Extractive membrane bioreactor (EMBR) for industrial wastewater treatment: From theory to practice

Abstract

The wastewaters generated from industrial source contain several organic and inorganic compounds which may pose serious hazardous effects to human health and aqua life. Among various wastewater treatment techniques, extractive membrane bioreactor (EMBR) is deemed as one of the promising technologies because of its perm-selective removal of pollutants from hostile wastewater. This review provides an insight into the past and present EMBR systems for treatment of industrial wastewaters. Earlier polydimethylsiloxane (PDMS) membranes employed in EMBR suffered significant mass transfer resistance due to increased membrane thickness. However, with the development of membrane technology, thin film composite (TFC) membranes showed remarkable increment in removal of variety of organic compounds due to unique surface features of membranes. Despite the excellent performance of TFC membranes in EMBR, biofilm formation on membrane surface remains a challenge to scale up the EMBR technology at industrial scale. In this review, together with the working principle of EMBR, the effects of EMBR components including wastewater unit, membrane and bioreactor (receiving unit) affecting mass transfer of organic compounds have been discussed in detail. Subsequently, the review provides progress and development on membranes from commercial PDMS to TFC potentially applied in different EMBR configurations for hostile wastewater treatment. In addition, the challenges, and perspectives of EMBR are discussed.