Enhancing the removal efficiency of microplastics in drinking water treatment

Microplastics (MPs) have been commonly detected in aquatic environments, however, the effectiveness of most drinking water treatment plants (DWTPs) in removing MPs is limited. The primary objective of this study was to investigate the efficacy of modified starch and traditional coagulants (PAC + PAM) in removing MPs through coagulation, followed by the application of biochar filtration for further removal of MPs present in the effluent from the coagulation process. The removal efficiency of MPs by modified starch / PAC + PAM was >80 %. Moreover, the incorporation of modified starch demonstrated a reduction in PAC coagulant dosage requirements. The main mechanism of modified starch was electrical neutralization, while the combination of modified starch with PAC + PAM effectively could utilize electric neutralization, adsorption bridge, and net sweep mechanisms. The MPs present in the coagulation effluent could be effectively eliminated by biochar, exhibiting a removal efficiency surpassing 90 %. And the coagulation-filtration process exhibited an exceptional efficacy in removing MPs, with removal efficiency reaching as high as 97 %.