BIODEGRADATION OF ANIONIC SURFACTANTS IN THE PRESENCE OF PETROLEUM CONTAMINANTS

Remediation of petroleum contaminated soils by surfactant cleaning is becoming an attractive option. Surfactants used for cleaning petroleum contaminated soils are biodegradable. Even though there has been cons iderable experimental and field work done on biodegradation of surfact ants, very little effort has been devoted to the study of biodegradati on of surfactant in the presence of hydrocarbon contaminants. The prob lem of surfactant biodegradation in the presence of petroleum contamin ants is addressed in this paper. Experimental study consisted of condu cting biodegradability tests for different concentrations of anionic s urfactants in the presence of petroleum contaminants. The effect of su rfactant concentration on microbial growth and biodegradability was al so investigated. It was found that the change in surfactant concentrat ion from 1% to 4% did not inhibit microbial growth or surfactant biode gradation. Experimental runs were conducted to determine the surfactan t biodegradation in the presence of kerosene. Experiments conducted wi th 5% and 10% kerosene with 1% surfactant solution indicated that kero sene degraded faster than anionic surfactant. Kerosene degraded along with surfactant but microbial communities seem to prefer to degrade ke rosene rather than surfactant. Experiments were conducted to examine t he effect of the soil-water system on surfactant biodegradability. It was found that the presence of surfactant enhances the biodegradation of the petroleum contaminant itself Thus, a synergestic process is obs erved.