title: Effects of sludge retention time on oxic-settling-anoxic process performance: Biosolids reduction and dewatering properties.
abstract: In this study, the effect of sludge retention time (SRT) on oxic-settling-anoxic (OSA) process was determined using a sequencing batch reactor (SBR) attached to external aerobic/anoxic reactors. The SRT of the external reactors was varied from 10 to 40d. Increasing SRT from 10 to 20d enhanced volatile solids destruction in the external anoxic reactor as evidenced by the release of nutrients, however, increasing the SRT to 40d did not enhance volatile solids destruction further. Relatively short SRT (10-20d) favoured the conversion of destroyed solids into inert products. The application of an intermediate SRT (20d) of the external reactor showed the highest sludge reduction performance (>35%). Moreover, at the optimum SRT, OSA improved sludge dewaterability as demonstrated by lower capillary suction time and higher dewatered cake solids content.
authors.affiliation: Strategic Water Infrastructure Laboratory, School of Civil, Mining and Environmental Engineering, University of Wollongong, Wollongong, NSW 2522, Australia.
authors.forename: Galilee U
authors.initials: GU
authors.lastname: Semblante
authors.affiliation: Strategic Water Infrastructure Laboratory, School of Civil, Mining and Environmental Engineering, University of Wollongong, Wollongong, NSW 2522, Australia. Electronic address: faisal@uow.edu.au.
authors.forename: Faisal I
authors.initials: FI
authors.lastname: Hai
authors.affiliation: Sydney Water, Parramatta, NSW 2124, Australia.
authors.forename: Heriberto
authors.initials: H
authors.lastname: Bustamante
authors.affiliation: Strategic Water Infrastructure Laboratory, School of Chemistry, University of Wollongong, Wollongong, NSW 2522, Australia.
authors.forename: William E
authors.initials: WE
authors.lastname: Price
authors.affiliation: Strategic Water Infrastructure Laboratory, School of Civil, Mining and Environmental Engineering, University of Wollongong, Wollongong, NSW 2522, Australia.
authors.forename: Long D
authors.initials: LD
authors.lastname: Nghiem
mesh_terms: D019149:Bioreactors; D012722:Sewage / Q000737:chemistry*
chemical_list: D012722:Sewage
keywords: Biosolids reduction; Capillary suction time; Dewatered cake; Oxic-settling-anoxic process; Sludge yield