Assessing the removal of microplastics, nanoplastics, and tire derived contaminants using chemically enhanced primary treatment

This study assesses the performance of chemically-enhanced primary treatment (CEPT) for removing micro- and nanoplastic contaminants from surface water and wastewater influent under different treatment conditions and varying environmental factors. Four contaminants were tested including polyester microfibers, polyethylene microspheres, tire crumb rubber, and polystyrene nanoplastics. Alternative coagulants, including ferric sulfate (FS) and aluminum chlorohydrate (ACH) improved treatment under conditions that were challenging for alum (pH > 8). In wastewater at pH 7, FS and ACH effectively removed tire crumb rubber (83% and 93%, respectively) compared to alum (27%). FS was an effective coagulant for treating surface water at pH 8.5 with high removal across all micro-sized plastic contaminants. Jar tests also showed that environmental factors such as the presence of laundry detergent and UV-irradiation impacted the extent of plastic contaminant removal. The highest nanoplastic removal were observed using alum (51%; pH 8.5; wastewater) and ACH (83%; pH 7; surface water). Results from this work offer new insights into the impact of treatment conditions, environmental factors, and plastic type and morphology on the performance of CEPT in plastic contaminant removal.