Determination of the Optimal Conditions for Bioremediation of Soil Total Pollutants Hydrocarbon

Emission of hydrocarbon pollutants requires application of refining methods that is appropriate and compatible with environment to reduce or eliminate pollution. The use of microorganisms، capable of feeding oil hydrocarbons with focus on methods of bioremediation oil decomposition was considered، and optimizing the growth conditions can increase their efficiency in refining. The purpose of this study is to determine the optimal conditions for the stimulation of soil microorganisms and investigation of oil hydrocarbon decomposition potential. Hence، Ray''s refinery contaminated soil was used and treatments including inoculation of bacteria''s such as: Bacillus subtitles، Bacillus megaterium، Pseudomonas putida were applied on this soil during the five time and analysis of total soil hydrocarbons petroleum (38%) were compared with the treatments in different conditions. Results showed that on the first and second period، animal manure treatment، bacteria mixed by animal manure and sawdust had the highest rate of pollution reduction but treatments included N + P + K fertilizers showed higher efficiency in the third period. The establishment of bacterial and application of NPK nutrients caused the stimulation of soil microorganisms and increase in their population. Eventually In the fifth period، the establishment of microbial treatment caused 19% reduction in comparison with intact treatment that is highest reduction in this treatment. It appeared this treatment had maximum efficiency for the establishment and stability of microbial community over required time.