The Use of Surfactants as Possible Enhancers in Bioremediation of Creosote Contaminated Soil

A study on five nonionic surfactants (Arkopal-N-060, Arkopal-N-080, Arkopal-N-100, Hosaf-541-KS and Tween-80)commercially available in South Africa was carried out todetermine their effect on the desorption and degradation ofcreosote in a soil contaminated with 250 000 mg kg^-1creosote with a view to developing a cost effective methodologyfor treating creosote contaminated soils. The surfactants werestudied in concentrations of 0.01, 0.1, 0.35, 0.5 and 1.0% (v/v) in liquid cultures. Results from the studies showedthat all the surfactants studied were able to enhance thedesorption and degradation of creosote to different extents. Theenhancement ranged from as little as <10% in 0.1% surfactant toas high as 45% in 0.5% surfactant. The effect on degradation ofcreosote was more obvious (30–65%) in the different surfactantsat different concentrations. Arkopal-N-060 was observed to be themost effective in the desorption and degradation of creosote. Theeffect of Hosaf-541-KS on the degradation of creosote was foundto be comparable with those of Arkopal-N-060, however, itsdesorption capabilities were much lower than those of Arkopa-N-060.The concentration of the surfactant was found to play asignificant role in desorption of creosote. It was observed thatsurfactant concentrations of 0.35 and 0.5% were the mosteffective in the desorption of creosote. Above and below theseconcentrations, the effect of the surfactants was observed todecrease. All surfactants studied were not found to inhibitmicrobial growth at the concentrations studied.