DESIGN AND OPERATION OF LANDFILLS FOR OPTIMUM STABILIZATION AND BIOGAS PRODUCTION

Most municipal landfills are constructed and operated with exposure to intermittent rainfall. Infiltration of rainfall, together with the in herent moisture content of landfilled wastes, promotes leachate produc tion and accelerates rates of conversion of waste constituents. As the se conversion processes proceed waste stabilization occurs, leachate q uality changes, and biogas is released in correspondence with the prev ailing phase of stabilization. The intensities and temporal and spatia l dimensions of these phases are waste-specific, a function of landfil l design and operational strategy employed, and characterized by chang es in physical, chemical and biological indicator parameters. Recogniz ing that most landfills exist as microbially mediated anaerobic waste conversion processes, with the sequential phases of acid formation and methane fermentation accounting for the majority of waste stabilizati on being accomplished, a fundamental understanding of these two princi pal phases of landfill stabilization is provided and used as a basis f or developing guidance for controlled landfill design and operation. T his guidance emphasizes optimization of stabilization efficiency, esta blishes cost-effective procedures for leachate management, and promote s regulated biogas production and utilization. To accommodate these ob jectives, the benefits of converting landfills into controlled bioreac tor systems through regulated leachate generation, containment, collec tion, aid in side recirculation for accelerated waste stabilization an d integrated biogas management are described, and opportunities for ul timate leachate disposal, biogas utilization aid landfill reclamation are illustrated and compared to relative costs of other management opt ions.