Hydrogen production from alcohol distillery wastewater using an anaerobic sequencing batch reactor under thermophilic condition

Abstract

The production of hydrogen from wastewater by anaerobic fermentation is considered to be the most efficient and economical process. In this research, hydrogen production via dark fermentation from alcohol distillery wastewater using an anaerobic sequencing batch reactor (ASBR) with a working volume of 4 L was investigated. The ASBR system was operated at different COD loading rates (30, 45, 60, and 75 kg/m³d) with a fixed feed COD of 40,000 mg/l under a thermophilic temperature of 55°C, with a controlled pH at 5.5 and a cycle time of 6 cycles/day. The produced gas composition and the concentration of volatile fatty acids (VFA) in the effluents were analyzed by a gas chromatograph (GC) with a thermal conductivity detector (TCD) and a flame ionization detector (FID). The results showed that under the optimum condition for maximum hydrogen production of a COD loading rate of 45 kg/m³d and a hydraulic retention time of 21 h, the produced gas contained 19.72% H₂, 73.87% CO₂ and 6.41% CH₄. A specific hydrogen production rate (SHPR) of 65.3 ml H₂/g MLVSS and a hydrogen yield of 56.1 ml H₂/g COD removed were obtained.