Micropollutant removal from agricultural drainage waters by nanofiltration and reverse osmosis processes

Abstract BACKGROUND The recovery of agricultural drainage water is crucial for sustainable irrigation, but the presence of pesticides and salinity poses significant obstacles to recovery. This study aimed to evaluate the performance of nanofiltration (NF) and reverse osmosis (RO) membranes (NF270, NF90, BW30) in the treatment of synthetic drainage water and, in particular, to elucidate their pesticide rejection mechanisms. RESULTS NF90 and BW30 membranes demonstrated exceptionally high rejection performance (>88%) in the presence of five selected pesticides and salt. Conversely, the NF270 membrane exhibited comparably lower rejection performances, especially for atrazine and imidacloprid. The rejection performance of the membranes was also impacted by the mode of filtration due to different hydrodynamic conditions; the rejection performance improved in the cross‐flow mode of operation. This improvement is attributed to the mitigation of concentration polarization. Process modelling confirmed that a full‐scale RO system could produce high‐quality irrigation water with a temperature‐dependent specific energy consumption of 0.59 kWh m −3 at 20 °C. CONCLUSION While dense membranes offer robust barrier properties, hydrodynamic control is critical for maximizing the performance of loose NF membranes against hydrophobic micropollutants. These findings demonstrate that advanced membrane technologies (NF and RO) can be safely used for recovering pesticide‐ and salt‐bearing agricultural drainage water, which is important to mitigate global water scarcity. © 2026 Society of Chemical Industry (SCI).