This is a power point presentation on design of a 30 MLD sewage treatment plant. It includes the different characteristics of waste water,various treatment units, design results and a layout of sewage treatment plant. Visit my slide share channel for downloading report of this project.

1. RAJ KUMAR GOEL INSTITUTE
OF TECHNOLOGY
CIVIL ENGINEERING
PROJECT LAB (NCE-851)
RATNESH KUSHWAHA
SHIVAM SHARMA
VAIBHAV SINGH
SURAJ MISHRA
GAURAV KUMAR
DESIGN OF 30 MLD SEWAGE TREATMENT PLANT
PRESENTED BY:-
PROJECT
MENTOR:-Mr. MOHIT

2. TABLE OF CONTENTS
 INTRODUCTION
 OBJECTIVES OF PROJECT
 CHARACTERISTICS OF WASTEWATER
DIFFERENT TESTS ON WASTEWATER SAMPLE
 COMPARING CALCULATED VALUES WITH PERMISSIBLE VALUES
 OBSERVATIONS
 FINALIZING OF TREATMENT UNITS
PROCESSES INVOLVED IN SEWAGE TREATMENT
DESIGN RESULTS OF WASTEWATER TREATMENT PLANT(WWTP)
 LAYOUT OF WWTP
SCOPE FOR FUTURE
 REFERENCES

3. INTRODUCTION
 Sewage treatment is a process of removing contaminants
from wastewater.
 It includes physical, chemical and biological processes to
remove contaminants from wastewater.
 Globally, only 20% of wastewater produced receive proper
treatment (UNESCO 2012).
Globally, 2 million tonnes of sewage, industrial and
agricultural waste discharged into world waterways per day
and about 1.8 million children die every year from water
borne diseases.
So, there is a necessity to treat sewage wastewater in such
a way that quality of water is improved and do not cause
harm to environment.

4. OBJECTIVE OF OUR PROJECT
There are three major objectives of our project-
Physical, chemical and biological characterization of wastewater.
Comparison with the prescribed standards.
Design of a sewage treatment plant by designing all its units.
CHARACTERISTICS OF SEWAGE TREATMENT
PLANT
 Must fulfill objective of purifying water.
 Should be cheap and efficient.
 The treatment plant should cover maximum land use in minimum
area.

5. CHARACTERISTICS OF
WASTEWATER Physical Characteristics:-
 Odour
 Colour
 Turbidity
 Temperature
 Chemical Characteristics:-
 Total solids
 pH value
 Chloride content
 Nitrogen content
 Fats, Oils & Greases
 Biological Characteristics:-
 Most probable number of coliform bacteria (MPN)
 Biochemical oxygen demand (BOD)

6. DIFFERENT TESTS ON WASTEWATER
SAMPLE
 pH-
pH meter is generally used for measuring pH of water sample.
pH value= -log [H+]
 Total solids:-
 The total amount of solids present in a given sewage can be
determined by evaporating a known volume of sewage sample
and weighing the dry residue left.
 The quantity of suspended solids can be determined by passing
a known volume of sewage sample through a glass-fiber filter
apparatus and weighing the dry residue.
 The quantity of dissolved solids is calculated as
DISSOLVED SOLIDS = TOTAL SOLIDS – SUSPENDED SOLIDS

7.  Chloride content
 Chlorides are derived from the kitchen wastes, human
excreta and industrial discharge.
 The chloride content can measured by titrating the waste
water with standard silver nitrate solution, using potassium
chromate as indicator.
 Nitrogen content
 It may occur in one or more of the following forms:
a) Free ammonia
b) Organic nitrogen
c) Nitrites
d) Nitrates
 The presence of nitrogen in sewage indicates the presence
of organic matter.

8.  Presence of fats, oils & greases
 These are derived in sewage from the discharges of animals,
kitchens of hotels, industries.
 In order to determine the amount of fats, greases etc, a
sample of sewage is first evaporated.
 The residual solids left are then mixed with ether and the
solution is then evaporated, leaving behind the fat, grease
as a residue.
 Biological oxygen demand (BOD)
 It is defined as the amount of oxygen required by the aerobic
bacteria to fully decompose the organic matter.
 The instrument directly records BOD reading at every 24
hour. After that the bottles are preserved in the incubators
for days as per need of study.

9. S.NO. PARAMETERS CALCULATED
VALUE
PERMISSIBLE
LIMITS
1 pH 7.125 7-8.5
2 TDS 1017 mg/l 100 mg/l
3 SS 428 mg/l N/A
4 DS 590 mg/l N/A
5 FREE AMMONIA 36.25 mg/l 50 mg/l
6 OILS & GREASES 21.9 mg/l 10 mg/l
7 CHLORIDES 98 mg/l 600 mg/l
8 BOD 189 mg/l 30 mg/l
TESTED PARAMETERS OF
SEWAGE

10. OBSERVATIONS
From the results of raw sewage some parameters are exceeding
from their permissible values. They are-
TDS(SS & DS)
FATS, OILS & GREASES
BOD
Hence, further treatment of raw sewage is required before its final
disposal.
PROCESS INVOLVED IN SEWAGE TREATMENT
 Preliminary Treatment:-
Consists simply of separating of floating materials and also the
heavy settleable inorganic solids. It also helps in removing oils &
greases etc from the sewage.
This treatment reduces about 15-30% BOD of the wastewater.
 The processes involved in preliminary treatment are-

11. SCREENING
Screening is the first unit operation used at wastewater
treatment plants.
Screening removes objects such as rags, paper, plastics, cloth,
woods, fecal solids etc to prevent damage and clogging of pipes
and adversely affect working of sewage pumps.
•Fine Screen:- 1.5 to 3mm
•Medium screens:- 6 to 40mm
•Coarse screens:- >50mm

12. GRIT CHAMBER
 Grit chambers it is intended to remove suspended inorganic
particles such as sandy and gritty matter from the wastewater.
 Grit chambers are designed to separate intended heavier
inorganic materials (specific gravity about 2.65) and to pass
forward the lighter organic materials.

13. SKIMMING TANKS
A skimming tank is a chamber so arranged that the floating
matter like oil, fat, grease etc., rise and remain on the surface
of the waste water (Sewage) until removed, while the liquid
flows out continuously under partitions.
It is necessary to remove the floating matter from sewage
otherwise it may appear in the form of scum on the surface of
the settling tanks or interfere with the activated sludge process
of sewage treatment.

14. PRIMARY TREATMENT
 Consists of settlement of suspended
solids by sedimentation in Settling
Basins.
 Sometimes preliminary and primary
treatments are classified together under
primary treatment.
SECONDARY TREATMENT
 It involves further treatment of effluent, coming from primary
sedimentation tanks.
This is generally accomplished through biological decomposition
under aerobic and anaerobic conditions.
 This treatment removes about 85-95% BOD of wastewater.

15. The processes involved are-
 Activated sludge process
Trickling filters
Oxidation ponds
Septic tanks.
ACTIVATED SLUDGE PROCESS
 The activated sludge process is a type of wastewater
treatment process for treating sewage.
General arrangement of an activated sludge process consists of :-
•AERATION TANK – From the PST, the sewage flows into aeration
tank and is mixed with activated sludge.
•SECONDARY CLARIFIER - To allow the biological flocs to settle,
thus separating the sludge from the clear treated water.

16. SLUDGE DIGESTION PROCESS
The residue that accumulates in STPs is called sludge.
Sewage sludge is the solid, semisolid, or slurry residual material
that is produced as a by-product of wastewater treatment processes.
Aerobic and anaerobic digestion convert about half of the organic
sludge solids to liquids and gases.
The gas produced from sludge digester helps wastewater treatment
plants self-sufficient in energy.

17. FINAL DISPOSAL OF SLUDGE
There are generally two methods for disposing the sewage
effluents-
(1) Disposal in water
(2) Disposal on land
TECHNIQUES OF DISPOSING DIGESTED SLUDGE -
By Shredding and Pulverisation
By Composting
 By Incineration and Pyrolysis

18. FLOW DIAGRAM OF SEWAGE TREATMENT PLANT

19. DESIGN RESULTS OF SEWAGE TREATMENT PLANT
 SCREENING -
• Shape of bars = M.S. Bars
• Size = 10mm x 50mm with clear spacing of 30mm
•Velocity of flow = 0.8m/sec
•No. of bars required = 33
•Size of Screen = 1.32m x 0.8m
•The screening produced are disposed of either by burning, or by burial
(Composting)
 GRIT CHAMBER -
• Critical horizontal velocity (Vc) = 0.228m/s
•Flow velocity (V) = 0.2m/s (V< Vc)
•Detention time = 60sec
•Size of Grit Chamber = 12m x 3m x 1.5m
• The grit deposited at bottom can be either incinerated with sludge or
disposed in low lying areas.

20. SKIMMING TANK –
• Detention time = 4 min
• Compressed air required = 1000 m3 per million liter
• Size of tank = 27m x 27m
•The oil & greasy material removed from tanks can be disposed either
by burning or burial.
• It is generally too polluted for any economic use.
 PRIMARY SEDIMENTATION TANK –
• In this design, continuous flow tank is to be provided.
• Velocity of flow through the tank = 0.3m/min
• Size of rectangular sedimentation tank = 36m x13m x6m.
•Since the tank is provided with mechanical cleaning arrangement, no
space at bottom is required for sludge zone.

21.  AERATION TANK –
• Providing conventional aeration process.
• No. of aeration tanks = 2
• BOD entering STP = 189mg/l
• BOD left at effluent = 25mg/l
• Minimum efficiency required in activated plant = 86.77% (85-92%)
• F/M Ratio = 0.3
• MLSS = 2500mg/l
• Sludge retention time = 5days
• Aeration tank dimension = 37m x 20m x 5.5m
 AERATOR SIZE –
• Oxygen requirement = 1kg/kg BOD applied
• Provide 10 Generators of 30 HP, with 1 generator at standby.
 SECONDARY CLARIFIER
• Recirculated flow(assuming 50% of total flow) = 15000m3/day.
• Surface loading rate of flow = 30m3/m2/hr.
• Solid loading rate = 112.5kg/day/m2.
• Size of secondary clarifier = 35m diameter with overall depth of 5.5m

22.  SLUDGE DIGESTION TANK –
• Mass of suspended solids in 30MLD wastewater = 12840kg/day
• Volume of digested sludge at 75% moisture content = 32.89 m3/day
• Digestion period = 30 days
• Provide a cylindrical sludge digestion tank 6m deep and of 22m diameter.
 ESTIMATION OF GAS PRODUCED FROM DIGESTER TANK –
• Total quantity of gas produced = 3154.79 cu. m.
• Assuming that gas produced contains 65% methane and 30% CO2.
Methane produced = 2050.6 cu. m.
CO2 produced = 1104.18 cu. m.
• Total fuel value = 73.82 MKJ.
• Assuming boiler efficiency is 80%, heat produced by boiler =59.06 MkJ
which is equal to 14.335 million kilo Calories.
• The gas collected may be utilized for operating engines, and for heating
sludge to promote quick digestion.

23. LAYOUT OF SEWAGE TREATMENT PLANT

24. SCOPE FOR FUTURE
As per future perspective of this project, the characteristics
of different units designed in this project can be compared
with alternate treatments units and their treatment
efficiencies can be calculated for designing of STP.
For example – We choose activated sludge process in
secondary treatment, but any other treatment processes like
trickling filters, aerated lagoons, oxidation ponds, RBCs etc
can also be taken as secondary treatment unit and is
designed. The design values & other parameters related to it
are compared and the graphs are plotted accordingly. The
best alternative should be selected as the final one.

25. REFERENCES
 Manual on water supply and treatment, C.P.H.E.E.O., Ministry
of Urban Development; Government of India, New Delhi.
 Manual on Sewerage and Sewage Treatment,
C.P.H.E.E.O.,Ministry of Urban Development; Government of
India,New Delhi.
 Jayshree Dhote, Sangita Ingole (2012); Review on Wastewater
Treatment Technologies Published in International Journal of
Engineering Research and Technology. pp. 2-5.
 IS: 3025 (PART 10) – 1984, Methods of sampling and test for
water and wastewater.
 IS: 4764 – 1973, Permissible limits for sewage effluents in
waste water.
 A.K. Jain; Environmental Engineering, Khanna Publishing
House.
 S.K. Garg; Water supply and Sewage Disposal Engineering Vol
1&2, Khanna Publishing House.