and the specific species involved. For more information.

3. Local burning restrictions vary with current atmospheric and weather conditions. To check whether or not there is a burning restriction in your area check the local air pollution authority that oversees your county or state.

4. Burning agricultural waste is a source of particulate matter and other criteria pollutants. It can greatly effect the regional air quality, visibility and ground level ozone potential.

5. Contact your state or local agency for a permit availability and a allocation location near you..

5.7 GLOSSARY

Air pollution has many disastrous effects that need to be curbed. In order to accomplish this, governments, scientists and environmentalists are using or testing a variety of methods aimed at reducing pollution. There are two main types of pollution control. Input control involves preventing a problem before it occurs, or at least limiting the effects the process will produce. Five major input control methods exist. People may try to restrict population growth, use less energy, improve energy efficiency, reduce waste, and move to non-polluting renewable forms of energy production. Also, automobile-produced pollution can be decreased with highly beneficial results. Output control, the opposite method, seeks to fix the problems caused by air pollution. This usually means cleaning up an area that has been damaged by pollution. Input controls are usually more effective than output controls. Output controls are also more expensive, making them less desirable to tax payers and polluting industries. Current air pollution control efforts are not all highly effective. In wealthier countries, industries are often able to shift to methods that decrease air pollution. In the United States, for example, air pollution control laws have been successful in stopping air pollution levels from rising. However, in developing countries and even in countries where pollution is strictly regulated, much more needs to be done.