What are the various methods for on site treatment of domestic sewage?

Answer 1

This is done with septic systems. You have primary treatment, a clarifier tank to settle out the grit and float the oils, and then secondary treatment where the effluent is distributed to a leech field where the soil bacteria eats up the biological oxygen demand.

There are different ways to do this and is usually a function of the available soil types in the area.

Answer 2

There is a cess pit which is a large holding tank that needs to be emptied when full. Better is the septic tank where anaerobic bacteria ie sealed from the atmosphere by a crust which forms on the surface,digest the solid waste which collects at the bottom. As more waste enters it overflows to a soakaway as treated sewage. If working properly should not need emptying