PROCESS AND DESIGN OF WATER

TREATEMENT PLANT

Smt.S.R.Patel Engineering College, Dabhi

PREPARED BY

1. Patel Vaibhav (100783106011)

2. Raval Bhavesh (110783106003)

3. Patel Jigar (110783106002)

4.Patel dharamendra (090780106026)

INTERNAL GUIDE

Prof. D.D. PATEL

OBJECTIVE

The main object of the water treatment processes is

remove the impurities of raw water and bring the quality of

water to the required standards. The objects may be

summarized as follows:

To remove the unpleasant and objectionable tastes and

odours from the water.

To remove the murkiness and colour of water.

To kill the pathogenic germs, which are harmful to the

human health.

To make water fit for domestic use as cooking and washing.

To make water fit for domestic, industrial and commercial

uses.

INTRODUCTION Water, is a basic human need. The population in India is likely to

be one hundred twenty crores by the turn of this century, with the

estimated 40% of urban population. This goes on to say that a

very large demand of water supply; for a domestic, industrial,

Fire- fighting, accordance with the rising population.

Absolute pure water is never found in nature, but invariable

contains certain suspended, colloidal and dissolved impurities

(organic and inorganic in nature generally called solids) in

varying degree of concentration depending upon the source.

Hence treatment of water to absolute removal of these

impurities become indispensable. Untreated or improperly

treated water, become unfit for intended use proves to be

detrimental for life.

The design of water treatment plant for Hajipur situated in

district Patan of Gujarat has done. The population of the

design plant of 1.9 lacks. So treated water supply for

domestic and small industry uses are very essential.

The method used to achieve this challenging goal was to

involve as many experts as possible experts, be they

scientists or practitioners, in the early phases of the project.

The use of Internet and Email facilities allowed for an

extensive technology research and valuable feedback from

virtually anywhere in the world.

“Water is life”

Water is of major importance to all living things.

Up to 60 percent of the human body is Water.

Therefore the quality of Water we drink is very important.

The Drinking Water should be totally clean, pure and free of

any disease causing MICROBES, and that’s why it should be

properly Treated and DISINFECTED before using it for

drinking purpose.

PROCESS OF WATER TREATMENT

PLANT

SCREENING

FLOCCULATION & COAGULATION

SEDIMENTATION

FILTRATION

DISINFECTION

MISCELLANEOUS PROCESS

Raw Water

Storage

Mixing Flocculation Sedimentation

Filtration

Clear Well

Distribution

Surface Water Treatment Plant

Coagulant, pH Adjustment Disinfectant (Cl2, NaOCl)

SCREENING

The purpose of Sedimentation is to remove the suspended

impurities. With the help of plain sedimentation, silt, sand etc.

can be removed. However, with the help of sedimentation with

coagulants, very fine suspended particles and some bacteria can

be removed.

SEDIMENTATION

FACTOR AFFECTING OF SEDIMENTATION TANK

PARTICLE SIZE:

The size and type of particles to be removed have a significant effect on the operation of the sedimentation tank. Because of their density, sand or silt can be removed very easily.

WATER TEMPERATURE:

When the temperature decreases, the rate of settling becomes slower. The result is that as the water cools. In most cases temperature does not have a significant effect on treatment.

FLOCCULATION & COAGULATION

“Coagulation” means a reduction in the forces which tend

to keep suspended particles apart. “Flocculation” is the

joining together of small particles into larger, settleable and

filterable particles.

Water treatment transforms raw surface and groundwater

into safe drinking water.

Water treatment involves two major processes: physical

removal of solids and chemical disinfection.

FILTRATION: The water passes through filters, some

made of layers of sand, and charcoal that help

remove smaller particles.

DISINFECTION: A small amount of chlorine

is added or some other disinfection

method is used to kill microorganisms

that may be in the water.

STORAGE: Water is placed in a

closed tank or reservoir

for disinfection to take

pace. The water then

flows through pipes to

home and business in the

community

WATER

FROM

SEDIMENTATION

FILTRATION & DISINFACTION

FILTRATION

The process of filtration forms the most important

stage in the purification of water. Filtration removes very

fine suspended impurities and colloidal impurities that may

have escaped the sedimentation tank. In addition to this, the

micro-organisms present in water are largely removed.

CLASSIFICATION OF FILTRATION

(a)Rapid sand filter:

Rapid sand filter uses gravity to pass water through sand.

Water is filtered at the rate of 5-10 cubic meter of water per

square meter per hour(5-10 m3 /m2 /hour).

(b)Pressure Filter:

When pressure is applied, the filtration rate can be

accelerated up to 15m3 /m2 /hour. Increased filtration rate

increase quantity of filtered water per hour and this reduces the

operational cost.

DISINFECTION

Some methods of Disinfection:

1) By use of Boiling

2) By use of Chlorine

3) By use of ozone

4) By use of excess lime

5) By ultra-violet rays etc…….

By use of Boiling:

The water can be disinfected by boiling for 15 to 20

minutes. By boiling water all the disease bacteria are

killed and the water becomes safe for use.

This method is very costly and can be used only

individually in emergency cases during the break up of

epidemics in the town or city. It is impossible to employ it

in water works.

By the use of chlorine:

Chlorine in its various forms is invariably and almost

universally used for disinfecting public water supplies. It

is cheap, reliable, easy to handle, easily measurable and

above all, it is capable of providing residual disinfecting

effects for long periods, thus affording complete

protection against future recontamination of water in the

distribution system.

It is only disadvantage is that when used in greater

amounts, its imparts bitter and bad taste to the water.

Forms of chlorine:

Chlorine is generally available in the following forms:

In the form of liquid chlorine.

In the form of gaseous chlorine.

In the form of chlorine dioxide.

In the form of chloramines i.e., the mixture of chlorine

and ammonia.

In the form of bleaching powder.

Types of chlorination:

Plain chlorination

Pre-chlorination

Post chlorination

Double chlorination

Break point chlorination

Super chlorination.

TESTING OF WATER Ph Test:

Test with Litmus Paper

If the color changes to any color (less than 7), the sample water is

acidic.

If the color changes to any color (greater than 7), the sample water is

acidic.

TDS (Total Dissolved Solids) TEST:

Take the reading on the digital display on the machine.

If the reading is between 700 and 1000, it is absolutely potable. a

reading up to 2000 is permissible to be considered as potable.

DESIGN CONSIDERATION

Sr. no. Design Consideration Values

1 Design periods (years) 30

2 Average rate of water supply (lpcd) 72

3 Quality of raw water

i) Ph

ii) Turbidity (mg/L)

iii) Total Hardness (mg/L) (as CaCo3)

iv) Chlorides (mg/L)

v) Carbonates (mg/L)

6.5 to 8.0

52

553

21

109

4 Design population (in lakes) 2

5 Source Supply-

A canal or river sufficient perennial flow to satisfy the

required demand

DESIGN OF WATER TREATMENT PLANT

Total population- 190000.

Per Capita Demand- 70 litre/day.

Total Quantity of Water to be treated- 13.30 × 106 litre/day.

Design of Filtration:

Assume rate of filtration of the rapid gravity filters may be

taken as 4500 litres/hours/sq.M.

Total area of filter bed required = 124 sq. M

Design for 4 rapid gravity filters for treating the water at a water work

Areas of each rapid gravity filter = 31 sq. M

Keeping the length of the filter 1.5 times its width

1.5 B × B = 31

B = 4.5 m , L = 6.8 m

Provide four numbers of rapid gravity filters, with the size of each unit as 6.8 × 4.5 m.

Design of Sedimentation Rectangular Tank:

Assume v=0.15m/minute.

Capacity of the sedimentation tank required = 2771 cu. M

Length of the tank:-

= velocity of flow × detention period

= 0.15 × 05 × 60

= 45 m

Cross Sectional Area= Capacity of Tank÷ Length of the Tank

= 61.57 sq.M

Assuming the depth of water as d= 6 m and D = 6+0.5 = 6.5M

So Required Width of Tank = 10.26 m

The length of the tank may be provided in one, two or three parts depending upon the shape of the available.

Design of Elevated Service Reservoir

Capacity of Tank:

Fire Demand:-

F = Q × T Q = 3182

= 3182 190

= 43860.84 lit/Min.

P

F = Q × T

= 43860.84 × 0.5

= 21930 Lit. Hour

Capacity of Tank: 10 lacs litre

Diameter of Tank:

Diameter of Tank = 12 m (Assume)

2 2 2

1 2

2 2 2

( ) 1.54 4 4

1000 12 ( 8 4 ) 1.54 4 4

1000 113.1H + (50.27+12.57) 1.5

1000 = 113.10H + 94.25

1000 94.25H =

113.10

H = 8.00 m

Volume D H d d

H

Design of Rising Main

Total Requirement of water per day = 13.30 ×106 litre.

Pumping Hours = 16 h.

:

3

3

3

Rate of pumping = 831.25 10

831.25 10Rate of Pumping =

60 60 1000

= 0.23 m / sec.

Economical Diameter of rising main can be found out by using lea’s formula :

D = 1.22

= 1.22 0.23

D = 0.58 m.

Say D = 0.60 m.

Q

SCANERIO ( Over View)

Now a day water pollution is become a major problems. Due to increase in the urbanization the problems become vast & going to increase a day by day.

To solve these problems we have to utilize modern technology so by this way we can minimized the occurrences of water pollution.

Water works engineer must be well conversant with the planning, designing, construction.

Planning, designing & construction are the main issue which should be consider during the commission of water treatment plant. So that we can overcome from this problems.

THANK YOU