Detoxification of Sewage Sludge by Natural Attenuation and its Application as a Fertilizer-A Review

Sewage sludge generated from the waste-water treatment systems can play an essential role as fertilizers in the agriculture system. Sewage sludges have hazardous toxic materials; therefore, their application is minimal. Proper dumping of sludge produced via waste-water treatment plants (WWTP) has been categorized as severe ecological trouble and a feasible option to be used in farming formerly sewage sludge is affluent in natural substance and nutrients. On the other hand, sewage sludge contains various toxic agents therefore special attention is required for its application in farming to evade any harm to the organisms as well as to the environment. Controlled and well monitored process of natural attenuation (biological, physical, and chemical processes) which is a part of the environment can detoxify the toxic substances present in the sewage sludges. This review will lead the readers towards the assessment of different processes used for the decontaminating sewage sludge naturally.