Critical review of fouling mitigation strategies in membrane bioreactors treating water and wastewater.

The current research was an effort to critically review all approaches used for membrane fouling control in the membrane bioreactors treating water and wastewater. The first generation of antifouling methods tried to optimize operational conditions, or used chemical agents to control membrane fouling. Despite their positive impacts on the fouling mitigation, these methods did not provide a sustainable solution for the problem. Moreover, chemical agents may affect microorganisms in bioreactors and has some environmental drawbacks. The improved knowledge of membrane fouling mechanism and effective factors has directed the attention of researchers to novel methods that focus on disrupting fouling mechanism through affecting fouling causing bacteria. Employing nanomaterials, cell entrapment, biologically- and electrically-based methods are the latest efforts. The results of this review indicate that sustainable control of membrane fouling requires employing more than one single approach. Large scale application of fouling mitigation strategies should be the focus of future studies.