The study of microbial removal efficiency of crude oil in contaminated soils of cold climates areas (case study: Tabriz refinery)

Petroleum pollution is the most important soil pollution. Bioremediation is an effective and usable technology for remediation of polluted soils. Some microorganisms have bioremediation potency for petroleum compounds. In this research Tabriz city was selected as a cold area of Iran for studying of native bacteria with biodegradation potency of crude oil. Soil samples were collected from polluted soils of Tabriz refinery and their bacteria were accommodated to crude oil. The bacterial strains exited in the samples were isolated، grouped and determined. The growth ability and petroleum removal efficiency were evaluated for the each bacterium at the different crude oil concentrations during a month. In this research، seven bacterial species were found that are well accommodated to crude oil. The highest petroleum removal efficiency (98%) was determined for Pseudomonas aerogenesis at concentration of 0. 5%. Biological removing of crude oil with high efficiency is possible by soil bacterial flora، as an environmental friendly method، even for soil cleaning of the industrial areas in cold temperature regions.