Low Technological Biological Treatment of Source Separated Waste in a Biocell

Abstract

In 2009 the Norwegian government banned biodegradable waste in landfills to mitigate climate gas production. To be able to stabilize source separated waste before landfilling a constructed biocell has been tested during a four year period. The research is part of a pilot project organized by Avfall Norge. A total amount of 12 000 tons of waste from both industry and households were embedded in the biocell. Before loading, the waste fractions were characterized both in macro and micro scale. Anaerobic testing in lab scale documented the methane potential in different waste fractions. Especially car fluff contained toxic components which suppressed biodegradation. To avoid greenhouse gas leakage the biocell was constructed as a closed system with synthetic capping and gas wells coupled to a compressor. While the biogas was flared the leachate was collected and recycled. Leachate contains both nutrients and DOC which is supposed to increase the biological activity. During the first part of the test period the BOD/COD was above 0.5 before it declined. In addition both inorganic and organic environmental harmful components were analyzed in the leachate. Levels of heavy metal decreased during treatment. The methane production was detected on-line with IR. Both the production and gas phase concentration varied during the test period. A total of five gas wells were positioned at different levels in the biocell. Only one of them produced biogas for a considerable period. This presentation will focus on biocell construction and waste degradation related to variation in leachate constituents as a function of time.