Electrocoagulation for Microplastic Removal: Quantification, Electrode Consumption, and Sludge Production

Abstract

The presence of microplastics (MPs) in liquid effluents has drawn increasing scientific concern owing to their ecological impacts and the limited efficacy of conventional treatment technologies. Electrocoagulation (EC) has emerged as a promising alternative for MP removal; however, few studies have addressed three practical aspects critical to scale-up: MP quantification, electrode consumption, and sludge generation. This study evaluates (i) the effectiveness of a mass-versus-turbidity approach for MP quantification, (ii) iron (Fe) electrode wear, and (iii) the concentration of EC-generated sludge. A synthetic effluent containing graded doses of polystyrene (PS) was treated in a previously optimized EC system using a 15-run experimental design with replication. The turbidity-based calibration showed an excellent linear relationship with MP mass (R2 = 0.997), supporting turbidity as a reliable surrogate for MP concentration. Under optimal operating conditions, Fe electrode consumption was 0.122 kg m−3, and sludge production was 0.619 kg m−3. These results provide actionable metrics for process design and cost estimation. Future work should include comprehensive physicochemical and toxicological characterization of the generated sludge to inform valorization and potential reuse pathways.