Advances in membrane separation of urban wastewater effluents for (pre)concentration of microcontaminants and nutrient recovery: A mini review

Abstract

This revision work focuses on the recent advances in the separation of microcontaminants from urban wastewaters, using ultrafiltration and Nanofiltration membranes. Conventional systems show advantages such as low pressure and fouling, competitive energetic- and maintenance costs compared to reverse osmosis, and higher rejection rates of organic microcontaminants compared to membrane distillation. However, these rejection rates strongly depend on temperature, flow, and pressure, as well as surface charge and concentration, challenging the adequate treatment of more complex matrices. Recent advances in material science strongly improved the implementation possibilities of different membrane types. In conventional industrial processes and especially in wastewater treatment, offering not only cost reducing solutions for urban wastewaters, but also more efficiency for the remediation of a high variety of industrial wastewaters. Moreover, membrane separation systems show great potential and applicability for added value substance recovery from wastewaters for the agricultural, chemical and consumer industry, for more sustainable natural resources use. Finally, perspectives on promising technologies for the implementation and combination of different membrane separation methods in treatment trains, such as advanced oxidation processes, are given, also aiming for zero-liquid discharge, to prevent microcontaminants and valuable resources from passing through conventional methods and focusing on closing the water cycle.