Biokinetic Study of a Laboratory-scale Fluidized Bed Bio Reactor for the Treatment of Industrial Wastewaters

Abstract

Industrial wastewaters with high biodegradable organic loads require treatment systems capable of retaining active biomass and maintaining effective mass transfer. This study evaluated a laboratory-scale fluidised-bed bioreactor (FBBR) using three support materials: commercially available moving bed biofilm reactor (MBBR) plastic media, pumice stones and high-density foam pieces. Wastewaters representing fish-processing, biodiesel and domestic sources were examined. Influent and effluent samples were analysed for biological oxygen demand (BOD) and chemical oxygen demand (COD), and microbial growth kinetics were assessed through the microbial decay coefficient kd. Samples were collected at operating times of 30, 60 and 90 min, and the acclimatisation periods for the plastic media, pumice stones and foam pieces were 15, 14 and 12 days, respectively. At 90 min, high-density foam produced BOD removal efficiencies of 85.25%, 87.39% and 85.03% for fish-processing, biodiesel and domestic wastewater, respectively. The corresponding COD removal efficiencies were 81.42%, 80.39% and 78.51%. The decay coefficients varied with wastewater type and support material, indicating that microbial behaviour was influenced by the tested operating conditions. Under the laboratory conditions used, foam pieces generally provided higher BOD and COD removal than the other media and required the shortest acclimatisation period. These findings support further condition-specific evaluation of foam as an alternative FBBR support material.