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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	國立高雄師範大學	申請系所	生物科技系(所)
專案主持人	陳士賢	職等/職稱	教授
專案中文名稱	應用示蹤劑技術於含氯有機溶劑污染場址最佳化整治設計
中文關鍵字	含氯有機溶劑場址,示蹤劑試騐,最佳化設計
專案英文名稱	Best Remediation Designs by Employing Tracer Tests in a Chlorinated Solvent Contaminated Site
英文關鍵字	Chlorinated solvent contaminated site, Tracer test, Best remediation design
執行金額	2,130,000元
執行期間	2024/12/1 至 2026/11/30
計畫中文摘要	對於重非水相液體(dense non-aqueous phase liquid, DNAPL)所造成的地下環境污染，傳統的復育方法在地下水層上有下列限制：(一)因地質結構的非均質化、水文的複雜性及異質性大，造成污染分布複雜，造成在污染場址特性界定時的不確定性，(二)對於污染源的特性無法確實掌握，DNAPL污染物在深層地下環境中經歷長期遷移，在多層含水層、阻水層構成的複雜地質條件下，若是流速快造成整治藥劑不易停留，從而影響整治策略的制定和實施效果。 本研究目的是在含氯有機物污染場址，進行現地示蹤劑傳輸試驗，評估污深層含水層中的地下水流場參數，為場址整治系統的設計和優化提供關鍵數據支持。本場址屬於汽車及其零件製造業，主要地下水污染物為1,1-二氯乙烯(0.152 mg/L)，本模場計劃分兩年進行，第一年聚焦在現地示蹤劑傳輸試驗方法的建立和其完善程度，依據場址土壤質地、地質結構、水文條件及污染團所在範圍及深度，進行包括示蹤劑藥劑選用評估、試驗設計、灌注工法、小尺度現場測試、數據分析等工作。第二年綜整小尺度現場測試成果，搭配場址現地整治藥劑灌注過程共同施作，進行大尺度的現地模場試驗，評析整治藥劑三維傳輸分布，並依據成果修正及優化整治操作參數，協助整治單位精確設計，評析現地示蹤劑傳輸試驗在深層高流速地下水污染整治中的適用性和侷限性。 為配合場址目前既設井位及避免干擾目前強化性生物復育加藥工作之進行，於4月、6月、及8月共啟動三次示蹤劑灌注實驗，在本場址北側污染熱區範圍內選擇單井灌注井及地下水下方處抽出井，灌注井與抽出井其距離約16.9公尺，灌注時在井中放入自計式導電度計，導電度紀錄間隔1 hr，示蹤劑在現場以溴離子電極測定或送樣至實驗室以離子層析法檢測。第一階段灌注實驗使用溴化鉀(KBr)作為非反應性示蹤劑，起始濃度為1000 mg/L，採重力灌注方式，總注入量為500 L，每分鐘灌注量約12.5 L，約40分鐘完成灌注，抽出井TW09在灌注後48小時後溴離子濃度為0.517 mg/L(地下40公尺)，在灌注72小時後至240小時溴離子伴隨地下水傳輸流佈，其濃度已低於偵測極限(<0.02 mg/L)，溴離子在縱向及橫向之傳輸及流場歧異性顯然超乎預期。 第二階段示蹤劑灌注實驗，調整KBr灌注濃度為10 g/L，總注入量為150 L，在灌注井TW08地下30公尺量測EC結果顯示，在灌注初期10小時，EC顯示急遽上升至約13500 S/cm，然後伴隨地下水傳輸，呈現穩定下降至約700 S/cm之情形，在抽出井TW09地下30公尺量測EC結果顯示，在灌注後歷經69小時，EC顯示由400 S/cm穩定下降至約190 S/cm之情形，在TW09地下37公尺量測EC結果顯示，在灌注初期5小時，EC由200 S/cm上升至295 S/cm，然後在灌注後歷經69小時，穩定下降至約175 S/cm，TW9在不同深度30公尺及37公尺的EC其變化明顯不同，且變化幅度相較TW8明顯小很多。量測抽出井TW09示蹤劑濃度顯示溴離子濃度介於200 mg/L至2000 mg/L，48小時後溴離子濃度介於400 mg/L至500 mg/L，示蹤劑濃度變化趨勢與EC變化大致相同。本次實驗使用溴電極現場量測以求即時性及提高監測頻率，但電極讀值會經常性跳動，造成測值之不確定性。 第三階段示蹤劑灌注實驗，因KBr供應商缺貨，因此改用性質相近之NaBr，NaBr之灌注起始濃度為10 g/L，總注入量為250 L，在灌注初期13小時，灌注井TW08於地下37公尺EC顯示急遽上升至約9900 S/cm，然後伴隨地下水傳輸，48小時候呈現下降至約4000 S/cm之情形，持續至60小時後EC再下降至500 S/cm，然後EC趨之平緩約在2500 S/cm。TW09於地下27公尺及37公尺處量測EC，地下27公尺之EC介於172 S/cm -180 S/cm，TW09地下37公尺EC變化亦不明顯，介於173 S/cm -177 S/cm之間，顯示示蹤劑灌注後未造成EC變動。於TW09現場示蹤劑濃度篩測濃度變化介於4 mg/L至30 mg/L，溴離子次高濃度20 mg/L出現在量測第36小時，最高濃度30 mg/L出現在量測之第39小時，除現場篩測外亦將樣品送實驗室以離子層析法測定，不同時間下樣品其示蹤劑濃度均低於偵測極限，與現場篩測顯示差異甚大。 以THMC軟體模式(Thermal Hydrology Geo-Mechanic Reactive Chemical Model)模擬示蹤劑傳輸結果顯示，歷經100小時後，灌注井TW08之溴離子濃度會從初始10000 mg/L降至1953 mg/L，抽出井TW09(地下15公尺)之溴離子濃度逐漸升至281 mg/L，至於在地下40公尺，抽出井TW09之溴離子濃度逐漸升至33.5 mg/L，實場示蹤劑試驗顯示溴離子濃度較模擬值低，顯示場址之流場複雜性較遠較預期高。 本計畫截至期末報告提送時，在一年執行期已完成示蹤劑相關文獻蒐集及研析，同時對於場址地質及水文結構、土壤質地進行資料蒐集及研析。在污染熱區初步界定示蹤劑試驗場地範圍，規畫小尺度實場測試，選擇適合地下水含氯有機物場址之非反應性示蹤劑及建立示蹤劑分析方法，並完成三次示蹤劑灌注試驗。由於第一含水層之流場非常紊亂，示蹤劑注入時可能會透過部分優勢路徑快速流失，反而不易掌握其可能去向，在偵測時濃度低於預期或不知去向，為避免相關情形發生，因此在下階段之示蹤劑試驗，除研擬提高溴離子濃度，以增加其可偵測濃度區域，同時提高監測頻率，對於注入井及抽除井相關井位之選擇將再作調整，嘗試選擇距離較短之試驗井位。
計畫英文摘要	At dense nonaqueous phase liquid (DNAPL) sites, two primary zones of interest may be recognized: (1) the source zone, defined as the volume of the vadose zone or the aquifer that has had contact with the DNAPL, and (2) the plume zone, which contains only the dissolved, adsorbed, or volatilized constituents transported away from the source. More frequent implementation of high-resolution site characterization techniques have enabled the development of far more accurate conceptual site models. Realistic conceptualization of aquifer structure recognizes that the majority of groundwater flow and contaminant mass flux occurs through the most permeable materials, and that these can represent a relatively small percentage of the overall aquifer volume at most sites. As a result, remediation system designers have an increased level of understanding of contaminant transport mechanisms that draws from a large body of empirical observations of plume dynamics and remediation system performance. The purpose of this study is to using tracer to assess the site-specific flow paths in a chlorinated solvent contaminated site in northern Taiwan. The effect of groundwater velocity on the transport of nonreactive tracer will be examined. The tracer test may serve a particularly useful remediation metric for NAPL-zone bioremediation treatment efforts because the same subsurface volume can be directly measured in essentially the same manner before and after bioremediation activity. The site manufacturing auto parts was previously contaminated by total petroleum hydrocarbons (TPH), trichloroethylene (TCE) and 1,1 dichloroethylene (1,1, DCE). Soil contaminated by TPH was remediated. Groundwater contamination was treated by pump and treat for several years then altered to enhanced bioremediation. Groundwater velocity varies between 0.02 m/day to 0.3 m/day in the contaminated site. Nonreactive tracer tests were conducted in this study. Initial tracer test including injection of 500 L of potassium bromide (KBr) with concentration of 1000 mg/L was performed by gravity infusion. The distance between injection well and extraction well is 16.9 m. Monitoring of bromide concentration in injection well TW08 was performed 48 and 96 hours later after tracer injection. The bromide concentration declined from 117 mg/L to 38.6 mg/L. Conductivity change was observed to drift from 1351 µS/cm to 190 µS/cm during tracer injection. Observation of bromide concentration in extraction well TW09 was conducted after 48 hours. Bromide concentration of 0.517 mg/L was detected in TW09 (40 m below surface). However, bromide concentration was below detection limit after 72 hours afterwards. Subsequently 150 L of 10 g/L of sodium bromide (NaBr) was adopted in the second tracer test. Real time monitoring of bromide concentration was performed on site by using bromide ion-selective electrode. Bromide concentration of 200 mg/L to 2000 mg/L was detected in extraction well TW09 after 24 hours. However, the bromide concentration was observed to be 400 mg/L to 599 mg/L after 48 hours. Conductivity increased was observed to 13500 µS/cm in TW08 (30 m below surface) after 10 hours and declined to 700 µS/cm. EC in TW09 at 30 m and 37 m showed change from 400 µS/cm to 190 µS/cm and 295 µS/cm to 175 µS/cm, respectively. Subsequently 250 L of 10 g/L of sodium bromide was used in the third tracer test. Bromide concentration ranging from 4 mg/L to 30 mg/L was detected in extraction well TW09. Conductivity increased was observed as 9900 µS/cm in TW08 (37 m below surface) after 13 hours and declined to 4000 µS/cm after 48 hours. Continuous decline of EC to 500 µS/cm was observed and rebound to 2500 µS/cm. EC in TW09 at 27 m and 37 m below surface maintained at 172 µS/cm to 180 µS/cm and 173 µS/cm to 177 µS/cm, respectively. Local developed Thermal Hydrology Geo-Mechanic Reactive Chemical Model (THMC) was used to simulate tracer transport in the subsurface environment. Bromide concentration was predicted to change from 10000 mg/L to 1953 mg/L in injection well TW08 after 100 hours. Simulation results indicated that bromide concentration of 281 mg/L in TW09 (15 m below surface). However, 33.5 mg/L of bromide was predicted in TW09 (40 m below surface) after 100 hours. Model simulation generated higher concentration of bromide than tracer tests. It was suspected that potential preferential flow path may be the cause. Tracer test data generated was critically evaluated for multiple confounding factors and artifacts in this project. Factors such as hydrogeological and biogeochemical characteristics of the source zone, heterogeneous DNAPL distributions, injection/extraction schemes, and prior activities in the source zone will be examined in the following tracer test design.