苯和菲在含水层的典型介质中迁移转化研究

石油烃污染会对人类生存的环境造成严重危害,地下水系统中石油烃污染物的研究已受到国内外的高度重视。本文针对某石油烃污染场地的污染状况及水文地质条件,利用模拟柱实验研究石油烃中常见组分苯和菲在典型含水层中的迁移转化,实验结果表明,苯和菲在4种含水层介质中(粉砂、中砂、粗砂、砾砂)受到的迁移阻滞作用都是随着粒径的减小而增大。菲在4种介质中的迁移速率要小于苯,说明4种介质对菲的阻滞作用要大于苯。通过检测各模拟柱出水中Fe2+、Fe3+、NH4+-N和NO3--N浓度的变化可知,在苯和菲的砾砂模拟柱中,由于水流速度快,试验周期短,模拟柱内各项指标变化较小,生物作用较弱;而在苯和菲的粗砂、中砂和粉砂模拟柱中,NO3--N浓度减少,NH4+-N和Fe3+含量增加,说明微生物开始利用NO3--N和Fe3+降解苯和菲,微生物对苯和菲在粗砂、中砂和粉砂中的迁移转化过程有显著的作用。

Study on Migration of Benzene and Phenanthrene in the Typical Aquifer Medium

The pollution of petroleum hydrocarbons is quite harmful to the environment.The pollution of petroleum hydrocarbons in the groundwater has already been widely concerned.According to the pollution status and hydrogeologic conditions of a petroleum pollution site,simulating column test was applied to study the migration of common components of the petroleum,benzene and phenanthrene,in the typical aquifer mediums.The results showed that the migration retardation of benzene and phenanthrene in four sorts of aquifer medium(silt,medium sand,coarse sand,gravel sand) increased with the decreasing of the particle size.The migration rate of phenanthrene was slower than that of benzene,which meant that the retardation of phenanthrene was stronger than benzene in the four sorts of medium.According to the determination of the influent and effluent concentrations of ions such as Fe2+,Fe3+,NH+4-N and NO-3-N of every column,it found that in the column of gravel sand the microbes hardly affected the migration of benzene and phenanthrene,with little change of concentrations,resulting from the high water flowing speed and short experimental period.While for the columns else it appeared reducing of NO-3-N concentration and increasing of concentrations of NH+4-N and Fe3+,which meant that the microbes started to use NO-3-N and Fe3+ to degrade benzene and phenanthrene and the microbes affected their migrations in silt,medium sand and coarse sand significantly.