模擬界面活性劑沖排應用於處理含氯有機污染場址

Simulation of Surfactant Flushing for Application of Chlorinated Organic Contaminant Site

方彥程(Yen-Cheng Fang) ； 林雅婷(Ya-Ting Lin) ； 梁振儒(Chenju Liang)

《土壤及地下水污染整治》 4卷3期 (2017/07) Pp. 159-170

https://doi.org/10.6499/JSGR.2017.0403.003

摘要

某場址之土壤及地下水皆遭受1,2-二氯乙烷及氯苯污染，為能有效移除土壤及地下水中之污染，本試驗嘗試應用界面活性劑沖排(flushing)之方式移除污染物。試驗規劃首先以地下水模擬系統(groundwater modeling system, GMS)模擬該場址以界面活性劑沖排之可行性，藉由模擬之結果，應用於現場施作，瞭解其處理成效。界面活性劑沖排模擬三種情境，分為淺層井 (8 m)灌抽、深層井(12 m)灌抽及深淺層井(皆開篩3 m)同時灌抽，由模擬結果得知，三種情境中淺層井灌抽可形成水力控制，且可達到灌抽平衡；而深層井及深淺層井同時灌抽，則可能因深井位置之水力傳導係數 (1.735 × 10^(-6) cm/s)較小，使得周圍水不及回補，因此，經模擬結果建議現場進行淺層井之灌抽。模場施作條件為灌注井流量0.09噸/小時、每口抽取井流量0.81噸/天，井間距3 m，於本場址高污染區之淺層井進行兩次界面活性劑沖排，由第一次界面活性劑沖排之結果，觀察到地下水中之污染物濃度明顯降低；經過40天後，再進行第二次界面活性劑沖排，發現地下水中之污染物濃度變高，土壤中之污染物濃度則降低，顯示界面活性劑確實可移除土壤及含水層中之含氯有機污染物。

關鍵字

氯苯 ； 1,2-二氯乙烷 ； 界面活性劑 ； 灌抽處理 ； 地下水模擬系統

並列摘要

Soil and groundwater has been contaminated by 1,2-dichloroethane and chlorobenzene at a site. This study attempted to apply the surfactant flushing technique for remediation of soil and groundwater contamination. The groundwater modeling system was initially used to simulate surfactant flushing in the subsurface. Then, according to the simulation results, the simulated test conditions were applied on site to assess the treatment efficacy. Three conditions were used for simulation of surfactant flushing, including (1) shallow injection/extraction (8 m), (2) deep injection/extraction (12 m), and (3) simultaneous shallow and deep injection/extraction (each of wells with 3 m screen length). The simulation results showed that shallow injection/extraction could act as hydraulic control, and achieve groundwater pumping balance; however, there was not enough groundwater recharging at near deep or simultaneous shallow and deep injection/extraction wells. This may be due to the relatively low hydraulic conductivity (1.735 × 10-6 cm/s) in the deeper soil media. The simulation results suggested that shallow injection/extraction could be suitable for operation at this site. The pilot-scale operating conditions for surfactant flushing at a contaminant hotspot zone in shallow wells were as follows: the injection well flow was 0.09 ton/h, each of the extraction well flow rates was 0.81 ton/d, and the spacing of the wells was 3 m. The results obtained after first flushing showed that the concentration of contamination was obviously reduced in the groundwater. Forty days later a second flushing was carried out, and it was observed that the contamination concentrations increased in the groundwater, while they decreased in the soils. The results thus suggested that surfactant flushing could potentially be applied for the removal of chlorinated organic compounds in aquifers.

並列關鍵字

chlorobenzene ； 1,2-dechloroethane ； surfactant ； injection/extraction treatment ； groundwater modeling system