title: Effects of dissolved oxygen on performance and microbial community structure in a micro-aerobic hydrolysis sludge in situ reduction process.
abstract: A sludge process reduction activated sludge (SPRAS), with a sludge process reduction module composed of a micro-aerobic tank and a settler positioned before conventional activated sludge process, showed good performance of pollutant removal and sludge reduction. Two SPRAS systems were operated to investigate effects of micro-aeration on sludge reduction performance and microbial community structure. When dissolved oxygen (DO) concentration in the micro-aerobic tank decreased from 2.5 (SPH) to 0.5 (SPL) mg/L, the sludge reduction efficiency increased from 42.9% to 68.3%. Compared to SPH, activated sludge in SPL showed higher contents of extracellular polymeric substances and dissolved organic matter. Destabilization of floc structure in the settler, and cell lysis in the sludge process reduction module were two major reasons for sludge reduction. Illumina-MiSeq sequencing showed that microbial diversity decreased under high DO concentration. Proteobacteria, Bacteroidetes and Chloroflexi were the most abundant phyla in the SPRAS. Specific comparisons down to the class and genus level showed that fermentative, predatory and slow-growing bacteria in SPL community were more abundant than in SPH. The results revealed that micro-aeration in the SPRAS improved hydrolysis efficiency and enriched fermentative and predatory bacteria responsible for sludge reduction.
authors.affiliation: College of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai 200090, China.
authors.forename: Tianhao
authors.initials: T
authors.lastname: Niu
authors.affiliation: College of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai 200090, China. Electronic address: zhouzhen@shiep.edu.cn.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Zhou
authors.affiliation: College of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai 200090, China.
authors.forename: Xuelian
authors.initials: X
authors.lastname: Shen
authors.affiliation: College of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai 200090, China.
authors.forename: Weimin
authors.initials: W
authors.lastname: Qiao
authors.affiliation: College of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai 200090, China.
authors.forename: Lu-Man
authors.initials: LM
authors.lastname: Jiang
authors.affiliation: Shanghai Municipal Sewerage Co., Ltd., Shanghai 200233, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Pan
authors.affiliation: Shanghai Municipal Sewerage Co., Ltd., Shanghai 200233, China.
authors.forename: Jijun
authors.initials: J
authors.lastname: Zhou
mesh_terms: D000332:Aerobiosis; D041963:Bacteroidetes; D044822:Biodiversity; D019149:Bioreactors; D041862:Chloroflexi; D004269:DNA, Bacterial / Q000032:analysis; D005285:Fermentation; D006868:Hydrolysis; D059013:Microbial Consortia; D010100:Oxygen / Q000737:chemistry*; D016133:Polymerase Chain Reaction; D020560:Proteobacteria; D017422:Sequence Analysis, DNA; D012722:Sewage / Q000382:microbiology*; D014865:Waste Disposal, Fluid; D062065:Wastewater; D014871:Water Microbiology; D018508:Water Purification / Q000379:methods*
chemical_list: D004269:DNA, Bacterial; D010100:Oxygen; D012722:Sewage; D062065:Wastewater
keywords: Micro-aeration; Microbial community; Sludge process reduction activated sludge (SPRAS) process; Sludge reduction; Wastewater treatment