annexures - Indian Institute of Technology Roorkee

Chapter - 5 Detailed Project Reports of Sewerage Schemesalignment of sewers to ascertain the type of soil at different depths and behaviour of theground water table and bearing capacity of the soil. The design of bedding may be donebased on actual ground conditions.h) Minimum depth of buried sewer shall be designed considering future rolling / point loadson city roads.i) Where sewers are proposed to be laid below sub-soil water table, justification for thesame and the precautionary measures to be taken during laying of sewers shall bementioned in the DPR.j) In case proposed sewer/rising main is crossing railway line/Highway and their bridges,copies of their permission and estimates for the same shall be annexed with the DPR.k) A plan of action for giving sewer connections year wise during the implementation periodof the work shall be prepared and a suitable provision be made in the byelaws to enforcecompulsory sewer connections and user charges on the beneficiaries. The DPR may beprepared to achieve 100 % house connections for the present population within theproject implementation period. This is necessary to assure flows in the sewer networkand optimum utilisation of STP capacity.l) Provision may be made in the DPR for house connections from the property lines up to thesewers including cutting and reinstatement of roads. This will also eliminate cutting ofroads from time to time.m) Suitable sewage cess / tariff / tax and sewer connection fee may be imposed on thebeneficiaries to recover at least the O&M cost of the project to start with. However, fullcost recovery at the earliest should be aimed at. ULBs may consider suitable incentiveprograms to encourage people to opt for sewer connection, e.g. property tax rebate for'one-time' sewer connection by individuals. Besides, non-willing households, particularlyhaving septic tank facilities may be penalized for discharging septic tank effluents in opendrains / not constructing soak pit at prescribed distance from water source, water supplypipelines etc.n) Design criteria as stipulated in CPHEEO Manual (http://urbanindia.nic.in/publicinfo/manual.htm) may be followed.5.7 SEWAGE PUMPING STATIONSDesign of pumping stations should take into consideration the lean, average and peak flows.Pumping configuration should be appropriate for effective pumping of sewage in any of theseflow conditions.Submersible sewage pumps are now available and being extensively used, which are moreeconomic in terms of both capital and running cost besides being operation friendly.The following configuration of sewage pumps may be adopted:44