本研究以北部某低滲透性 TPH 污染場址為研究對象，探討 DPE 結合 AS 應用於低滲透性土壤中之整治效能。由於低滲透性粉質黏土地層常受高含水率、毛細阻隔、水封效應、氣相傳輸受限及 Smear Zone 污染滯留等因素影響，SVE 於此類場址中往往難以有效啟動污染物移除機制。因此，本研究透過實場操作試驗，分析地下水位控制、鼓風機操作頻率、抽水深度、曝氣操作、連續與間歇運轉模式，以及綜合優化策略對污染物移除行為與能源使用效率之影響。研究結果顯示，地下水位控制為低滲透性地層中啟動氣相污染物移除之關鍵條件。於未抽水之 SVE 階段，尾氣 VOCs 濃度偏低，顯示高地下水位及水封效應限制氣相傳輸；當 DPE 啟動並造成地下水位洩降後，尾氣 VOCs 濃度明顯提升，顯示 Smear Zone 暴露與未飽和帶擴大可有效促進污染物揮發與氣相移除。進一步分析顯示，本場址最小有效水力控制深度約為地表下 4.8–5.0 m，當地下水位降至此區間後，污染物釋出反應明顯增強。在操作頻率方面，20–25 Hz 已可維持相對穩定之抽氣流量與較佳能源效率；當頻率提高至 35–40 Hz 時，雖污染物濃度略有增加，但功率需求明顯上升，導致 EI 惡化，顯示高強度操作不必然帶來等比例整治效益。AS 曝氣操作則可於部分時段造成尾氣 VOCs 濃度短暫提升，反映曝氣有助於促進局部污染物釋放，但其效果仍受低滲透性地層氣體通道分布限制。連續式與間歇式操作比較亦顯示，停機期間污染物可由低通量基質向流動區重新釋放，形成濃度回升現象，說明間歇操作可作為改善質傳受限與降低無效能耗之操作策略。綜合而言，本研究證實 DPE/AS 聯合技術應用於低滲透性 TPH 污染場址時，整治成效並非單純取決於抽氣或曝氣強度，而是受地下水位控制深度、氣相傳輸條件、質傳受限程度及能源效率共同影響。建議未來低滲透性場址整治設計應導入最小有效水力控制深度、EI 指標及動態操作優化機制，以取代固定操作模式，作為提升污染物移除效率、降低能源消耗及修訂現行整治技術指引之參考依據。;This study investigated the remediation performance and operational optimization strategies of combined Dual-Phase Extraction (DPE) and Air Sparging (AS) at a petroleum hydrocarbon-contaminated site characterized by low-permeability soils in northern Taiwan. Low-permeability silty clay formations are commonly affected by high moisture content， capillary barriers， water-sealing effects， restricted vapor transport， and contaminant retention within the Smear Zone， which often limit the effectiveness of conventional Soil Vapor Extraction (SVE) systems in initiating contaminant removal. Therefore， field-scale operational tests were conducted to evaluate the effects of groundwater level control， blower operating frequency， pumping depth， air sparging operation， continuous and intermittent operating modes， and integrated optimization strategies on contaminant removal behavior and energy efficiency.The results demonstrated that groundwater level control is the key factor governing the initiation of vapor-phase contaminant removal in low-permeability formations. During the SVE-only stage without groundwater extraction， exhaust-gas VOC concentrations remained relatively low， indicating that elevated groundwater levels and water-sealing effects restricted vapor transport. Following DPE implementation and subsequent groundwater drawdown， exhaust-gas VOC concentrations increased substantially， suggesting that exposure of the Smear Zone and expansion of the vadose Zone effectively enhanced contaminant volatilization and vapor-phase removal. Further analysis indicated that the minimum effective hydraulic control depth at the study site was approximately 4.8–5.0 m below ground surface. Once groundwater levels were lowered to this interval， contaminant release and removal responses increased significantly. Regarding operational frequency， blower frequencies of 20–25 Hz maintained relatively stable extraction flow rates and achieved superior energy efficiency. Although contaminant concentrations increased slightly at higher frequencies (35–40 Hz)， power consumption increased disproportionately， resulting in deteriorated Energy Intensity (EI) performance. This finding indicates that higher operating intensity does not necessarily translate into proportional remediation benefits. Air sparging operations caused temporary increases in exhaust-gas VOC concentrations during certain periods， suggesting that injected air promoted localized contaminant mobilization and volatilization. However， the effectiveness of AS remained constrained by gas-flow pathways within the low-permeability formation. Comparisons between continuous and intermittent operation further revealed that contaminant concentrations rebounded during shutdown periods due to contaminant transfer from low-permeability matrix Zones back into preferential flow pathways. This behavior suggests that intermittent operation may alleviate mass-transfer limitations while reducing unnecessary energy consumption. Overall， the study confirms that remediation performance of the combined DPE/AS system at low-permeability petroleum hydrocarbon-contaminated sites is not solely determined by extraction or sparging intensity. Instead， remediation effectiveness is jointly controlled by groundwater drawdown depth， vapor transport conditions， mass-transfer limitations， and energy efficiency considerations. The results suggest that future remediation designs for low-permeability sites should incorporate the concepts of minimum effective hydraulic control depth， Energy Intensity (EI) evaluation， and dynamic operational optimization mechanisms rather than relying on fixed long-term operating conditions. These findings provide a practical basis for improving contaminant removal efficiency， reducing energy consumption， and refining existing remediation guidance for low-permeability contaminated sites.
