Potential of bioaugmentation and biostimulation for enhancing intrinsic biodegradation in oil hydrocarbon-contaminated soil

Studies were conducted using a 10-chamber Micro-Oxymax (Columbus, OH, USA) respirometer to determine the effect of bioaugmentation and biostimulation (by diverse ways of O 2 supply) on enhancing biodegradation of oil hydrocarbons to reduce risk at a former military airport in Kluczewo, Poland. Indigenous or exogenous bacteria bioaugmentation was used to degrade hydrocarbons. Aerated water and/or aqueous solutions of H 2O 2 or KMnO 4 were used to supply O 2. The intrinsic and enhanced biodegradation was evaluated by the O 2 uptake and CO 2 production rates obtained using a linear regression of the cumulative O 2 uptake and CO 2 production curves. Generally, in all cases biodegradation rates enhanced by bioaugmentation were two to four times higher than the rates of intrinsic biodegradation. Moreover, application of indigenous bacteria was more efficient in comparison to the exogenous consortia. The highest CO 2 production rates were achieved when aqueous solution of KMnO 4 was applied, as the increase of CO 2 production rates were about 71% to 97% higher compared to a control. The aqueous solution of H 2O 2 did not cause any significant improvement of the biodegradation rates. Compared to a control, the addition of aerated water resulted in a decrease of CO 2 production rates. Most probably the excessive soil moisture could reduce the air-filled porosity and, consequently, the oxygen contents in soil. Copyright © 2007 Taylor and Francis Group, LLC.