INSTALLATION OF BENCH SCALE ANAEROBIC FLUIDIZED BED REACTOR : FEASIBILITY STUDIES

Abstract

In the.fifties and sixties aerobic processes were very popular in biological treatment of wastewaters. Increasing energy costs of aerobic treatment systems stimulated interest in anaerobic treatment as an energy producing treatment technology. Conventional anaerobic digestors require higher HRTs resulting in large volumes and higher costs. With the advent of High rate Anaerobic reactors viz., upflow Anaerobic filters, upflow Anaerobic sludge Blanket (UASB) reactors, downflow Anaerobic fixed film reactor and Anaerobic fluidized bed reactors it has been become possible, to reduce HRTs and costs. The upflow anaerobic filters though simple in construction and operation suffers from clogging resulting in short circuiting, and non uniform effluent quality. The down flow stationary fixed film systems suffers from low surface area to volume ratio and lower efficiencies at low organic loadings due to improper mixing. Though the performance of UASB is good at higher organic loadings, its performance with low strength waste water and low loadings has been reported to be hampered due to non pellatization because of low gas production which results in the formation of filamentious sludge affecting the effluent quality. Present studies o Anaerobic fluidized bed reactor using wastewater (Dilute Molasses) having COD of 600 mg/1 (falling in the range of the effluent of first stage anaerobic treatement of sugar mill waste) have shown removal efficien-cies of 78, 81.5 and 84% at HRT of 6,9 & 12 hrs. In the cost analysis Anaerobic fluidized bed reactor has been found