Nanofiltration and reverse osmosis processes for the removal of micro-pollutants

Abstract Pressure-driven membrane processes, nanofiltration (NF), and reverse osmosis (RO) are favorable advanced treatment processes for micropollutant removal due to their high micropollutant rejections. An array of complex mechanisms under the influence of process operating conditions involving interactions between micropollutants, water matrix, and membrane contribute to the overall removal of micropollutants in NF and RO processes. The extensive research in this area has contributed to knowledge advancement that has aided process optimization and development of new NF and RO membranes. However, most research is conducted in lab-scale studies, which may not accurately represent the micropollutant rejection behavior and performance at full-scale operation. Long-term full-scale NF and RO systems assessment would be useful to evaluate the fluctuations in feed and operation variables, and to establish the dataset for more accurate model prediction. Continuous effort in systematic research is required to fill the knowledge gap of this dynamic research topic as the list of micropollutants continues to expand with the development of new membrane materials and process operations. Further challenges in the treatment and management of NF and RO concentrates would need to be addressed to provide an overall barrier and to safeguard the environment from potential adverse impacts of micropollutants.