title: Sulfate removal and sulfur transformation in constructed wetlands: The roles of filling material and plant biomass.
abstract: Sulfate in effluent is a challenging issue for wastewater reuse around the world. In this study, sulfur (S) removal and transformation in five batch constructed wetlands (CWs) treating secondary effluent were investigated. The results showed that the presence of the plant cattail (Typha latifolia) had little effect on sulfate removal, while the carbon-rich litter it generated greatly improved sulfate removal, but with limited sulfide accumulation in the pore-water. After sulfate removal, most of the S was deposited with the valence states S (-II) and S (0) on the iron-rich gravel surface, and acid volatile sulfide was the main S sink in the litter-added CWs. High-throughput pyrosequencing revealed that sulfate-reducing bacteria (i.e. Desulfobacter) and sulfide-oxidizing bacteria (i.e. Thiobacillus) were dominant in the litter-added CWs, which led to a sustainable S cycle between sulfate and sulfide. Overall, this study suggests that recycling plant litter and iron-rich filling material in CWs gives an opportunity to utilize the S in the wastewater as both an electron acceptor for sulfate reduction and as an electron donor for nitrate reduction coupled with sulfide oxidation. This leads to the simultaneous removal of sulfate, nitrate, and organics without discharging toxic sulfide into the receiving water body.
authors.affiliation: Key Laboratory of Yangtze Water Environment of Ministry of the State Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China; Department of Applied Ecology, Faculty of Environmental Sciences, Czech University of Life Sciences, Prague, 16521, Czech Republic.
authors.forename: Yi
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Key Laboratory of Yangtze Water Environment of Ministry of the State Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China. Electronic address: weny@tongji.edu.cn.
authors.forename: Yue
authors.initials: Y
authors.lastname: Wen
authors.affiliation: Key Laboratory of Yangtze Water Environment of Ministry of the State Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Zhou
authors.affiliation: Institute of Environmental Science and Engineering, Hangzhou Dianzi University, Hangzhou 310018, PR China.
authors.forename: Jingang
authors.initials: J
authors.lastname: Huang
authors.affiliation: Department of Applied Ecology, Faculty of Environmental Sciences, Czech University of Life Sciences, Prague, 16521, Czech Republic.
authors.forename: Jan
authors.initials: J
authors.lastname: Vymazal
authors.affiliation: Department of Environmental Biotechnology, Helmholtz Centre for Environmental Research -UFZ, Permoserstr. 15, Leipzig, 04318, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Kuschk
mesh_terms: D018533:Biomass; D010084:Oxidation-Reduction; D013431:Sulfates; D013455:Sulfur; D032401:Typhaceae; D014865:Waste Disposal, Fluid; D053833:Wetlands
chemical_list: D013431:Sulfates; D013455:Sulfur
keywords: Bacterial sulfate reduction; Constructed wetlands; Denitrification; Plant litter; Sulfur oxidation