Question

Class: (Sanitary Engineering)

The sewer design criteria and design methods and sewer lining?

Answer 1

Sewers are used for carrying if drainage water and waste matters through underground pipelines. There are various criterias that are to be considered while designing a sewer. Those criterias are listed below :

• Size of sewers
• Bedding options
• Depth of the flow
• Velocity of the flow
• Ground water Infiltration
• Pipeline material and leakage amount.

All the above criterias should be considered while designing a sewer. A proper methodology is being followed While designing a sewer and no step should be missed if proper sewer system is to be constructed.

Different zones are being formed for different cities and towns and by the same categories zones are also formed in sewers and it is the basic step in design. Then the arrangement of sewer network is to be done such that from where the sewer is going to come and where to be disposed and further the calculation is being done for the amount of waste that needs to be transferred. The flow velocity is being obtained by empirical formulas and at last the section area of sewer is found out and hence the method of design will be completed and sewer will be constricted by the given design and calculations.

Sewer Lining : Sewer lining is being used to repair cracked pipes without completely replacing the pipelines. Total excavation of sewer system can cause lot of collateral damage hence lining of sewer is preferred and it is more economic also. There are four types of sewer lining methods which are listed below :

1. Cured - in place
2. Pulled - in place
3. Pipe Bursting
4. Internal pipe coating