Anaerobic-aerobic treatment of distillery wastes

Abstract

In this study an attempt has been made to find a solution to the problem of disposal of distillery effluents through anaerobic followed by aerobic treatment. Accordingly, experimental studies were planned and carried out in two phases. The first phase experimentation was conducted to study the performance of Semicontinuous Fixed Film Anaerobic Reactors (SCFFAR) which simulate Downflow Stationary Fixed Film anaerobic reactors (DSFF) for partial treatment of distillery waste. Second phase experimentation included studies on degradation of anaerobically treated effluent employing semicontinuous aerobic reactors with sludge recycle. The results indicated that the distillery waste should be diluted to bring down the COD to about 50 000 mg L⁻¹ before the same is treated by stationery fixed film anaerobic reactors and this dilution can be achieved by circulating the treated effluent. Further the reduction of COD beyond 9000 to 10 000 mg L⁻¹ by anaerobic treatment appears to be uneconomical. Results of second phase of the study show that the aerobic degradation of anaerobically treated effluent can achieve significant COD reduction (approx. 67%). However, reduction of COD of final effluent below 500 mg L⁻¹ appears to be very difficult. The settling characteristics of the sludge produced in aerobic study depended on the BSRT value and improved with increase in BSRT.