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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	國立中興大學	申請系所	環境工程系
專案主持人	梁振儒	職等/職稱	特聘教授
專案中文名稱	現地緩釋滲流化學氧化整治未飽和層土壤殘留相氯化有機物消弭地下水長期污染之潛勢
中文關鍵字	未飽和層土壤、地下水污染、含氯有機溶劑、現地化學氧化法、滴灌
專案英文名稱	In-Situ Chemical Oxidation with Controlled Infiltration Release for Remediation of Unsaturated Zone Soils Contaminated by Residual Chlorinated Organics - Aimed at Mitigating Long-Term Groundwater Pollution Potential
英文關鍵字	To be provided uponapproaval of the proposal.
執行金額	2,400,000元
執行期間	2024/11/1 至 2026/11/30
計畫中文摘要	本研究計畫為針對三氯乙烯(Trichloroethylene, TCE)於未飽和層所形成之殘留相污染問題，提出一創新之現地化學氧化整治技術(In situ chemical oxidation, ISCO)。TCE常因大量洩漏滲流至地表下，形成液滴相或土壤吸附殘留相，並於遇低滲透性土層(Low permeability zone, LPZ)時停止移動，進一步以正向擴散進入LPZ。此殘留污染物雖可能符合土壤管制標準，但雨水滲流或地下水位變化接觸污染土壤之影響，因濃度梯度反轉而發生反向擴散(Back-diffusion)，造成污染回復(Rebound)現象，再度污染地下水超過法規標準，成為污染場址整治之重大挑戰。為因應上述之困境，本研究開發一應用於未飽和層土壤之ISCO系統，選用於地表下相對穩定之過硫酸鈉(Sodium persulfate, SPS)作為氧化劑，並透過農業滴灌原理設計滲透管緩釋灌注系統，利用控制滲流頻率、水量與壓力參數，將氧化劑緩慢釋入土壤中，以毛細作用停留於土壤顆粒間並誘發氧化反應，有效提升反應效率並降低優勢流風險。相較於傳統ISCO僅限於飽和含水層應用，此技術可望擴展ISCO應用至未飽和層土壤，並針對殘留相TCE進行整治去除。 於現階段研究成果，研究團隊已完成滲透管緩釋灌注系統之裝置設計與製作。裝置之主體採304不鏽鋼製成，具備剛性高與耐氧化特性。裝置結構上採四片帶孔不鏽鋼護板，並組合為通道型空間使滲透管穿越其中，孔洞之設計亦可使氧化劑液體有效釋出於土壤之中。裝置經通過初步測試，可順利將氧化劑穩定滲漏，顯示其具備實地操作應用性。同時，研究團隊亦完成機電控制系統設計，整合蠕動馬達、定時電控閥、流量與壓力感測器，以及可程式邏輯控制器系統，同時執行進行十隻滲透管之自動化緩釋灌注，利於整治作業之推進，並可支援資料即時記錄與後端分析。另為掌握整治期間土壤含水率之動態變化，研究團隊選用具備分段量測與降低土壤干擾特性之GroPoint Profile 120 cm多層式土壤含水率探針進行試驗，並整合無紙式紀錄系統，配合後續現地施作進行含水率即時監測。此外，研究團隊亦完成Hydrus模擬軟體之採購並進行訓練，Hydrus用以模擬未飽和多孔介質中水分與氧化劑溶質遷移傳輸行為，於後續研究中搭配實測含水率資料進行模擬與模型校正，提升對氧化劑滲流與反應範圍之預測進而調整滲透管緩釋灌注系統之操作。 綜而言之，本研究計畫第一年執行成果已完成整體整治架構之設備組件，包括滲透管緩釋灌注系統、機電控制系統與含水率監測設備，並完成Hydrus模擬軟體之初步模擬，同時完成建立整治系統標準作業流程(SOP)，整體進度符合預期目標進度，為後續場址整治施作建立良好基礎。
計畫英文摘要	This research project proposes an innovative in-situ chemical oxidation (ISCO) technology specifically designed to address residual-phase contamination of trichloroethylene (TCE) in the unsaturated zone. TCE often leaks in large quantities and migrates below the surface, forming non-aqueous phase liquids or adsorbed residues on soil particles. Its movement typically halts upon encountering low-permeability zones (LPZs), from where it can gradually diffuse into the LPZ. Although the residual contamination may meet regulatory soil standards, changes in groundwater levels or infiltration from rainfall can reverse the concentration gradient, triggering back-diffusion. This leads to contaminant rebound, where TCE re-enters the groundwater at concentrations exceeding regulatory limits, posing a significant challenge for site remediation. To address this issue, the study develops an ISCO system tailored for unsaturated zone soils. Sodium persulfate (SPS), a relatively stable oxidant under subsurface conditions, is selected as the chemical oxidant. A slow-release infiltration system, inspired by agricultural drip irrigation, is designed to control the delivery frequency, volume, and pressure of the oxidant. This approach allows the oxidant to gradually infiltrate the soil, remain within the soil pores via capillary action, and then initiate oxidation reactions. The method enhances reaction efficiency while minimizing the risk of preferential flow. Compared to conventional ISCO methods, which are typically limited to saturated zones, this technique has the potential to extend ISCO applications to the unsaturated zone and effectively remediate residual-phase TCE contamination. At the current stage of research, the team has completed the design and fabrication of a porous pipe-based controlled-release injection system. The main structure of the injection device is made of 304 stainless steel, which offers high rigidity and excellent oxidation resistance. Structurally, the device features four perforated stainless-steel protective plates assembled into a channel-like configuration and specifically designed to enable effective release of oxidizing agents into the surrounding soil. Initial testing has demonstrated that the system can steadily and reliably release the oxidant, confirming its potential for field application. The team has also completed the design of the electromechanical control system, integrating a peristaltic pump, timed solenoid valves, flow and pressure sensors, and a programmable logic controller (PLC). This setup allows automated controlled release through ten porous tubes simultaneously, supporting large-scale remediation efforts and enabling real-time data logging and back-end analysis. To monitor dynamic changes in soil moisture during the remediation process, the team selected the GroPoint Profile 120 cm multi-layer soil moisture probe, which offers segmented measurement and reduced soil disturbance. This probe was integrated with a paperless recording system to support real-time soil moisture monitoring in future field applications. Additionally, the team has completed the early procurement and training for the Hydrus simulation software. Hydrus will be used to model water flow and oxidant solute transport in unsaturated porous media. Combined with the measured soil moisture data, the software will support simulation and model calibration to improve predictions of oxidant infiltration and reaction zones, thereby informing adjustments to the operation of the controlled-release injection system. In summary, during the first year of project execution, the research team has successfully completed the setup of the experimental remediation framework, including the controlled-release infiltration system, electromechanical control unit, and soil moisture monitoring instruments. Initial Hydrus simulations and the standard operating procedures (SOP) for the remediation system have also been established. The overall progress aligns with the planned objectives and lays a solid foundation for future on-site remediation implementation.