生物通风技术修复柴油污染土壤的土柱模拟实验

生物通风技术是将土壤气相抽提和生物降解结合起来的原位强迫氧化降解方法,对于修复因地下储油罐泄漏引起的土壤污染具有广阔的应用前景。通过室内土柱模拟柴油泄漏污染土壤,分析了不同历时残余总石油烃(total pe-troleum hydrocarbon,TPH)的平衡分布规律以及土壤中不同深度柴油量、总柴油量的变化。结果表明:(1)各柱残余TPH剖面分布差异的原因受土柱的初始装填情况的影响较大;(2)残余TPH平衡分布曲线呈双峰型的土柱,柴油的去除主要以挥发作用及生物降解作用为主;(3)挥发作用主要是由通风孔隙体积数及土壤含水率来影响的;重力作用则主要是由初始油浓度、土壤含水率、C∶N∶P影响的;除通风方式外,其余4个因素都对生物降解作用有影响;(4)初始油浓度较大,土壤含水率较小的柱8和柱11,生物降解作用最明显,柴油去除效果最好。该成果可为生物通风过程的强化提供理论依据。

Soil column simulation experiment of remediating soil contaminated by diesel using bioventing technology

Bioventing is an in situ forced oxidative soil remediation technology which combines soil vapor extraction with biodegradation.It has broad application prospects of soil contamination caused by underground storage tank leakage.In this paper,soil column experiment,which was used to simulate diesel contamination,was conducted.The law of balance distribution of residual TPH at different times and the change of diesel quantity in soil at different depths,together with total diesel quantity of the whole column were analyzed.The results showed that:(1) The profile distribution difference of residual TPH was influenced largerly by the initial loading conditions of soil column.(2) The diesel in soil was removed mainly by volatilization and biological degradation for the column which the balance distribution curves of residual TPH was bimodal.(3) Volatilization was mainly influenced by pore volume number during soil venting and soil moisture content,and gravity was mainly influenced by initial diesel concentration,soil moisture content and the ratio of carbon,nitrogen and phosphate.In addition to venting mode,the other factors affect the biodegradation.(4) For the soil column 8 and 11,which the initial diesel concentration were higher and the soil moisture content were both less,the biodegradation was the most significant and the removal effect of diesel in soil column was the best.The results could provide a theoretical basis for the enhancement of bioventing process.