HOW THE SYSTEM WORKS

Human waste contains about 75% water. The rest 25% is made up of biodegradable organic materials. Waste water treatment is mainly concerned with the biodegradation of organic carbon or BOD. This is carried out by heterotrophic or carbonaceous bacteria which are mainly aerobic, anaerobic and facultive. They take up and hence remove organic carbon molecules from the activated sludge and use the energy for the growth of new biomass.

The biological septic tanks apply two principles;

1. a) Bio-degradation

The gases help to stir the sludge, scum and liquid layer which promotes digestion of solids. Digestion takes place aerobically and an-aerobically due to the presence of both aerobic and anaerobic bacteria that makes the process a success.

1. b) Displacement

The amount of water flashed into the tank displaces the same amount through the outlet baffle into the French drain (soakage). The displacement process makes it impossible for the tank to fill up and therefore does not require exhausting/emptying.