Research On Biodegradation And Risk Control Of Petroleum Hydrocarbon In Groundwater At A Contaminated Site

Petroleum Hydrocarbon is a common contaminant in soil and groundwater at contaminated sites.The sources of Petroleum Hydrocarbon in the polluted sites includes oil extraction,petrochemical production,gas stations and oil depots,etc.Petroleum hydrocarbons could damage the ecosystem,cause pollution and pose threat to human health when the contaminants enter soil and groundwater.Because of its stability,volatility and toxicity,petroleum hydrocarbon has become a main pollution source in the environment and has been listed as a priority pollutant in many countries.The composition of petroleum hydrocarbon is complex.At present,the screening value and control value of petroleum hydrocarbon(C10-C40)in soil were stipulated in the Soil Standard of Construction Land(GB36600-2018)in China.While,the relevant standard of petroleum hydrocarbon of groundwater is still absent in the Standard for Groundwater Quality(GB / T14848-2017)in China.At present,investigation,risk assessment and remediation of soil and groundwater in many petroleum hydrocarbon contaminated sites have been carried out in China.The pump & treat and chemical oxidation were often used as main technologies for groundwater remediation at petroleum hydrocarbon contaminated site.This paper summarized the research progress on the natural attenuation process of petroleum hydrocarbons by domestic and foreign scholars,and analyzed the main ways of the natural attenuation process of petroleum hydrocarbons.The soil samples were collected at a petrochemical enterprise in north China.The screened indigenous microorganisms in surface contaminated were enriched and cultured in laboratory,and then added into the petroleum hydrocarbons contaminated groundwater in different proportions.Variation of the community structure in groundwater samples were analyzed.At last,the risk management and control technologies for petroleum hydrocarbon contaminated sites were proposed.The main achievements of this paper are as follows:(1)The mainly natural attenuation ways of petroleum hydrocarbon include volatilization,dispersion,adsorption and biodegradation.For VOCs in petroleum hydrocarbon,volatilization is the mainly attenuation process.While,the main natural attenuation process is biodegradation for other organic components.(2)Single colony was obtained through microbial screening,isolation and purification at the surface soil in a petrochemical enterprise in north China.After enrichment culture of single colony,the bacterial suspension was added to the petroleum hydrocarbon contaminated groundwater in different proportion.The results showed that addition of bacterial suspension had a significant impact on the bacterial structure,and the bacteria could degrade petroleum hydrocarbon.(3)Design a risk management and control plan for a site,and conduct research on technical selection,working procedures,and control objectives.The results can not only provide a theoretical basis for the enhanced microbial remediation of petroleum hydrocarbon contaminated soil and groundwater,but also provide more suggestions and references for the management of contaminated sites and the selection of remediation technical solutions in China.