Regional leachate discharge, monitoring and the associated riverine pollutants propagation model simulation of Sungai Sarawak in Malaysia

The Sarawak River also known as Sungai Sarawak serves as a vital water source for the residents in Kuching City and surrounding popular areas. Like many urban rivers elsewhere, Sungai Sarawak and its main tributaries are exposed to the potential pollution caused by leachate discharge and other pollutants. In order to preserve the cleaner water production, mundane sustainable water source as well as provide green environmental spots for tourist attraction, the water quality of the river needs to be continuously monitored to avoid or minimize potential unwanted water source contamination. The present work aims primarily to conduct a parametric study to predict the impact of leachate and other pollutants towards the water quality of Sungai Sarawak and its main tributaries. Relevant water quality parameters were selected as the indicators to assess the impacts of leachate discharges and other relevant pollutants by employing QUAL2K modelling system. The environmental parameters include DO, BOD, NH3-N, and total suspended solids (TSS) were evaluated. The simulation results illustrated the leachate discharge and other pollutants would not significantly deteriorate the water quality of Sungai Sarawak during normal operations (baseline situation). In the event of unwanted leakages, untreated and sudden release of leachate at Sungai Sarawak Kiri in normal riverine flow (Scenario #1) and low riverine flow (Scenario #2) would result in serious contamination of these rivers. High deterioration of Sungai Sarawak water quality also can be seen in Scenario #3 where the unwanted leakages or untreated and sudden release of leachate at the river mainstem with a low riverine flow which the concentrations of water quality parameters would degrade to Class III-V. The model also shows that three parameters that highly contributed to the deterioration of the baseline water quality based on Scenario #1, #2 and #3 which are BOD, NH3-N, and TSS. The BOD concentration increases by 270% in Scenario #1, 370% in Scenario #2 and 510% in Scenario #3. The NH3-N concentration increases by 390% in Scenario #1, 456% in Scenario #2 and 583% in Scenario #3. The TSS concentration also increases by 275% in Scenario #1, 367% increase in Scenario #2 and 385% in Scenario #3. This study recommends continuous monitoring, proper planning and, control of human activities to ensure that developments within the watershed do not contribute to the degradation of Sungai Sarawak water quality. The study also makes comparisons with other rivers elsewhere and comes up with recommendations in the effort to have more practical and implementable measures as a safety framework for Sungai Sarawak and its tributaries. Lastly, suitable advanced treatment systems such as industrial-scale hybrid membrane-microbial fuel cell systems are recommended for slow-to medium flow rate leachate-riverine treatment applications. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

The Sarawak River, also known as Sungai Sarawak, is a vital water source for residents in Kuching City and surrounding areas, but is threatened by leachate discharge and other pollutants. The study found that in the event of accidental leakages, the water quality of the Sarawak River may be seriously contaminated.