Bioremediation of Petroleum Hydrocarbon Contaminated Soil Using Indigenous cultures

Abstract

This research consisted of studying the biodegradation potentialof Total Petroleum Hydrocarbon (TPH) in a diesel contaminated soil using indigenous cultures. From a site investigation conducted on a polluted site in Argentia (Newfoundland, Canada), typical soil profiles and contaminants were determined for helping in setting upon Environmental Test Facility. The potential br bioremediation of soils in that area was studied in the laboratory. Four kinds of cultures were isolated from the petroleum hydrocarbon (diesel) contaminated soil, enriched in the laboratory and incubated in to the soil as a seed to incease the population of cultues. The contaminated soils were incubated in closed reactor at temperatures ranging from 25 to 5 C and pH values from 6 to 8. The addition of mineral salts as nutrients was a h included. Surfactants were used as addition alchernid to enhance the rate ofbioremediation. The degradation of TPH was evaluated by concentration monitoring (Gas Chromatography) and bacteria counting. Temperature effects study showed that biotreatability markediy decreased with decreasing temperature. The optimal rate of bioactivity was obtained in a neutral o r slight acid condition, and suffactant Triton X-100 showed an enhancement of degradation of petroleum hydrocarbon, while the surfactant Tween 60 did not improve degradation. Nutrient requirement was also clearly identified Under optimal condition, the TPH removal efficiency reached 50% of the initial value. Itwas also observeci that bacteria seediag is possible and echances the remediation rate. Surfactants were used to wash diesel out of the contaminateci soils in column tests, Distilled water, 0.5% ( w h ) aqueous solution of surfactant Tween 60 and 0.5% (w/w) aqueous solution of surfactant TritonX-100 were used as leaching solutions. Corresponding TPH remova is were obtained as 5.3%, 21.7%, and 67.8% respectively, demomtrating potential efficiency of combining physical and biologicai remediation methods.