强化生物通风修复过程中柴油衰减规律及其影响因素研究

Study on attenuation of diesel oil and influencing factors during remediation of contaminated soil by enhancing bioventing

强化生物通风技术对于修复因地下储油罐泄漏引起的土壤污染具有很大的应用前景。通过室内土柱模拟柴油泄漏污染土壤，从土柱中总石油烃（total petroleum hydrocarbon，TPH）剖面分布随时间的变化及降解模式角度，分析了其自然衰减和强化生物通风过程。结果表明：初始柴油浓度直接影响着各柱在自然衰减和强化生物通风过程中柱内的残余TPH平衡分布曲线的形状和浓度峰值位置；在前期自然衰减过程中（约1个月），当土壤中的柴油浓度为5000～40000mg油／kg土时，整个柱内TPH变化的主要原因是重力扩散迁移的结果；当土壤中的柴油浓度≤5000mg油／kg土时，其TPH的变化不仅是重力扩散迁移作用的结果，生物降解作用也存在；通风约2个月后，抽提作用对于保持土柱上部柴油浓度稳定变化的意义较为突出。

Enhancing bioventing technology has great application prospects for remediating soil contamination caused by leaking underground storage tanks. In this study indoor soil column experiment was conducted. Natural attenuation of diesel oil in leaking contamination soil and the course of enhancing bioventing were ana- lyzed from the viewpoint of the changes of total petroleum hydrocarbon （TPH） in soil column profile with sampiing time and degradation pattern. The results showed that the shape of residual TPH distribution curves and the location of the peak concentration were directly affected by initial diesel concentration in each column during natural attenuation and enhancing bioventing. Early in the process of natural attenuation （about 1 month） , when diesel concentration in soil was 5 000 - 40 000 mg oil/kg soil, the changes of TPH in the whole column were mainly influenced by gravity migration. When diesel concentration in soil was less than or equal to 5 000 mg oil/ kg soil, the changes of TPH were not only influenced by gravity migration, but also biodegradation. Approximately 2 months＇venting later,extraction was prominent to maintain stable changes of the diesel concentration on the top of soil column.