Water Quality of Water Treatment Plant for Daily Usage in Serpong, Indonesia: Evaluation of Microplastic Characteristics and its Removal Efficiency

Microplastics have been detected in raw water sources, including rivers and water treatment plants (WTPs), which rely on these rivers for their supply. This study aims to assess the characteristics of microplastics, such as their shape, size, abundance, and material composition, and to evaluate their removal efficiency using WTP. Specifically, this research focuses on the WTP in Serpong Indonesia, which sources its water from the Cisadane River (CDR). Sampling was conducted at several main locations, including the CDR, critical points within the WTP, and end-user areas such as residential and office environments. Raw water from the Cisadane River for the WTP Serpong contains fiber and fragment forms of microplastics with nearly equal distributions (51% and 49%, respectively). Fiber-shaped microplastics predominantly measure 1000 and 5000 µm and are primarily identified as polyethylene terephthalate. Conversely, fragment-shaped microplastics, typically ranging from 100 to 500 µm in size, are commonly polyethylene and polypropylene. The highest microplastic removal efficiency (MRE) was observed during the preliminary stage of the WTP process, with a removal rate of 51%, followed by the coagulation-sedimentation stage, contributing an additional 44% removal efficiency. The rapid sand filtration stage accounted for a reduction of 4%. Overall, the entire WTP process achieved an overall MRE of 94%. These findings highlight the effectiveness of conventional WTP technology in microplastic removal, with the preliminary stage and coagulation-sedimentation being the most significant processes.