title: System evaluation and microbial analysis of a sulfur cycle-based wastewater treatment process for Co-treatment of simple wet flue gas desulfurization wastes with freshwater sewage.
abstract: A sulfur cycle-based wastewater treatment process, namely the Sulfate reduction, Autotrophic denitrification and Nitrification Integrated process (SANI(®) process) has been recently developed for organics and nitrogen removal with 90% sludge minimization and 35% energy reduction in the biological treatment of saline sewage from seawater toilet flushing practice in Hong Kong. In this study, sulfate- and sulfite-rich wastes from simple wet flue gas desulfurization (WFGD) were considered as a potential low-cost sulfur source to achieve beneficial co-treatment with non-saline (freshwater) sewage in continental areas, through a Mixed Denitrification (MD)-SANI process trialed with synthetic mixture of simple WFGD wastes and freshwater sewage. The system showed 80% COD removal efficiency (specific COD removal rate of 0.26 kg COD/kg VSS/d) at an optimal pH of 7.5 and complete denitrification through MD (specific nitrogen removal rate of 0.33 kg N/kg VSS/d). Among the electron donors in MD, organics and thiosulfate could induce a much higher denitrifying activity than sulfide in terms of both NO3(-) reduction and NO2(-) reduction, suggesting a much higher nitrogen removal rate in organics-, thiosulfate- and sulfide-based MD in MD-SANI compared to sulfide alone-based autotrophic denitrification in conventional SANI(®). Diverse sulfate/sulfite-reducing bacteria (SRB) genera dominated in the bacterial community of sulfate/sulfite-reducing up-flow sludge bed (SRUSB) sludge without methane producing bacteria detected. Desulfomicrobium-like species possibly for sulfite reduction and Desulfobulbus-like species possibly for sulfate reduction are the two dominant groups with respective abundance of 24.03 and 14.91% in the SRB genera. Diverse denitrifying genera were identified in the bacterial community of anoxic up-flow sludge bed (AnUSB) sludge and the Thauera- and Thiobacillus-like species were the major taxa. These results well explained the successful operation of the lab-scale MD-SANI process.
authors.affiliation: Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Qian
authors.affiliation: Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
authors.forename: Rulong
authors.initials: R
authors.lastname: Liu
authors.affiliation: Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
authors.forename: Li
authors.initials: L
authors.lastname: Wei
authors.affiliation: School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, China. Electronic address: lvhui3@mail.sysu.edu.cn.
authors.forename: Hui
authors.initials: H
authors.lastname: Lu
authors.affiliation: Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China. Electronic address: ceghchen@ust.hk.
authors.forename: Guang-Hao
authors.initials: GH
authors.lastname: Chen
mesh_terms: D052818:Autotrophic Processes; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000378:metabolism; D058893:DNA Barcoding, Taxonomic / Q000379:methods; D020564:Deltaproteobacteria / Q000235:genetics / Q000378:metabolism; D058440:Denitrification; D005618:Fresh Water / Q000737:chemistry* / Q000382:microbiology; D006863:Hydrogen-Ion Concentration; D009566:Nitrates / Q000737:chemistry / Q000378:metabolism; D058465:Nitrification; D009573:Nitrites / Q000737:chemistry / Q000378:metabolism; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012722:Sewage / Q000737:chemistry* / Q000382:microbiology; D013431:Sulfates / Q000737:chemistry / Q000378:metabolism; D013447:Sulfites / Q000737:chemistry / Q000378:metabolism; D013455:Sulfur / Q000737:chemistry* / Q000378:metabolism; D020628:Thauera / Q000235:genetics / Q000378:metabolism; D013855:Thiobacillus / Q000235:genetics / Q000378:metabolism; D013885:Thiosulfates / Q000737:chemistry / Q000378:metabolism; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater / Q000737:chemistry* / Q000382:microbiology
chemical_list: D009566:Nitrates; D009573:Nitrites; D012336:RNA, Ribosomal, 16S; D012722:Sewage; D013431:Sulfates; D013447:Sulfites; D013455:Sulfur; D013885:Thiosulfates; D062065:Wastewater
keywords: Autotrophic and heterotrophic denitrifiers; MD–SANI process; Microbial structure analysis; Organics and nitrogen removal; Sulfate/sulfite-reducing bacteria (SRB)