Managing organic pollutant loads in the Lower Cileungsi River, Indonesia

ABSTRACT The regency of Bogor has become the regency with the highest population in Indonesia. The regency's 5.4 million population has been driving increased pollutant buildup in areas like those around the Lower Cileungsi watershed, impacting the quality of the river. This study aims to provide input on pollution control strategies in the Lower Cileungsi River based on the load capacity of pollutants from point and non-point sources. This study modeled total potential organic pollutant loads with existing and critical water flows. Organic pollutant load reductions were also simulated to meet the river water quality standard stipulated by Indonesian Government Regulation No. 22 of 2021 for the river. Monitoring data showed that biochemical oxygen demand (BOD) and dissolved oxygen (DO) concentrations in the river did not meet the standard, placing the river water quality status as slightly polluted with an average pollution index value of 2.57. The total potential BOD load from all sectors was 32,851.65 kg/day, exceeding the river's capacity by 21,785.6 kg/day. The modeling suggested reductions in BOD load by 87% for industries, 90% for lake outlets, 60% for domestic, and 20% for agriculture. No BOD reduction is required in the livestock sector.