Long term emissions from pretreated waste : lysimeter studies.

Abstract

Landfill emissions are the major environmental impact associated with the landfilling of solid wastes. These emissions which are mainly gases and leachate are a result of the anaerobic biochemical breakdown of the waste in landfills. The long term emissions from these solid wastes in landfills can be significantly reduced by Mechanical Biological Pretreatment of the waste prior to landfilling. Mechanical Biological Pretreatment of solid wastes is aimed at reducing the long term polluting potential from landfills through accelerated stabilization of the organic constituent material present in the waste body by biological degradation before the waste is placed in landfills. This research is part of a broader investigation on the applicability of Mechanical Biological Pretreatment of solid wastes prior to disposal in the South Africa Waste Management context. General waste disposed at Bisasar Road Landfill Site in Durban which has been pretreated for 16 weeks in passively aerated windrows was collected and screened using a rotatory drum screen to generate an over-sieved waste fraction with particles of diameter greater than 50mm and an under-sieved waste fraction characterized by particles diameter less than 50mm. The long term behavior of these heavily pretreated wastes was then simulated using large anaerobic reactors (Lysimeter) in relation to grain size distribution. A third lysimeter containing general waste without pretreatment collected from Bisasar Road Landfill Site was also set up in order to study the effect of pretreatment on solid waste samples. The results of this research were then used to make recommendation on the appropriateness of Mechanical Biological in the South Africa Waste Management context.