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