Designing of sewage pumping system

[Ramakrishnaiah]

I am associated with designing of pumping system of waste water and sewage system of large municipalities in Andhra Pradesh. The manual on sewage system published by Central Public Health Department of India indicates design of system based on DWF(Dry Weather Flow ) with one 1DWF one 2DWF and one 3 DWF pumps for small stations. May I get some literature on DWF pumps and method of calculating their capacities.