Efficiency of a microplastic removal system from synthetic wastewater using a chemical process combined with simple...

Microplastic contamination in freshwater ecosystems poses a critical environmental challenge, necessitating effective removal technologies in wastewater treatment. This research aims to evaluate the efficiency of a hybrid removal system for polyethylene microplastics (particle sizes 0.15-1 mm) by integrating chemical coagulation with simple sand filtration. The performance of three coagulants-alum, polyaluminium chloride (PAC), and ferric chloride-supplemented with chitosan as a coagulant aid, was optimized across various dosages and pH levels, followed by the evaluation of a sand filter column under different flow rates. The results indicated that coagulation efficacy was pH-dependent, peaking at pH 7, where PAC achieved the highest removal efficiency of 77.41 ± 4.47% for fine 0.15 mm particles, followed by alum (73.22 ± 3.54%) and ferric chloride (63.18 ± 3.63%); notably, the combined system operating at a flow rate of 15 mL/min (Experimental Set 1) attained an exceptional overall removal efficiency of 99.93%. These findings demonstrate that coupling chemical coagulation with low-cost sand filtration offers a robust and scalable solution for significantly reducing microplastic discharge in synthetic wastewater applications.