Wastewater renders a potential threat to the environment. The ' types of wastes are many and different like domestic, agricultural, - industrial, hospital, Radioactive wastes etc . Among-these, the problem due to domestic wastewater wil be encountered at al l places where human beings dwell and this causes a great hazard. The domestic, waste which is devoid of celluloid matter that is non-biodegradable, 'is amenable to bio-chemical treatment. This type of treatment activated by' • bacteria is very economical, especially in tropical countries. It depends' highly on the environmental conditions of the locality
