Nutrient Dynamics and Recovery Potential In The Tukad Badung River, Indonesia

Abstract

This study explores the spatiotemporal variations in nitrogen and phosphorus pollutants in the Tukad Badung River, an essential water source for Bali's communities, increasingly impacted by agricultural, domestic, and industrial discharges. Bi-daily sampling at six strategically selected sites along the river's 18-kilometer stretch revealed substantial fluctuations in water quality, with downstream sites consistently exhibiting elevated pollutant concentrations. Ammonia concentrations varied from 1.5 to 4.2 mg/L, nitrate levels ranged from 5.0 to 11.6 mg/L, and total phosphorus concentrations spanned 0.5 to 2.5 mg/L, all of which were highest during afternoon sampling, likely due to reduced flow and increased anthropogenic inputs. Total suspended solids (TSS) exhibited temporal and spatial variability, ranging from 80 to 127 mg/L, with the highest concentrations observed at midstream sites, suggesting localized sedimentation from human activities. The nutrient dynamics displayed marked temporal variations, with concentrations rising during afternoon hours, reflecting shifts in human activity and changes in river flow conditions. Furthermore, the study assessed nutrient recovery technologies, such as precipitation and adsorption, which were able to recover up to 80% of extractable nutrients. These findings not only characterize the pollution trends but also highlight the potential of nutrient recovery techniques in reducing dependency on synthetic fertilizers. This research emphasizes the need for integrated watershed management and adaptive recovery strategies to mitigate nutrient pollution and enhance the sustainability of river ecosystems for future generations.