Yang Xiaomin, Beckmann Dennis, Fiorenza Stephanie, Niedermeier Craig
BP p.l.c., 28100 Torch Parkway, Warrenville, Illinois 60555, USA.
Environ Sci Technol. 2005 Sep 15;39(18):7279-86. doi: 10.1021/es050084h.
Recent laboratory-scale studies strongly suggested an advantage to operating air-sparging systems in a pulsed mode; however, little definitive field data existed to support the laboratory-scale observations. This study aimed to evaluate the performance of a field-scale pulsed air-sparging system during a short-term pilot test and during long-term system operation. The air-sparging system consisted of 32 sparging points and had been previously operated in a continuous mode for two years before the field study was performed. The field study used instruments with continuous data logging capabilities to monitor the dynamic responses of groundwater and soil vapor parameters to air injection. The optimum pulsing frequency was based on the evidence that the hydrocarbon volatilization and oxygen dissolution rates dramatically dropped after the air-sparging system reached steady state. The short-term pilot test results indicated a substantial increase in hydrocarbon volatilization and biodegradation in pulsed operation. On the basis of the results of the pilottest, the air-sparging system was set to operate in a pulsed mode at an optimum pulsing frequency. Operation parameters were collected 2, 8, and 12 months after the start of the pulsed operation. The long-term monitoring results showed thatthe pulsed operation increased the average hydrocarbon removal rate (kg/day) by a factor of up to 3 as compared to the previous continuous operation. The pulsed air sparging has resulted in higher reduction rates of dissolved benzene, toluene, ethylbenzene, and xylenes (BTEX) than were observed during the continuous operation. Among BTEX, benzene's reduction rate was the highest during the pulsed air-sparging operation.
近期的实验室规模研究有力地表明，以脉冲模式运行空气注入系统具有优势；然而，几乎没有确凿的现场数据来支持实验室规模的观察结果。本研究旨在评估现场规模的脉冲空气注入系统在短期试点测试和长期系统运行期间的性能。该空气注入系统由32个注入点组成，在进行现场研究之前，此前已连续运行了两年。现场研究使用具有连续数据记录功能的仪器来监测地下水和土壤蒸汽参数对空气注入的动态响应。最佳脉冲频率基于这样的证据，即空气注入系统达到稳态后，碳氢化合物挥发和氧溶解速率急剧下降。短期试点测试结果表明，脉冲运行中碳氢化合物的挥发和生物降解大幅增加。根据试点测试结果，空气注入系统设置为以最佳脉冲频率进行脉冲模式运行。在脉冲运行开始后的2、8和12个月收集运行参数。长期监测结果表明，与之前的连续运行相比，脉冲运行使平均碳氢化合物去除率（千克/天）提高了高达3倍。脉冲空气注入导致溶解的苯、甲苯、乙苯和二甲苯（BTEX）的去除率高于连续运行期间观察到的去除率。在BTEX中，脉冲空气注入运行期间苯的去除率最高。
