Removal process of nutrients and heavy metals in tropical biofilters

Biofilters are relatively new pollution control technology used to treat urban stormwater runoffs. Biofilters generally consist of vegetated top soil layer for nutrient uptake and sand-based filter media for heavy metals filtration. While the complex process of pollutant removal is studied for a temperate environment, only a few studies have been conducted under tropical climate conditions. This study aims to study the removal process of total nitrogen, total phosphorus and 6 heavy metals including copper, iron, manganese, nickel, lead, and zinc in a tropical biofiltration system. In this study, using the curve fitting analysis, the parabolic function was found to be the most fitted function to explain the relationship between pollutant concentration in the effluent and the infiltration rate of the system when the first flush phenomenon is simulated. Results demonstrated that the natural variation of infiltration rate during the saturation process of soil influences the performance of the system in removing some pollutants such as phosphorus, iron, and zinc.