SIMULTANEOUS SPILLS OF DIESEL AND ETHANOL — A CONTROLLED-RELEASE EXPERIMENT

Natural attenuation was investigated in a controlled release experiment to simulate simultaneous spills of ethanol and diesel in Florianópolis, Santa Catarina, Brazil. Results of four field-monitoring campaigns indicate that the highest aqueous ethanol concentration was on the order of 10,000 mg/L, which suggests that cosolvency is not enhancing the solubilization of BTEX and PAHs in the aquifer. After 18 months since the beginning of the spill, the concentrations of BTEX and PAHs are still increasing near the source zone and most of the ethanol was biodegraded. However large concentrations of acetate in the area caused a decrease of one order magnitude in pH. The presence of large concentrations of acetate and methane in the experimental area indicate that BTEX and PAHs degradation is being hindered by the presence of ethanol and its biodegradation products.