2.water supply

URBAN WATER SUPPLY SYSTEM

By Dr. Rabidyuti Biswas

Sources of water Surface water

Ground waterIntake works

Raw water storage

Water treatment plant

Clean water storage

Water distribution system

Water to consumers

Waste water Waste water treatment

Disposal River, lake, water bodies

Demand

COMPONENTS OF URBAN WATER SUPPLY

SYSTEM

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Available waterSurface water

EXISTING WATER SUPPLY SYSTEM

Underground water

Storage and treatmentDemand assessment

Distribution system

Consumers: - residential/ commercial/ industrial

Waste water collection

Treatment of wastewater

Disposal to steams/ drains / rivers (90%)

Irrigations / horticulture (<10%)

BASIC PLANNING CONSIDERATIONS• Area• Population• Per capita demand• Nature and location of facilities• Location of treatment plant, intake, wastewater disposal• Optimization through alternative plans and cost benefit analysis• Water quality and quantity• Plant siting• Mechanization/ instrumentation/ automation• Service building/ other utilities• Design period• Population forecast• Per capita supply/ based on demand• Quantity standard

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Water Balance

Total Water on Earth 1.36 X 109 Km3

Water in the Sea 97.3%Fresh Water 2.7%The Fresh Water is Distributed in to:Ice Caps & Glaciers 2.0844%Ground & Soil Moisture 0.6048% Lakes & Swamps 0.00945%In Atmosphere 0.00108%Streams 0.000027%

WATER SOURCES

6URBAN WATER SUPPLY R. Biswas

Sources of water


URBAN WATER SUPPLY R. Biswas

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Surface Water sources are fresh water collected on the ground or in a stream, river, lake, or wetland.

http://upload.wikimedia.org/wikipedia/commons/4/49/Parinacota.jpg

Surface water sources



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Sub-Surface water, or groundwater, is fresh water located in the pore space of soil and rocks. It is also water that is flowing within aquifers below the water table.

It is estimated that 15% of world-wide water use is for household purposes.

http://en.wikipedia.org/wiki/Image:Groundwater_flow_times_usgs_cir1139.png

Choice of site

• Quantity of water available• Quality of source• Possibility of dam construction• Distance of source• Elevation of supply

GROUND WATER SOURCES


INTAKE POINTS


INTAKE POINTS


Dam intake

INTAKE POINTS

Lake water intake

River water intake


Intake systems

• Device or structure placed in a surface water source to permit the withdrawal of water from the source.

• Used to draw water from lake, reservoirs or rivers in which there is either wide fluctuation in water level or when it is proposed to draw water at the most desirable depth.

Location of intake

• Best quality of water available,• Absence of current, ice float • Navigation channel should be avoided• Away from flooding,• Accessibility, distance of pump station,• Location of power stations and

connectivity.

Total Utilization

Immediate Evaporation

70

Surface Water

115

Year 1974 Year 2025

Percolation into the Soil

215

Irrigation 95

Other Uses

3

Other Uses

28Irrigation

77

Total Precipitation in Million Hectare Metre

Availability of Water in India

WATER DEMAD / USES


WATER DEMAND /USES


Purpose Consumption

lits/capita/day % Consumption

1 Drinking 05 2.5 2 Cooking 05 2.5 3 Personal cleaning 10 5 4 Washing utensil 10 5 5 Washing cloths 30 15 6 Bathing 70 35 7 Flushing of

toilets 45 22.5

8 Others 25 12.5 Total 200 100

Domestic Water Consumption IS1172: 1993

IS 1172:1993: Code of basic requirements for water supply, drainage and sanitation.

Domestic water consumptionDrinking

3%

Cooking3%

P.Cleaning5%

Utensil w sh5%

Cloth w sh15%

Bathing34%

Toilet f lsh22%

Others13%

Drinking

Cooking

P.Cleaning

Utensil w sh

Cloth w sh

Bathing

Toilet f lsh

Others

IS 1172: 1993

Water consumption standards for Indian cities

Town size (population) Consumption rate (lpcd)Up to 10,000 70- 100

10,000 – 50,000 100- 125

> 50,000 125-200


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Source: UDPFI Guideline, 1996

Standards for water supply

Purpose Potable @30 gpcd (135lpcd)

Non-potable @20 gpcd (90 lpcd)

1 Drinking 05 2 Cooking 10 3 Washing cloths 30 4 Washing utensil 20 5 Washing hand and

faces 10

6 Bathing 60 7 Floor washing 30 8 Flushing of toilets 60 Total @225lpcd 135lpcd 90lpcd

Source: Khare et al 2006.

Estimated Break up of Domestic Water Demand in Delhi

Domestic water demand for DelhiDrinking

2%

Cooking4%

Washing cloths13%

Washing utensil9%

Washing Hand and face

4%

Bathing28%

Floor washing13%

Toilet flushing27%

Continue…..

Continue…….


30SOURCE: WSP-SA-2007.


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IMPOUNDING RESERVOIR

Impounding reservoir is a tank, used for storage of untreated surplus rainwater for use in dry season. This is also called raw water reservoir

STORAGE OF WATER

Storage of water may be required for raw water and also for clean potable water to meet average daily fluctuation and also for emergency use

Impounding reservoir

• It is a constructed pond in the valley of a stream to store water during excess stream flow and supply water when the flow of the stream is in sufficient to meet demand for water.

RAW WATER STORAGE


TREATMENT


TREATMENT

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Water treatment/ purification is the process of removing contaminants from a raw water source.

Water purification may remove:

• Particulate sand; suspended particles of organic material; parasites, bacteria; algae; virus; fungi; etc. • Minerals calcium, silica, magnesium, etc., and Toxic metals lead; copper; chromium; etc.

Some purification may be selective in the purification process like smell (hydrogen sulphide remediation), taste (mineral extraction), and appearance (iron in capsulation).

Water treatment

The aim of water treatment is To produce and maintain water that is

hygienically safe, aesthetically attractive and palatable in an economic manner.

Treatment process

• Clarification• Sedimentation• Filtration• Disinfection • Other specific treatment


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TREATMENT


Location of treatment plant

• Hill side is better location, • Highest flood level should be considered,

and platform should be above the level,

Other components

• Service building with – houses, laboratories, offices, washing room,

store room, chemical house and • pump house are required in all treatment

plant or even in pumping station.

CLEAN WATER RESERVOIR The clean water reservoir used for the

storage of pure/ filtered water after treatment until it is pumped into distribution or into service reservoir before distribution to the consumer and it provides for fluctuations in demand. Maximum one-day storage is recommended for clean water for sanitary point of view.


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CLEAN WATER RESERVOIR• The clean water reservoir’s wall must be of brick/ RCC or

stone masonry wall inside plastered with 2.5 cm cement mortar and made watertight.

• The reservoir should be divided into compartments so that the repair and cleaning may be possible in turn.

• The accessories required for these types of reservoirs are inlet, outlet, water level indicator, and manhole, ladder, overflow pipes etc.

• These reservoirs are generally made underground.


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CLEAN WATER STORAGE


SERVICE RESERVOIRS• Service reservoirs are built to provide storage to

meet the fluctuating demands and to serve as balancing tanks to maintain the pressure during the hours of greatest demand.

• These reservoirs allow the pumps to work for a normal rate and to take rest. They meet emergent demands due to fire and failure of pumps and also reduce the hours of pumping.


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Types of service reservoirs Ground service reservoir Elevated service reservoir or high service

reservoir or overhead tank Balancing reservoir


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Location of service reservoir

• Used to regulate pressure in the distribution system

• Central location is the ideal place• However tail end reservoir is also

preferable

Service reservoirs


Capacities of service reservoirs

• The capacity should be such that the reservoirs may store excess water for balancing the rate of pumping.

• Pumping is usually done for 8 to 10hrs a day and hence the minimum capacity must be of 14-16hrs average daily flows for storage when the pump is idle.


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DISTRIBUTION SYSTEM


Design of distribution system

Depends on • Topography• Layout/ spread and expansion of city• Existing population, expected future

population, commercial and industrial land use

• Layout of road


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DISTRIBUTION SYSTEM


Fire hydrant


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Fire hydrant


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IS 908:1987: Specifications for fire hydrants

DISTRIBUTION SYSTEM


WASTE WATER


WASTE WATER MANAGMENT

• Treatment• Reuse / recycling• Disposal


WASTE WATER DISPOSAL



GREY WATER RECYCLE

Conceptual waste water reuses system Estimated Grey and black water generation system (Per capita wastewater generation in group housing apartments)

Grey water Total 100 lpcd (48 %) Black water, total 110 lpcd (52% of total wastewater) To sewer systems To grey water Treatment systems (With in the group housing plot)

Kitchen Sink (20lpcd)

Flushing of toilets (60lpcd) (27% of demand)

Bath, washing of hand & face (60+10) lpcd

Washing cloths (30lpcd)

Floor cleaning (30lpcd)

Case I Grey water Can be used for irrigation and Horticulture (can be acceptable for road side & parks out side residential plots) Case II Grey water

Can be used for flushing of toilet and fire demand. Acceptable option to the resident.

Case III Grey water

Can be used for drinking (high cost) May not be acceptable by resident

Septic tank (storage)

Septic tank (storage) Disinfections Simple

Filtration

Septic tank (storage) Disinfections Filtration ,

UV or RO

Process of Grey water for different uses

Sources of water Surface water

Ground waterIntake works

Raw water storage

Water treatment plant

Clean water storage

Water distribution system

Water to consumers

Waste water Waste water treatment

Disposal River, lake, water bodies

Rainwater

Grey water

Recycled

Flushing,horticulture

Demand

Reduceddemand

Ground water recharge

80

Available water Surface water

CONCEPTUAL WATER SUPPLY SYSTEM

Underground water

Storage and treatment

Potable water demandDistribution system

Consumers: - residential/ commercial/ industrial

Waste water collection

Treatment of wastewater

Disposal to steams/ drains / rivers

Irrigations / horticulture

Recycled water (20-30%)

Rainfall/ runoff (10 - 15%) Recharge

Non-potable water demand

Demand reduction/ water saving equipments/ policy (20 - 25%)


PLANNING OF WATER SUPLLY

ORGANISATIONS AND JURISDICTIONS

1.National level – CPH&EEO2.State level or regional level – PHE3.Individual community/ town/ city – Local Government

Though the responsibility of the various organizations in charge of planning of water supplies in each of these cases is different, still they have to work/ function with in the priority fixed by the national and stage governments.

PHYSICAL PLANNER & URBAN WATER SUPPLY

1. WATER SYPPLY SYSTEM

2. CLASSIFICATION

3. METHODS

4. COMPONETS

5. AREA REQUIREMENTS WITH CAPACITIES

6. POLICIES AND INSTITUTIONAL ARRANGEMENT

7. MANGEMENT APPROACHES

8. MANAGEMENT PRACTICES

9. BEST MANAGEMENT PRACTICES (ABROAD AND INDIA)


2.water supply

Engineering