title: Oxidation reduction potential as a parameter to regulate micro-oxygen injection into anaerobic digester for reducing hydrogen sulphide concentration in biogas.
abstract: This study aims to evaluate the use of oxidation reduction potential (ORP) to regulate the injection of a small amount of oxygen into an anaerobic digester for reducing H2S concentration in biogas. The results confirm that micro-oxygen injection can be effective for controlling H2S formation during anaerobic digestion without disturbing the performance of the digester. Biogas production, composition, and the removal of volatile solids (VS) and chemical oxygen demand (COD) were monitored to assessment the digester's performance. Six days after the start of the micro-oxygen injection, the ORP values increased to between -320 and -270 mV, from the natural baseline value of -485 mV. Over the same period the H2S concentration in the biogas decreased from over 6000 ppm to just 30 ppm. No discernible changes in the VS and COD removal rates, pH and alkalinity of the digestate or in the biogas production or composition were observed.
authors.affiliation: Strategic Water Infrastructure Laboratory, School of Civil Mining and Environmental Engineering, University of Wollongong, Wollongong, NSW 2522, Australia. Electronic address: longn@uow.edu.au.
authors.forename: Long D
authors.initials: LD
authors.lastname: Nghiem
authors.affiliation: Strategic Water Infrastructure Laboratory, School of Civil Mining and Environmental Engineering, University of Wollongong, Wollongong, NSW 2522, Australia.
authors.forename: Patrick
authors.initials: P
authors.lastname: Manassa
authors.affiliation: Sydney Water Corporation, Parramatta, NSW 2124, Australia.
authors.forename: Marcia
authors.initials: M
authors.lastname: Dawson
authors.affiliation: Sydney Water Corporation, Parramatta, NSW 2124, Australia.
authors.forename: Shona K
authors.initials: SK
authors.lastname: Fitzgerald
mesh_terms: D000693:Anaerobiosis; D056804:Biofuels; D019149:Bioreactors; D006862:Hydrogen Sulfide / Q000737:chemistry*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry*
chemical_list: D056804:Biofuels; D010100:Oxygen; D006862:Hydrogen Sulfide
keywords: Anaerobic digestion; Biogas; Hydrogen sulphide; Micro-aeration; Oxidation reduction potential (ORP)