Improved Methods for Decontamination of Contaminated Soil

One of the in situ methods used for cleaning up soils that are contaminated by hydrocarbons from petrol industry is the so called DCR (i.e. Dispersion by Chemical Reactions) process, where hydrophobic CaO is injected into the soil to form Ca(OH)2/with water. By adsorption effects, hydrocarbon molecules are fixed at the hydrophobic surface of fine Ca(OH)2/soil-particles. Additionally, alkalophilic microorganisms, like Bacillus alcalophilus are degradating the mineral oil hydrocarbons to CO2 and H2O at pH 8 – 11.5, resulting in carbonatization and formation of CaCO3, which encapsulates the rest of the hydrocarbons that are not biologically decomposed. In the present contribution, an improvement of the DCR-process is reported by application of the socalled AKB (Encapsulation by Adsorption and Biological Degradation)-technique, and results are presented on the in situ remediation of soil contaminated by petrol industry. When hot-spot samples from an oil spill are treated by the AKB-technique, reductions between 90 – 97 % have been achieve for petrol hydrocarbons contamination in soil.