Studies on the treatment of an industrial pharmaceutical wastewater in a submerged membrane bioreactor

Abstract

Environmental awareness among the people of several well developed and developing countries have forced the various governments to continuously evolve and implement stringent effluent standards for disposal. Hence, newer technologies like the application of membrane separation (micro or ultra filtration) technique coupled with biological processes (known as membrane bioreactor ? MBR) were developed, having several distinct advantages over the conventional treatment process/(es). The last decade witnessed a tremendous growth in the use of MBR. However, critical review of literature has revealed that the MBR technology is very scarcely used for the treatment of recalcitrant nature of effluent (ie., pharmaceutical wastewater). Hence, in this study an industrial pharmaceutical wastewater was considered for treatment using a (submerged) membrane bioreactor. Extensive laboratory investigations were carried out using a commercially available membrane (ZENON make; pore size ? 0.04 µm and made of a polymeric material) for studying the treatment efficiency of an industrial pharmaceutical wastewater (obtained from a company manufacturing ?analgesic? drug). Chemical Oxygen Demand (COD) removal (%) was obtained by operating the MBR under various organic loading rates (OLRs) ranging between 0.277 to 36.57 Kg.COD/m3.d, hydraulic retention times (HRTs) ranging from 24h to 4h without and with bioaugmentation. Mathematical models based on already published literature were used to predict the biomass concentration and slowly biodegradable substrate concentrationThe results from the mathematical models were validated with experimental data. Some of the significant parameters of the treated wastewater were compared with those of the National and International standards for disposal of effluent, to assess the overall performance of the MBR treatment process. Based on extensive experimental investigations and mathematical model studies, it is concluded that (i) the bioaugmentation process adopted in the MBR