Research On Bioremediation Of Petroleum Contaminated Soils In Zhongyuan Oil Field

With rapid development of petroleum industry, soil contaminated condition become more and moer serious.But the purification technology and bioremediation process can not match the environmental requirement. Currently,research on Bioremediation of petroleum contaminated soil become a key factor to ensure the rehabilitation of petroleum contaminated soil . In order to provide both theoretic parameters and practical techniques for phytoremediation of petroleum contaminated soil, According to the actual state of petroleum contaminated soil and main problems in bioremediation of petroleum contaminated soil, under guidance of the pollution ecology theory,Taking petroleum contaminated soil of Zhongyuan Oil Field,native plants and indigenous microorganisms as the research object, bioremediation of petroleum contaminated soil was was studied.Studying the effect of artificial oil-contaminated soil on the germination and growth of plant seedling by the pot-planting experiment screen plants with experimental potential to phytoremediation.Taking petroleum as the unique Source of carbon and nutrition, the microorganisms which degradated the petroleum were screened from the petroleum contaminated soil which was collected from Zhongyuan oil field .petroleum and uncontamined Fluvo-aquic soil around Zhongyuan Oil Field are mixed together in different ratio to test oil degrading effects of microorganisms, plants and plants combined with microorganisms and study effects of environmental factors (total salt content, water content, straw etc.)on the bioremediation of petroleum contaminated soil by pot experiments.the in-situ remediation pot simulation experiment of petroleum contaminated soil which collected from Zhongyuan oil field was conducted to investigate environmental adaptability and oil degrading effects of microorganisms combined with cotton and Bermuda grass, microorganisms combined with cotton , microorganisms combined with Bermuda grass.The main results are as follows:(1) The sprouting ratio, height and fresh weight of sunflower, cotton, Bermuda grass, sorghum sudanense have no significantly change with the concentrations of soil oil from 0 to 45 g/kg. They could grow on oil contaminated soil, and They can help to rehabilitate the polluted soil. Bermuda grass can be fit to grow on the crude oil-contaminated soils by itself, it is a plant with a biggest experimental potential to phytoremediation oil-contaminated in this experiment. (2) The micro-organism which can obviousiy rehabilitate the petroleum-polluted soil exist in oil contaminated soil of Oil Extraction Area of Zhongyuan Oil Field. They was added to the soil, 120 days later, 67.0% pollution was removed.The plants , such as sunflower, cotton, Bermuda grass, sorghum sudanense can naturally grow with native micro-organism to rehabilitate soil.The cotton combined with microorganisms got the best effect in four groups and the degradation rate of petroleum was 85.67% after 120d. more than the sum of their individual ability. (3) Environmental factors have important influence on Bioremediation of Petroleum Polluted Soil.Commonly,with the addition of salt in the soil, removed speed of petroleum slow down. The favorable soil moisture to Bioremediation of petroleum contaminated soil was 65 to 75 percent of field capacity.The optimum straw content in the soil was 20g/kg for the Bioremediation of petroleum contaminated soil. And meanwhile it is ecessary to keep soil under proper condition, suchas good ventilation. All these were helpful to accelerate the decomposition rate of pollutant. (4) In the simulation test of Bioremediation of Petroleum Polluted Soil in the Oil Extraction Area of Zhongyuan Oil Field, The microorganisms combined with cotton and Bermuda grass got the best effect in all the treatments and the degradation rate of petroleum was 56.38% after 120d.