Developments in membrane bioreactor technologies and evaluation on case study applications for recycle and reuse of miscellaneous wastewaters

Abstract Membrane bioreactor (MBR) systems are developed as an alternative technology to conventional activated sludge systems. In these systems, the final settling requirement in the conventional activated sludge process is eliminated by an integrated filtration system. The MBR system consists of a combination of activated sludge process with micro or ultrafiltration technologies. When this technology is used for landfill leachate treatment beside the municipal and industrial wastewater treatment, it allows the reuse of water treatments due to the high output water quality. First generation type MBRs, used for the treatment of municipal or domestic wastewater in urban, had been used mostly to treat very small flow rates, the regions’ wastewater not connected to sewer system and to recycle and reuse of wastewater. Second generation type MRBs has been activated as a result of increase in the first generation applications and technological developments. The most important characteristic of it is that the addition of nitrogen and phosphorus removal features compared to the first generation type. The main objective of the third generation type MRBs which had been to increase membrane flux and capacity, are to reduce the solids retention time and biomass and to optimize the total cost. Nowadays, when we consider applicable system capacities, there is a development toward fourth generation type MRBs. The last few years, when constructed or under construction MBRs were considered, it is shown that there is an increase in the number of MBRs not only in terms of total number but also the large-scale MBRs treated the wastewater which has different characteristics and large volume. So, in this study, MBR applications were compared with conventional activated sludge system and then sector-specific evaluations were done. Twelve different applications were evaluated such as textile, leather tanning, pulp and paper, pharmaceutical, dairy, wine, petrochemical industries wastewater treatment, respectively. When all these applications are evaluated in terms of wastewater recycling and reuse, it is concluded that the treatment of all wastewaters which have both complex/high pollution and moderate pollution with MBR technology, was found more effective than the conventional system and the water treated with this system is reusable for all type of industrial application.