Micro-degradation Of The Oil Wastewater

With the rapid development of oil industry, oil pollution becomes more and more serious and constitutes a threat against environment and human being. Biological treatment by utilizing microbes which have high ability to degrade all kinds of pollutants has become the most common measure for environmental protection.The aim of this study is to isolate bacterial strains that are able to degrade crude oil and to study the principle of degradation crude oil so that the strains can be applied to degradation with the immobilization.In this study, a strain QK-1 which was able to degrade crude oil was isolated from the water in biochemical pool of an oil refinery. And was identified as Bacillus alcalophilus.The characteristics of degradation of crude oil by the strain QK-1 was examined. The optimal cultivation condition was as follows: glucose, 10.0 g/L, beef extract, 6.0 g/L, yeast extract, 1.5 g/L, pH 8.5. The optimal condition of crude oil degradation was as follow: ammonium nitrate, 2.0 g/L, potassium dihydrogen phosphate, 1.0 g/L, solution of microelements, 4.0 ml/L, pH 9.0, QK-1,40 ml/L.The sample was analyzed by using gas chromatography, and the results showed that different compositions in the oil could be taken up selectively by the cells. The mechanisms of oil transport in this bacterium and the crude oil of intermediates of metabolism in the cells of the cell of the QK-1 were carried out. The tiptop of crude oil loss in the minimal medium (C11~ C13) and the next was C15~ C18. QK-1 can analysis hydrocarbon of the most stabilizing in crude oil.Microorganism QK-1 was immobilized on wood crumbs and the immobilized biomass could remove crude oil from aqueous solution. The removal rate of the crude oil by the immobilized biomass was higher than that by only QK-1 or the mixture of QK-1 and wood crumbs. The experimental results showed that the removal rate was 75.53~ 94.29% when the crude oil concentration was 10.0~ 30.0g/L, and the optimum strain dosage was 15.0 g/L (dry weight). The results also indicated that the culture medium was a crucial factor in oil removing, especially carbon and nitrogen sources. The optimum composition of immobilized culture medium was as follows: sucrose, 10.0 g/L; beef extract, 6.0 g/L; yeast extract, 1.5 g/L; pH 8.0.