title: Carbon monoxide from composting due to thermal oxidation of biomass.
abstract: Emissions of carbon monoxide (CO) were observed from decomposing organic wastes and litter under laboratory, pilot composting plant, and natural conditions. Field studies included air from inside a compost heap of about 200 m3, emissions from composting of livestock wastes at a biologically operating farm, and leaf litter pile air samples. The concentration of CO was up to 120 micromol mol(-1) in the compost piles of green waste, and up to 10 micromol mol(-1) in flux chambers above livestock waste windrow composts. The mean CO flux rates were approximately 20 mg CO m(-2) h(-1) for compost heaps of green waste, and varied from 30 to 100 mg CO m(-2) h(-1) for fresh dung windrows. Laboratory studies using a temperature and ventilation-controlled substrate container were performed to elucidate the origin of CO, and included hay samples of fixed moisture content at temperatures between 5 and 65 degrees C, including nonsterilized as well as sterilized samples. The concentration of CO was up to 160 micromol mol(-1) in these experiments, and Arrhenius-type plot analyses resulted in activation energies of 65 kJ mol(-1) for thermochemically produced CO from the nonsterilized compost substrate. Sterilized samples showed dramatically reduced CO2 but virtually unchanged CO emissions, albeit at a slightly lower activation energy, likely a result of the high-temperature sterilization. Though globally and regionally these CO emissions are only a minor source, thermochemically produced CO emissions might affect local air quality in and near composting facilities.
authors.affiliation: Leibniz Institute for Agricultural Engineering Potsdam-Bornim (ATB), Max-Eyth-Allee 100, Potsdam, Germany. jhellebrand@atb-potsdam.de
authors.forename: H J
authors.initials: HJ
authors.lastname: Hellebrand
authors.forename: G W
authors.initials: GW
authors.lastname: Schade
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D018533:Biomass; D002245:Carbon Dioxide / Q000032:analysis; D002248:Carbon Monoxide / Q000032:analysis*; D004784:Environmental Monitoring; D006358:Hot Temperature; D008372:Manure; D010084:Oxidation-Reduction; D018515:Plant Leaves; D012987:Soil; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D000393:Air Pollutants; D008372:Manure; D012987:Soil; D002245:Carbon Dioxide; D002248:Carbon Monoxide