ENHANCING BIODEGRADATION OF PETROLEUM-HYDROCARBONS WITH GUANIDINIUM FATTY-ACIDS

Bioremediation of hydrocarbon-contaminated soils is an attractive proc ess for treating contaminated soils because it converts contaminants i nto harmless byproducts at low cost. However, the process is slow and typically requires months to years to reach regulated end points. In l aboratory studies, we have been able to improve the process by adding selected guanidinium fatty acids to the contaminated soils. One of the se materials, guanidinium cocoate, was synthesized from coconut acid a nd guanidine carbonate in a facile one-step process. Rates of biodegra dation enhancement of nonvolatile hydrocarbons were evaluated using ei ther oxygen and carbon dioxide respirometry in soil slurries or period ic measurements of extractable hydrocarbon residues in unsaturated soi l microcosms. Results show rate enhancements in both soil slurries and unsaturated soil microcosms when these systems were treated with 500- 1500 ppm of the surfactant. Adding small amounts of CGS to a silty cla y soil containing aged lubricant-type hydrocarbons increased rates of hydrocarbon disappearance, mineralization, and oxygen utilization in u nsaturated soil and soil slurry systems. Based on these initial invest igations, doses of approximately 2 Ib of CGS/t of soil appear effectiv e at increasing rates of biodegradation.