The development of an action plan for the Jeneberang River pollution control based on the calculation of the total maximum daily load

Abstract

Jeneberang Watershed is one of the priority watersheds set by the Ministry of Environment and Forestry in the Sulawesi Island region and is the location of various important economic activities that contributes around 2% to the national gross domestic product (GDP). The results of water quality monitoring in 2018 and 2019 show that the average water quality status of the Jeneberang river was moderately polluted. This study aimed to develop an action plan for water pollution control derived from the calculation of the total maximum daily load (TMDL) to meet the river water quality standard. The method used in this study was the application of a numerical model of water quality combined with the spatial approach for calculating the TMDL. The calculation results indicated that the load of existing pollutants entering the Jeneberang river was 4,844.87 kg- BOD/day while the TMDL was 3,552.97 kg-BOD/day, therefore a load reduction of 1291.9 was required. Furthermore, it was necessary to reduce the water pollution load from domestic, industrial, and livestock activities by 871.37, 14.86, 337.28 kg-BOD/day, respectively, and from the combination of agriculture and built-up land by 68.39 kg-BOD/day. The action plan resulting from the development of TMDL is the construction of 122 units of communal sewage treatment plant with a budget of IDR 121.86 billion and 350 units of biodigester with a total budget of IDR 7.35 billion. Meanwhile, 46 inspectors and a budget of IDR10 billion per year are required to supervise industries. Thus, the study revealed that TMDL can be used as the basis for the development of an action plan.