Impact of Slow-Release Fertilizer and Struvite in Enhancement of Biodegradation in Filter Drains to Prevent Groundwater Pollution

Filter drains are usually laid along the margins of highways and highway runoffs are polluted with hydrocarbons and high levels of total dissolved solids. Hence, effective pollution removal mechanism is necessary in order to avoid contamination of surrounding soils and groundwater. Biodegradation is amongst pollution removal mechanism in filter drains, but is a relatively slow process which is dependent on wide range of factors including the type of pollutant and availability of nutrients. This paper reports on a study conducted to investigate
the performance of slow-release fertilizer and struvite in enhancement of biodegradation of hydrocarbon in filter drains. French drain models incorporated with geotextile were challenged with cumulative oil loading of 17.8mg/m2
/week with a view to comparing the efficiency of these two nutrient sources under high oil pollution loading and realistic rainfall conditions of 13mm/week. Nutrients and street dust were applied at one - off rate of 17g/m2
and 1.55g/rig respectively. The impact of the nutrients was studied by monitoring bacterial and fungal growth using Nutrient Agar, Rose Bengal Agar media and CO2 evolution. EC, pH, Heavy metals, TPH, elemental analysis, SAR were used to investigate water quality of effluent of filter drains for potential application as irrigation fluid. The results show that nutrient application encouraged microbial activities and enhanced biodegradation rates with
differences in type of nutrient applied. Furthermore, it was observed that incorporation of geotextiles in filter drains enhanced pollution retention and there is a potential opportunity for utilization of Struvite in SUDS systems as sustainable nutrient source.