The Evaluation On The Complex System That Compounded The Chemical Oil Spilled Dispersant With The Environmentally Friendly Microbial Inoculum For Oil Spills

With the development of industry, oil exploration and transportation is more frequent on the sea, and the oil spill accidents have been increasing year after year. The marine environment and organisms are susceptible to the oil spills, and the oil spills also affect land species, human, and the economics further. In recent years, remediation methods to oil spills were widely studied. There are three main methods to remediate oil spills, including physical method, chemical method and biological method. The disadvantage of physical method is consumable that it was easily affected by the surroundings, and the degradation was not completely. The chemical oil dispersants can emulsify the oil into small droplets; reduce the risks of the oil spills for a large scale. In the biological method, the environmental friendly microbial inoculum is widely used, it can degradate the spilled oil into small molecules which is non-toxicity and easy to degradate. This paper was combining the chemical method with the biological methods, the emulisification and degradation effects for a complex system which concluded the dispersants and microbial inoculum were researched, with the purposed of improving the degradation rate, and decreased the usage of dispersants as much as possible.In this paper, the emulsification efficiency of four chemical oil dispersants (A, B, C, D) were analyzed, chose the best performance, and then applied to blending with the microbial inoculum B-1, the growth conditons were observered under different concentrations of dispersants. At last, compounding the microbial inoculum B-1with different concentrations of dispersants, the degradation rate on crude oil was determined, and the experiment conditions were optimized, then chose the best performance of dispersant usage. The conclusions were as follows: (1) The results showed that Dispersant B performed best emulsification efficiency in the four dispersants. The Dispersant B can meet the utilization demand in oil spills (The30s emulsification ratio>60%and the1Omin emulsification ratio>20%) when its DOR was0.3～0.35at25℃,0.45at20℃and over0.5at17℃.(2) The emulsification efficiency of dispersants was influenced considerably by temperature, while the emulsion ability was also increased by salinity, but non-significantly. And along with the increase of DOR, the emulsion ability and stability were obviously improved.(3) In the nutrient medium, the microbial inoculum B-1was not affected when the different dispersants were added after the stationary phase, and it was also not influenced when the dispersants were mixed at the beginning of the growth, when the dispersants were served as the carbon sources, the microbial inoculum B-1was affected to varying degrees, when20g/L dispersants were added into the culture medium, the bacterium numbers were108CFU/mL, the numbers were107CFU/mL when50g/L dispersants were added,107CFU/mL when100g/L were added, and106CFU/mL when150g/L were added. Along with the increasing concentration of the dispersants, the microbial inoculum B-1performanced different degrees of inhibition.(4) The microbial inoculum B-1showed the best biodegradation when100g/L dispersants were added into the culture medium, and the maximum degradation ratio is73.5%. And the best conditions for the blending experiments were:crude oil for3g/L, incubation time for7d, culture temperature for25℃, culture medium salinity for35.