Membranes for the water biotreatment

Membranes are efficiently used as advanced treatments to conventional activated sludge (CAS) processes. In particular, membrane biological reactors (MBRs) combine the biological treatment of CAS and the filtration action of membranes in one-unit operation, thus providing an alternative to the sequential application of membrane separation downstream of conventional biological treatment. The MBR technology has many advantages over the traditional CAS processes, including reduction of required reactor size and footprint. However, MBR also presents greater operational issues and higher costs, both related to membrane fooling. In fact, membrane fouling still represents the major drawback of MBR technology; for this reason, fouling limitation and prevention strategies must be implemented when designing an MBR plant. One of the most common strategies includes the optimization of some key operation parameters, especially regarding aeration. However, since aeration is one of the most expensive aspects of MBR technology, a future challenge is the implementation of economically sustainable fouling mitigation and control methods which can make MBRs more and more competitive with traditional CAS processes.