Remediation Of Oil Contaminated Seawater By Immobilized Microorganism Of Biological Carbon

With the continuous exploitation of the seabed and coastal oil, the environmental pollutionespecially the marine oil pollution caused by oil spilling due to drilling and transporting is moreand more prominent, it has brought great distress to the marine environment and human’ssurvival and development, also caused a great waste of resources. As the methods of control oilpollution developed, there are three kinds at present are principal, physical, chemical andbiological method.Tradition physical method, such as oil boom, oil absorbing materials, oil skimmer and so on,need a lot of people, material and financial resources, although it can remove most of the floatingoil to avoid further injury to the sea water and the creature in a relatively short time, but the costis usually very expensive and it’s hard to completely remove the surface oil and a small portiondissolved in the water; chemical method is mainly the use of chemical dispersants, it canincrease the contact area between oil and water, quicken oil emulsion, promote microbialdegradation, but itself has a certain toxicity, affect the marine creature’s and human’s health, itcan pollute the marine environment also, which getting more difficult to control the oil pollution;biological method is the key research in recent years, which is mainly use the microorganisms todegrade the oil in seawater, it not only reduces the treatment cost but also no secondary pollutionemerged, so this paper take control of seawater oil pollution by biological method.Oil degrading of immobilized bacteria was studied in this paper to find a friendly waysuitable for marine environment, including screening immobilization carrier and oil degradingbacteria, researching the effect of microbial degradation and its degradation conditions. The mainresults are as follows:Biological carbon made of three kinds of crop straws (pine needles, grass and corn cob)floating properties are different in artificial seawater. Three kinds of same preparationtemperature biological carbon’s floating rate (P) is: P pine carbon>P corncob carbon>P grasscarbon. Also three kinds of carbon of different sizes were researched, three kinds of carbonshowed that larger diameter performed a larger floating rate. In order to find the optimalbiological carbon, the pine needle which has a high floating rate was distinguished by differentpreparation temperature, the preparation temperature were300,400,500℃, so we find thepreparation temperature at400℃was the best. Therefore, this experiment adopted the biologicalcarbon is the carbon of pine needles prepared at400℃and the diameter is more than30mesh.Because of the immobilized bacteria is put into the sea, so the adsorption properties of pineneedles is mainly studied, especially on oil and degrading bacteria. Results showed that thecarbon of pine needle’s adsorption was great, the maximum adsorption of oil could be five times their own, because the adsorption, the carbon stayed together forming a spherical mixturefloating on the surface of the artificial seawater, which is very easy to take. Oil carbon ratio andthe adsorption ratio was studied, adsorption ratio is used to represent each gram of carbon’sadsorption capacity, the adsorption ratio increasing with the oil carbon ratio growing, themaximum could reach5; the capacity of adsorbing bacteria could be numbered80%.In order to determine the suitable bacteria for marine environment that can degradepetroleum, laboratory existing strains which can tolerant high salt selected in the oilcontaminated soil were put into the seawater to screening, after one week‘s degradation, thehighest degradation rate occurs on1--the Bacillus subtilis, a week’s degradation rate reached30%, survived well and the number reached2×108cfu/ml.Based on the adsorption capacity of pine needles carbon, microbial inoculum was prepared,used for degrading the seawater oil a week as simulation experiment, the rate of degradationcaught up to40%a week, the best dosage of seawater with crude oil (1%) per100ml was0.5g;through the analysis of the four components of the oil, saturated hydrocarbon degraded most,secondly aromatic, resin and asphaltene was rarely followed by degradation; five weeks’degradation experiment were executed to determine the optimum degradation time, the microbialinoculum can absorb99%of the oil, the degradation rate was up to70%in the fifth weeks.