green park village : dewats technical description-1

7/30/2019 Green Park Village : Dewats Technical Description-1

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GREEN PARK VILLAGE ECO FRIENDLY HOTEL

ENERGY/ DEWETS PROJECT

SOLAR POWER

WATER

BIO GASS

BIO FUEL


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Technical Description about DEWATSJune 06

DECENTRALIZED WASTEWATER TREATMENT SYSTEMS

The Decentralized Wastewater Treatment Systems (DEWATS) framework is tailored to improve sanitation

conditions in densely populated areas and provide reliable low cost sanitation and wastewater treatment

solutions. The demand for reliable, efficient and low cost wastewater treatment systems is increasing

worldwide especially in compactly populated urban regions, where adequate wastewater treatment systems do

not exist. Uncontrolled discharge of wastewater in such areas endangers environmental health and water

resources.

The DEWATS Community Based System (CBS) approach is an alternative option that fills the significant gap

between inappropriate site sanitation and the shortcoming of sewage collection and treatment systems. Within

the CBS approach communities are able to make their own informed demands. They are educated about the

connection between sanitation, hygiene and diseases and are encouraged to organize the operation andmaintenance of sanitation infrastructure.

Advantages of decentralized systems include: quick and effective tools to close sanitation gaps and mobilize

local resources; simplification and reduction of sewer systems; re-use of the treated wastewater in irrigation

water and soil improver; utilization of biogas for cooking and heating; low running cost and low cost of the

project life cycle. The basic CBS system consists of a toilet component, a collection component (biogas

digester), a treatment component and a disposal component/re-use component.

BIOGAS TECHNOLOGY

Biogas Technology produces and utilizes the products of anaerobic digestion, which are biogas and manure.

Besides energy and fertilization, other benefits of biogas technology are improved sanitation and

environmental protection. Biogas technology has proved to be a viable technology in the physical and socio-

economic conditions, where common problems of the developing world (such as increase energy demand) put

a pressure on the countrys resources. The daily biogas production is measured in liters of biogas produced by

l kg of total solids added per day.

Anaerobic digestion is the technology that is gaining wider acceptance in the present scenario over aerobic

treatment. This is due to benefits such as lower energy requirements, high degree of waste stabilization, high

organic loading rates, lower production of excess sludge, easier preservation of a well adapted sludge and the

production of biogas which can further be used for meeting part of the energy demand. The total potential for

energy generation from the anaerobic digestion of industrial wastewater is estimated to be 2,963 x 106 kWh,

equivalent to electric energy per annum. This is equivalent to a 565 MW power plant installation.

Since the introduction of the concept of sustainable development, anaerobic reactor technology has received

worldwide attention as it offers several opportunities within decentralized sanitation strategies, especially for

developing countries. Moreover, it opens up a wide variety of resource recovery options and opportunities for

industries to improve part of their investment costs by utilizing the energy produced in the form of biogas and

reduce huge energy bills.

Biogas digester technology is airtight, plastered fixed dome plants, which enable collection and utilization ofbiogas. This on- site reactor is fed with animal manure and domestic waste and after retention of several

weeks or months the digested wastes are well stabilized and pass through active bacteria sludge in each


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baffled chamber and used as fertilizer on gardens or agricultural fields. There are several biogas technology

advantages. These include:

- To reduce pressure on the conventional energy supply

- To reduce the energy loss due to long distance transportation- To avoid environmental pollution caused by conventional energy combustion

- Less intensive capital investment for the establishment of decentralized energy supply systems

- Easily planned at a local level

- To use the local resources efficiently and rationally

BIOGAS PURIFICATION AND BOTTLING PLANT

Biogas can be used in automobiles after its purification (removing CO 2, H2S and water vapour pressure). A

CO2 scrubbing and bottling technology has been designed and developed at Indian Institute of Technology

Delhi, based on physical absorption of CO2 in water at elevated pressure. The scrubbing system is able to

remove CO2 from raw biogas when pressurized biogas is fed into the packed bed scrubbing column and

pressurized water is sprayed from top, in counter current action. The enriched biogas is compressed up to

20MPa pressure using a three-stage compressor after moisture-removal and is filled in special high-pressure

steel cylinders. The enriched biogas filled CNG cylinders are being used successfully as fuel for vehicles in

many countries.

One of the greatest advantages according to literature is that the biogas fuel has lower emission than natural

gas and diesel. The Green Park Village Estate Development Project will purchase and install the purification

plant for bottling biogas into cylinders to be used as vehicle fuel. The technology ensures sustainable

development and energy security, as well as employment generation using cattle dung and biomass.

Description of the DEWATS Plant

Generals about DEWATS

With increasing water pollution and current conventional centralised treatment systems proving to be

inadequate and failing to offer sustainable solutions to the wastewater and treatment problems, there is a

need to change the perspective towards treatment systems. Many developing countries cannot afford to

provide sustainable treatment systems to their populations, as the initial cost and operation of conventional

systems are much too expensive. A possible solution to the transformation of wastewater to reusable form is

the concept of decentralised treatment systems. The key approach of this system is not to promote any

particular kind of technology but to bring forward a new philosophy of dealing with waste and wastewater.

This approach is based on a systematic implementation of material-flow-oriented recycling process. This

system will help minimize water pollution ensuring that water is used economically and is reused to the

maximum possible extent after treatment. This treated water can be reused for irrigation, groundwater

recharge or even direct reuse. The conversion from wastewater to reusable water is possible and a

decentralised treatment system is the alternative and sustainable concept.

A Decentralised Wastewater Treatment System (DEWATS) is based on the principle of decentralization,simplicity and reuse of the treatment products. Simplicity is expressed by on-site treatment without chemicals

and technical energy inputs and low-maintenance. This treatment system cannot be switched off intentionally


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and it provides state-of-the-art technology at affordable prices. To operate the treatment unit, skills of the

level of a gardener or a caretaker are enough.

DEWATS applications provide treatment for both domestic and industrial sources of wastewater and are

reliable, long lasting and tolerant towards inflow fluctuations. A DEWATS unit can be designed to treatwastewater flows from 1-1000 m3 per day. The applications are based on mainly four treatment principles

(modules), combined according to their specific characteristics to a customized treatment system.

Primary treatment and sedimentation called as settler, optional in combination biogas

collection

Secondary anaerobic treatment in fixed-bed or baffled upstream reactors

Tertiary aerobic/anaerobic treatment in subsurface flow filters (planted gravel filter)

Tertiary aerobic treatment in ponds.

DEWATS applications are designed in such a way that treated water meets requirements stipulated byenvironmental laws and regulations.

Biogas Plant

The biogas plant is designed as half-ball shape, made by bricks and is integrated into the ground. The

function is, to separate the incoming wastewater in liquid and solid and to digest biologically the organic

solids. That process takes place without oxygen input under anaerobic condition and generate biogas useful

for cooking, light and heating.

Fig. 1: Biogas digester


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Anaerobic Baffled Reactor (ABR)

The baffled reactor consists of a series of chambers in which the wastewater flows up-stream. Here, the

suspended and dissolved solids in the pre-settled wastewater undergo anaerobic degradation. The activated

sludge settles down at the bottom of each chamber and the influent wastewater is forced to flow through this

sludge blanket where anaerobic bacteria make use of the pollutants for their metabolism. Progressive

decomposition occurs in the successive chambers. A part of the last chambers can optionally be filled up with

coarse filter material like stones, cinder or plastic rings. The filter material acts as carrier material for an attached

bio-film consuming the organic water pollutants. That kind of reactor is called combined ABR. In ABR plants the

BOD reduction rate is up to 90% and the pathogen reduction ranges between 40 - 75%. The baffled reactor is

resistant to shock load and variable inflow. It operates by gravity and maintenance is reduced to desludging of

the chambers at intervals of 1-2 years. Sub-soil construction of the module saves space.

Fig. 2: Baffled reactor with integrated settler

Planted Gravel Filter

Planted Gravel Filter (PGF) is a constructed wetland suitable for wastewater with low percentage of suspended

solids that have already been removed by pre-treatment. The main removal or treatment mechanisms are

biological conversion, physical filtration and chemical adsorption. PGF is made of planted filter bodies

consisting of graded gravel. The bottom slope is 1% and the flow direction is mainly horizontal. The main

plants used in this filter bed are Canas indica, Reed juncus, Papyrus, Phragmites andArunda donax. The plant

selection is mainly based on their ability to grow on wastewater and have their roots go deep and spread

wide. Plants transport oxygen via their roots into the ground. However, in the present DEWATS design the use

of plants is only to act as catalysts rather than actually be a treatment medium. BOD reduction rate isbetween 75 - 90% and pathogen removal is over 95%. The operation and maintenance of the system are

simple. The spatial requirements for construction are compensated through pleasing landscapes.

gas

manholes

inflow

scum outflow

sludge

sedimentation inoculation of fresh wastewater with active sludge final settler

internal water level

inflow manhole

upper sand layer central outlet shaft

final outlet

cross

distribution

trench filled

with rocks

main filter body filled with coars gravel cross

collection

trench filled

with rocks

perforated pipe

connected to

swivel pipe for

adjustable height

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Fig.3: Planted gravel filter

Fig.4: DEWATS plant incl. settler, ABR, PGF and water storage

NOTE:

0 The DEWATS constructin cost (pos.1) `indicate a budget and shall not be understood as a

biding quotation. In close consultation with the client the system will be adapted and

otimized to the local requirements especially regarding separation of black and grey water,

required treatment steps re-use of treated waste water and utilization of generated biogas.

The most appropriate and cost effective solution shall be chosen. The construction cost

might finally vary / 15% from the cost indicated under pos. 1.

1 DEWATS plant to treat and dispose 32 m per day domestic wastewater. The system 1 item USD 32,000 USD 32,000

will be designed to treat wastewater from kitchen, toilets, bathrooms and laundry of a

population of about 250 people by using a mechanical/ biological septic system. Gray

& black water will be separated. The generated and collected biogas can be utilized for

cooking on ordinary gas stove modified for biogas application. The treated effluent

can be used for irrigation purposes, excess water will evaporate and infiltrate into

the ground through French drain. The system consist of:

Brick built and gas tight biogas plant 25m with gas outlet and 3x cast-iron

manhole covers,800 m PEHD gas pipe incl. Fittings, biogas stove. Gas pressure 1 item

max. 60 cm WC with a gas storage of 4m

Anaerobic baffled reactor (ABR), 10 m 1 item

Planted gravel filter(constructed wetland), 250 m 1 item

Polishing and fish pond, 20 m 1 item

Septic tank for grey water 1 item

French drain 20m length 1 item

Irrigation system is not included 1 item

Sewers to the DEWATS plant are not included 0 item

Total land requirement

Engineering of a sustainable and low maintenance wastewater treatment and 1 item USD 4,000USD 4,000

disposal system to the requirement of the Green park village. Scope of work:

Basic assessment and wastewater related land survey


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Layout design

Execution design

Supervision

O&M care taker training

Travel and accommodation cost

Total USD 36,000

Solar power 110 KVA

550 M panel cost usd 150,000

green park village : dewats technical description-1

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