Analytical Modeling for Water Chemistry Changes in River Bank Filtration Systems

Abstract

Riverbank filtration system is considered one of the economic and sustainable solutions to river water pollution especially in tropical countries such as Malaysia. In this work, an analytical model is developed to simulate the contaminant attenuation in riverbank filtration systems by using the separation of variables method. The basic aim of the model is to understand the role of microbial activity that occurs in riverbed sediments on reducing the concentration of the contaminant in the aquifer and changing the water characteristics. Graphically, it is found that the model can simulate the infiltration process of polluted river water effectively. Also, the analytical model results, as well as experimental data, show that nitrate (18.6 and 34.1 mg-NO3/L) and sulphate (20.9 – 22.1 mg-SO4/L) can be consumed by bacteria in the first 0.5 m of the aquifer, and reduced by more than 95% for both compounds. The model is applied for the first riverbank filtration system in Malaysia. Sensitivity analysis results highlight the importance of dissolved organic matter (DOM) concentration (ranged from 1.0 to 12.4 mg/L) for RBF efficacy in which a higher concentration of DOM leads to faster consumption of pollutants.