Biodegradation of Diesel Oil in Soil by a Microbial Consortium

Biodegradation of diesel oil was performed using adiesel oil-degrading bacterial consortium, in bothlaboratory and pilot scale experiments. The bacterialconsortium was prepared in liquid for laboratory testsand for pilot scale experiments, it was prepared intwo steps, liquid and then in soil. The concentrationof diesel in soil treated with the bacterialconsortium was reduced to <15% of the initialconcentration, within a period of five weeks in bothlaboratory (135 to 19.32 g diesel kg (soil dryweight)^-1) and pilot scale (118 to 17.5 g dieselkg (soil dry weight)^-1) experiments, incomparison with controls (without bacterialconsortium), in which initial concentration of dieselwas reduced by only 5 and 15%, respectively. Dieselbiodegradation rate with the bacterial consortium was2.13 g diesel kg (soil dry weight)^-1 d^-1, itwas slightly enhanced by the addition ofNH₄NO₃ in the presence of bacterialconsortium 2.78 g diesel kg (soil dry weight)^-1d^-1. The enhancement of the microbial activity inhydrocarbon-contaminated soil can be achieved with thecombination of stepwise soil inoculation and nutrient additions.