title: Effect of temperature on methane production from field-scale anaerobic digesters treating dairy manure.
abstract: Temperature is a critical factor affecting anaerobic digestion because it influences both system heating requirements and methane production. Temperatures of 35-37°C are typically suggested for manure digestion. In temperate climates, digesters require a considerable amount of additional heat energy to maintain temperatures at these levels. In this study, the effects of lower digestion temperatures (22 and 28°C), on the methane production from dairy digesters were evaluated and compared with 35°C using duplicate replicates of field-scale (FS) digesters with a 17-day hydraulic retention time. After acclimation, the FS digesters were operated for 12weeks using solids-separated manure at an organic loading rate (OLR) of 1.4kgVSm(-3)d(-1) and then for 8weeks using separated manure amended with manure solids at an OLR of 2.6kgVSm(-3)d(-1). Methane production values of the FS digesters at 22 and 28°C were about 70% and 87%, respectively, of the values from FS digesters at 35°C. The results suggest that anaerobic digesters treating dairy manure at 28°C were nearly as efficient as digesters operated at 35°C, with 70% of total methane achievable at 22°C. These results are relevant to small farms interested in anaerobic digestion for methane reduction without heat recovery from generators or for methane recovery from covered lagoon digesters.
authors.affiliation: USDA-ARS, Beltsville Agricultural Research Center, Sustainable Agricultural Systems Laboratory, Beltsville, MD 20705, USA; University of Maryland, Department of Environmental Science and Technology, College Park, MD 20742, USA; Istanbul Technical University, Department of Environmental Engineering, Istanbul 34469, Turkey. Electronic address: arikan@itu.edu.tr.
authors.forename: Osman A
authors.initials: OA
authors.lastname: Arikan
authors.affiliation: USDA-ARS, Beltsville Agricultural Research Center, Sustainable Agricultural Systems Laboratory, Beltsville, MD 20705, USA.
authors.forename: Walter
authors.initials: W
authors.lastname: Mulbry
authors.affiliation: University of Maryland, Department of Environmental Science and Technology, College Park, MD 20742, USA.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Lansing
mesh_terms: D000693:Anaerobiosis; D019149:Bioreactors; D003612:Dairying; D004980:Ethane / Q000737:chemistry; D005740:Gases; D008372:Manure; D008697:Methane / Q000737:chemistry*; D013696:Temperature
chemical_list: D005740:Gases; D008372:Manure; D004980:Ethane; D008697:Methane
keywords: Anaerobic digestion; Dairy manure; Methane; Psychrophilic; Temperature