Feasibility of an Anaerobic Baffled Reactor (ABR) In Treating Starch Industry Wastewater

The anaerobic baffled reactor (ABR) includes a mixed anaerobic culture separated into compartments and a novel process with a series of vertical baffles at each compartment. It dose not require granulation for its operation, resulting in shorter start-up time. In this study, the feasibility of the ABR process was investigated for the treatment of wheat flour starch wastewater. Simple gravity settling was used to remove suspended solids from the starch wastewater and used as feed. Start-up of a reactor (13.5L with five compartments) using a diluted feed of approximately 4500 mg/L chemical oxygen demand (COD) was accomplished in about 9 weeks using seed sludge from the anaerobic digester of a municipal wastewater treatment plant. The reactor with a hydraulic retention time (HRT) of 72 h at 35°C and an initial organic loading rate (OLR) of 1.2 kgCOD/m3.d showed a removal efficiency of 61% COD. The best reactor performance was observed with an organic loading rate of 2.5 kgCOD/m3.d (or hydraulic retention time of 2.45 d) when a COD conversion of 67% was achieved. The main advantage of using an ABR comes from its compartmentalized structure. The first compartment of an ABR may act as a buffer zone to all toxic and inhibitory materials in the feed and, thus, allows the later compartments to be loaded with a relatively harmless, more uniform, and mostly acidified influent. In this respect, the later compartments would be more likely to support active populations of the relatively sensitive methanogenic bacteria.