Methane Oxidation in Landfill Biocaps Constructed with Partially Stabilized Compost

摘要

Methane is a greenhouse gas that is thought to contribute to global warming. In the past, fully-stabilized leaf compost has been used to oxidize methane in biofilters and biocaps with promising results. In some landfill situations, fully-stabilized compost may not be available in sufficient quantities to construct compost biocaps and needs to be mixed with other material. At the Calgary Biocell, an award winning sustainable landfill project, intermediate thin biocovers were constructed with leaf compost mixed with partially stabilized grass and plant matter. Subsequent field measurements of methane gas surface emissions using a closed flux chamber showed little methane oxidation and no methanotrophic activity in the biocap material. To verify these results, a partially-decomposed organic matter (pdo) proxy was tested for methane oxidation under laboratory conditions. No significant methane oxidation was observed. A biological analysis was undertaken to identify methanotrophic bacteria. Oxygen uptake rates (OUR) were also evaluated and exceeded the maximum recommended value of 150 mg O_2/kg Organic Matter-hour. C/N ratios were also evaluated.