Sewer Flows mimimum lpcd
Sewer Flows mimimum lpcd
(OP)
We have a World Bank project to rehabilitate/improve water supply and wastewater to 7 towns in a developing country. The Client has aspirations of piped water and main sewer systems. Current water consumption is as low as 20 lpcd. (litres per capita per day). Limited resources mean that even after rehabilitation supply is unlikely to exceed 50 lpcd. It is suggested for a self cleansing foul sewer system a reliable water supply and a minimum consumption of 100 lcpd are basic requirements (WHO).
I am looking for any guidance, references, papers etc. on minimum foul sewer inflows to give relative maintenance free self cleansing operation.
I am looking for any guidance, references, papers etc. on minimum foul sewer inflows to give relative maintenance free self cleansing operation.





RE: Sewer Flows mimimum lpcd
The 20 lpcd is probably an average inflow rate, use that to design treatment facilities, not conveyance.
Use Qpeak for conveyance, apply a PF between 1 to 4.5, depending on population, usually between 3 and 4. This takes the Qdesign to 60-80 litres.
But even using the 20 lpcd, the system might work. If the system is designed for 100 lpcd capacity, but only achieves 20 lpcd inflow, v/vf will be about 0.78. As long as v at Q/Qf is 2 fps or greater, the system should scour.
Remember: The Chinese ideogram for “crisis” is comprised of the characters for “danger” and “opportunity.”
-Steve
RE: Sewer Flows mimimum lpcd
- "Conventional sewerage systems are designed as waste transportation systems in which water is used as the transportation medium. Reliable water supply and a consumption of 100 Lpcd are basic requirements for problem free operation of conventional sewerage systems" - .
With a supply of only 20 Lpcd (5 gals/day/capita) waste would comprise practically only solids.
#
cheers
RE: Sewer Flows mimimum lpcd
You probably want to investigate the Shallow Sewerage system. A toilet, usually in-house, flushed using lower volumes of water than either conventional sewerage or septic tanks, to smaller diameter sewers laid at flatter gradients and shallower depths between dwellings on a block. On-site shallow inspection chambers are also provided.
Look at the South Africa examples here:
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http://www
RE: Sewer Flows mimimum lpcd
1) You are correct the project is not financially sustainable but the client does not understand. The World Bank are dumping money on non sustainabale projects!.
2) Septic tanks and small bore effluent piping is a good technical solution.
- thanks for the links