water quality

1. • Water supply system
• Sanitary Engineering
• Pollution control
Course Code : 15O - 1305
Course Name : Environmental
Engineering and Pollution Control (E.E)

2. COURSE OUTCOMES
C502.1 : Illustrate the quantity and quality of
water, intake and conveyance of water
supplying system
C502.2 : Treatment of water and distribution
systems
C502.3 : The collection and conveyance of
sewage and sewer appurtenances
C502.4 : Explain sewage treatment, disposal
of sewage and solid waste
C502.5 : Identify the various pollution and
their preventions and Illustrate about
environment impacts assessments

3. Unit – 1 ( Water Supply Engineering)
Quantity of Water : Water Supply - Need For
Protected Water Supply - Objectives of Public Water
Supply System – Demand -Types of Demand - Per
Capita Demand - Prediction of Population - Problems
In Arithmetical Increase Method, Geometrical
Increase Method, Incremental Increase Method -
Sources of Water - Surface And Subsurface Sources-
Reuse And Recycle of Waste Water

4. QUANTITY OF WATER
Introduction
The important requirement of any life including human is
water. It is nature’s gift to lives. It is available in various forms
such as rivers, lakes, streams, ponds etc. The development of
any city is based on the source of water supply.
Need of protect water supplies:
The water when exposed to atmosphere definitely contains
several contaminants which are dangerous to any living
organisms. Consumption of polluted water may cause serious
diseases to the health of living beings. Hence it is very much
needed to protect water supplies.
Objectives of water supply:
The following are the objectives of water supply system
1. Through the supply of whole some water, the public health
will be improved
2. Sanitation of surroundings will be improved
3. Fire safety will be ensured
4. The living standards of people will be improved by
industrialization

5. DEMAND:
when an engineer has to design a water supply scheme for a community, he
has to ascertain the required quantity of water and its availability. The quantity
of water required to meet out the various needs of communities is called
demand of water.
The following are the types of demand.
1. Domestic demand
2. Civic or public demand
3. Industrial demand
4. Waste and loss
Domestic Demand
1. Drinking - 2 lit
2. Cooking - 5 lit
3. Bathing - 40 lit
4. Washing hands, face etc., - 10 lit
5. House hold sanitary purpose - 50 lit
6. Gardening - 15 lit
7. Domestic animals & vehicles - 13 lit
thus the quantity of water required for domestic purposes can be calculated as
above. Normally
it varies from 100 lit – 135 lit per head per day.

6. Public:
The quantity of water for these purposes can be divided into road
washing, sanitation purposes ornamental purposes and fire
demands. Normally this category is taken as 10 lit per head per day
Industrial purposes:
The quantity of water required for this purpose is taken into account
as factories, power stations, railways etc. And it will be taken as 50 lit
per head per day.
Waste and losses:
The quantity of water for these categories is taken into account as
careless use of water, leakages, unauthorized usage of water etc.,
Normally it is assumed as 75 lit per head per day
per capita demand or rate of demand :
The quantity of water required by a person per day for his personal
use is termed as an average Indian towns per capita consumption of
water per day for domestic, civic or public, industries and waste and
loss are worked out between 150 and 300 litres.

7. Factors affecting per capita demand:
1. Climatic condition
2. Cost of water
3. Distribution pressure
4. Habits of population
5. Industries
6. Metering
7. Quality of water
8. Sewerage
9. Size of city
10. System of water supply

8. 1. Climatic condition:
The climate of nature will affect the per capita demand.
The requirement of water in summer is more than that in
winter. Hotter places require more water than cooler
places.
2. Cost of Water:
If the water supplied to the consumers is charged, it will
affect the per capita demand. The higher is the cost, the
lower will be the consumption. If it is free supply, the
consumption will be
more.
3. Distribution pressure:
More pressure leads to more consumption and less
pressure leads to low consumption.

9. 4. Habits of population:
The living standards of people influence the rate of
consumption. Rich peoples may consume more quantity
of water, middle class peoples use an average quantity
and poor people consume less quantity of water.
5. Industries:
The presence and absence of industries in a town may
affect the rate of demand.
6. Metering:
The quantity of water supplied is recorded by a meter
and the consumption will be charged accordingly. The
installation of meter may affect the rate of demand.

10. 7. Quality of water:
The good quality of water may increase the rate of
consumption. Poor quality of water leads to less
consumption.
8. Sewerage:
The existence of good sewerage system will increase the
consumption of water and thus affect the rate of demand.
9. Size of city:
Smaller the town, the lower is the rate of consumption.
But the presence of water consuming industries in small
towns results more consumption and thus affects the rate
of demand.

11. 10. System of water supply:
The continuous supply of water may increase the rate of
consumption and the intermittent system of supply leads to
less consumption of water
POPULATION :
The total number of human beings residing in an area
is taken as population. Population is an important
factor for the estimation of a water supply project.
Hence it is necessary to predict the future population
with the help of any suitable method. Usually the
population will be predicted in terms of decades. A
decade contains of ten years. Normally the
design period of a water supply project
varies from 30 years to 50 years.

12. Prediction of Population:
The design of water supply project is not designed only
for present population. But it is
made to accommodate the future population. Hence it
is necessary to predict the future population.
The following methods are adopted to forecast the
future population.
1. Arithmetical increase method
2. Geometrical increase method
3. Incremental increase method
4. Graphical method
5. Zoning method
6. Comparative method