This paper describes how two soils were bioremediated in a field-scale land treatment unit and the bioremediation process performance was assessed with respect to reductions in chemical concentration, relative toxicity and chemical mobility. In addition, a batch rate of release (ROR) procedure was used to determine the rate and extent of release of hydrocarbons from the untreated and bioremediated soils.
For one soil containing aged crude oil (Hilbig), no reductions in hydrocarbon concentrations occurred. However, no toxicity and little chemical mobility were measured in the soil. For a second soil containing a fresh diesel fuel spill (Gideon), land treatment reduced both chemical concentrations and toxicity, and the chemicals in the soil exhibited little potential mobility.
Results of ROR studies were used to verify that the chemicals in the Hilbig soil and those remaining in the treated Gideon soil were not available to be released from the soil. Thus, an environmentally acceptable endpoint had been achieved for the Hilbig soil before treatment and for the Gideon soil after land treatment.
Author(s): Raymond C. Loehr, Matthew T. Webster, The University of Texas at Austin
Paper Number: SPE 84916