Methane (CHt) is a greenhouse gas with a global warnling potential. Much is released into the atmosphere from landfill waste disposal sites. Bio-waste compost could be used as cover material to support the microbial oxidation of methane. Mature compost supported higher CH4 oxidation rates than fresher materials (0.42 to 0.01 mg CH4 h-I gol), and was inversely related to NH/. dissolved organic carbon and humic substance concentrations. The diffusivity of CH4 through an aqueous compost extract was on average 64% lower than tl4at observed through dH20, thereby lowering the amount that is available for oxidation by metlianotrophic bacteria. Methanotroph Melhylosinus lrichosporium (OB3b) reproduced less well in a compost extract solution, adhering to humic-like substances in the extract. Use of the 13C stable isotope showed that proportionally less I3C-C02 evolves from the oxidation of 13C-CH4 at high NH/ concentrations (>2000 Jlg gol compost). A landfill-based field experiment identified complex variation in landfill gas: CH4, C02 and N20 concentrations over time and space. Bio-waste compost oxidized CH4 as effectively as he silt material currently used as a cover. A PCR-DGGE protocol was successfully developed to identify methanotrophs in bio-waste compost. DGGE analysis revealed a variety of methanotrophs present in different composts, thereby promoting its use as a landfill cover solution for Ct!4 emissions abatement. Much bio-waste compost is presently produced without a market. Finding alternative applications for this material is an important aspect of maintaining a sustainable waste management system. Its use as a landfill cover appears to be as good as the conventional silt material at promoting CH4 oxidation, but has not been extensively investigated. Further research optimizing the production ofbio-waste compost for landfill cover application has the potential to reduce CH4 emission, but more importantly turns' waste material into a valuable resource.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:485426 |
| Date | January 2008 |
| Creators | Chapman, Mark Martin |
| Publisher | Imperial College London |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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