Microplastics (MPs) have been detected in drinking water and raw water sources. Therefore, it is important to know the performance of drinking water treatment process. The rapid sand filter (RSF) is one of the water treatments that can be an alternative treatment in removing MPs after several configuration processes (pre-sedimentation, coagulation-flocculation, and sedimentation). This study aims to determine the effectiveness of RSF to remove MPs. The artificial samples were made from plastics bags and tyre flakes, with sizes from 10 μm to more than 500 μm. Bentonite was added to represent turbidity in the water. The average removal efficiency of plastics flakes before entering the filter was 50.48% (using bentonite) and 47.78% (without bentonite). Overall, the removal efficiency for the tyre flakes was 90.72% (using bentonite) and 93.03% (without bentonite). The filtration used in this study was varied between 4 and 10 m/h. Removal efficiency using RSF for plastic flakes on which the Effective Size (ES) filter media 0.39 mm was 97.7% and on which ES 0.68 mm was 94.3%. Meanwhile, the removal efficiency of the tyre flakes for ES 0.39 mm were 90.6% and ES 0.68 mm was 85.2%. However, in this study, RSF mostly removed MPs particles greater than 200 μm in size.

Microplastics have been found in all hemispheres of the world. However, studies on microplastics are mainly conducted in Europe, North America, and East Asia. Few studies are reported in the Southeast Asian region, where a large number of plastic waste is disposed of improperly into the water. This study investigated the abundance and characteristics of microplastics in the surface water of the Chao Phraya River (Thailand), Citarum River (Indonesia), and Saigon River (Vietnam). Samples were collected at urban and estuary zones of these rivers. The numbers of microplastics at the urban zones were 80±60, 12±6, and 68±20 items/m3 at the Chao Phraya, Citarum, and Saigon River, respectively. At the estuary zones, the numbers of microplastics were 48±8, 0±0 (0.08±0), and 42±5 items/m3 at the Chao Phraya, Citarum, and Saigon River, respectively. Microplastics with morphologies of fragments and fibres were mainly found in the rivers. Polypropylene and polyethylene particles were the most abundant in all collected samples. Since the selected rivers play important roles in water supply and aquaculture activities, the presence of microplastics in these rivers may negatively impact aquaculture and human health. Potential plastic management strategies to minimize microplastic problems in the selected rivers were also proposed in this study.

Microplastic is generally defined as synthetic polymers which size less than 5 mm. Based on the latest research, microplastics pollutions have many impacts on the environment and human. Jatiluhur, as one of the biggest freshwater reservoir in Indonesia, has potential to be polluted by microplastics because the water source of this reservoir streamed from Citarum watershed. Citarum River is one of the most polluted river in Indonesia. To find the occurrence of microplastics and to facilitate future policies in order to overcome microplastic pollution which occurs in Jatiluhur Reservoir, a study of microplastic abundance is conducted. Primary data is obtained by using the volume reduced sampling method. Manta trawl is pulled beside a boat for 5 -15 minutes for each sample and flow meter installed onto the mouth of manta trawl to determine the towing distance in surface water. Microplastic abundance in surface water presented in the form of microplastics amounts per unit surface area. Furthermore, microplastic characteristics analyzed with visual analysis, particle density analysis, and polymer analysis using FTIR. Based on seven sampling locations, microplastics have found in Jatiluhur Reservoir ranging from 0.71×10⁴ – 4.59×10⁵ particles/km². The most type of microplastic found is fragmented polyethylene.