Design Criteria for Sewer System
Sewer system must be properly planned, designed and operated in order to protect the environment and people from serious diseases, as more than 50 diseases spread from sewage. Some of the important and relevant terms for sewer system are discussed below.
Sewage
It is Liquid Waste or Waste Water produce as a result of water use.
Sewer
It is the pipe or conduit for carrying sewage. It is generally closed and flow takes place under gravity (Atmospheric Pressure).
Sewerage
Sewerage is the system of collection of waste water and conveying it to a point of final disposal with or without treatment.
Sources of waste water
Following are the principal sources of waste water
Domestic
It is the waste water from houses, offices, other buildings, hotels and institutions.
Industrial
It is the liquid waste from the industrial places from their different industrial processes like dying, paper matting, tanneries, chemical industries, etc.
Storm Water
It includes surface runoff generated from rainfall and the street wash.
Types of Sewer Systems
Following are the types of sewerage.
Separate System
It is the system in which storm water is carried separately from domestic and industrial waste water. This system is preferred when
It is the type of system in which sewer carries both the sanitary and storm water. Combined system is favored when
It is flow derived from the sanitary and industrial sewage that is the raw water from these industries and houses, so it means it has direct relation with the amount of water consumed.
Generally 80 to 90 % of the water consumption is taken as sewage or waste water flow.
Variation in sewage flow
Like water supply, sewage flow varies from time to time. Since sewers must be able to accommodate Maximum Rate of Flow, the variation in the sewage flow must be studied.
Design criteria document includes following;
Infiltration
Sewer System
Sewer Pumping Station
Design Equation
Minimum (Self Cleansing) Velocity
Maximum velocity
Minimum Sewer Size
Minimum Cover of Sewer
Spacing of Manhole (WASA, Criteria)
Design of Sewer
Slope of Sewer
Invert Level
Joints in sewer pipes
Man Holes
Sewage Pumping Station
Pump Station Components
Design Procedure
Design of Wet Well
You can download complete design criteria and calculation along with procedure for sewer system design from below attachment.
Sewer system must be properly planned, designed and operated in order to protect the environment and people from serious diseases, as more than 50 diseases spread from sewage. Some of the important and relevant terms for sewer system are discussed below.
Sewage
It is Liquid Waste or Waste Water produce as a result of water use.
Sewer
It is the pipe or conduit for carrying sewage. It is generally closed and flow takes place under gravity (Atmospheric Pressure).
Sewerage
Sewerage is the system of collection of waste water and conveying it to a point of final disposal with or without treatment.
Sources of waste water
Following are the principal sources of waste water
Domestic
It is the waste water from houses, offices, other buildings, hotels and institutions.
Industrial
It is the liquid waste from the industrial places from their different industrial processes like dying, paper matting, tanneries, chemical industries, etc.
Storm Water
It includes surface runoff generated from rainfall and the street wash.
Types of Sewer Systems
Following are the types of sewerage.
Separate System
It is the system in which storm water is carried separately from domestic and industrial waste water. This system is preferred when
- There is an immediate need for collection of sanitary sewage but not for storm water
- When sanitary sewage needs treatment but the storm water does not.
It is the type of system in which sewer carries both the sanitary and storm water. Combined system is favored when
- Combined sewage can be disposed off without treatment
- Both sanitary and storm water need treatment
- Streets are narrow and two separate sewers can not be laid Partially Combined System.
It is flow derived from the sanitary and industrial sewage that is the raw water from these industries and houses, so it means it has direct relation with the amount of water consumed.
Generally 80 to 90 % of the water consumption is taken as sewage or waste water flow.
Variation in sewage flow
Like water supply, sewage flow varies from time to time. Since sewers must be able to accommodate Maximum Rate of Flow, the variation in the sewage flow must be studied.
Design criteria document includes following;
Infiltration
Sewer System
Sewer Pumping Station
Design Equation
Minimum (Self Cleansing) Velocity
Maximum velocity
Minimum Sewer Size
Minimum Cover of Sewer
Spacing of Manhole (WASA, Criteria)
Design of Sewer
Slope of Sewer
Invert Level
Joints in sewer pipes
Man Holes
Sewage Pumping Station
Pump Station Components
Design Procedure
Design of Wet Well
You can download complete design criteria and calculation along with procedure for sewer system design from below attachment.
