Rapid landfill stabilization and improvements in leachate quality by leachate recirculation

Leachate recirculation is an important new concept in municipal solid waste (MSW) leachate management, and the full-scale applications of the practice are only now being implemented. The Worcester County, Maryland, Central landfill Facility (CLF) has been recirculating leachate since opening in April 1990. EA Engineering, Science, and Technology, Inc. designed the landfill in 1988, and has been providing operational consulting on the process since 1990. Rapid stabilization of the waste mass is the primary objective of leachate recirculation. The Enhanced Natural Degradation process (ENDpro(SM))is facilitated by wetting with the recirculated leachate. From a practical standpoint, this results in increased available disposal volume, reduced leachate disposal costs, and a dramatic reduction in the strength of the leachate. The 8-year operational history at the CLF has shown leachate chemistry stabilization comparable to conventional MSW landfills typically with 30-year stabilization time frames. Analytical trends which demonstrate accelerated biological activity are rapid decreases in biological oxygen demand, metals and volatile organic compounds as well as increased pH to neutral. Other electron accepters such as sulfate and nitrate are also assessed in relation to enhanced biodegradation processes.