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年度	113	專案性質	實驗性質
專案類別	模場試驗	研究主題	整治
申請機構	淡江大學學校財團法人淡江大學	申請系所	水資源及環境工程學系
專案主持人	張麗秋	職等/職稱	教授
專案中文名稱	建立地下水LNAPL傳導係數分析方法與優化抽除效率(第二年)
中文關鍵字	地下水, LNAPL, 整治, 傳導係數, 提取試驗
專案英文名稱	Developing the analysis method of groundwater LNAPL Transmissivity for optimizing remediation efficiency
英文關鍵字	Groundwater, LNAPL, Remediation, Transmissivity, Bail-down test
執行金額	2,000,000元
執行期間	2024/12/12 至 2025/11/30
計畫中文摘要	本計畫旨在探討輕質非水相液體(Light Non-Aqueous Phase Liquid, LNAPL)在地下環境中之分布特性、傳輸行為與回收效能，並透過提取試驗(Bail-down test)與模式分析，建立適用於國內污染場址之LNAPL提取試驗與評估方法。第一年度主要聚焦於不同數值模型與監測條件對試驗數據的影響，第二年度則進一步透過不同井徑現地試驗、不同解析解進行傳導係數(T值)估算、不同模擬條件進行效益分析，並建立本土化操作手冊以優化未來之LNAPL整治技術。第一年度成果指出，油層厚度薄時，易受人工操作及環境干擾影響，進而影響LNAPL體積估算之準確性；而在數值模型方面，煎餅模型基於浮油厚度計算，常低估LNAPL體積，垂直平衡模型則考慮毛細管作用與飽和度梯度，能更合理反映異質性地層中LNAPL之分布。第二年度(本年度)則延續前期經驗，針對不同井徑配置調整操作策略，為提高數據可靠性，亦全面改用整治泵並搭配自計式水位計，以延長液位監測時間，確保試驗期間能完整觀測油水位回復行為。此外，在T值估算方面，本計畫比較B&R、C&J、CB&P等三種解析解方法，結果顯示B&R適合於短時間且濾料影響小的情況，可快速取得估算值；C&J可修正初期補注效應，但需謹慎設定參數；CB&P則更適用於長期試驗與地層效應顯著的情境，能提供較準確的T值。由於LNAPL與地下水的化學性質迥異，故進一步利用推算結果確認不得直接套用地下水T值於LNAPL模擬，必須透過現地提取試驗實測獲得LNAPL的T值，方能提升污染評估與整治規劃的可靠性。另由數值模式模擬結果指出，LNAPL回收潛力受浮油厚度、T值及地層特性共同控制，並呈現「初期高效－中期衰減－末期低效」的典型動態，雖然最終回收總量受含水層厚度與油層體積支配，但T值決定抽除效率與時程，對整治規劃之影響實為關鍵。本計畫在第二年度建立「LNAPL提取試驗操作手冊」，使現場作業流程標準化，涵蓋設備選擇、液位監測、數據紀錄與結果分析等要點，不僅提升數據一致性與可比性，也提供後續場址應用的實用依據。另以W16為例進行效益分析，顯示整治技術提升約25.5%、整治成本降低約42.6%、能源效率提升約119.2%，充分展現本計畫在技術優化、經濟效益、能源利用方面的多重價值。
計畫英文摘要	This project aims to investigate the distribution characteristics, transport behavior, and recovery efficiency of Light Non-Aqueous Phase Liquids (LNAPLs) in subsurface environments and to establish a field-validated LNAPL bail-down testing and evaluation methodology applicable to contaminated sites in Taiwan through integrated field extraction experiments and modeling analyses. The first-year research primarily focused on the influence of monitoring conditions and numerical models on experimental data, while the second-year extended the scope to evaluate the effects of different well diameters through field trials, estimate transmissivity (T) using multiple analytical solutions, conduct benefit analyses under various simulation conditions, and develop a localized operational manual to optimize future LNAPL remediation practices. The first-year results indicated that thin oil layers are highly susceptible to errors caused by manual measurements and environmental disturbances, which reduce the accuracy of LNAPL volume estimation; moreover, model comparison showed that the pancake model, which calculates based on apparent oil thickness, often underestimates LNAPL volumes, whereas the vertical equilibrium model, by incorporating capillary pressure and saturation gradients, provides a more realistic representation of LNAPL distribution in heterogeneous strata. Building upon these findings, the second-year work optimized operational strategies according to well diameter configurations and, to improve data reliability, employed remediation pumps in combination with automated water level loggers to extend monitoring duration and capture complete water-oil interface recovery behavior. In terms of T-value estimation, three analytical methods—B&R, C&J, and CB&P—were compared: B&R was found suitable for short-duration tests with minimal filter media effects, C&J corrected for early-time recharge influences but required careful parameterization, while CB&P was most appropriate for long-duration tests where stratigraphic effects were significant, yielding more reliable T estimates. Considering the physicochemical differences between LNAPLs and groundwater, the study further confirmed that groundwater T-values cannot be directly applied to LNAPL transport simulations, highlighting the necessity of site-specific bail-down testing to obtain representative LNAPL transmissivity values for accurate assessment and remediation planning. Numerical simulations additionally revealed that LNAPL recovery potential is jointly governed by oil layer thickness, transmissivity, and aquifer characteristics, following a typical “high-efficiency in the early stage, decline in the mid-term, and low-efficiency in the late stage” dynamic pattern. While the ultimate recoverable volume is constrained by aquifer thickness and oil mass, transmissivity plays a critical role in controlling recovery rate and schedule, underscoring its importance in remediation design. To standardize field practices, a “LNAPL Bail-Down Test Operational Manual” was developed, covering equipment selection, water level monitoring, data recording, and result analysis, thereby enhancing data consistency, comparability, and practical applicability across sites. Furthermore, a benefit analysis using well W16 as a case study demonstrated that remediation technology improved by approximately 25.5%, remediation costs were reduced by about 42.6%, and energy efficiency increased by around 119.2%, collectively illustrating the project’s contributions not only in technical optimization but also in economic feasibility and energy efficiency, thus providing a robust scientific basis for future LNAPL remediation strategies.