Micro-Ecosystem and Its Influence to the Bioremediation Feasibility of Oil Contaminated Soils

Based on the investigation and analysis of oilfields in different regional area of China, the character of micro-ecosystem including biotic and abiotic factors and its general influence to bioremediation of oil hydrocarbon polluted soils was investigated. And then, the microbial properties, especially the restriction by water and oil content were discussed and the bioremediation feasibility was revealed in this paper. Results showed that the high oil content in soils would suppress the microbial action and community. On the other hand, the column chromatography and GC-MS revealed that more than 50% pollutants were bioavailable and low eco-toxic to the microbes. Generally, constant nutrient in oil polluted soils was lower than normal level, while trace nutrient metal were plentiful for microbial growth and metabolism. There was certain amount and active microbe in the oil contaminated soils, which applied the functional subject for bioremediation. Total microorganisms were almost as widely distributed from 10⁷ to 10⁹cell/g dry soil, while oil degrading microbe 10⁵-10⁶ cell/g dry soil. Simultaneously, the microbial density and activity were restricted by water and oil content. Generally, the high water quantity (>6%) and optimal oil pollutant could stimulate the proliferation, and promote the bioremediation efficiency.