Microplastics removal from urban WWTP through microfiltration

The production of reclaimed water for aquifer recharge or upstream discharge has gained interest as an alternative to tackle increasing hydric stress worldwide. In line with the European Reused Water Regulation 2020/741, which anticipates microplastics (MPs) regulation by 2028, this work aims to assess the effectiveness and the operational performance of three microfiltration membranes -with different spacer thickness and shapes- for the removal of microplastics within a wastewater treatment plant (WWTP) to avoid their release into water bodies. Sampling points upstream (i.e. Pretreatment effluent) and downstream (i.e. WWTP effluent) from a WWTP were used to assess whether the microfiltration should be used as an intermediate treatment or as a polishing technology. Results showed that although microfiltration membranes were capable to effectively reject microplastics, the permeate flux reduction was significantly lower when it is used as polishing technology, thus enlarging the membrane element lifespan. In addition, the membrane with corrugated spacer (V0.2-5CB-1812F) showed the best performance in terms of initial flux and flux reduction along the filtration experiments. This work highlights the feasibility of using microfiltration for the prevention of microplastics release into water bodies from WWTP, but further studies are needed to assess the long-term performance of the membrane elements.