Study On Remediation Of Diesel Contaminated Soil By Microorganism Enhanced By Surfactant

As the center of economy and transportation in north China,shenyang is also developed in industry and transportation.Diesel consumption is huge,which will cause soil pollution in the process of diesel use and transportation.Besides,there are a large number of oil fields in xinmin area of shenyang city,which also aggravates the diesel pollution problem in shenyang area.This project takes diesel oil as the representative pollutant of organic pollution in shenyang soil,takes the diesel degradation bacteria owned by the laboratory and the degradation bacteria screened by diesel contaminated soil for a long time as the research object,and optimizes its degradation condition.Through literature research and other work,choose the biosurfactant sugar fat in mice?RL?,chemical surfactant polysorbate 80?Tween 80?,sodium dodecyl benzene sulfonate?SDBS?and sodium dodecyl benzene sulfate?SDS?were used as surfactant,single surfactant with compound surface active agent was studied in diesel elution ability of pollutants in soil,and the impact of surfactants on advantage degrading bacteria growth experiment,on this basis,promotes the surfactant enhanced microbial restoration technology research,for the repair of contaminated soil,the improvement of residents'living environment,provides technical support to ensure the safety of soil.The main research results are as follows:?1?diesel oil as sole carbon source,the diesel oil contaminated soil in shenyang xinmin region enrichment culture,through separation and purification,screen out 3 strains?named W,R,Y?,at the same time using the laboratory from the original 2 strains?N,C?for diesel repair test,the results showed that the bacteria W,R C strains of bacteria contamination for diesel tolerance,and Y,N bacteria for diesel fuel efficient degradation bacteria.N bacteria is the methyl Bacillus methylotrophicus,which is now stored in the center of general microbiology of the China microbial species preservation and management committee.The preservation number is 12461.After morphological observation,physiological and biochemical identification and 16SrDNA sequence analysis,the strain was identified as bacillus subtilis,which was the first case study on efficient degradation bacteria as diesel contaminated soil.The most suitable temperature,the most suitable salt content and the most suitable growth medium of bacteria Y and N were the same,both of which were 35°C,0.5%NaCl and inorganic salt medium.?2?through the diesel restoration experiment compares the strain W,R,Y,N,C repairing effect of diesel oil contaminated soil,determined the Y bacteria and N bacteria treatment for diesel oil contaminated soil bioremediation,after 15 d after training,Y bacteria and N bacteria highest degradation rate were 94.13%and 81.54%respectively,compared with blank treatment?CK?increased by 8.96 times and 7.8 times respectively,but Y bacteria and N bacteria for diesel pollution soil degradation rate is only 29.37%and22.68%in real terms,the degradation efficiency is only part of the liquid diesel degradation experiment effect were 31.2%and 28.3%.?3?the surfactant elution test showed that in Tween 80,SDS and SDBS,the surfactant with a concentration of 3,000 mg·l^-1 was the most cost-effective eluent,and the SDS had the highest elution efficiency?81.27%?.For biological surfactant RL,RL eluting effect of500mg·l^-1 is good,which is 74.64%.Compared with the pure SDS elution,the elution effect of mixed surfactant in each proportion still has a large gap.?4?through the experiment of the effect of surfactants on the toxicity of the bacteria,the results showed that the absorbance value of the bacteria solution was only 70.05%to23.86%of the blank group after adding RL and SDBS surfactants to the bacteria,which was not conducive to the growth of the bacteria.Surfactant Tween80 and SDS were beneficial to the growth and reproduction of Y bacteria,and its OD₆₀₀ value was 1.08 times to 1.19 times of that of the white group.For N bacteria,anion surfactant SDS and SDBS had inhibitory effect on N bacteria.The OD₆₀₀ value of surfactant with different concentrations was 80.91-29.77%of the blank group.While Tween80 and RL are favorable for the growth and reproduction of N bacteria,and their OD₆₀₀ value is 1.09times to 1.26 times of the blank control group.?5?developed suitable for diesel oil contaminated soil surfactant enhanced microbial remediation technologies,in type methyl nutrition bacillus,2000 mg·L 1 Tween80strengthening methyl nutritional bacillus repair diesel oil in soil repair effect?46.11%?than500 mg·L 1 RL repair effect?45.32%?,at the same time has good economy and has good application prospect.For bacillus subtilis,the repair effect of SDS?59.32%?was better than that of Tween80?51.11%?.Therefore,3000mg·l^-1 SDS can be selected to strengthen bacillus subtilis to repair diesel contaminated soil.