The Bio septic tank is an improved version of the technology developed by DRDO, Gwalior. It has three compartments with the interconnecting flow. A common manhole with cover is provided for the first two compartments. Inoculum has been used to digest human waste. Polygrass lining has been provided to increase the surface area and to anchor anaerobic bacteria. Bio media is filled in the second compartment to increase the surface area and serve as a growth medium for the bacteria. The last compartment is used for pumping the treated effluent