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BIOREACTOR DESIGN - OUTER LOOP LANDFILL, LOUISVILLE, KY
Citation:
Carson*, D A., R. B. Green, W J. DavisHoover*, AND G. R. Hater. BIOREACTOR DESIGN - OUTER LOOP LANDFILL, LOUISVILLE, KY. Presented at Solid Waste Association of North America, Louisville, KY, June 17 - 19, 2002.
Impact/Purpose:
To inform the public.
Description:
Bioreactor field demonstration projects are underway at the Outer Loop Landfill in Louisville, KY, USA. The research effort is a cooperative research effort between US EPA and Waste Management Inc. Two primary kinds of municipal waste bioreactors are under study at this site. First, new twin landfill cells are being constructed with the express purpose of being operated as sequential bioreactors. At a different location on the site, a filled cell will be converted to an operating landfill bioreactor. Both sites are supported statistically by a negative control where waste is disposed in a conventional manner.
The new bioreactor cells are lined modern composite landfill liners, overlain by a leachate collection system. As the waste is placed, distribution pathways for liquid and air injection are placed after each lift of waste. Initially, air will be introduced into the waste mass to degrade those constituents of the waste mass that are degradable aerobically. Air injection will proceed for a relatively short time frame, on the order of several weeks, then stopped in favor of the introduction of landfill leachate. As the next layer is placed, this procedure is repeated until the landfill cell is filled, at which time an intermediate cap is emplaced and the entire landfill becomes a leachate circulating anaerobic bioreactor. This sequential treatment of the waste in situ is thought to offer rapid and more complete degradation of conventionally landfilled municipal waste.
At the existing landfill cells that are being converted to operate as bioreactors, a large landfill was modified to allow leachate circulation. In order to accomplish statistical relevance to the experiment, two landfill pseudo subcells were created by distance separation, and the cover was modified to insert distribution systems for leachate and a gas collection suitable for experimentation. The existing landfill will modify the circulated leachate to control nitrogen conditions in the leachate in an attempt to control ammonia conditions in the landfill as the bioreactor operates over time.
The former landfill cells were receiving waste and began operation in early 2002, while in October 2001 the latter modified existing landfill began circulating leachate and collecting data.