Development of Bioremediation Process for Treating Soil Pollutants Based on Immobilized Biofilm to Carriers Treated with Cold Plasma

Ravit Farber, Chemical Engineering, Ariel University, Ariel, Israel

The industrial use of toxic organic compounds such as oil or chlorinated compounds leads to soil and groundwater contamination. In this research, we have developed a method for improvement the bioremediation process for treating toxic organic contaminated soil. The method is based on agricultural waste, which is served as a carrier for biofilm of toxic organic degrading bacteria. The agricultural waste was treated using cold plasma to increase the surface hydrophobicity in attempt to increase the biofilm formation. The industrial waste with the attached biofilm will be disperse in several types of soil and the biodegradation ability will be examine in different conditions of pollutants concentration, contaminated type, humidity and aeration.

Examination of the biofilm formation on the agricultural waste was done using a colorimetric method based on the activity of dehydrogenases (MTT analysis). In was found the biofilm formation on agricultural waste in the presence of exogenic bacteria in the presence of toluene and MTBE reached 2.3 OD at 540 nm while in the absence of exogenous bacteria it reached only 1.5 OD. In the presence of toluene and exogenic bacteria, the MTT analysis reached 1.3 OD while in the absence of toluene only, 0.5 OD at 540 nm. Examination of the biofilm development on agricultural waste in soil polluted with toluene and in the presence of toluene degrading bacteria, the MTT analysis reached 2.4 OD at 540nm while without the addition of the bacteria it reached only 0.8 OD.

Treatment of the agricultural waste using cold plasma led to increase of the surface hydrophobicity and biofilm formation of 22% higher than on agriculture waste that was not treated with cold plasma.

In summary, biofilm immobilization to agricultural waste is not only to improve the biodegradation ability but also to enable soil aeration to encourage the bacterial activity