Sanitary Landfills 2003 - From Dry Tombs to Wet Bioreactors August 2003

摘要

The science and potential benefits of a bioreactor landfill have been researched, promoted, and considered over the last 25 plus years. Accelerated waste stabilization is the mantra today versus the "dry tomb" of subtitle D in the early 1990's. The documented performance of engineered "containment" landfills over the last 20 years has only now, allowed bioreactor landfills to be pursued on a full-scale basis. Much bench-scale work has been performed which has attempted to model full or large-scale performance. Long-term case studies are in progress which document short-term bioreactor performance. The short-term results support and reinforce the science and benefits obtained. As time marches on, full-scale operating results indicate that bioreactor landfills will dominate municipal solid waste disposal operations. The competitive solid waste landfill business provides momentum to increase the environmental effectiveness of our nations solid waste management practices. Environmental management systems (EMS, ISO 14,000) further promote bioreactor technology with the goal of maximizing existing resources and environmental benefits. Onyx Waste Services, Inc. (previously known as Superior Services, Inc.) has aggressively pursued the bioreactor technology. Currently Onyx operates 14 MSW subtitle D landfills as bioreactors by performing and enhancing biodegradation via moisture conditioning the waste mass under anaerobic conditions. The main benefits Onyx has realized using the bioreactor technology are as follows: 1. Decrease potential environmental impact of landfills by a degrading waste mass. 2. Decrease leachate toxicity by the anaerobic digestion process. 3. Increase waste density thus maximizing landfill airspace. 4. Increase landfill gas production to enhance the economic viability of landfill gas utilization projects. 5. Lower landfill operating and fixed costs thus increasing profitability. The leachate recirculation systems deployed among the different landfill sites vary from a simple system of distributing the leachate at the working face to more sophisticated systems with automated infrastructures. This paper will describe four Onyx landfill facilities that enhance the bioreactor technology; what methods they use and how it has affected waste densities, gas volumes, and leachate analytical. This paper will also provide macro-scale results that have been documented to date, and a conclusion based on these results.