| With the rapid development of offshore oil industry, transportation, the oil exploration, and the expanding of the submarine pipeline, Oil-spill pollution in the marine environment has become a significant hazard potential. An efficient, friendly method about the removal of the petroleum hydrocarbon becomes the great concern to the international research field. The bioremediation developed in the microbial degradation has many advantages like more effective, low cost and friendly to environment in dealing with environmental oil pollutants. With 30 years developing, biotechnology is often applied, and which has already been accepted as the attractive and versible method of crude oil elimination in the envrionment. However, the oil-spilled shoreline is a complicated project that is related with the characteristics of contaminated sites, the structure of microbial ecology, as well as various environmental conditions. So before the implementation of the project in bioremediation, it must have the small scale and field pilot study on the feasibility of the project.With different treatments including adding water-soluble fertilizer, addition of slow release fertilizer,slow release fertilizer nutrients with experimental microbial inoculums and water soluble fertilizer with petroleum-degrading bacterium, This paper mainly study on the effect of bioremediation in different types of oil-spilled shoreline about BXPT crude oil and heavy crude oil SZ36-1 through field pilot tests. Trials of bioremediation were conducted in coarse sand-pebble shoreline, fine sand shoreline and silt-mud shoreline. the various of chemical and biological factors are measured in situ, including temperature, salinity, pH, dissolved oxygen concentration, total dissolved nitrogen and phosphorus in pore water, and total petroleum hydrocarbons and components as well as biological factors, including the total number of bacteria, density of petroleum hydrocarbon degrading bacteria, and density of alkanes degrading bacteria, and the density of aromatic hydrocarbon degrading bacteria, as well as the microbial community structure and mycobacterium diversity, etc.. To determine the feasibility of the bioremediation technology in different types of oil-spilled shoreline and find the key factor of affecting biodegradation of oil pollutants, we did in principal component analysis. The main results are as follows:(1) Different shoreline contaminated in BXPT crude oil has different indigenous microbial communities and also difference in natural degradation rate of petroleum hydrocarbon. It turns that The silt-mud matrix has the highest degradation rate, which is 17.6%, and the degradation of the coarse sand-pebble shoreline are close to the fine sand shoreline, which are 8.5% and 7.0%. However, the average degradation rates of aromatic hydrocarbon are similar among the three shorelines. These show that different shoreline is different in Environmental Characteristics, and The sensitivity of biological restoration measurements are also different.(2) For the different shorelines contaminated in BXPT crude oil, the low content of nitrogen and phosphorus are the main factors to limit the biodegradation of petroleum hydrocarbons, addition of nutrients can significantly improve the number of the indigenous hydrocarbon degrading bacteria in different shoreline, and also improve the biodegradation rate of oil pollution, but effects between the addition of slow release fertilizer and water-soluble are different. In 60 days of bioremediation, The biodegradation system inoculated with slow-release fertilizer are better than the system inoculated with water-soluble fertilizer in Coarse sand-pebble shoreline and fine sand shoreline, The average ratio of alkanes degradation are more 1.3 times and 2.2 times than the control system, and more 1.3 times and 1.3 times than each system inoculated with water-soluble fertilizer; however the biodegradation system inoculated with water-soluble fertilizer are higher degradation rate than the system with addition of slow-release fertilizer, The average ratio of alkanes degradation rate are more 2.1 times than the control system, and more 1.4 times than system treated with addition of water-soluble fertilizer. However the average of aromatics degradation rate is nearly or even lower compared with the control. These results show that the addition of nutrients can promote the degradation of alkanes, but the degradation rate of aromatic hydrocarbon is inhibited.(3) the degradation rate of the biodegradation system inoculated with oil-degrading bacteria agentâ… and nutrients are different in different shorelines contaminated in BXPT crude oil. For coarse sand-pebble shoreline, fine sand shoreline, while adding nutrients and inoculums of the system, not only can significantly improve content of nitrogen and phosphorus in pore water in the two kinds of matrix, and promote the hydrocarbon degrading bacteria and indigenous bacteria to grow rapidly, but also improve the microbial community structure in the matrix, increase the mycobacterium diversity, and thus improve the efficiency of bioremediation. The average ratios of alkane degradation rate are more 4.8 times and 5.1 times than the each own control system, and the average degradation rate of aromatic degradation rate are considerable as control system. But for the biodegradation system inoculated with oil-degrading bacteria agentâ… and nutrients in the silt-mud shoreline, although the nutrients can promote growth of the indigenous hydrocarbon degrading bacteria, but additional agents are in competition with indigenous bacteria, which leads the lower degradation rate of petroleum hydrocarbons than the only addition of nutrients system.(4) for the silt-mud shoreline contaminated in heavy crude oil SZ36-1, the biodegradation system inoculated with oil-degrading bacteria agentâ… orâ…¡and slow-release fertilizer have different degradation rate in two concentrations of petroleum hydrocarbons. The agentâ…¡is in compound of agentâ… and two surfactant bacteria. In the high concentration of oil pollution conditions, for the system which is added agentâ… and slow-release fertilizer, The average ratio of alkane and aromatic degradation rate are more2.9 times and 1.3 times than the control system. In the low concentration of oil pollution conditions, the systems which are adding slow-release fertilizer and agentâ… orâ…¡all increase the efficiency of bioremediation, In 60 days of bioremediation, the degradation rates of alkane are 2.8 and 2.9 times than the control, while the ratio of aromatic degradation fate of each treatment are 1.3 and 1.3 times than the control system. Further comparing the results of the microbial community diversity PCR-DGGE during the different treatments system, it can be found that in the beginning of the bioremediation, the microbial community diversity in the system added agent and nutrients are higher than the control, With the increasing in repair times, in system which is added agentâ… and agentâ…¡, the microbial community diversity is the same, between them the similarity coefficient is more than 70%; in the last period, advantage of growth in agentâ… andâ…¡disappeared. Microbial community structure in the processing system are not different from the control group, it shows that indigenous microorganisms in the system begin to show great competitive advantage(5) In the field experiment of bioremediation of different types of oil polluted shorelines, the environmental parameters (dissolved oxygen and pH, Salinity and temperature) are suitable for the growth of microorganisms in the field experiment, which are not significantly different (P> 0.05) between the test pool, so they are not the limiting factors for bioremediation in different types of oil-spilled shoreline.
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