BTEX污染含水层中氧化还原环境的空间变化

Spatial Changes of Redox Environment in Aquifer Contaminated by BTEX

采用一维柱实验模拟方法,研究了地下水受BTEX污染过程初期,含水层中顺序氧化还原环境的空间变化规律,并对模拟柱不同高度出水中BTEX各组分的浓度进行监测.结果表明,模拟柱中各氧化还原灵敏性指标的浓度分布呈现以下规律：距离污染源80～98 cm处的氧还原环境较强;60～80 cm之间硝酸盐还原环境较强;35～60 cm之间以铁还原环境为主;24～50 cm之间形成硫酸盐还原环境;0～30 cm处HCO3-的浓度最低则产甲烷作用较明显.BTEX各组分从模拟柱底部至顶部呈急剧减少规律,其中苯、甲苯、乙苯、对二甲苯和间邻二甲苯的去除率分别达到99.94％、99.96％、99.94％、99.49％和98.3％.

The changes of redox environment conditions and the concentrations of BTEX in different conditions are monitored in this study through setting simulated column. The results showed that the concentration of redox components presented zoning in the simulated column. Oxygen reduction zone formatted in 80～98 cm away from the source, Nitrate reduction zone formatted in 60～80 cm, Iron reduction zone formatted in 35～60 cm, and Sulfate reduction zone formatted in30～50 cm. At the bottom of the column, the methane zone formatted in 0 ～ 30 cm because of the decreasing of HCO3--. The concentration of BTEX components showed a sharp decline. The degradation rates of benzene, toluene, ethylbenzene, xylene and o-xylene reached 99.94%, 99.96%, 99.94%, 99.49% and 98.3%, respectively.