The project site had suffered a significant diesel leak from underground infrastructure, resulting in about 1 million litres of boiler-grade diesel collecting as a Light Non-Aqueous Phase Liquid (LNAPL) in a sandy gravel aquifer approximately 4 metres below the surface.
EESI Group was employed to install an insitu bioremediation system to degrade the remaining diesel entrapped within the pores of the aquifer. The chosen approach involved enhancing the stimulation of naturally adapted alkane degraders. Nutrient and calcium peroxide were emplaced in socks in upgradient wells or wells in and around the infrastructure. Additionally, surfactant and nutrient-enriched water were injected into other wells and infiltration galleries, depending on the contaminant location and installation ease. The project included monitoring of wells, experiment design, soil sampling across various variables, and comprehensive assessment and statistical analysis of the data.
The bioremediation project at Rio Tinto successfully managed the diesel contamination. Despite fluctuations in the water table, which could potentially cause TPH (Total Petroleum Hydrocarbons) rebound, no significant recontamination was observed after three years of injection and water table variation. This success illustrates EESI's expertise in handling complex environmental challenges and implementing innovative bioremediation techniques effectively in challenging conditions.
The Environmental Earth Sciences International Group acknowledges the Traditional Custodians of country throughout Australia and their connections to land, sea and community. We pay our respect to their Elders past, present and emerging and extend that respect to all Aboriginal and Torres Strait Islander peoples today.
