title: Investigation on thiosulfate-involved organics and nitrogen removal by a sulfur cycle-based biological wastewater treatment process.
abstract: Thiosulfate, as an intermediate of biological sulfate/sulfite reduction, can significantly improve nitrogen removal potential in a biological sulfur cycle-based process, namely the Sulfate reduction-Autotrophic denitrification-Nitrification Integrated (SANI(®)) process. However, the related thiosulfate bio-activities coupled with organics and nitrogen removal in wastewater treatment lacked detailed examinations and reports. In this study, S2O3(2-) transformation during biological SO4(2-)/SO3(2-) co-reduction coupled with organics removal as well as S2O3(2-) oxidation coupled with chemolithotrophic denitrification were extensively evaluated under different experimental conditions. Thiosulfate is produced from the co-reduction of sulfate and sulfite through biological pathway at an optimum pH of 7.5 for organics removal. And the produced S2O3(2-) may disproportionate to sulfide and sulfate during both biological S2O3(2-) reduction and oxidation most possibly carried out by Desulfovibrio-like species. Dosing the same amount of nitrate, pH was found to be the more direct factor influencing the denitritation activity than free nitrous acid (FNA) and the optimal pH for denitratation (7.0) and denitritation (8.0) activities were different. Spiking organics significantly improved both denitratation and denitritation activities while minimizing sulfide inhibition of NO3(-) reduction during thiosulfate-based denitrification. These findings in this study can improve the understanding of mechanisms of thiosulfate on organics and nitrogen removal in biological sulfur cycle-based wastewater treatment.
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: School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, 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.
authors.forename: Yanxiang
authors.initials: Y
authors.lastname: Cui
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: 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; SYSU-HKUST Joint Research Centre for Innovative Environmental Technology, Sun Yat-sen University, Guangzhou, China. Electronic address: ceghchen@ust.hk.
authors.forename: Guang-Hao
authors.initials: GH
authors.lastname: Chen
mesh_terms: D061249:Batch Cell Culture Techniques; D001673:Biodegradation, Environmental; D019149:Bioreactors; D058440:Denitrification; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D064307:Microbiota; D009584:Nitrogen / Q000302:isolation & purification*; D009930:Organic Chemicals / Q000302:isolation & purification*; D010084:Oxidation-Reduction; D010802:Phylogeny; D013431:Sulfates / Q000737:chemistry; D013447:Sulfites / Q000737:chemistry; D013455:Sulfur / Q000737:chemistry*; D013885:Thiosulfates / Q000737:chemistry*; D062065:Wastewater / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
chemical_list: D009584:Nitrogen; D009930:Organic Chemicals; D013431:Sulfates; D013447:Sulfites; D013455:Sulfur; D013885:Thiosulfates; D062065:Wastewater
keywords: Biological sulfate/sulfite reduction; Chemolithotrophic denitrification; Organics and nitrogen removal; Sulfur cycle-based wastewater treatment process; Thiosulfate bio-transformation