title: Influence of co-substrate on textile wastewater treatment and microbial community changes in the anaerobic biological sulfate reduction process.
abstract: This study investigated the anaerobic treatment of sulfate-rich synthetic textile wastewater in three sulfidogenic sequential batch reactors (SBRs). The experimental protocol was designed to examine the effect of three different co-substrates (lactate, glucose, and ethanol) and their concentrations on wastewater treatment performance. Sulfate reduction and dye degradation were improved when lactate and ethanol were used as electron donors, as compared with glucose. Moreover, under co-substrate limited concentrations, color, sulfate, and chemical oxygen demand (COD) removal efficiencies were declined. By reducing co-substrate COD gradually from 3000 to 500 mg/L, color removal efficiencies were decreased from 98.23% to 78.46%, 63.37%, and 69.10%, whereas, sulfate removal efficiencies were decreased from 98.42%, 82.35%, and 87.0%, to 30.27%, 21.50%, and 10.13%, for lactate, glucose, and ethanol fed reactors, respectively. Fourier transform infrared spectroscopy (FTIR) and total aromatic amine analysis revealed lactate to be a potential co-substrate for further biodegradation of intermediate metabolites formed after dye degradation. Pyrosequencing analysis showed that microbial community structure was significantly affected by the co-substrate. The reactor with lactate as co-substrate showed the highest relative abundance of sulfate reducing bacteria (SRBs), followed by ethanol, whereas the glucose-fed reactor showed the lowest relative abundance of SRB.
authors.affiliation: Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University, Qatar Foundation, PO BOX 5825, Doha, Qatar.
authors.forename: Kashif
authors.initials: K
authors.lastname: Rasool
authors.affiliation: Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University, Qatar Foundation, PO BOX 5825, Doha, Qatar.
authors.forename: Khaled A
authors.initials: KA
authors.lastname: Mahmoud
authors.affiliation: Department of Environmental Engineering, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu 702-701, Republic of Korea. Electronic address: daesung@knu.ac.kr.
authors.forename: Dae Sung
authors.initials: DS
authors.lastname: Lee
mesh_terms: D000693:Anaerobiosis; D010084:Oxidation-Reduction; D013431:Sulfates / Q000737:chemistry*; D013783:Textile Industry; D062065:Wastewater; D014871:Water Microbiology; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D013431:Sulfates; D062065:Wastewater; D014874:Water Pollutants, Chemical
keywords: Co-substrate; Decolorization; Direct Red 80; Microbial community; Sulfidogenic sludge