Microplastics Monitoring in an Extended Aeration Sewage Treatment Plant in Malaysia: Abundance, Characteristics, Removal and Environmental Emission

Abstract

Wastewater treatment plants have drawn the attention of scientists as one of the key point sources of microplastics leakage into the environment. This study examined the abundance, characteristics, and removal of microplastics in an extended aeration sewage treatment plant in Penang, Malaysia. During a two-week period, 3 L of influent and 8 L of final treated effluent, were collected from the facility using a stainless-steel bucket. The average microplastic concentration in the influent was 13.75 MPs/L, which decreased to 1.5 MPs/L in the final treated effluent. Despite attaining an average microplastics removal efficiency of 88.67%, the treatment plant still discharges between 2.37 million (2,370,000) and 4.74 million (4,740,000) microplastics per day into a local stream that feeds into the Kerian River. Fibres constitute a significant portion of the microplastic shapes detected in both the influent and effluent, accounting for 52.50% and 58.33%, respectively. The microplastics consisted of polyethylene/ethylene vinylacetate blend (PE/EVA), thermoplastic elastomers (TPE), chlorinated polyethylene (CM/CPE), styrene-ethylene-butylene-styrene (SEBS), and polyacrylamide (PARA). Among these, PE/EVA was the predominant polymer, representing 44.44% in the raw influent and 50% in the final treated effluent.