USING HYDRODYNAMIC MODEL TO UNDERSTAND MICROPLASTIC DISTRIBUTION IN JATILUHUR RESERVOIR

• Main Author: Hikmahtiar Ramadan, Attar
• Format: Theses
• Language: Indonesia
• Subjects: Teknik saniter dan perkotaan; teknik perlindungan lingkungan
• Online Access: https://digilib.itb.ac.id/gdl/view/46984
• Institution: Institut Teknologi Bandung

Jatiluhur, as one of the biggest freshwater reservoir in Indonesia, has the potential to be polluted by microplastics. 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 Reservoir has a high indication 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 microplastic distribution pattern in order to overcome microplastic pollution which occurs in Jatiluhur Reservoir, a study of microplastic abundance is conducted and modelling. Primary data is obtained by using the volume reduced sampling method, and the results are presented as the microplastic amount in water. 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 0.71x104 – 4.59x105 particles/km2. The most type of microplastic found is fragmented polyethylene (PE). The modeling was conducted in hydrodynamic modeling using the MIKE 3 program and continued with particle tracking with the Lagrangian principle. Simulations in this study were conducted for 5 months in May - October 2019. The assumptions of this modeling are in 2D. Modeling is done in 2 types, there are PE and PP microplastic modeling and theoretical modeling for microplastic types other than those found in water samples of Jatiluhur Reservoir. Based on the results of calibration tests and validation of microplastic models in water using the analysis of Root Mean Square Error (RMSE) and Relative Error (RE) analysis on average, the results obtained with variations of 0.05 m2/s (RMSE 0.55 and relative error 100 , 62%), 0.1 m2/s (RMSE 0.50 and relative error 96.23%), 0.2 m2/s (RMSE 0.42 and relative error 77.85%) and 0.5 m2/s (RMSE 0.44 and relative error 79.64%). Based on these results, it can be seen that the model value closest to the field data is simulation using a dispersion coefficient of 0.2 m2/s. Modeling results for other types of microplastics indicate that PS, PET and PVC have a tendency to be more sedimented and limited in horizontal distribution. In addition, the results of modeling shows that microplastic hotspots at several reservoir points. This results can be use as consideration to locate the intake of cleanwater treatment plant and the fishnet (KJA) of fisheries industries in Jatiluhur Reservoir.