确定空气注射技术影响半径的现场试验——以北京某焦化厂为例

摘要

以北京某焦化厂地下水污染场地为例,设计和建立了一套由1口注射井、3口地下水监测井和5口土壤气监测井组成的现场试验系统,并进行了现场注气压力与流量测试,地下水压力响应测试,溶解氧测试,氦气示踪测试与土壤气测试,确定了试验区域的最佳注气压力与流量和影响半径.注气压力与流量测试确定了最佳注气压力与流量为0.03MPa,23.2m3/h.在最佳注气条件下,地下水监测井G3、G5、G8中,水位分别在10,15,15min后上升到最大值0.36,0.11,0.04m,地下水溶解氧浓度分别在60,65,75min后增加到7.35、2.47、0.74mg/L,以上结果表明,G3和G5响应较明显,G8响应不明显.土壤气监测井S2、S4、S5中氮气浓度分别在10,7,6min后达到最大值83％、13％、41％,S6中氦气无检出；S2、S3、S4、S5、S6中O2浓度分别上升到19.9％、19.6％、19.2％、19.0％、16.6％,以上结果表明,S2～55响应较明显,S6响应不明显.综合分析以上4种测试结果,确定试验区域的影响半径为5m.%A pilot test scheme, which consists of 1 injection well, 3 groundwater monitoring wells and 5 soil gas monitoring wells, was designed and installed in a Beijing coke plant. Injection pressure and flow rate test, groundwater response test, dissolved oxygen test, helium tracing test and soil gas test were carried out for determining the optimum injection pressure and flow rate and radius of influence (ROI) of the air sparging system. The injection pressure and flow rate test shows that 0.03MPa, 23.2 mVh are the optimum injection pressure and flow rate. Under the suggested optimum injection pressure and flow rate, water tables in groundwater monitoring well G3, G5, G8 rose up to 0.36, 0.11, 0.04m in 10, 15, 15min, respectively, and DO rose up to 7.35, 2.47, 0.74mg/L in 60, 65, 75min, respectively, suggesting that response was obvious in G3 and G5, not G8. The highest helium concentration was 83%, 13%, 41% in S2, S4, S5 at 10, 7, 6min, and none in S6; the oxygen concentration was 19.9%, 19.6%, 19.2%, 19.0%, 16.6% in S2, S3, S4, S5, S6, respectively, suggesting that injection air has relatively significant influence on S2-S5. The ROI in the test area is suggested to be 5m based on the comprehensive analysis of the above results.