Microplastic occurrence and characteristics in a municipal wastewater treatment plant in Jakarta

Abstract

Wastewater treatment plants (WWTPs) can act as both a barrier but also as an entrance route for microplastics (MPs) into aquatic environment. This study investigated the first occurrence and characteristics of MPs in Setiabudi Jakarta WWTP. Sampling technique, extraction methods, and quantification as well as characterization of MPs was carried out based on some related previous studies. The results showed that MPs concentration detected in the influent was 17.1 (± 5.65) items/L, and it was reduced to 1.41 (± 0.01) items/L in the effluent, indicating that approximately 91.29% of MPs in raw wastewater was removed during the treatment. Based on the daily effluent discharge, it is estimated that around 352.5 of MPs are released from the WWTP each day. The light microscopic method used for quantification and characterization revealed that MPs was widely distributed in the 100-5000 μm range. The color of MPs in both influent and effluent was mainly composed of white or transparent (35%) and black (17-25.4%). Based on shape category, fibers (68-70.17%) are the dominantly found in two sampling points, followed by fragments (23.68-26.24%), films (0.71-2.9%), microbeads (0.4-1.4%) and foams (1.4-2.8%). Our findings demonstrates that the presence of Setiabudi WWTP can significantly reduce the MPs pollution from raw wastewater, however, MPs discharged into the environment was still considerably high.