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DESIGN OF SEWERAGE COLLECTION SYSTEM & COST ESTIMATION
Submitted By:
VIJAY KUMAR
DEPARTMENT OF CIVIL ENGINEERINGJAMIA MILLIA ISLAMIA
Objective of study
Review of design criteria of existing system of sewerage system.
Design of sewerage system.
Cost estimation of sewerage system as per Delhi Schedule of Rates 2012 (DSR).
NECESSITY OF SEWERAGE SYSTEMTo transport water or waste water from one location to another by means of connecting pipes through gravity.
To provide a hygienic and healthy environment.
Increases the aesthesis and property value.
TYPES OF SEWERAGE SYSTEM
Combined system
Sanitary system
Strom system
Combined Sewer• Collects sanitary sewage & storm water run off in a single
pipe system.• Can cause serious water pollution problems due to
combined sewer overflows• Caused by large variations in flow between dry and wet
weather.• This type of sewer design is no longer used in building new
communities.
Sanitary Sewer• Used for transporting sewage from houses and commercial
buildings• Sanitary sewers serving industrial areas also carry Industrial
sewage.• Sanitary sewage is collected with the help of sanitary sewer
line• The sanitary sewer is attached to a main sewer.• The main sewer runs directly to the sewage treatment
plant.
Storm Sewer• A storm sewer collects storm water with the help of gutter &
catch basin• Gutter allow the storm water to drain from the street directly
into the storm sewer.
SEWER APPURTENANCES
ManholeDrop ManholeFlushing TankLamp holeVent shaftInverted SiphonStorm Water Inlets /Street InletsCover and FramesCatch Basin
Types of Manhole1.Straight-Through Manhole
2.Junction Manhole
3.Side Entrance Manhole
4.Drop Manhole
5.Scraper (Service) Type Manhole
6.Flushing Manhole
Typical Construction Detail of Manhole
Typical Construction Detail of Drop Manhole
Typical Construction Detail of Flushing Manhole
DESIGN REQUIREMENTSQuantity of sewage to be handled
Land use pattern
Contour Layout
DESIGN CONSIDERATIONDesign period
Discharge
Self cleansing velocity (Vmin)
Scouring velocity (Vmax)
Roughness of pipes
Depth of sewer
Gradient
Post monsoon ground water table
Design Consideration As Per CPHEEO ManualDesign Period of Civil Work (Trunk, Main Branch Sewer & Appurtenances) - 30 Years
Sewage Generated - 80% of Total Water supplyFlow Assumptions - Minimum Flow Varies
from 1/3 to ½ of average flow
Ground Water Infiltration -500 to 5,000 litres/km/dayManning’s Roughness Coefficient - 0.013 Velocity of Flow - 0.60 m/s to 3.0 m/sRate of Flow - 80% Running Full Minimum Size of Sewer - 150 mm
MINIMUM GRADIENT OF SEWERMinimum gradient for sewers shall be designed to fulfill the requirement of self cleansing velocity
Present Peak Flow (Cumec)
Recommended slope 1 in
0.002 165
0.003 250
0.005 320
0.010 500
0.015 770
0.020 835
0.030 1000
FLOW VARIATION
Contributory
Population Range
Peak Factor
Up to 20,000 3.0
20,000 to 50,000 2.5
50,000 to 7,50,000 2.25
Above 7,50,000 2.0
FORMULA USED
MANNINGS FORMULA
and
Q= A x V
WhereQ = Discharge S = Slope of hydraulic gradientD = Internal dia of pipe lineR = Hydraulic radius in mV = Velocity in m/sn = Manning's roughness coefficient
PROJECT DETAILSThe Problem has been taken from the Manual on Sewerage and sewage Treatment-1993 of Central Public Health and Environmental Engineering Organization (CPHEEO).
Layout Plan of Manual. Ground Levels of various nodes. Total Population of the Area is
two Lacs. Total Area = 101.02 ha.
Design Calculation Average Length of sewer line between Manhole = 30 m Water supply = 150 L/C/day Total Population = 2 lacs Total Length of sewer line = 7275.12 m Population Equivalent = (200000/7275.12)
= 27.49 Persons/m Rate of Infiltration = 5000 Lit/Km/Day Minimum cover to be provided over
the crown of the sewer = 1.0 m Minimum velocity in sewer at peak flow = 0.6 m/s Maximum Velocity in sewer = 2 m/s Minimum size of the sewer = 150 mm Peak factor = 3.0
Manual DesignSection From MH-69 to MH-70
Diameter of Sewer Line = 150 mm
Min. Velocity = 0.60 m/s
Slope of the sewer Line = 1 in 160
Detail Design
DRAWINGS Layout Plan of the Area
Sewer Network
Hydraulic Design Sewer Lines
Colour Coding Plan of the Network
Typical L-section of Sewer Line
Typical Details of Appurtenances
Typical Details of Excavation Pipe Bedding
SUMMARYSl. No.
Description of Item
Maximum Minimum
1 Ground Level 39.00 Mtr. 32.00 Mtr.
2 Discharge 0.625 Cumec 0.0027 Cumec
(2.70 Lit.)
3 Slope 1 in 1100 1 in 100
4 Velocity 1.83 m/s 0.61 m/s
5 Dia of Pipe 1000 mm 150 mm
CALCULATION OF QUANTITIESDiameter (mm) Length of Pipe (m)
150 Φ 1936.01200 Φ 2015.31250 Φ 1169.21300 Φ 642.06350 Φ 180.76400 Φ 233.00500 Φ 493.86600 Φ 212.91900 Φ 305.00
1000 Φ 87.00Total Length 7275.12 m
CALCULATION OF QUANTITIES
Circular type manhole 0.91m internal diameter (at bottom) beyond 0.91m to 1.67m
129
Circular type manhole 1.22m internal diameter (at bottom) beyond 1.68 m to 2.29 m :
67
Circular type manhole 1.52 m internal diameter (at bottom) beyond 2.30 m :
60
ABSTRACT OF COST Total Cost of Excavation(Rs.) = 25.16 Lacs Total Cost Of Manholes (Rs.) = 33.83 Lacs Total Cost of Pipes (Rs.) = 33.08 Lacs Total Cost of Foot Rest (Rs.) = 3.69 Lacs Cost of P.C.C. (1.2.4) (Rs.) = 1.69 Lacs
Total cost of the Project (Rs.) = 97.46 Lacs
Avg. cost / Km (Rs.) = 13.40 Lacs
BIBLIOGRAPHYManual on sewerage and sewage treatment
(Second edition-1993)Manual on sewerage and sewage treatment (Final
Draft-2012) Delhi Schedule of Rates – 2012, Delhi analysis of Rates Vol. I & II, Environmental Engineering Vol. II, by S.K.Garg
(Twenty Second Edition)Basic Environmental Engineering by Jeery
A.Nathson.www.google.co.in/Images for logo of Jamia,
images and photos etc.
THANKS