title: A micro-aerobic hydrolysis process for sludge in situ reduction: performance and microbial community structure.
abstract: A sludge process reduction activated sludge (SPRAS) system by inserting a sludge process reduction (SPR) module, composed of a micro-aerobic tank and a settler, before activated sludge process was operated for sludge in situ reduction. The average removal efficiencies of COD and ammonium nitrogen were 86.6% and 87.9%, respectively. Compared to anoxic/aerobic (AO) process, SPRAS process reduced sludge production by 57.9% with observed sludge yield of 0.076 gVSS/gCOD. Pyrosequencing analyses revealed that the relative abundance and stability of microbial communities in SPRAS system were higher than AO system. Fermentative acidogenic classes Anaerolineae, Actinobacteria, Cytophagia and Caldilineae were enriched in the SPR module and responsible for sludge reduction. Specific comparison down to the genus level identified the enrichment of oxyanion-reducing bacteria (Sulfuritalea; Azospira; Ramlibacter), fermentative acidogenic bacteria (Propionivibrio; Opitutus; Caldilinea), slow growers (Ramlibacter) and predatory bacteria (Myxobacteria) in SPRAS system. Nitrifiers were also more abundant in SPRAS system than AO system.
authors.affiliation: College of Environmental and Chemical Engineering, Shanghai University of Electric Power, 2588 Changyang Road, 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, 2588 Changyang Road, 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, 2588 Changyang Road, Shanghai 200090, China.
authors.forename: Can
authors.initials: C
authors.lastname: Xing
authors.affiliation: College of Environmental and Chemical Engineering, Shanghai University of Electric Power, 2588 Changyang Road, 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, 2588 Changyang Road, Shanghai 200090, China.
authors.forename: Dalong
authors.initials: D
authors.lastname: Hu
authors.affiliation: College of Environmental and Chemical Engineering, Shanghai University of Electric Power, 2588 Changyang Road, Shanghai 200090, China.
authors.forename: Luochun
authors.initials: L
authors.lastname: Wang
mesh_terms: D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors; D006868:Hydrolysis; D012722:Sewage / Q000382:microbiology; D062065:Wastewater / Q000737:chemistry*; D014871:Water Microbiology; D018508:Water Purification / Q000379:methods*
chemical_list: D012722:Sewage; D062065:Wastewater
keywords: Microbial community; Pyrosequencing; Sludge process reduction activated sludge (SPRAS) process; Sludge reduction; Wastewater treatment