title: Greenhouse gas emissions from green waste composting windrow.
abstract: The process of composting is a source of greenhouse gases (GHG) that contribute to climate change. We monitored three field-scale green waste compost windrows over a one-year period to measure the seasonal variance of the GHG fluxes. The compost pile that experienced the wettest and coolest weather had the highest average CH4emission of 254±76gCday-1dry weight (DW) Mg-1and lowest average N2O emission of 152±21mgNday-1DW Mg-1compared to the other seasonal piles. The highest N2O emissions (342±41mgNday-1DW Mg-1) came from the pile that underwent the driest and hottest weather. The compost windrow oxygen (O2) concentration and moisture content were the most consistent factors predicting N2O and CH4emissions from all seasonal compost piles. Compared to N2O, CH4was a higher contributor to the overall global warming potential (GWP) expressed as CO2equivalents (CO2eq.). Therefore, CH4mitigation practices, such as increasing O2concentration in the compost windrows through moisture control, feedstock changes to increase porosity, and windrow turning, may reduce the overall GWP of composting. Based on the results of the present study, statewide total GHG emissions of green waste composting were estimated at 789,000Mg of CO2eq., representing 2.1% of total annual GHG emissions of the California agricultural sector and 0.18% of the total state emissions.
authors.affiliation: Department of Land, Air and Water Resources, University of California, Davis, United States. Electronic address: wyjzhu@ucdavis.edu.
authors.forename: Xia
authors.initials: X
authors.lastname: Zhu-Barker
authors.affiliation: Department of Land, Air and Water Resources, University of California, Davis, United States.
authors.forename: Shannon K
authors.initials: SK
authors.lastname: Bailey
authors.affiliation: Department of Land, Air and Water Resources, University of California, Davis, United States.
authors.forename: Kyaw Tha
authors.initials: KT
authors.lastname: Paw U
authors.affiliation: Department of Land, Air and Water Resources, University of California, Davis, United States.
authors.forename: Martin
authors.initials: M
authors.lastname: Burger
authors.affiliation: Department of Land, Air and Water Resources, University of California, Davis, United States.
authors.forename: William R
authors.initials: WR
authors.lastname: Horwath
mesh_terms: D000383:Agriculture; D000641:Ammonia / Q000032:analysis / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry; D002245:Carbon Dioxide / Q000032:analysis; D057231:Climate Change; D004784:Environmental Monitoring; D005740:Gases / Q000032:analysis; D057232:Global Warming; D055772:Green Chemistry Technology; D017752:Greenhouse Effect; D008697:Methane / Q000032:analysis / Q000737:chemistry*; D015233:Models, Statistical; D009584:Nitrogen / Q000032:analysis / Q000737:chemistry; D009609:Nitrous Oxide / Q000032:analysis; D010100:Oxygen / Q000737:chemistry; D016062:Porosity; D012037:Refuse Disposal / Q000379:methods; D012621:Seasons; D012987:Soil / Q000737:chemistry*; D013696:Temperature
chemical_list: D005740:Gases; D012987:Soil; D002245:Carbon Dioxide; D002244:Carbon; D000641:Ammonia; D009609:Nitrous Oxide; D009584:Nitrogen; D008697:Methane; D010100:Oxygen
keywords: Ammonia oxidation; Denitrification; Global warming potential; Methane; Nitrous oxide