Combined In-Situ / Ex-Situ Remediation of PFAS at Hazardous Waste Sites

土壤和地下水中的多氟烷基和全氟烷基物质（PFAS）目前通过提取 受污染的地下水，通过颗粒活性炭（GAC）或其他吸附剂进行异地处理 仅将污染物转移到仍需要处理的另一介质的吸附剂。这是一个很长的- 长期和昂贵的过程，因为1）它需要几十年的土壤上吸附的PFAS被提取通过 地下水泵和处理（P&T），2）碳必须经常更换，3）处理（通过高 温度再生或焚化）是昂贵的。最近，希金斯（希金斯，克里斯，2016年“治疗和 多氟烷基和全氟烷基物质的缓解策略”，报告#4322，水研究基金会，丹佛，CO） 结果表明，低分子量的PFAS比其他化合物更快地突破GAC。此外，P&T 技术可能永远不会达到EPA健康咨询浓度的含水层。PFAS是氟化的 美国环保局和全球卫生组织已确定为有毒，持久性， 具有生物累积性和高度可降解性，耐水解、光解和生物降解。PFAS 被用于许多产品，包括水成膜泡沫，以打击化学火灾在军事和 在民用消防训练区，它们是环境中PFAS的常见来源。他们一直 在地表沃茨中发现，在使用后多年仍存在于地下水中， 饮用水供应。截至2014年，仅美国国防部就确定了664起火灾/坠机/训练事件， 可能存在PFAS污染的地点。因此，迫切需要一种更具成本效益的 和现场修复方法，用于修复PFAS污染场地，这在未来只会增加 年我们的团队将进一步开发和展示一种创新的原位/非原位组合技术， 以具有成本效益的方式加快超级基金场地的PFAS处理。拟议的专有处理列车 结合1）无毒的环状糖（CS）以从原位土壤中冲洗吸附的PFAS，2）CS的提取， PFAS与地下水复合，处理效率高达99+%，去除率为70 ppt（万亿分之一） 一个异位反应器，使用一个增强泡沫的过程从抽取的地下水中去除PFAS 形成分离和浓缩PFAS到一个单独的反应器，在那里它被破坏， 浓缩至70 ppt总PFAS。将低浓度CS改良剂处理后的水回注 进入地下继续冲洗蓄水层第一阶段试验表明：1）PFAS能有效地 从高度PFAS污染的土壤中冲洗，冲洗量相对较小，2）PFAS可以 从抽取的地下水中有效分离并在浓缩物中破坏。实验室规模测试将 可用于评估优化特定地点PFAS从土壤中解吸、分离 的萃取CS-PFAS复合物，并最终破坏的PFAS浓缩物在异位反应器。一 将在第II阶段进行现场特定的现场中试试验，以证明通过该工艺进行PFAS处理。 1

Poly- and perfluoroalkyl substances (PFAS) in soil and groundwater are currently remediated by extracting the contaminated groundwater for ex-situ treatment via adsorption onto granular activated carbon (GAC) or other sorbents which only transfers contaminants to another media that still needs to be treated. This is a very long- term and expensive process because 1) it takes decades for the sorbed PFAS on soil to be extracted via groundwater pump and treat (P&T), and 2) the carbon must be changed frequently and 3) treatment (by high temperature regeneration or incineration) is costly. Recently, Higgins (Higgins, Chris, 2016 “Treatment and Mitigation Strategies for Poly and Perfluoroalkyl Substances”, Report #4322, Water Research Foundation, Denver, CO) showed that low molecular weight PFAS breakthrough GAC faster than other compounds. In addition, P&T technology may never achieve EPA Health Advisory concentrations in the aquifer. PFAS are fluorinated anthropogenic pollutants that the USEPA and global health organizations have identified as toxic, persistent, bioaccumulative and highly recalcitrant, being resistant to hydrolysis, photolysis, and biodegradation. PFAS were used in many products, including aqueous film-forming foams to combat chemical fires at military and civilian fire training areas where they are a common source of PFAS to the environment. They have been identified in surface waters and they persist in groundwater years after use, contaminating and threatening drinking water supplies. As of 2014, the U.S. Department of Defense alone has identified 664 fire/crash/training sites alone that potentially have PFAS contamination. Thus, there is a critical need for a more cost-effective and in-situ remediation approach for remediating PFAS contaminated sites that will only increase in the coming years. Our team will further develop and demonstrate an innovative combined in-situ/ex-situ technology to cost-effectively expedite treatment of PFAS at Superfund sites. The proposed proprietary treatment train combines 1) a non-toxic cyclic sugar (CS) to flush sorbed PFAS from the in-situ soil, 2) extraction of the CS- PFAS complex with groundwater and treatment in a high efficiency 99+% removal to 70 ppt (parts-per-trillion) ex-situ reactor that removes the PFAS from the extracted groundwater using a process to enhance foam formation that separates and concentrates the PFAS into a separate reactor where it is destroyed in the concentrate to 70 ppt total PFAS. The treated water with a low concentration of CS amendment is re-injected into the subsurface for continued aquifer flushing. In Phase I, it was shown that: 1) PFAS can be effectively flushed from highly PFAS contaminated soils with a relatively small flushing volume, and 2) the PFAS can be effectively separated from the extracted groundwater and destroyed in the concentrate. Bench scale tests will be used to evaluate those parameters needed to optimize site-specific PFAS desorption from soil, separation of the extracted CS-PFAS complex, and ultimate destruction of the PFAS concentrate in the ex-situ reactor. A site-specific field pilot test to demonstrate PFAS treatment by the process will be performed in Phase II. 1