Intakes, sedimentation principles, gorund water quality and quantity ...

choppedspleenMécanique

22 févr. 2014 (il y a 3 années et 3 mois)

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VARDHAMAN COLLEGE OF
ENGINEERING

DEPARTMENT OF CIVIL ENGINEERING


ENVIRONMENTAL ENGINEERING





By

M. Rajasekhar

Assistant Professor

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OBJECTIVES
:


On the completion of this topic, you will be able to
know:





The importance of different units in water treatment plant for
purification water
.





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Treatment of water



Objectives:


To remove




Pathogens



Dissolved gases and solids.



Objectionable ,unpleasant odour.



Taste and colour



To make the water suitable for the domestic and


Industrial purposes.

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Click on the stage
number to view the
contents


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3


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6

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Fig.1
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SOURCES OF WATER

Ponds, Lakes, Streams, Rivers and Impounding Reservoirs

Fig.2
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PRELIMINARY TREATMENT

The

first

operation

encountered

in

preliminary

treatment

of

water

is

called

as

screening
.


A

screen

is

a

device

with

uniform

openings

used

to

retain

floating

solids

in

the

raw

water

by

mechanical

straining

action
.

PRE
-
CHLORINATION

Addition

of

Chlorine

to

raw

water

before

treatment

in

sedimentation

tanks

and

filter

beds

is

called

Pre
-
Chlorination
.

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Coagulation and Flocculation

The Process of adding certain chemicals for accelerating sedimentation process

and effective removal of very fine and colloidal particles is known as Coagulation

Fig.3

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FILTRATION

The

process

of

passing

the

water

through

a

filter

media

consisting

of

thick

layer

of

sand

to

remove

impurities

is

called

Filtration
.

Fig.4

POST
-
CHLORINATION ( DISINFECTION)

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Application

of

chlorine

gas

or

its

compounds

like

bleaching

powder

for

disinfecting

water

is

known

as

Chlorination
.


Addition

of

chlorine

after

filtration

is

called

Post
-
Chlorination
.

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SEDIMENTATION

The

Process

of

settling

the

suspended

solids

by

virtue

of

gravity

is

called

Sedimentation
.

Fig.5

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The

treated

water

has

to

be

supplied

to

the

people

in

required

quantities

at

the

point

of

consumption

through

network

of

pipes

is

called

as

Distribution

System
.

Clear
Water

Point of
Consumption

Distribution System

Fig.6

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Treatment of water


Major units in water treatment plant are:




Aeration



Plain Sedimentation



Sedimentation with coagulation



Filtration



Disinfection