FACTORS AFFECTING THE NONIONIC SURFACTANT-ENHANCED BIODEGRADATION OF PHENANTHRENE

This research addresses the influence of nonionic surfactants on the b iodegradation of poorly soluble organic compounds in soil and water. B atch- and continuous-flow column biodegradation studies of phenanthren e were carried out in the presence of four commercial nonionic surfact ants at sub-critical micelle concentration (CMC). Surfactants were tes ted to determine their effectiveness in solubilizing phenanthrene, the ir sorption-desorption characteristics to soil, their biodegradability , and their effect on the adsorption and biodegradation of phenanthren e. Solubility enhancement of phenanthrene by the surfactants was mainl y a micellar phenomena. Sorption of phenanthrene and the surfactants c ould be represented by a linear isotherm model. Sorption of phenanthre ne to soil was enhanced significantly in the presence of the surfactan ts. A mixed enriched microbial culture acclimated to phenanthrene as t he sole organic carbon source was used as the inocula. Biodegradation experiments indicated that low surfactant concentrations promoted mine ralization of phenanthrene without inhibitory or toxic effects. The st udy indicates that surfactant selection for in situ bioremediation pur poses will depend on a number of factors, with main emphasis on its hy drocarbon solubilizing power, sorptive properties, low toxicity to bac teria, and fate in the environment.