Potential of Bioaugmentation and Biostimulation for Enhancing Intrinsic Biodegradation in Oil Hydrocarbon-Contaminated Soil

Abstract

ABSTRACT 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 O2 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 H2O2 or KMnO4 were used to supply O2. The intrinsic and enhanced biodegradation was evaluated by the O2 uptake and CO2 production rates obtained using a linear regression of the cumulative O2 uptake and CO2 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 CO2 production rates were achieved when aqueous solution of KMnO4 was applied, as the increase of CO2 production rates were about 71% to 97% higher compared to a control. The aqueous solution of H2O2 did not cause any significant improvement of the biodegradation rates. Compared to a control, the addition of aerated water resulted in a decrease of CO2 production rates. Most probably the excessive soil moisture could reduce the air-filled porosity and, consequently, the oxygen contents in soil.