drinking water industry

8/3/2019 Drinking Water Industry

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DRINKING WATER INDUSTRY

INTRODUCTION

High quality water is more than the dream of the conservationists, more than a

political slogan; high quality water, in the right quantity at the right placeat the right time, is essential to health, recreation, and economic growth.

Edmund S. Muskie, U.S. Senator; speech, March 1, 1966

Drinking water can be produced from any natural sources like groundwater, lakesand rivers (surface waters) or seawater.Drinking water standards are set by the WorldHealth organisation or by the European Union. Drinking water must be free of suspendedsolids, microorganisms and toxic chemicals. Mineral concentration recommendation varyfrom country to country but most of the minerals have a maximum concentrationrecommended to ensure safe, equilibrated and pleasant water to drink.

For municipal drinking water, a special focus is carried on the corrosivity andscaling potential of the water to maintain distribution piping in good shape. Typical pH 8,TAC 8 and TH 8 are applied, when possible. For bottled water, taste can vary uponcalcium, magnesium, sulfate and iron content.

Drinking water, like every other substance, contains small amounts of bacteria.Most of these bacteria are common ones and they are generally not harmful. Chlorine isusually added to drinking water to prevent bacterial growth while the water streamsthrough pipelines. This is why drinking water also contains minimal amounts of chlorine.Water mostly consists of minerals and other inorganic compounds, such as calcium.

Drinking water can come from different resources. For one, it can be pumpedfrom the ground through wells. This groundwater is than purified, so that it will containno more contaminants and is suited to drink. Drinking water can also be prepared directly

from surface water resources, such as rivers, lakes and streams. Usually surface water hasto undergo many morepurification steps than groundwater to become suited to drink.Preparing drinking water out of surface water is much more expensive due to this. Still66% of all people are served by a water system that uses surface water. Part of ourdrinking water is pumped from the ground, usually under sand dunes. In sand duneswater can also be infiltrated. As it sinks into the ground through the dunes it is naturallypurified. This costs much less money than the purification of surface water. Part of ourdrinking water originates from dune water.
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Treating water to make it suitable to drink is much like wastewater treatment. Inareas that depend on surface water it is usually stored in a reservoir for several days, inorder to improve clarity and taste by allowing more oxygen from the air to dissolve in itand allowing suspended matter to settle out. The water is then pumped to a purificationplant through pipelines, where it is treated, so that is will meet government treatment

standards. Usually the water runs through sand filters first and sometimes throughactivated charcoal, before it is disinfected. Disinfection can be done by bacteria or bymeans of adding substances to remove contaminants from the water. The number ofpurification steps that are taken depend on the quality of the water that enters thepurification plant. In areas with very pure sources of groundwater little treatment isneeded.

There are several problems that can endanger the quality of drinking water.Someone can detect coliform bacteria in drinking water. Coliform bacteria are a group ofmicrorganisms that are normally found in the intestinal tract of humans and other warm-blooded animals, and in surface water. When these organisms are detected in drinking

water this suggests contamination from a subsurface source such as barnyard run-off. Thepresence of these bacteria indicates that disease-causing microrganisms, known aspathogens, may enter the drinking water supply in the same way if one does not takepreventive action. Drinking water should be free from coliform.

Yeasts and viruses can also endanger the quality of drinking water. They aremicrobial contaminants that are usually found in surface water. Examples are Giardia andCryptosporidium. Giardia is a single cell organism that causes gastrointestinal symptoms.Cryptosporidium is a parasite that is considered to be one of the most significant causesof diarrhoeal disease in humans. In individuals with a normal immune system the diseaselasts for several days causing diarrhoea, vomiting, stomach cramps and fever. People

with weakened immune systems can suffer from far worse symptoms, caused bycryptosporidium, such as cholera-like illnesses.

Nitrate in drinking water can cause cyanosis, a reduction of the oxygen carryingcapacity of the blood. This is particularly dangerous to infants under six months of age.

Lead can enter the water supply as it leaches from copper pipelines. As the waterstreams through the pipes, small amounts of lead will dissolve in the water, so that itbecomes contaminated. Lead is a toxic substance that can be quickly absorbed in thehuman systems, particularly those of small children. It causes lead poisoning.

Legionella is a bacterium that grows rapidly when water is maintained at atemperature between 30 and 40 degrees for a longer period of time. This bacterium canbe inhaled when water evaporates as it enters the human body with aerosols. The bacteriacan cause a sort of flue, known as Pontiac fever, but it can also cause the more seriousdeathly illness known as legionellosis.

All countries have their own legal drinking water standards. These prescribewhich substances can be in drinking water and what the maximum amounts of these
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substances are. The standards are called maximum contaminant levels. They areformulated for any contaminant that may have adverse effects on human health and eachcompany that prepares drinking water has to follow them up. If water will be purified tomake it suitable to drink it will be tested for a number of dangerous pollutants, in order toestablish the present concentrations. After that, one can determine how much of the

contaminants have to be removed and if necessary purification steps can be progressed.

Many people worry about getting sick from tap water, because of articles on thenews and in the papers, for instance about Legionella outbreaks. They may either drinkbottled wateror install expensive water purification systems as a result of this. However,studies have indicated that many of these consumers are being ripped off due to theexpenses of bottled water and in some cases they may end up drinking water that is dirtierthen they can get from their taps. To be safe, consumers that buy bottled water shoulddetermine wheather the company that supplies them with water belongs to theInternational Bottled Water Association (IBWA) and lives up to the testing requirements

of drinking water. The IBWA sends inspectors to its companies annually, to ensure that aplant produces safe drinking water. People can also spare themselves the costs of bottledwater and have theirtap watertested by local health authorities or private labs. If anycontaminants are discovered they can buy a unit that removes the contaminant in concern,but for most households this is not necessary because their tap water is safe enough.

ADVANTAGES OF DRINKING WATER

1. Lose weight: Drinking water helps you lose weight because it flushes down the by-

products of fat breakdown. Drinking water reduces hunger, its an effective appetite

suppressant so youll eat less. Plus, water has zero calories.

2. Natural Remedy for Headache: Helps to relieve headache and back pains due to

dehydration. Although many reasons contribute to headache, dehydration is the

common one.

3. Look Younger with Healthier Skin: Youll look younger when your skin is

properly hydrated. Water helps to replenish skin tissues, moisturizes skin and

increases skin elasticity.

4. Better Productivity at Work: Your brain is mostly made up of water, thus drinking

water helps you think better, be more alert and more concentrated.

5. Better Exercise: Drinking water regulates your body temperature. That means youll

feel more energetic when doing exercises. Water also helps to fuel your muscle.
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6. Helps in Digestion and Constipation: Drinking water raises your metabolism

because it helps in digestion. Fiber and water goes hand in hand so that you can have

your daily bowel movement.

7. Less Cramps and Sprains: Proper hydration helps keep your joints and muscles

lubricated, so youll less likely get cramps and sprains.

8. Less Likely to Get Sick and Feel Healthy: Drinking plenty of water helps fight

against flu and other ailments like kidney stones and heart attack. Water adds with

lemon is used for ailments like respiratory disease, intestinal problems, rheumatism

and arthritis etc. In another words one of the benefits of drinking water is that it can

improve your immune system.

9. Relieves Fatigue: Water is used by the body to help flush out toxins and waste

products from the body. If your body lacks water, your heart, for instance, needs to

work harder to pump out the oxygenated blood to all cells, so are the rest of the vitalorgans, your organs will be exhausted and so will you.

10.Good Mood: Your body feels very good and thats why you feel happy.

11.Reduce the Risk of Cancer: Related to the digestive system, some studies show that

drinking a healthy amount of water may reduce the risks of bladder cancer and colon

cancer. Water dilutes the concentration of cancer-causing agents in the urine and

shortens the time in which they are in contact with bladder lining.

MATERIALS DISSOLVED IN WATER

Inorganic Compounds - Compounds that typically do not contain the element Carbon.

They can become dissolved in water from natural sources or as the result of human

activity.

1

.

Dissolved gases (oxygen, carbon dioxide, nitrogen, radon, methane, hydrogen sulfide,

etc.) - no appreciable health effects, except for hydrogen sulfide and dissolved

radioactive gases like radon. Both methane and hydrogen sulfide can be inflammable.Carbon dioxide dissolved in water creates carbonic acid - a weak acid that gives

carbonated water its "bite" and plays an important role in the weathering of limestone

and other carbonate rocks. Caverns are a product of eons of erosion by carbonic acid

laced water.

2 Metal and metalloid positive ions - (aluminum, arsenic {MCL=0.05}, lead


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. {MCL=0.015}, mercury {MCL=0.002}, calcium, magnesium, sodium, potassium, zinc,

copper {MCL=1.3}, etc.) Some of these ions (lead, mercury, and arsenic) are

dangerous at extremely low concentrations and can be introduced into drinking water

either though natural processes or as a result of human activity. Other ions in this group

(for example, calcium, magnesium, sodium, and potassium) are essential to human

health - in the correct amounts.

Calcium and magnesium are interesting ions. Although their presence in drinking water

is actually a health benefit, they are the prime culprits in most hard water, and are

considered undesirable contaminants by those who must live with scaly deposits of

calcium carbonate on their faucets (and in their pipes and water heaters) or who can not

get their soap to lather.

3

.

Negative ions - (fluoride {MCL=4.0}, chloride, nitrate {MCL=10.0}, nitrite

{MCL=1.0}, phosphate, sulfate, carbonate, cyanide {MCL=0.2}) As with the positive

ions, some of these negative ions are necessary to life in proper concentrations

(chloride and carbonate), others can be dangerous to health at moderate concentrations

(nitrates and nitrites - look at the ingredients in the next slice of ham, bacon, or hot dog

you eat), and others are dangerous at even small concentrations (cyanide). Some, like

fluoride, have raised quite a controversy over its safety as an additive (in many areas) to

drinking water in an effort to lessen tooth decay, particularly in children.

4

.

Radon - Radon is a radioactive gas which comes from the natural breakdown

(radioactive decay) of radium, which is itself a decay product of uranium. The primary

source of radon in homes is from the underlying soil and bedrock. However, an

additional source could be the water supply, particularly if the house is served by a

private well or a small community water system.

Organic Compounds - These compounds all contain the element Carbon. Although

there are many exceptions, naturally occurring organic compounds (sugars, proteins,

alcohol's, etc.) are synthesized in the cells of living organisms, or like raw petroleum and

coal, formed by natural processes acting on the organic chemicals of once living

organisms.

1. Synthetic Organic Chemicals - Organic chemicals can also be synthesized in

laboratories and by chemical companies. A growing number of these synthetic organic

compounds are being produced. They can include pesticides used in agriculture, plastics,

synthetic fabrics, dyes, gasoline additives like MTBE, solvents like carbon tetrachloride

{MCL=0.005}, and many other chemicals. Many synthetic organic chemicals, like

benzene {MCL=0.005} carbon tetrachloride, and vinyl chloride {MCL=0.002}, vaporize

easily in air and are grouped under the category of volatile organic chemicals (VOCs).

Methyl tertiary butyl ether (MTBE) is a common synthetic organic chemical used for a

number of years as a gasoline additive. In January 2000 it received national notariety on
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CBS' 60 Minutes because of its ability to contaminate water supplies after leaking from

storage tanks.

The potential for water contamination by synthetic organic chemicals can be understood

by the fact that Denver Water (the company that supplies municipal water to much of the

metro Denver area) tests for 54 VOCs (21 with MCLs established by the EPA), 73

different pesticides (23 with MCLs), 25 different chemicals classified as synthetic

organic compounds (5 with MCLs), and 7 as non-specific organics. Nearly all of these

chemicals tested below the levels of detectability. It somewhat disconcerting to realize

that Denver water tests for only 150 or so of the thousands of the synthetic organic

chemicals manufactured, and the EPA has established MCLs for even fewer. These are

not nice chemicals to have in your water, many of them are presumed to increase the risk

of various cancers in humans, often after many years of low-level exposure, others may

affect the nervous system. Some researchers are reporting that yet other synthetic

chemicals can cause hormonal disruptions. Most laboratory tests of the effects of these

chemicals are done using a single chemical, but there may be several organiccontaminants together in a water source.

2

.

Trihalomethanes {MCL=0.1} There is a class of organic compounds that is important

because their formation and presence in drinking water is a direct result of the most

common and economical process used to kill harmful pathogens, chlorination. This

chemical group is the trihalomethanes (THMs). THMs are formed when the chlorine

that is added to the water interacts with organic material also in the water, like leaf

fragments, etc. The level of THMs in water is usually greater in water systems where

surface water is the source, and levels typically vary seasonally with the organic

content of the source water supply. Chloroform is usually the most common THM, andin Denver for instance, it varies from about 10 micrograms per liter in the winter to

about 50 micrograms per liter in the summer with an average around 20-25 micrograms

per liter. These levels are well below the EPA's Maximum Contaminant Level (MCL)

of 100 micrograms per liter, even drinking water with THM levels below 100

microgram per liter over a 40-50 year period might increase the risk of certain cancers.

Evidence has also been reported that disinfection byproducts can cause adverse

reproductive outcomes.
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The graph above was created using published data from the The Santa Clara Valley

Water District's Water Quality Laboratory reports for an eight month period in 1997.

THMs were reported and graphed here as milligrams per liter. The red line on the graph

is the EPA MCL level of 0.10 milligram or 100 micrograms per liter. The intent here is

not to imply that the water from this particular water treatment facility is bad, unsafe, or

any worse than water from other facilities that chloronate surface water, in fact, like

Denver Water, they produce a quatity product. Though, that it is important to understand

that a fairly large percentage of people in the United States and in other countries that

chlorinate their water are drinking small quantities of chloroform and related substances

on an ongoing basis.

DRINKING WATER STANDARDS

EU's ( The European Union ) drinking water standards

Council Directive 98/83/EC on the quality of water intented for human

consumption. Adopted by the Council, on 3 November 1998:

Chemical parameters

Parameter Symbol/formula Parametric

value (mg/l)

Acrylamide C3H5 NO 0.0001

Antimony Sb 0.005
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Arsenic As 0.01

Benzene C6H6 0.001

Benzo(a)pyrene C20H12 0.00001

Boron B 1.00

Bromate Br 0.01

Cadmium Cd 0.005

Chromium Cr 0.05

Copper Cu 2.0

Cyanide CN = 0.05

1,2-dichloroethane Cl CH2 CH2 Cl 0.003

Epichlorohydrin C3H5OCl 0.0001

Fluoride F 1.5

Lead Pb 0.01

Mercury Hg 0.001

Nickel Ni 0.02

Nitrate NO3 50

Nitrite NO2 0.50

Pesticides 0.0001

Pesticides - Total 0.0005

PAHs C2 H3 N1 O5 P13 0.0001

Selenium Se 0.01

Tetrachloroethene and

trichloroethene

C2Cl4/C2HCl3 0.01

Trihalomethanes -

Total

0.1
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Vinyl chloride C2H3Cl 0.0005

Indicator parameters

Parameter Symbol/

formula

Parametric value

Aluminium Al 0.2 mg/l

Ammonium NH4 0.50 mg/l

Chloride Cl 250 mg/l

Clostridium perfringens

(including spores)

0/100 ml

Colour Acceptable to consumers and no

abnormal change

Conductivity 2500 S/cm @ 20oC

Hydrogen ion concentration [H+] 6.5 and 9.5

Iron Fe 0.2 mg/l

Manganese Mn 0.05 mg/l

Odour Acceptable to consumers and no

abnormal change

Oxidisability 5.0 mg/l O2

Sulfate SO4 250 mg/l

Sodium Na 200 mg/l

Taste Acceptable to consumers and no

abnormal change

Colony count 22o No abnormal change

Coliform bacteria 0/100 ml

Total organic carbon (TOC) No abnormal change
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Turbidity Acceptable to consumers and no

abnormal change

Tritium H3 100 Bq/l

Total indicative dose 0.10 mSv/year

Microbiological parameters

Parameter Parametric value

Escherichia coli (E. coli) 0 in 250 ml

Enterococci 0 in 250 ml

Pseudomonas aeruginosa 0 in 250 ml

Colony count 22oC 100/ml

Colony count 37oC 20/ml

DRINKING WATER TREATMENT METHODS

1. REVERSE OSMOSIS (RO)

Osmosis is based upon the fundamental pursuit for balance. Two fluids containing

different concentrations of dissolved solids that come in contact with each other will mix

until the concentration is uniform. When these two fluids are separated by a semi

permeable membrane (which lets the fluid flow through, while dissolved solids stay

behind), the fluid containing the lower concentration will move through the membraneinto the fluid containing the higher concentration of dissolved solids. After a while the

water level will be higher on one side of the membrane. The difference in height is called

the osmotic pressure.

By applying a pressure that exceeds the osmotic pressure, the reverse effect

occurs. Fluids are pressed back through the membrane, while dissolved solids stay

behind. To purify water by Reverse Osmosis membrane, the natural osmosis effect must
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be reversed. In order to force the water of the brine stream (high salt concentration) to

flow towards the fresh stream (low salt concentration), the water must be pressurized at

an operating pressure greater than the osmotic pressure. As a result, the brine side will get

more concentrated. The operating pressure of seawater is around 60 bar.

1. Water flows from a column with a low dissolved solids content to a column with a

high dissolved solids content

2. Osmotic pressure is the pressure that is used to stop the water from flowing through the

membrane, in order to create balance

3. By pursuing pressure that exceeds the osmotic pressure, the water flow will bereversed; water flows from the column with a high dissolved solids content to the column

with a low dissolved solids content

The advantages of Reverse Osmosis

include:

Reverse osmosis significantly reduces salt, most other inorganic material present


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in the water, and some organic compounds. With a quality carbon filter to remove

any organic materials that get through the filter, the purity of the treated water

approaches that produced by distillation.

Microscopic parasites (including viruses) are usually removed by properly

functioning RO units, but any defect in the membrane would allow these

organisms to flow undetected into the "filtered" water - they are not

recommended for use on biologically unsafe water.

Though slower than a carbon or sediment water filter, RO systems can typically

purify more water per day than distillers and are less expensive to operate and

maintain.

Reverse Osmosis systems also do not use electricity, although because they

require relatively high water pressure to operate, they may not work well in some

emergency situations.

The disadvantages of Reverse Osmosis include:

Point of Use RO units make only a few gallons of treated water a day for drinking

or cooking.

RO systems waste water. Two to four gallons of "waste" water are flushed down

the drain for each gallon of filtered water produced.

Some pesticides, solvents and other volatile organic chemicals (VOCs) are not

completely removed by RO. A good activated carbon post filter is recommended

to reduce these contaminants.

Many conditions affect the RO membrane's efficiency in reducing the amount of

contaminant in the water. These include the contaminant concentration, chemical

properties of the contaminants, the membrane type and condition, andoperating conditions (like pH, water temperature, and water pressure).

Although RO filters do not use electricity, they depend on a relatively high water

pressure to force the water molecules through the membrane. In an emergency

situation where water pressure has been lost, these systems will not function.

* However, if a high quality activated carbon filter is used for the post filter, it could

probably be disconnected and used to siphon water through in an emergency to

reduce many contaminants.

RO systems require maintenance. The pre and post filters and the reverse

osmosis membranes must be changed according to the manufacturer's

recommendation, and the storage tank must be cleaned periodically.Damaged membranes are not easily detected, so it is hard to tell if the system is

functioning normally and safely.


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Diagram for Sand Filtration

B. Absorption / Activated Carbon

Adsorption is a process where a solid is used for removing a soluble substance from thewater. In this process active carbon is the solid. Activated carbon is produced specificallyso as to achieve a very big internal surface (between 500 - 1500 m2/g). This big internalsurface makes active carbon ideal for adsorption. Active carbon comes in two variations:Powder Activated Carbon (PAC) and Granular Activated Carbon (GAC). The GACversion is mostly used in water treatment, it can adsorb the following soluble substances:

Datasheet Active Carbon

Adsorption of organic, non-polar substances such

as:o Mineral oil

o BTEX

o Poly aromatic hydrocarbons (PACs)

o (Chloride) phenol

Adsorption of halogenated substance: I, Br, Cl, Hen F

Odor Taste Yeasts Various fermentation products

Non-polar substances (Substances which are nonsoluble in water)

Examples from active carbon in different processes:

Ground water purification The de-chlorination of process water Water purification for swimming pools The polishing of treated effluent

Water is pumped in a column which contains active carbon, this water leaves the columnthrough a draining system. The activity of an active carbon column depends on thetemperature and the nature of the substances. Water goes through the column constantly,which gives an accumulation of substances in the filter. For that reason the filter needs tobe replace periodically. A used filter can be regenerated in different ways, granularcarbon can be regenerated easily by oxidizing the organic matter. The efficiency of theactive carbon decreases by 5 - 10% 1). A small part of the active carbon is destroyedduring the regeneration process and must be replaced. If you work with different columns
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in series, you can assure that you will not have a total exhaustion of your purificationsystem.

Molecules from gas or liquid phase will be attached in a physical way to a surface, in thiscase the surface is from the active carbon. The adsorption process takes place in three

steps:

Macro transport: The movement of organic material through the macro-poresystem of the active carbon (macro-pore >50nm)

Micro transport: The movement of organic material through the meso-pore andmicro-pore system of the active carbon (micro-pore


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Figure 1 gives a

specific adsorption

isotherm for active

carbon. On the

horizontal axis you

can find the

concentration and

on the vertical axis

you can find the

necessary quantity

of carbon. You canuse this kind of

figures to optimize

you column.

Figure 2 tells about theexhaustion duringusage of you column.Point C3 the columnstarts to break troughand near C4 yourcolumn is not purifyinganymore. Betweenpoint C3 and C4 youneed to regenerate youcolumn.

Factors that influence the performance of active carbon in water:

The type of compound to be removed. Compounds with high molecular weight andlow solubility are better absorbed.

The concentration of the compound to be removed. The higher the concentration, thehigher the carbon consumption.

Presence of other organic compounds which will compete for the available adsorption

sites. The pH of the waste stream. For example, acidic compounds are better removed at

lower pH.

According to this we can classify some chemicals by their probability of being efficientlyadsorbed by active carbon in water:

1. Chemicals with very high probability of being adsorbed by active carbon:

2,4-D Deisopropyltatrazine Linuron

Alachlor Desethylatrazine MalathionAldrin Demeton-O MCPA


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C. IRON AND MANGANESE REMOVAL

Iron and manganese are unaesthetic parameters present mostly in groundwater, causing

unwanted precipitation and color.

Iron removal

Iron removal is based on the precipitation of dissolved iron (Fe2+) into its oxidized

form (Fe3+), as Fe(OH)3 or Fe2O3.

Iron removal by physical-chemical way consists in iron oxidation by air followed by sand

filtration, but other techniques exist as well:

Oxidation + sand filtration

(physical chemical way)

For water with pH > 7, low redox potential, low

iron content (< 3mg/L)

Oxidation + sand filtration + MnO2filter

For higher iron content and/or manganese

Oxidation + green sandMore efficient than sand filtration but required

KMnO4 regeneration

Oxidation + Limestone contactor

For acidic water with low redox potential, the

limestone contactor increases aggressive water pH

by binding CO2

Ion exchangeRecommended for continuous process with low

iron content. Not pH dependent

Oxidation can be carried out by various chemicals like chlorine, ozone but is mostly done

by compressed air. Complex bound iron and manganese, e.g. complex bound with humic

acids, can be very difficult to remove. In this case oxidation with ozone can be a solution.

Manganese removal

For manganese removal only, Manganese dioxide (MnO2) is used as an adsorbent

according to the following reaction:

Mn + MnO2 (s) --> 2 MnO (s)

Manganese oxides are then adsorbed on MnO2 grains. When all MnO2 has been

consumed, it can be regenerated by sodium hypochlorite.

Manganese removal by physical-chemical way (aeration and sand filtration) can also be
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used but manganese oxidation kinetics are too slow at pH< 9.

Iron removal plant flow diagram

D. SEDIMENT FITERS

Solid Particles are Strained Out of the Water.

i. Fiber Filters: These filters contain cellulose, rayon or some other material spun into amesh with small pores. Suspended sediment (or turbidity) is removed as water pressureforces water through tightly wrapped fibers. Some small organic particles that causedisagreeable odors and taste may also be removed. These filters come in a variety of sizesand meshes from fine to coarse, with the lower micron rating being the finer. The finerthe filter, the more particles are trapped and the more often the filter must be changed.

Fiber filters are often used as pre-filters to reduce the suspended contaminants thatcould clog carbon or RO filters.

Fiber filters will not remove contaminants that are dissolved in the water, like chlorine,lead, mercury, trihalomethanes or other organic compounds.

ii. Ceramic Filters: Ceramic filters are much like fiber filters and use a process wherewater is forced through the pores of a ceramic filtration media. This provides mechanicalfiltration only. This type of filter can reduce asbestos fibers,cysts (if the pores are onemicron or smaller), some bacteria (with pore sizes in the 0.2 - 0.8 micron range**) andother particulate matter.

Ceramic filters will not remove contaminants that are dissolved in the water, likechlorine, lead, mercury, trihalomethanes or other organic compounds, nor will they


19/41

remove viruses. These filters may be used as a back-end to an activated carbon filter toprovide a more thorough removal of contaminants.

E. ACTIVATED ALUMINA

Activated Alumina is a granulated form of aluminum oxide. In this process, water

containing the contaminant is passed through a cartridge or canister of activated alumina

which adsorbs the contaminant. The cartridge of activated alumina must be replaced

periodically. Activated alumina devices can accumulate bacteria, so treated water may

have higher bacteria counts than raw water.

The advantages of Activated Alumina filters include:

An effective way to reduce levels of fluoride, arsenic, and selenium

The disadvantages of Activated Alumina filters include:The use of other treatment methods would be necessary to reduce levels of other

contaminants of health concern

3.BOILING

In an emergency, boiling is the best way to disinfect water that is unsafe because of the

presence of protozoan parasites or bacteria.

If the water is cloudy, it should be filtered before boiling. Filters designed for use when

camping, coffee filters, towels (paper or cotton), cheesecloth, or a cotton plug in a funnelare effective ways to filter cloudy water.

Place the water in a clean container and bring it to a full boil and continue boiling for at

least 3 minutes (covering the container will help reduce evaporation). If you are more

than 5,000 feet above sea level, you must increase the boiling time to at least 5 minutes

(plus about a minute for every additional 1,000 feet). Boiled water should be kept

covered while cooling.

The advantages of Boiling Water include:

Pathogens that might be lurking in your water will be killed if the water is boiledlong enough.

Boiling will also drive out some of the Volatile Organic Compounds (VOCs) that

might also be in the water. This method works well to make water that is

contaminated with living organisms safe to drink, but because of the

inconvenience, boiling is not routinely used to treat drinking water except

in emergencies.


20/41

The disadvantages of Boiling Water include:

Boiling should not be used when toxic metals, chemicals (lead, mercury, asbestos,

pesticides, solvents, etc.), or nitrates have contaminated the water.

Boiling may concentrate any harmful contaminants that do not vaporize as the

relatively pure water vapor boils off.

Energy is needed to boil the water

4. DISTILLATION

In many ways, distillation is the reverse of boiling. To remove impurities from water by

distillation, the water is usually boiled in a chamber causing water to vaporize, and the

pure (or mostly pure) steam leaves the non volatile contaminants behind. The steam

moves to a different part of the unit and is cooled until it condenses back into liquid

water. The resulting distillate drips into a storage container.

Salts, sediment, metals - anything that won't boil or evaporate - remain in the distiller and

must be removed. Volatile organic compounds (VOCs) are a good example of a

contaminant that will evaporate and condense with the water vapor. A vapor trap, carbon

filter, or other device must be used along with a distiller to ensure the more complete

removal of contaminants.

The advantages of Distillation include:

A good distillation unit

produces very pure water.This is one of the few practical ways to

remove heavy metals, nitrates, chloride,

and other salts that carbon filtration can

not remove.

Distillation also removes pathogens in the

water, mostly by killing and leaving them

behind when the water vapor evaporates.

If the water is boiled, or heated just short

of boiling, pathogens would also be killed.

As long as the distiller is kept clean and isworking properly the high quality of treated

water will be very consistent regardless of

the incoming water - no drop in quality over

time.

No filter cartridges to replace, unless a carbon filter is used to remove volatile

organic compounds.


21/41

The disadvantages of Distillation include:

Distillation takes time to purify the water, It can take two to five hours to make a

gallon of distilled water.

Distillers uses electricity all the time the unit is operating

Distillers requires periodic cleaning of the boiler, condensation compartment, and

storage tank.

Countertop Distillation is one of the more expensive home water treatment

methods, using $0.25 to $0.35 of electrical energy per gallon of distilled water

produced - depending on local electricity costs.

Most home distillation units require electricity, and will not function in an

emergency situation when electrical power is not available.

5. DISINFECTION

A. OZONATION

The formation of oxygen into ozone occurs with the use of energy. This process is carried

out by an electric discharge field as in the CD-type ozone generators (corona discharge

simulation of the lightning), or by ultraviolet radiation as in UV-type ozone generators

(simulation of the ultra-violet rays from the sun). In addition to these commercial

methods, ozone may also be made through electrolytic and chemical reactions.

Ozone is a naturally occurring component of fresh air. It can be produced by the

ultraviolet rays of the sun reacting with the Earth's upper atmosphere (which creates a

protective ozone layer), by lightning, or it can be created artificially with an ozone

generator.

The ozone molecule contains three oxygen atoms whereas the normal oxygen molecule

contains only two. Ozone is a very reactive and unstable gas with a short half-life before

it reverts back to oxygen. Ozone is the most powerful and rapid acting oxidizer man can

produce, and will oxidize all bacteria, mold and yeast spores, organic material and viruses

given sufficient exposure.

The advantages of using Ozone include:

Ozone is primarily a disinfectant that effectively kills biological contaminants.

Ozone also oxidizes and precipitates iron, sulfur, and manganese so they can befiltered out of solution.

Ozone will oxidize and break down many organic chemicals including many that

cause odor and taste problems.

Ozonation produces no taste or odor in the water.

Since ozone is made of oxygen and reverts to pure oxygen, it vanishes without

trace once it has been used. In the home, this does not matter much, but when


22/41

water companies use ozone to disinfect the water there is no residual disinfectant,

so chlorine or another disinfectant must be added to minimize microbial growth

during storage and distribution.

The disadvantages of using Ozone include:

Ozone treatment can create undesirable byproducts that can be harmful to health ifthey are not controlled (e.g., formaldehyde and bromate).

The process of creating ozone in the home requires electricity. In an emergency with

loss of power, this treatment will not work.

Ozone is not effective at removing dissolved minerals and salts.

Caution - The effectiveness of the process is dependent, on good mixing of ozone with

the water, and ozone does not dissolve particularly well, so a well designed system that

exposes all the water to the ozone is important.

In the home, ozone is often combined with activated carbon filtration to achieve a morecomplete water treatment.

B. ULTRAVIOLET LIGHT (UV)

Water passes through a clear chamber where it is exposed to Ultra Violet (UV) Light.

UV light effectively destroys bacteria and viruses. However, how well the UV system

works depends on the energy dose that the organism absorbs. If the energy dose is not

high enough, the organisms genetic material may only be damaged rather than

disrupted.

The advantages of using UV include:No known toxic or significant nontoxic byproducts introduced

Removes some organic contaminants

Leaves no smell or taste in the treated water

Requires very little contact time (seconds versus minutes for chemical disinfection)

Improves the taste of water because some organic contaminants and nuisance

microorganisms are destroyed

Many pathogenic microorganisms are killed or rendered inactive.

Does not affect minerals in water

The disadvantages of using UV include:UV radiation is not suitable for water with high levels of suspended solids, turbidity,

color, or soluble organic matter. These materials can react with UV radiation, and

reduce disinfection performance. Turbidity makes it difficult for radiation to

penetrate water and pathogens can be 'shadowed', protecting them from the light.

UV light is not effective against any non-living contaminant, lead, asbestos, many

organic chemicals, chlorine, etc.
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Tough cryptosporidia cysts are fairly resistant to UV light.

Requires electricity to operate. In an emergency situation when the power is out,

the purification will not work.

DRINKING WATER TREATMENT PROCESS

Coagulation removes dirt and other particles suspended in water. Alum and other

chemicals are added to water to form tiny sticky particles called "floc" which attract the

dirt particles. The combined weight of the dirt and the alum (floc) become heavy enough

to sink to the bottom during sedimentation.

Sedimentation.The heavy particles (floc) settle to the bottom and the clear water movesto filtration.

Filtration. The water passes through filters, some made of layers of sand, gravel, and

charcoal that help remove even smaller particles.

Disinfection . A small amount of chlorine is added or some other disinfection method is

used to kill any bacteria or microorganisims that may be in the water.


24/41

Storage. Water is placed in a closed tank or reservoir in order for disinfection to take

place. The water then flows through pipes to homes and businesses in the community

DRINKING WATER PURIFICATION PROCESS

a: Prefiltration

1) The uptake of water from surface waters or groundwater and storage in reservoirs.

Aeration of groundwater and natural treatment of surface water usually take place in the

reservoirs. Often softening and pH-adjustments already happen during these natural

processes.

2) Rapid sand filtration or in some cases microfiltration in drum filters.

b: Addition of chemicals

3) pH adjustment through addition ofcalcium oxide and sodium hydroxide.

4) FeCl3 addition to induce flocculation for the removal of humic acids and suspended

particulate matter, if necessary with the addition of an extra flocculation aid. Flocs are

than settled and removed through lamellae separators. After that the flocs are concentrated

in sludge and pumped to the exterior for safe removal of the particulates and sludge

dewatering.

5) Softening in a reservoir, through natural aeration or with sodium hydroxide, on to 8,5

oD. This is not always necessary. For instance, in case natural filtration will be applied,softening takes place naturally.

c: Natural filtration

6) Drinking water preparation step that is specific forthe Netherlands: Infiltration of the

water in sand dunes for natural purification. This is not applied on all locations The water

will enter the saturated zone where the groundwater is located and it will undergo further

biological purification. As soon as it is needed for drinking water preparation, it will be

extracted through drains.

d: Disinfection

7) Disinfection with sodium hypochlorite or ozone. Usually ozonation would be preferred,

because ozone not only kills bacteria and viruses; it also improves taste and odour

properties and breaks down micro pollutants. Ozone diffuses through the water as small

bubbles and enters microrganisms cells by diffusion through cell walls. It destroys
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25/41

microrganisms either by disturbance of growth or by disturbance of respiratory functions

and energy transfers of their cells. During these processes ozone is lost according to the

reaction O3 -> O2 +(O).

e: Fine filtration

8) Slow sand (media) filtration for the removal of the residual turbidity and harmful

bacteria. Sand filters are backwashed with water and air every day.

9) Active carbon filtration for further removal of matter affecting taste and odourand

remaining micro pollutants. This takes place when water streams through a granular

activated carbon layer in a filter. Backwash is required regularly due to silting up and

reactivation of an active carbon filter should be done once a year.

f: Preservation and storage

10) Addition of 0.3 mg/L sodium hypochlorite to guarantee the preservation of the

obtained quality. Not all companies chlorinate drinking water. The water will eventually

be distributed to users through pipelines and distribution pumps.

11) Aeration for recovery oxygen supply of the water prior to storage. This is not always

applied.

12) Remaining water can be stored in drinking water reservoirs.

In the following schematic representation of the drinking water preparation process dotted

arrows represent the incoming chemicals and red arrows represent the outgoing flows.
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Water that is distributed in cities or communities is treated extensively. Specific water

purification steps are taken, in order to make the water meet current water standards.

Purification methods can be divided up into settling of suspended matter, physical/

chemical treatment of colloids and biological treatment. All these treatment methods have

several different applications.

1. Physical water purification

Physical water purification is primarily concerned with filtration techniques. Filtration is
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a purification instrument to remove solids from liquids. There are several different

filtration techniques. A typical filter consists of a tank, the filter media and a controller to

enable backflow.

Screens

Filtration through screens is usually done at the beginning of the water purification

process. The shape of the screens depends on the particles that have to be removed.

Sand filtration

Sand filtration is a frequently used, very robust method to remove suspended solids from

water. The filter medium consists of a multiple layer of sand with a variety in size and

specific gravity. When water flows through the filter, the suspended solids precipitate in

the sand layers as residue and the water, which is reduced in suspended solids, flows out

of the filter. When the filters are loaded with particles the flow-direction is reversed, inorder to regenerate it. Smaller suspended solids have the ability to pass through a sand

filter, so that secondary filtration is often required.

Cross flow filtration

Cross flow membrane filtration removes both salts and dissolved organic matter, using a

permeable membrane that only permeates the contaminants. The remaining concentrate

flows along across the membrane and out of the system and the permeate is removed as it

flows along the other side of the membrane.

There are several different membrane filtration techniques, these are: micro filtration,ultra filtration, nano filtration and Reversed Osmosis (RO). Which one of these

techniques is implemented depends upon the kind of compounds that needs to be

removed and their particle size. Below, the techniques of membrane filtration are

clarified.

1) Microfiltration

Microfiltration is a membrane separation technique in which very fine particles or other

suspended matters, with a particle size in the range of 0.1 to 1.5 microns, are separated

from a liquid. It is capable of removing suspended solids, bacteria or other impurities.

Microfiltration membranes have a nominal pore size of 0.2 microns.

2) Ultrafiltration

Ultrafiltration is a membrane separation technique in which very fine particles or other

suspended matters, with a particle size in the range of 0.005 to 0.1 microns, are separated

from a liquid. It is capable of removing salts, proteins and other impurities within its

range. Ultrafiltration membranes have a nominal pore size of 0.0025 to 0.1 microns.
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3)Nanofiltration

Nanofiltration is a membrane separation technique in which very fine particles or other

suspended matters, with a particle size in the range of approximately

0.0001 to 0.005 microns, are separated from a liquid. It is capable of removing viruses,

pesticides and herbicides.

4)Reversed Osmosis (RO)

Reversed Osmosis, or RO, is the finest available membrane separation technique. RO

separates very fine particles or other suspended matters, with a particle size up to

0.001 microns, from a liquid. It is capable of removing metal ions and fully removing

aqueous salts.

Cartridge filtration

Cartridge filtration units consist of fibres. They generally operate most effectively and

economically on applications having contamination levels of less than 100 ppm. For

heavier contamination applications, cartridges are normally used as final polishing filters.

2. Chemical water purification

Chemical water purification is concerned with a lot of different methods. Which methodsare applied depends on the kind of contamination in the (waste)water. Below, many of

these chemical purification techniques are summed up.

Chemical addition

There are various situations in which chemicals are added, for instance to prevent the

formation of certain reaction products. Below, a few of these additions are summed up:

- Chelating agents are often added to water, in order to prevent negative effects of

hardness, caused by the deposition ofcalcium and magnesium.

- Oxidizing agents are added to act as a biocide, or to neutralize reducing agents.- Reducing agents are added to neutralize oxidizing agents, such as ozone and chlorine.

They also help prevent the degradation of purification membranes.

Clarification
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Clarification is a multi-step process to remove suspended solids. First, coagulants are

added. Coagulants reduce the charges of ions, so that they will accumulate into larger

particles called flocs. The flocs then settle by gravity in settling tanks or are removed as

the water flows through a gravity filter. Particles larger than 25 microns are effectively

removed by clarification. Water that is treated through clarification may still contain

some suspended solids and therefore needs further treatment.

Deionisation andsoftening

Deionisation is commonly processed through ion exchange. Ion exchange systems consist

of a tank with small beds of synthetic resin, which is treated to selectively absorb certain

cations or anions and replace them by counter-ions. The process of ion exchange lasts,

until all available spaces are filled up with ions. The ion-exchanging device than has to be

regenerated by suitable chemicals.

One of the most commonly used ion exchangers is a water softener. This device removes

calcium and magnesium ions from hard water, by replacing them with other positively

charged ions, such as sodium.

Disinfection

Disinfection is one of the most important steps in the purification of water from cities and

communities. It serves the purpose of killing the present undesired microrganisms in the

water; therefore disinfectants are often referred to as biocides. There are a variety of

techniques available to disinfect fluids and surfaces, such as: ozone disinfection, chlorine

disinfection and UV disinfection.

Chlorine has a downside: it can react to chloramines and chlorinated hydrocarbons,

which are dangerous carcinogens. To prevent this problem chlorine dioxide can be

applied. Chlorine dioxide is an effective biocide at concentrations as low as

0.1 ppm and over a wide pH range. ClO2 penetrates the bacteria cell wall and reacts with

vital amino acids in the cytoplasm of the cell to kill the organism. The by-product of this

reaction is chlorite. Toxicological studies have shown that the chlorine dioxide

disinfection by-product, chlorite, poses no significant adverse risk to human health.

Ozone has been used for disinfection ofdrinking waterin the municipal water industry in

Europe for over a hundred years and is used by a large number of water companies,where ozone generator capacities up to the range of a hundred kilograms per hour are

common. When ozone faces odours, bacteria or viruses, the extra atom ofoxygen

destroys them completely by oxidation. During this process the extra atom of oxygen is

destroyed and there are no odours, bacteria or extra atoms left. Ozone is not only an

effective disinfectant, it is also particularly safe to use.
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UV-radiation is also used for disinfection nowadays. When exposed to sunlight, germs

are killed and bacteria and fungi are prevented from spreading. This natural disinfection

process can be utilised most effectively by applying UV radiation in a controlled way.

Distillation

Distillation is the collection of water vapour, after boiling the wastewater. With a

properly designed system removal of organic and inorganic contaminants and biological

impurities can be obtained, because most contaminants do not vaporize. Water will than

pass to the condensate and the contaminants will remain in the evaporation unit.

Electro dialysis

Electro dialysis is a technique that employs an electrical current and special membranes,

which are semi permeable to ions, based on their charge. Membranes that permeate

cations and membranes that permeate anions are placed alternately, with flow channelsbetween them, and electrodes are placed on each side of the membranes. The electrodes

draw their counter ions through the membranes, so that these are removed from the water.

pH-adjustment

Municipal water is often pH-adjusted, in order to prevent corrosion from pipes and to

prevent dissolution of lead into water supplies. The pH is brought up or down through

addition ofhydrogen chloride, in case of a basic liquid, or natrium hydroxide, in case of

an acidic liquid. The pH will be converted to approximately 7 to 7.5, after addition of

certain concentrations of these substances.

Scavenging

Most naturally occurring organics have a slightly negative charge. Organic scavenging is

done by addition of strong-base anion resin. The organics will fill up the resin and when

it is loaded it is regenerated with high concentrations of sodium chloride.

3. Biological water purification

Biological water purification is performed to lower the organic load of dissolved organic

compounds. Microrganisms, mainly bacteria, do the decomposition of these compounds.

There are two main categories of biological treatment: aerobic treatment and anaerobic

treatment.

The Biological Oxygen Demand (BOD) defines the organic load. In aerobic systems the

water is aerated with compressed air (in some cases merely oxygen), whereas anaerobic

systems run under oxygen free conditions.
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WATER PROBLEM TABLE

Color of WaterWater

ProblemContaminant Source of Contaminant Health Effect(s) Treatment(s)

Blue to Blue-

greenCopper

Much of copper

contamination comes

from home plumbing and

fixtures when the water

is corrosive.

If you have copper

contamination due to

corrosion, you may

also have lead in your

water since the

conditions responsible

for leaching copper out

of a pipe or fixture are

the same as those that

will leach lead, if

present.

lead does NOT leave

sensory clues at

dangerous levels!

Essential mineral

Mostly a nuisance,

although In fairly high

doses copper can

cause

gastrointestinal

problems.

More important as

an indicator of

possible lead

contamination -

consider having your

water tested for lead.

Acid neutralization of

whole house water to

minimize corrosion.If contamination is from

natural sources, use ion

exchange for whole house

(& possibly POU).

Reverse osmosis and

distillation are effective

POU treatment methods

Cloudy, or

Milky Small air bubbles

Air dissolved in the waterbefore or during pumpingor treatment, maynaturally be in well water.

HarmlessBubbles will eventually riseto the surface anddisappear

Methane bubbles

Methane is odorless,so unless the water alsocontains odor-causingchemicals like hydrogensulfide, methane will bedifficult to identify.

Methane isextremely

flammable orexplosive ifconfined!

Bubbles will eventually riseto the surface anddisappear

For methane, aerate thewater prior to use. Theaerator must be vented tothe open air to permit thegas to escape into theatmosphere.

Very fine dirt or clayparticles, or organic

Naturally, from soil,rocks, and living things.

Normally just anuisance. However,

Cloudiness from these

contaminants will not clear


32/41

matter

Abnormalcloudiness can bean indication thatfiltration of moreharmful invisiblecontaminants (like

bacteria and cysts)has failed - test thewater - locate &correct cause of theproblem.

on standing like bubbles

will.

Treat with sediment

filtration unless there arepathogens in the water -then disinfect and filter.

Reddish -

orangeIron

Naturally, from soil &

rocks, sometimes from

galvanized pipes if water

is corrosive.

Nuisance Iron removal

Dark brown toBlack

Manganese Naturally, from soil &rocks

Nuisance Manganese removal

Yellow Tannins (humic acid)Naturally, from organicsoil and vegetation

Nuisance - watermay also have abitter taste

Activated CarbonFiltration

Up to 3.0 ppm:Absorption with an ionexchange resin

greater than 3.0 ppm:Chlorination followed byfiltering

Deposits, Spots, & Sediment

Water

ProblemContaminant Source Health Effect(s) Treatment(s)

Soap scum

and Bathtub

rings. Also,

failure of

soap to lather

well

Calcium and

magnesium carbonate

(Hard water)


rocks

Essential mineral

Nuisance in water

over about 5 grains

of hardness

Standard water softener ion

exchange.

Scaly, whitish

deposit on

fixtures,

plumbing

lined with

Calcium and

magnesium carbonate

(Hard water)


rocks

Essential mineral

Nuisance in water

over about 5 grains

of hardness

Standard water softener ion

exchange.

Clean deposits on the

fixtures with a rag soaked i

vinegar


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scale.

Spots on

clothing

Calcium and

magnesium carbonate

(Hard water)


rocks

Essential mineral

Nuisance in water

over about 5 grains

of hardness

Standard water softener

ion exchange.

Spots on

dishes,

glassware,

and flatware

Calcium andmagnesium carbonate(Hard water)

Naturally, from soil &rocks

Essential mineralNuisance in water

over about 5 grainsof hardness

Standard water softenerion exchange.

High levels of TotalDissolved Solids (TDS)

(also hard water)

natural sources

or from humancontamination

Usually a nuisance.May be harmful,

depending on thecontaminant(s)

present. Usecommon sense andyour home's location(for instance, do youlive in an agriculturalor industrial area, ornext to a wastedump) to decide iftesting is warranted.

TDS can be a mix of manychemicals.

Use whole house ionexchange and activated

carbon to remove manycontaminants.Reverse osmosis and

distillation are effectivePOU treatment methods

A solid block, activatedcarbon filter will reliablyremove most of the organicTDS

Spotting,

mottling, or

pitting of

teeth

Fluoride

Naturally from soil &

rocks

Fluoride can also beadded by watertreatment companies.

At about 1 mg/l

Fluoride helps

prevent tooth decay.

Above about 3 - 4

mg/l Fluoride can

cause staining of the

tooth enamel and

other problems.

Activated alumina

filtrationReverse osmosis and



Red - brown

or black -

brown slime

in plumbing

system

Iron or Manganese

Bacteria

The bacteria feed on iron

or manganese dissolved

in the water

Nuisance - can clog

plumbing and filters

Chlorine or permanganate

treatment of well

Reddish -

brown

sediment.

Typically

clears after

Iron Dissolved iron

precipitates when

oxygen reaches it.

Sometimes the iron

sediment in the

distribution system or

Nuisance If the problem is caused

by dissolved iron in water,

using iron removal method

If the problem is caused

by disturbed sediment from


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running the

water for a

few minutes

home pipes is disturbed -

when this happens, the

water can get really

"thick" with sediment for

a while.

pipes, run the water for a

while, and it should clear.

The sediment can be

filtered as well.

Grittiness,

abrasiveness

of water, and

sediments at

the bottom of

tubs and

sinks

Fine sand, grit

Sand or very fine

sediments that gets

through the filtering

screens in wells or

resists the coagulation

stage during water

treatment.

NuisanceSedimentation or Sedimen

Filter

Staining

Water


Blue-green

stains on sink

and porcelain

fixtures

Copper or brass

Much of copper

contamination comes

from home plumbing and

fixtures when the water

is corrosive.

If you have copper

contamination due to

corrosion, you

probably also have

lead contamination

Essential mineral

Mostly a nuisance,

although In fairly high

doses copper can

cause

gastrointestinal

problems.

More important asan indicator of

possible lead

contamination

Acid neutralization of

whole house water to

minimize corrosion.

If contamination is from

natural sources, use ion

exchange for whole house

(& possibly POU).

Reverse osmosis and



Brown-red

stains, and

discolored

clothing

Iron


rocks, sometimes from

galvanized pipes if water

is corrosive.

Mostly a Nuisance -

Neurological effects

at very high levels

Iron removal

Black stainson fixtures

and laundry

ManganeseNaturally, from soil &

rocks.

Mostly a Nuisance -Neurological effects

at very high levels

Manganese removal

Blackening

and pitting of

metal sinks

Hydrogen sulfide(gas) Naturally occurring,more common in wells

than surface water.

Usually present in

Promotes corrosion

due to its activity as a

weak acid. Also, its

presence in the air

Low to moderate

concentrations - use

oxidizing filter followed by

carbon filter
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35/41

and fixtureswater with high levels of

iron and a low pH.

causes silver to

tarnish in a matter of

seconds

High hydrogen

sulphide

concentrations areboth inflammable and

poisonous. While

such concentrations

are rare, their

presence in drinking

water has been

known to cause

nausea, illness and

in extreme cases,

death.

Aeration followed byfiltration

medium to high

concentrations - use

chlorination followed by

activated carbon

Gray stains Aluminum

The primary source of

aluminum in drinking

water is from the use of

aluminum sulfate (alum)

as a coagulant in water

treatment plants.

Probably just a

nusianc. Although

there was some

concern several

years ago that

aluminum contributed

to Alzheimer's

disease, research

does not seem to

have supported that

idea.

Reverse osmosis or

Distillation

Yellow stainson fabrics,china dishesand sinks,fixtures, etc.

Tannins (humic acid)Naturally, from organicmaterials in soil and fromvegetation

Nuisance - watermay also have abitter taste

Activated CarbonFiltration

Up to 3.0 ppm:Absorption with an ionexchange resin

greater than 3.0 ppm:Chlorination followed byfiltering

Taste

Water


Alkaline taste(bitter, "soda"taste)

Hydroxides,

Carbonates and

Bicarbonates

Bicarbonates are themost common sources ofalkalinity.

Nuisance pH correction using either aneutralizing filter orchemical feed pump to


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High pH waterRecommended pHlevels 6.5 to 8.5

Almost all naturalsupplies have ameasurable amount ofthis ion.

lower the pH

Metallic taste

Iron, manganese,

copper, lead, or other

metals

wide range of possible

sources, depending on

metal

Nervous systemdisorders from lead,

mercury, arsenic.

Possible cancer

risk from nickel,

arsenic, chromium.

Cation exchange forwhole house treatment.

Reverse osmosis,

distillation, or specialized

ion exchange resin for POU

treatment

Salty,

brackish taste

and pitting of

fixtures.

Sodium, chloride,

sulfate, inorganic salts

Sodium salts are present

to a greater or lesser

degree in all natural

waters.

Sodium can cause

problems for people

with hypertension.

Sulfate can cause

gastrointestinalproblems.

Reverse osmosis,

distillation, or specialized

ion exchange resin for POU

treatment

Sharp

chemical

taste or odor,

or "oily"

consistency

Pesticides or semi-

volatile compounds

All are synthetic

organic compounds.

Contamination of water

supply from storage tank

leaks, agricultural

applications, dumping,

improper disposal, etc.

Risk of cancer. Could

affect any bodily

organ system

If these contaminants are

present in levels that can

be easily tasted or smelled

immediately STOP using

the water for drinking and

cooking and drink bottled

water - probably shouldn't

bathe in it either - until the

contaminant level goes

down significantly.

A high quality, solid block

activated carbon filter will

remove undetectable, but

dangerous, concentration o

these chemicals that might

be present even after publi

water treatment.

Odor

Water


Chlorine

smell (like

bleach or

Chlorine, Chloramines Disinfection chemicals.

Some "residual

disinfectant" must remain

in the water during

Chlorine does not

appear to cause

health problems at

Activated Carbon

Filtration for whole house

reduction of chlorine


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swimming

pool)

distribution to prevent

reinfection of the water.

levels normally used

for disinfection.

The possible health

problems result from

the formation of

disinfection

byproducts (DBPs)

discussed elsewhere.

A POU, high quality, solidblock, activated carbon filtewill remove chlorine and,more importantly,disinfection byproducts

from drinking and cookingwater.

Distillation and RO willalso remove thesecontaminants.

Detergent

smell (foamy

water)

Foaming agents, dilute

sewage

Discharges from the

septic system into

sources of underground

water supply;

Accidental presence of

detergent in the water

supply or wellsIf this occurs with

municipal water, it could

mean problems with the

treatment system.

Risk of disease if

bacteria are present.

Could harm infants.

For wells, locate and

eliminate source followed

by strong dose of chlorine

An activated charcoal

filter absorbs small

amounts of detergent

Sweet,

perfume odor

Volatile (or semi-volatile) organic

compounds like MTBE

All are synthetic

organic compounds.

Contamination of water

supply is from storage

tank leaks, dumping,

improper disposal, etc.If these contaminants

are present in levels that

can be easily tasted or

smelled, STOP using the

water for drinking and

cooking immediately and

drink bottled water until

the level is reduced.

Risk of cancer.Could affect kidney,

liver, or central

nervous system.

Find and remove source

of contamination if it is from

a single source, or find a

new source of water.

A high quality, solid blockactivated carbon filter will

remove undetectable, but

dangerous, concentration o

these chemicals that might

be present even after publi

water treatment.

Smells like

fish

Barium, Cadmium Barium is a naturallyoccurring metal found

primarily in the Midwest.Cadmium makes its

way into the watersupplies as a result ofdeterioration ofgalvanized plumbing,industrial waste orfertilizer contamination

Barium is highly toxicwhen its soluble salts

are ingested

Standard water softenerion exchange.

Reverse OsmosisDistillation


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Organic matter Naturally occurring Nuisance Activated Carbon Filtration

Chloramine

Traces of chlorine andammonia compoundsused for desinfection

of wastewater.

Nuisance Activated Carbon Filtration

Smells likerotten eggs

Hydrogen sulfide

(gas)

Naturally occurring,more common in wellsthan surface water.

Usually present inwater with high levels ofiron and a low pH.

Promotes corrosiondue to its activity as aweak acid. Also, itspresence in the aircauses silver totarnish in a matter ofseconds

High hydrogensulphideconcentrations areboth inflammable andpoisonous. Whilesuch concentrationsare rare, theirpresence in drinkingwater has beenknown to causenausea, illness andin extreme cases,death.

Low to moderateconcentrations - useoxidizing filter followed bycarbon filter

Aeration followed byfiltration

medium to highconcentrations - usechlorination followed byactivated carbon

Oil or gas

smell

Methane

Wells that containmethane are generally

located in areas wheregas and oil wells arecommon sights

Danger of fire orexplosion

Aerate water prior to use.The aerator must be vented

to the open air to permit thegas to escape into theatmosphere.

Gasoline or semi-volatile organiccompounds

All are distilled orsynthetic organiccompounds.

Contamination of watersupply is from storagetank leaks, dumping,improper disposal, etc.

If these contaminantsare present in levels that

can be easily tasted orsmelled, immediatelySTOP using the water fordrinking and cooking anddrink bottled water untilthe level is reduced.

Risk of cancer.Could affect kidney,liver, or central

nervous system.

Find and remove sourceof contamination if it is froma single source, or find anew source of water.

A high quality, solid blockactivated carbon filter willremove undetectable, but

dangerous, concentration othese chemicals that mightbe present even after publiwater treatment.

Smells like Selenium The concentration found Essential mineral Ion exchange
http://www.ianr.unl.edu/pubs/water/g1275.htmhttp://www.ianr.unl.edu/pubs/water/g1275.htm


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sewage

in drinking water isusually low, and comesfrom natural sources.

A nuisance if iteffects water odor.

Can be toxic athigh levels ofexposure

Reverse OsmosisDistillation

Sewage

Leakage from a septicsystem, waste treatmentplant, feed lot, farmyard,etc.

High probability ofcontamination with E.coli and otherpathogens as well asnitrates.

If raw sewage is presentin levels that can be easilysmelled, immediatelySTOP using the water fordrinking and cooking anddrink bottled water until theproblem has been identifiedand fixed.

Musty, earthy

smell

Decaying Organic

matter (leaves, algae)

Naturally occurring,usually in surface or

shallow wells

Nuisance, usually

Activated carbon filtration

for whole house treatment.

Combine with sedimentfilter if particulates are

present.

RO, distillation, or

Activated carbon filtration

for POU treatment

CONCLUSION


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Water on Earth moves continually through the hydrological cycle ofevaporation andtranspiration (evapotranspiration), condensation,precipitation, and runoff, usuallyreaching the sea. Evaporation and transpiration contribute to the precipitation over land.

Safe drinking wateris essential to humans and other lifeforms. Access to safe drinking

water has improved over the last decades in almost every part of the world, butapproximately one billion people still lack access to safe water and over 2.5 billion lackaccess to adequate sanitation. There is a clear correlation between access to safe waterand GDP per capita. However, some observers have estimated that by 2025 more thanhalf of the world population will be facing water-based vulnerability. A recent report(November 2009) suggests that by 2030, in some developing regions of the world, waterdemand will exceed supply by 50%. Water plays an important role in the world economy,as it functions as a solvent for a wide variety of chemical substances and facilitatesindustrial cooling and transportation. Approximately 70% of the fresh waterused byhumans goes to agriculture.

REFERENCES

1. http://en.wikipedia.org/wiki/Industry

2. www2.emersonprocess.com/.../Liq_Brochure_91-6030.pdf

3. http://www.cyber-nook.com/water/concerns.html#concern

4. http://water.epa.gov/drink/index.cfm

5. http://www.cyber-nook.com/water/tbl_gene.html

6. http://water.epa.gov/learn/kids/drinkingwater/watertreatmentplant_index.cfm

7. http://www.lenntech.com/applications/drinking/standards/who-s-drinking-water-

standards.htm

8. http://www.mangosteen-natural-remedies.com/benefits-of-drinking-water.html

9. http://www.lenntech.com/applications/drinking/drinking-water.htm#ixzz1e9ey9SD3

10. http://www.activated-carbon.com

11. http://www.aapspharmscitech.org/scientificjournals/pharmscitech/volume2issue1/

056/manuscript.htm
http://en.wikipedia.org/wiki/Hydrological_cyclehttp://en.wikipedia.org/wiki/Evaporationhttp://en.wikipedia.org/wiki/Transpirationhttp://en.wikipedia.org/wiki/Evapotranspirationhttp://en.wikipedia.org/wiki/Condensationhttp://en.wikipedia.org/wiki/Precipitation_(meteorology)http://en.wikipedia.org/wiki/Runoff_(water)http://en.wikipedia.org/wiki/Seahttp://en.wikipedia.org/wiki/Drinking_waterhttp://en.wikipedia.org/wiki/Humanshttp://en.wikipedia.org/wiki/Gross_domestic_producthttp://en.wikipedia.org/wiki/World_populationhttp://en.wikipedia.org/wiki/World_economyhttp://en.wikipedia.org/wiki/Solventhttp://en.wikipedia.org/wiki/Fresh_waterhttp://en.wikipedia.org/wiki/Agriculturehttp://en.wikipedia.org/wiki/Hydrological_cyclehttp://en.wikipedia.org/wiki/Evaporationhttp://en.wikipedia.org/wiki/Transpirationhttp://en.wikipedia.org/wiki/Evapotranspirationhttp://en.wikipedia.org/wiki/Condensationhttp://en.wikipedia.org/wiki/Precipitation_(meteorology)http://en.wikipedia.org/wiki/Runoff_(water)http://en.wikipedia.org/wiki/Seahttp://en.wikipedia.org/wiki/Drinking_waterhttp://en.wikipedia.org/wiki/Humanshttp://en.wikipedia.org/wiki/Gross_domestic_producthttp://en.wikipedia.org/wiki/World_populationhttp://en.wikipedia.org/wiki/World_economyhttp://en.wikipedia.org/wiki/Solventhttp://en.wikipedia.org/wiki/Fresh_waterhttp://en.wikipedia.org/wiki/Agriculture


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12. http://en.wikipedia.org/wiki/Water

drinking water industry

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