Study On Surfactant Combined With Indigenous Microorganisms To Remediation Of Petroleum Hydrocarbon-contaminated Soil

With the rapid development of petrochemical industry,soil pollution caused by petroleum hydrocarbons is still one of the environmental pollution problems that people pay close attention to.This paper studies surfactant technology combined with indigenous petroleum hydrocarbon degradation bacteria to repair petroleum hydrocarbon contaminated soil.Five kinds of surfactants were used for the remediation of petroleum hydrocarbon contaminated soil,and the optimal remediation conditions and toxicity to petroleum hydrocarbon degrading bacteria were investigated.The indigenous petroleum hydrocarbon-degrading bacteria were isolated from the contaminated soil and domesticated.The effects of surfactants on the domestication process and the evolution of microbial communities were explored.Five strains of surfactant-producing strains isolated from different contaminated sites were combined with indigenous degrading bacteria to successfully construct highly efficient degrading bacteria and improve the efficiency of microbial repair.The findings are as follows:(1)Temperature and surfactant concentration had a significant effect on the repair effect.TRS-1 surfactant was suitable for the treatment of soil.The best experimental conditions were surfactant concentration of 2000 mg/L,temperature of 35 °C,and oscillation time of 45 min.The removal rate of petroleum hydrocarbons in the soil can reach 60%-70%.Surfactants had a better effect on the removal of low-molecular-weight alkane.When the number of carbon atoms of the alkane was less than 18,the other four surfactants except SDBS showed that the removal rate of alkane with odd-number of carbon atoms was higher than that of even-number of carbon atoms.Surfactants had a certain modification effect on the surface hydrophobicity of relatively hydrophilic bacterial cells under initial conditions,making their surface properties develop in the direction of enhanced hydrophobicity.(2)With the increase in the concentration of petroleum hydrocarbons,the microorganisms in the degrading flora continuously changed,and the dominant species gradually dominated.The final domesticated flora was mainly Acinetobacter,Burkholderia,and Trypanobacterium,Thermophilus,Sphingomonas and other petroleum hydrocarbon-degrading bacteria.Among them,Acinetobacter had the highest community abundance,reaching 96.27%.The addition of surfactants had adverse effects on the domestication process,including reducing the abundance of the dominant flora and the degradation capacity of the flora.(3)Among the isolated surfactant-producing strains,BS2 and BS5 showed good performance and successfully blended with indigenous degrading bacteria.The efficient removal of petroleum hydrocarbons by constructing highly degrading bacteria reached 84.20%,which effectively improved degradation of petroleum hydrocarbons by microorganisms.(4)In soil remediation experiments,the composite bacteria group showed better remediation effect than the indigenous degrading bacteria group,and its removal rate of petroleum hydrocarbons in the soil reached 89.91%,which was 26.50% higher than the indigenous degrading bacteria group.It can be effective improve the efficiency of microorganisms in remediation of petroleum hydrocarbon contaminated soil.