Natural Attenuation Of The Typical Petroleum Hydrocarbons In The Shallow Groundwater

Groundwater resources play a very important role in industrial and agricultural production and in human life, especially being the most directly used drinking water, groundwater is of great value. With the rapid development of industrial economy, the oil industry has been developed rapidly all over the world. Oil brings not only great benefits but also serious harm to human. Petroleum hydrocarbons are carcinogenesis, teratogenicity and mutagenesis. Groundwater environment is anoxic, dark, faint microbial activities, low temperature, velocity and mixed rate, and no volatile. Once organic pollutants enter into groundwater, it is very hard to be removed by natural degradation as surface water dose. These organic pollutants may be persistent and can be accumulated in the environment, which may threat the environment safety and human health. Therefore, researches on the natural attenuation laws of organic pollutants in groundwater were significant and provide theoretical support on the migration regularities and removing pathways of pollutants.This work chooses benzene and phenanthrene as the object pollutants, the research are operated in a self-made rotating device through indoor simulation experiments. The natural attenuation of benzene and phenanthrene is investigated in both single-component solution and mixed-component solution. In addition, the degradation bacterium from sandy soil was domesticated, and was used to degrade benzene and phenanthrene. The research results can not only provide data support for migration laws and pollutant condition, but also found theoretical basis for groundwater pollution management and control.The results were as follows:(1) The natural attenuation of benzene and phenanthrene in four aquifer media (silt sand, medium sand, coarse sand and gravel sand.) all follows the first-order kinetics both in of the single-component and mixed-component solution.(2) Among the four aquifer media, benzene and phenanthrene attenuates as following sequences:the silt sand > the medium sand > the coarse sand > the gravel sand.(3) The microdegradation plays an important part in the natural attenuation of benzene, while the adsorption is significant in natural attenuation of phenanthrene.(4) in mixed-components solutions, the natural attenuation of benzene and gets faster, but the natural attenuation of phenanthrene slowed.(5) while the temperature rose, the natural attenuation of benzene got faster, while the natural attenuation of phenanthrene slowed.(6) The degradation bacteria mainly come from sandy sand but not from groundwater. The bacteria group can degrade benzene and phenanthrene effectively. The first-order kinetics simplified dynamics equation of Monod equation to describe the microbial degradation process of concentrations of benzene and phenanthrene is not only simple, but accurate.