title: Long-term effects of increasing acidity on low-pH sulfate-reducing bioprocess and bacterial community.
abstract: An ethanol-fed, sulfate-reducing anaerobic baffled reactor was operated over a period of 260 days to assess the effects of sequentially more acidic conditions (pH 4.5-2.5) on sulfate reduction and bacterial community. Results showed that the reactor could reduce sulfate and generate alkalinity at progressively lower pH values of 4.5, 3.5, and 2.5 in a synthetic wastewater containing 2500 mg/L sulfate. About 93.9% of the influent sulfate was removed at a rate of 4691 mg/L/day, and the effluent pH was increased to 6.8 even when challenged with influent pH as low as 2.5. Illumina MiSeq sequencing revealed that a step decrease in influent pH from 4.5 to 2.5 resulted in noticeable decrease in the biodiversity inside the sulfidogenic reactor. Additionally, complete and incomplete organic oxidizers Desulfobacter and Desulfovibrio were observed to be the most dominant sulfate reducers at pH 2.5, sustaining the low-pH, high-rate sulfate removal and alkalinity generation.
authors.affiliation: College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhao
authors.affiliation: College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China. di.fang@njau.edu.cn.
authors.forename: Di
authors.initials: D
authors.lastname: Fang
authors.affiliation: College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China.
authors.forename: Pengfei
authors.initials: P
authors.lastname: Zhang
authors.affiliation: College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China.
authors.forename: Lixiang
authors.initials: L
authors.lastname: Zhou
mesh_terms: D000143:Acids; D019149:Bioreactors / Q000382:microbiology*; D045858:Desulfitobacterium; D003901:Desulfovibrio; D006863:Hydrogen-Ion Concentration; D010084:Oxidation-Reduction; D013431:Sulfates; D013995:Time; D062065:Wastewater / Q000382:microbiology
chemical_list: D000143:Acids; D013431:Sulfates; D062065:Wastewater
keywords: Anaerobic baffled reactor; Bacterial community; Illumina sequencing; Low pH; Sulfate-reducing bioprocess; Wastewater treatment