title: Performance of green waste biocovers for enhancing methane oxidation.
abstract: Green waste aged 2 and 24months, labeled "fresh" and "aged" green waste, respectively, were placed in biocover test cells and evaluated for their ability to oxidize methane (CH4) under high landfill gas loading over a 15-month testing period. These materials are less costly to produce than green waste compost, yet satisfied recommended respiration requirements for landfill compost covers. In field tests employing a novel gas tracer to correct for leakage, both green wastes oxidized CH4 at high rates during the first few months of operation - 140 and 200g/m(2)/day for aged and fresh green waste, respectively. Biocover performance degraded during the winter and spring, with significant CH4 generated from anaerobic regions in the 60-80cm thick biocovers. Concurrently, CH4 oxidation rates decreased. Two previously developed empirical models for moisture and temperature dependency of CH4 oxidation in soils were used to test their applicability to green waste. Models accounted for 68% and 79% of the observed seasonal variations in CH4 oxidation rates for aged green waste. Neither model could describe similar seasonal changes for the less stable fresh green waste. This is the first field application and evaluation of these empirical models using media with high organic matter. Given the difficulty of preventing undesired CH4 generation, green waste may not be a viable biocover material for many climates and landfill conditions.
authors: Faculty of Geoscience and Environmental Engineering, Southwest Jiaotong University, Chengdu, Sichuan 610031, China; Department of Civil and Environmental Engineering, University of Delaware, Newark, DE 19716, USA.
authors: Changgen
authors: C
authors: Mei
authors: Yolo County Planning & Public Works Department, Division of Integrated Waste Management, Woodland, CA 95776, USA; Air Quality Research Center, University of California, Davis, CA 95616, USA.
authors: Ramin
authors: R
authors: Yazdani
authors: Department of Civil and Environmental Engineering, University of Delaware, Newark, DE 19716, USA.
authors: Byunghyun
authors: B
authors: Han
authors: Department of Civil and Environmental Engineering, University of Delaware, Newark, DE 19716, USA; Now at Terra Pacific Group, Irvine, CA 92618, USA.
authors: M Erfan
authors: ME
authors: Mostafid
authors: Department of Oceanography, Florida State University, Tallahassee, FL 32306, USA.
authors: Jeff
authors: J
authors: Chanton
authors: Department of Biological and Agricultural Engineering, University of California, Davis, CA 95616, USA.
authors: Jean
authors: J
authors: VanderGheynst
authors: Department of Civil and Environmental Engineering, University of Delaware, Newark, DE 19716, USA.
authors: Paul
authors: P
authors: Imhoff
mesh_terms: D000393:Air Pollutants / Q000737:chemistry*; D000397:Air Pollution / Q000517:prevention & control*; D008697:Methane / Q000737:chemistry*; D008962:Models, Theoretical; D010084:Oxidation-Reduction; D012037:Refuse Disposal / Q000295:instrumentation / Q000379:methods*; D012987:Soil / Q000737:chemistry; D064091:Waste Disposal Facilities
chemical_list: D000393:Air Pollutants; D012987:Soil; D008697:Methane
keywords: Biocover; Carbon balance approach; Methane oxidation; Yard waste