Study Of The Bioremediation Process Of The Coastal Spill Oil

Oil spill not only affect the seawater, but also affect seacoast because of waves and tide action.Due to the special characteristical of coastal environment, using microbiological methodto deal with coastal spill oil is a viable approach. In this paper, we used laboratory-preserved bacteria Lz-2 to deal with coastal spill oil in a simulated environment. Studyingthe desorption process, degradation process, number and communities of bacteria, nutrient concentrations of the simulated experiment.Besides, the effect of oil, dispersant and bacteria fermentation broth to the algal also were researched.The main results were listed as follows:(1) Shake flask experiments showed that bacteria Lz-2 had a highest degradation rate in the first week, which was 47.3%. In the second week, the degradation rate had a small increase, reached 50.7%.The degradation rates of mixed bacteriawere less than single bacteria. Biosurfactant produced by bacteria Lz-2 has a good surface activity and it can reduce the oil viscosity effectively.(2) In simulated experiment, after added bacteria Lz-2 fermentation broth to the experimental tank, the concentration of petroleum hydrocarbon in seawater maintained at 1.1 mg/L while maintained at 0.6 mg/L in the control tank.The oil adsorption amount of intertidal and subtidal sand in experimental tank reached at 0.017 mg/g and 0.025 mg/grespectively, higher than control tank. These studies indicated that more oil was desorbed from the rock in the experimental tank because of the fermentation broth.(3) The GC-FID results showed that through 52 days experiment, over 21.9% of the oil was degraded by bacteria after accounting for weathering losses in the control. N-alkanes had different biodegradation rates. The loss of the n-alkanes is related tothe length of carbon chain. Naphthalene was found to be easier to utilize by the bacteria. The δ13C values for the n-alkanes were nearly no obvious change during the total experiment period. Dimensional fluorescence spectra also showed that bacteria Lz-2 degraded the oil in the experimental tank.(4) In simulated experiment, the concentration of nutrients in the experimental tank showed a quickly decrease. In the control tank, the concentrations of phosphate and ammonium maintained a low level. Bacteria Lz-2 also experienced a rapidly decrease period in the experimental tank but higher than the bacteria in the control tank.(5) Toxicity test results show that algal had strong resistance to the low concentrations of petroleum hydrocarbons. Chemical dispersants will inhibit growth and reproduction of algal whileP and N nutrients in bacteria fermentation broth will promote the growth of algaLThis study used laboratory-preserved bacteria to deal with coastal spill oil in a simulated environment.The results demonstratedthat bacteria Lz-2 could accelerate desorption process of coastal spill oil and could effectively degrade the oil. Meanwhile this method has small impact on the environment. The results may provide a theoretical basis for the bioremediation of coastal spill oil.