- 期刊
污染場址綠色及永續導向型整治評估架構與方法於含氯地下水污染場址之應用
Application of Green and Sustainable Remediation for a Chlorinated-Solvent-Contaminated Groundwater Site
摘要
土壤與地下水為珍貴之自然資源，由於人為活動蓄意或疏失導致的污染事件，我國在過去20多年間投入於土壤及地下水污染調查與整治的時間、經費、人力與物力甚鉅。然目前仍有數千筆污染場址尚未完成污染改善工作，而在這些污染場址當中，受含氯有機污染物污染的場址整治工作挑戰與困難甚高，所需花費的時間往往也較長，因此在污染範圍的釐清與污染改善技術的選用上，實需妥善規劃管理，方能以有效率的方式解決污染問題。我國近年導入綠色及永續導向型整治觀點進行場址管理，檢視場址調查、污染改善方案選取與設計、污染改善系統建置、污染改善系統操作與維護及定期監測等管理工作可能衍生的環境、社會與經濟影響，以生命週期觀點全面思考污染場址管理的最適方針。本研究以我國環保署所研擬之綠色及永續導向型整治架構、指標、評估程序與工具，評估一含氯有機物地下水污染場址的污染改善工作。結果顯示在該污染場址之改善系統建置、改善系統操作與維護及定期監測等三個場址生命週期階段中，系統操作與維護產生的環境足跡最高；在人體健康風險部分，無論整治前或整治中，污染場址調查與整治相關活動對廠區人員與污染整治工作人員皆無健康風險之虞。故根據評估結果，本研究針對該場址之狀況，提出未來執行整治的最佳管理措施建議。本案例為綠色及永續導向型整治應用於污染改善中之場址，然將來應盡量應用於場址生命週期初期，從場址調查或污染改善方案之選取時即導入，比較不同污染改善方案的綜合表現，擬定合理的污染改善方案、期程與經費，以符合綠色及永續導向型整治之目標。
並列摘要
Soil and groundwater are precious natural resources, and thus pollution due to deliberate actions or lack of concern causes both government and industry to spend tremendous amounts of time, money, labor and material resources on soil and groundwater contamination investigation and remediation. Currently, there are thousands of such sites that still need to be dealt with in Taiwan. Among these sites, the remediation of chlorinated-solvent-contaminated sites is particularly challenging, as well as usually more costly and requiring a longer time to clean up than other polluted sites. Appropriate management of the site characterization efforts and selection of the appropriate remedial actions are thus very important for these locations. Taiwan has recently adopted the concept of Green and Sustainable Remediation (GSR) in the past few years, an approach that handles such sites using a holistic method by evaluating the environmental, social and economic effects caused by the activities related to site management. This research thus applied the GSR framework, indicators, procedures and tools developed by the Taiwan EPA at a site contaminated with chlorinated solvents. The results showed that the operation and maintenance of the remedial system have the highest environmental footprint among the various life-cycle stages, including construction of a remedial system, operation and maintenance of the remedial system, and periodic monitoring. With regard to the human health risk, the results indicate that site activities before remediation and during the remedial work do not create health concerns for either employees of the site or the remedial staff. Based on the assessment results, the case study identifies opportunities for optimizing the remedial system by planning feasible best management practices (BMPs). This case study has applied the GSR concept to a site with ongoing remediation. However, the adoption of GSR should begin at a much earlier stage, such as in the investigation or the remedy selection phase, by comparing the environmental, social and economic impacts of the alternatives to determine a reasonable remedial technology, time frame and budget. 1. Introduction The administration of soil and groundwater contamination investigation and remediation has matured in Taiwan since the enactment of the Soil and Groundwater Pollution Remediation Act in 2000. However, most of the parties responsible for pollution tend to choose remediation technologies which can reach the related standards as fast as possible in order to be delisted, while neglecting possible negative effects generated by the remedial activities. The government and remediation industry both recognize that cleanup activities may include many energy/resource intensive actions, with high environmental footprints. Aside from evaluating remedial actions from an environmental perspective, the social and economic effects of remedial activities should also be considered. Green and sustainable remediation, which defined by the Taiwan EPA as ＂any technique, strategy, or management plan that considers environmental, economic and social aspects, which can reduce environmental footprints, negative social and economic impacts throughout the remediation process, from site investigation, remedy design, operation and management to site closure, while still meeting the regulatory requirements,＂ has been adopted to maximize the overall environmental, societal, and economic benefits of such activities in Taiwan. 2. Materials and Methods GSR can be adopted in all stages of working with a site, starting from site investigation, remedy selection and design, remedial construction, remedial operation and maintenance, long-term monitoring to the completion of remediation. However the objective of a GSR assessment depends on the management stage of the site. At sites for which the remedy has not been determined, the goal of a GSR assessment is to compare the environmental, social and economic performances of different remedial alternatives by using the remedy selection decision support system. At sites with an already determined remedy or ongoing remediation work, the goal is to apply various tools to evaluate the remedy system circumstances and plan BMPs based on the results. This research followed the GSR framework and executive flow chart established by the Taiwan EPA, and conducted environmental footprint assessment and human health risk assessment at a site contaminated with chlorinated organic compounds. Data for constructing and operating the In situ chemical oxidation (ISCO), Air sparging (AS) and Soil vapor extraction (SVE) system was collected. With regard to the human health risk assessment, in addition to the risk for employees of the site, this research also evaluated the health risk for the remedial staff due to their operations and periodic sampling. Feasible BMPs were chosen from the BMPs screening list provided by the Taiwan EPA. 3. Results and Discussion The results showed that the operation and maintenance of the remedial system had the highest environmental footprint among the various life-cycle stages, including construction of remedial system, operation and maintenance of the remedial system, and periodic monitoring. For human health risk, the results indicated that the site activities before and during remediation do not present health concerns for either employees of the site or the remedial staff. Based on the assessment results, the case study identifies opportunities for optimizing the remedial system by planning feasible best management practices (BMPs). Some BMPs listed in this paper had already been conducted before the assessment, and the benefits of these were addressed in the study, while some BMPs are recommendations by the author. 4. Conclusion This study demonstrated how the GSR concept can be applied at a contaminated site. Generally, it follows the process of evaluation, identification of the major sources of any adverse effects, and taking action to mitigate the adverse effects. It is widely acknowledged that it is best to implement GSR in the early stages, where improvement actions can be taken in advance. This study did not conduct social questionnaires or interviews with the local community, since the site was located in an industrial area. However, for sites located in residential areas efforts at communication with the public would be very important. Site managers are thus encouraged to interact with the local community by holding meetings, handing out news letters or arranging site visits. In addition, future site use should be taken into consideration at the beginning of the remedial plan in order to choose the appropriate remedial technology. The area studied in this research will continue to be an operating facility after remediation, so the effects on land are not that critical compared to sites in urban or farmland areas. The adoption of GSR for site management has become a trend in the global remedial industry and hopefully more related case studies can be conducted in the future in Taiwan.