Removal of microplastics from wastewater through electrocoagulation-electroflotation and membrane filtration processes

Abstract

Wastewater treatment plants (WWTPs) are one of the major vectors of microplastics (MPs) pollution for the recipient water bodies. Therefore, the recovery of MPs from WWTPs is extremely important for decreasing their accumulation and impact in aquatic systems. In this present study, the electrocoagulation-electroflotation (EC/EF) and membrane filtration processes were investigated in removing MPs from wastewaters. The effectiveness of different electrode combinations (Fe-Al and Al-Fe), current density (10–20 A/m2), pH (4.0–10.0) and operating times (0–120 min) on the removal of two different polymer particles in water were investigated to obtain maximum treatment efficiency. The effect of pressure (1–3 bar) on membrane filtration removal efficiency was also investigated. The maximum removal efficiencies were obtained as 100% for both polymer types with electrode combination of Al-Fe, initial pH of 7, current density of 20 A/m2 and reaction time of 10 min. The membrane filtration method also displayed a 100% removal efficiency. In addition, these laboratory-scale results were compared with the one-year average data of a plant treating with real-scale membranes. The results indicated that the proposed processes supplied maximum removal efficiency (100%) compared to conventional secondary and tertiary treatment methods (2–81.6%) in the removal of microplastics. HIGHLIGHTS One of the few laboratory-scale studies on microplastics removal.; First study on microplastic removal by electrocoagulation.; 1-year average result data for real-scale membrane filtration efficiency.;

Keywords

• electrocoagulation
• electroflotation
• fibers
• membrane filtration
• microplastic
• wastewater treatment