中文摘要：

为了解乙醇混合汽油主要溶解组分在地下水中的迁移,开展了含水砂槽多孔介质的投注试验,投注物是含有溴化物、乙醇和汽油的混合溶液.试验结果表明:水动力弥散和混合电子受体条件下的土著微生物降解是乙醇和单环芳香烃(BTEX)自然衰减的主要过程.乙醇迁移没有滞后性(阻滞系数为1.0),在生物作用参与下随迁移距离增加而逐渐消失;但乙醇对生化氧量的高需求延迟了甲苯和乙苯的生物降解.苯与甲苯的阻滞系数为1.18,乙苯和二甲苯的阻滞系数为1.28;苯的晕体延伸最长,持续时间最长.基于守恒示踪剂溴离子的浓度校正,乙醇与BTEX的一级降解速率存在明显的大小顺序,即乙醇>甲苯>乙苯>间、对二甲苯>邻二甲苯/苯,与它们的迁移晕体长度大小顺序(即苯>间、对二甲苯/邻二甲苯>乙苯>甲苯/乙醇)具有相反的对应关系.这表明改善乙醇生物降解条件和加速其生物降解速率,是BTEX污染修复的一个有效策略.

英文摘要：

For understanding the fate and transport of ethanol blended monoaromatic hydrocarbons in groundwater, a laboratory-scale experiment was conducted with an aquifer tank, in which 2L mixture including bromide, ethanol and saturated gasoline groundwater was injected under the controlled hydraulic condition. The results show that hydrodynamic dispersion and indigenous biodegradation under mixed electron accepter conditions are primary mechanisms for the attenuation of ethanol and BTEX in porous media. Ethanol transported without retardation but its plume became shorter and shorter with rapid disappearance in the cooperation of biodegradation. The biodegradation and high biochemical oxygen demand of ethanol likely hindered the onset of toluene and ethylbenzene biodegradation. Benzene is most recalcitrant and has the longest plume. The coefficients of retardation are 1.18 for both benzene and toluene and 1.28 for both ethybenzene and xylene isomers. The first-order degradation rate of ethanol and BTEX are in a distinct sequence according to the magnitude, which is reversely corresponding to the length of their transport plume. It implies that to enhance the biodegradation of ethanol is an efficient strategy in the bioremediation of the ethanol blended BTEX contamination in groundwater.