title: Anaerobic co-digestion of forage radish and dairy manure in complete mix digesters.
abstract: Pilot-scale digesters (850 L) were used to quantify CH4 and H2S production when using forage radish cover crops as a co-digestion feedstock in dairy manure-based digesters. During two trials, triplicate mixed digesters were operated in batch mode with manure-only or radish+manure (27% and 13% radish by wet weight in Trial 1 and 2, respectively). Co-digestion increased CH4 production by 11% and 39% in Trial 1 and 2, respectively. As H2S production rapidly declined in the radish+manure digesters, CH4 production increased reaching high levels of CH4 (⩾67%) in the biogas. Over time, radish co-digestion lowered the H2S concentration in the biogas (0.20%) beyond that of manure-only digestion (0.34-0.40%), although cumulative H2S production in the radish+manure digesters was higher than manure-only. Extrapolated to a farm-scale (200 cows) continuous mixed digester, co-digesting with radish could generate 3150 m(3) CH4/month, providing a farmer additional revenue up to $3125/month in electricity sales.
authors.affiliation: Department of Environmental Science and Technology, University of Maryland, 1449 Animal Science/Ag Engineering Building, College Park, MD 20742, USA.
authors.forename: Ashley J
authors.initials: AJ
authors.lastname: Belle
authors.affiliation: Department of Environmental Science and Technology, University of Maryland, 1449 Animal Science/Ag Engineering Building, College Park, MD 20742, USA. Electronic address: slansing@umd.edu.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Lansing
authors.affiliation: United States Department of Agriculture-Agricultural Research Service, Environmental Management and Byproducts Laboratory, Beltsville, MD 20705, USA.
authors.forename: Walter
authors.initials: W
authors.lastname: Mulbry
authors.affiliation: Department of Environmental Science and Technology, University of Maryland, 1449 Animal Science/Ag Engineering Building, College Park, MD 20742, USA.
authors.forename: Ray R
authors.initials: RR
authors.lastname: Weil
mesh_terms: D000693:Anaerobiosis; D000818:Animals; D019149:Bioreactors; D002417:Cattle; D003612:Dairying; D006862:Hydrogen Sulfide / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D008372:Manure / Q000032:analysis*; D008697:Methane / Q000096:biosynthesis; D009584:Nitrogen / Q000032:analysis; D010758:Phosphorus / Q000032:analysis; D031224:Raphanus / Q000737:chemistry*; D012037:Refuse Disposal / Q000295:instrumentation* / Q000379:methods*; D013455:Sulfur / Q000032:analysis; D014865:Waste Disposal, Fluid
chemical_list: D008372:Manure; D010758:Phosphorus; D013455:Sulfur; D009584:Nitrogen; D008697:Methane; D006862:Hydrogen Sulfide
keywords: Anaerobic digestion; Biogas; Cover crops; Hydrogen sulfide; Methane