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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)
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.
“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.