Kinetics of Solid Waste Biodegradation in Laboratory Lysimeters

Solid waste biodegradation kinetics determine the time it takes to achieve stabilization of solid waste in landfills. This paper reports the results of a laboratory scale investigation aimed at evaluating the effect of different enhancement techniques on solid waste biodegradation kinetics. The experiments were carried out in a group of five lysimeters. The effect of temperature and leachate recirculation was investigated. Total Volatile Solids (TVS) and fiber content under controlled conditions of temperature and moisture were monitored for a period of nine months. The experiments were carried out under both mesophilic and thermophilic conditions. The moisture of solid waste was controlled through the process of leachate recirculation. The results of kinetic analysis showed that solid waste degradation follows first order kinetics. The optimal conditions for solid waste biodegradation were found to be mesophilic temperature of about 38oC and moisture content of about 65%. It was concluded that leachate recirculation enhanced the biodegradation process over the whole studied range of moisture content, while the temperature influence was the maximum during mesophilic stage. The biodegradation under thermophilic conditions was decelerated as compared to control lysimiter. The results obtained by this study may be applied to a real scale bioreactor landfill.