Benner M L, Stanford S M, Lee L S, Mohtar R H
Agricultural and Biological Engineering Department, Purdue University, West Lafayette, IN, USA.
J Hazard Mater. 2000 Feb 25;72(2-3):217-36. doi: 10.1016/s0304-3894(99)00141-7.
An in-situ air sparging operation was used to remediate the sandy subsurface soils and shallow groundwater under a drum storage site near Chicago, IL, where either periodic or random spillage of a light non-aqueous phase liquid (LNAPL) occurred between 1980 and 1987. Both field measurements and model simulations using commercially available computer software suggested that microbial degradation was the most significant contributor to the removal of contaminant mass. Toluene, ethylbenzene and total xylenes (TEX), which were of major concern with regards to reaching clean-up criteria at the site, were observed to decline by 88% in concentration. Furthermore, up to 97% of the total mass removed through microbial degradation consisted of TEX. Of the total contaminant spill, up to 23% of initial organic chemical mass was removed through microbial degradation compared to less than 6% by physical stripping. Greater loss to microbial degradation is most likely attributed to the relatively low air injection rate used during the course of the air sparging remediation. Evaluation of air sparging at the site using model simulations supported this analysis by estimating 140 and 620 kg of total contaminant mass being removed through volatilization and biodegradation, respectively. An evaluation of several system design parameters using model simulations suggested that only the type of sparging operation (i.e. pulsed or continuous) was significant in terms of total contaminant removal time, while both the sparging operation and air injection rate were significant in terms of removal of a critical species, total xylenes.
伊利诺伊州芝加哥附近一个桶装储存场地下方的砂质地下土壤和浅层地下水采用了原位空气注入法进行修复，该场地在1980年至1987年间发生过轻质非水相液体（LNAPL）的定期或随机泄漏。现场测量和使用商用计算机软件进行的模型模拟均表明，微生物降解是去除污染物总量的最主要因素。该场地达到清理标准的主要关注污染物甲苯、乙苯和总二甲苯（TEX）的浓度下降了88%。此外，通过微生物降解去除的总质量中高达97%为TEX。在总的污染物泄漏量中，高达23%的初始有机化学物质质量通过微生物降解得以去除，而通过物理剥离去除的比例不到6%。微生物降解造成的损失更大很可能归因于空气注入修复过程中使用的相对较低的空气注入速率。通过模型模拟对该场地的空气注入法进行评估，估计分别通过挥发和生物降解去除的总污染物质量为140千克和620千克，从而支持了这一分析。通过模型模拟对几个系统设计参数进行评估表明，就总污染物去除时间而言，只有空气注入操作类型（即脉冲式或连续式）具有显著影响，而就关键物种总二甲苯的去除而言，空气注入操作和空气注入速率均具有显著影响。
