title: Effects of ORP, recycling rate, and HRT on simultaneous sulfate reduction and sulfur production in expanded granular sludge bed (EGSB) reactors under micro-aerobic conditions for treating molasses distillery wastewater.
abstract: An expanded granular sludge bed (EGSB) reactor was adopted to incubate the sludge biogranule that could simultaneously achieve sulfate reduction and sulfide reoxidization to elemental sulfur for treating molasses distillery wastewater. The EGSB reactor was operated for 175 days at 35 °C with a pH value of 7.0, chemical oxygen demand (COD) loading rate of 4.8 kg COD/(m³ d), and sulfate loading rate of 0.384 kg SO(4)(2-)/(m³ d). The optimal operation parameters, including the oxidation reduction potential (ORP), recycling rate, and hydraulic retention time (HRT), were established to obtain stable and acceptable removal efficiencies of COD, sulfate, and higher elemental sulfur production. With an ORP of -440 mV, a recycling rate of 300%, and HRT of 15 h, the COD and sulfate removal efficiencies were 73.4 and 61.3%, respectively. The elemental sulfur production ratio reached 30.1% when the elemental sulfur concentration in the effluent was 48.1 mg/L. The performance results were also confirmed by the mass balance calculation of sulfate, sulfide, and elemental sulfur over the EGSB reactor.
authors: Hezhou University, Guangxi 542800, China.
authors: Xie
authors: X
authors: Qinglin
authors: Li
authors: L
authors: Yanhong
authors: Bai
authors: B
authors: Shaoyuan
authors: Ji
authors: J
authors: Hongda
mesh_terms: D000332:Aerobiosis; D019149:Bioreactors; D057168:Distillation; D019649:Food Industry; D007220:Industrial Waste / Q000032:analysis*; D008965:Molasses; D010084:Oxidation-Reduction; D010101:Oxygen Consumption; D013431:Sulfates; D013455:Sulfur; D013997:Time Factors; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D007220:Industrial Waste; D013431:Sulfates; D013455:Sulfur