ABSTRACT
Sludge disposal is a worldwide problem and a wide variety of disposal routes have been adopted as per the local conditions. The technologies utilised for sludge disposal as well as the environmental effects incurred are dictated largely by the choice of final resting place which can either be land, air or water. Disposal of sludge to the air largely employs high temperature incineration or pyrolysis. Incineration converts all the organic matter present in the sludge to carbon dioxide and leaves behind most of the inorganic material as a dry ash. Land disposal is generally considered the ideal option for sewage sludge disposal for a number of reasons. Despite the potential advantages of soil injection, land spreading is the most common method of land disposal of sludge. Most pathogens of the raw sewage get concentrated into the sewage sludge and present a considerable hazard when any handling of the sludge is considered.
