Design of septic tank and soakpit

Can anyone help me to design a septic tank and soakpit system for 250 students in a hostel. The soil within the site is impervious and is waterlogged in rainy season. Pls suggest a suitable filter media.

 

[dcornelius]

The first thing you do is talk to the local inspector. then you do the perc test. It will probably fail, given you comments. Then start looking at mound system.

 

[GeoEnvGuy]

Septic tank size is based on the flows for the building. The prefabricated concrete suppliers in your area can also make suggestions. As recommended above you will need to mound the soakaway pit, commercial suppliers also sell plastic systems to increase drainage areas. As a drainage media typically well graded sand and gravel are used. I've seen septic designers just drop off available sand to get the estimated permeability from grain size to use as a design permeability.