title: Comparison of mesophilic and thermophilic anaerobic digestion of sugar beet pulp: performance, dewaterability and foam control.
abstract: Digestion of sugar beet pulp was assessed in relation to biogas and methane production, foaming potential, and digestate dewaterability. Four 4-litre working volume digesters were operated mesophilically (37±0.5 °C) and four thermophilically (55±0.5 °C) over three hydraulic retention times. Digesters were operated in duplicate at organic loading rates (OLR) of 4 and 5 g volatile solids l(-1) day(-1) without water addition. Thermophilic digestion gave higher biogas and methane productivity than mesophilic and was able to operate at the higher OLR, where mesophilic digestion showed signs of instability. Digestate dewaterability was assessed using capillary suction time and frozen image centrifugation. The occurrence of, or potential for, stable foam formation was assessed using a foaming potential test. Thermophilic operation allowed higher loadings to be applied without loss of performance, and gave a digestate with superior dewatering characteristics and very little foaming potential.
authors.affiliation: Faculty of Engineering and the Environment, University of Southampton, Southampton SO17 1BJ, UK; Department of Agricultural Industry Technology, Faculty of Agricultural Technology, University of Brawijaya, Malang 64145, Indonesia. Electronic address: ssuhartini@ub.ac.id.
authors.forename: Sri
authors.initials: S
authors.lastname: Suhartini
authors.affiliation: Faculty of Engineering and the Environment, University of Southampton, Southampton SO17 1BJ, UK. Electronic address: sh7@soton.ac.uk.
authors.forename: Sonia
authors.initials: S
authors.lastname: Heaven
authors.affiliation: Faculty of Engineering and the Environment, University of Southampton, Southampton SO17 1BJ, UK. Electronic address: cjb@soton.ac.uk.
authors.forename: Charles J
authors.initials: CJ
authors.lastname: Banks
mesh_terms: D000693:Anaerobiosis; D027461:Beta vulgaris / Q000737:chemistry*; D001673:Biodegradation, Environmental; D019149:Bioreactors / Q000382:microbiology; D008855:Microscopy, Electron, Scanning; D009930:Organic Chemicals / Q000032:analysis; D062611:Solid Waste; D013696:Temperature; D014865:Waste Disposal, Fluid / Q000379:methods*; D014867:Water / Q000737:chemistry*
chemical_list: D009930:Organic Chemicals; D062611:Solid Waste; D014867:Water
keywords: Anaerobic digestion; Dewatering; Digestate; Foam formation; Sugar beet pulp