Collaborative Research: ERASE-PFAS: Hydrothermal Treatment as a Strategy for Simultaneous PFAS Destruction and Recovery of Energy and Nutrients from Wastewater Residual Solids

全氟和多氟烷基物质(PFAS)是一种氟化有机化学品，用于许多消费品和工业应用。在过去的十年中，由于人们越来越关注其持久性、稳定性以及在环境中积累时对人类和其他生物的毒性，全氟辛烷磺酸已成为优先考虑的污染物。在水资源回收设施(WRRF)的污泥和生物固体中检测到越来越多的全氟辛烷磺酸，这引起了人们对在农业和农业中将这些固体用作土壤改良剂以及有机物和养分来源的严重关切。该合作项目的目标是评估使用热液液化(HTL)作为一种平台技术，以促进同时销毁全氟辛烷磺酸并从污泥中回收液体燃料和营养物质。HTL工艺使用高温(250-350°C)和高压(100-250bar)在专门设计的反应器中分解WRRF中的PFAS-In污泥。拟议的研究将评估HTL在生产液体燃料和营养物质的同时修复含有全氟辛烷磺酸的污泥的有效性。这一项目的成功完成将通过发展新的基本知识和技术，推动对富含全氟辛烷磺酸的废物管理系统产生的淤泥进行具有成本效益的补救和管理，从而造福社会。科罗拉多矿业学院的一名研究生和伊利诺伊大学厄巴纳-香槟分校的一名研究生将通过外展和教育活动获得更多的社会效益。在农田和农场中检测到全氟辛烷磺酸，并将污泥应用于土地，引起了人们对污泥土地应用的严重担忧，这是一种通常用于改善土壤质量和作物产量的耕作做法。这项合作研究的目的是评估和促进热液液化(HTL)作为管理水资源回收设施(WRRF)中含有PFAS的污泥的替代技术的应用。这一目标将通过实验和建模工作相结合来推进，重点放在两个关键目标上：(1)确定HTL工艺条件，确保销毁堆积在WRRF污泥中的PFAS；以及(2)开发和应用系统建模框架，通过回收燃料和有价值的产品(例如营养物质)，同时安全地销毁PFAS污染物，来优化污泥的计价。拟议的实验将评估全氟辛烷磺酸的破坏情况，并跟踪污泥HTL过程中产生的碳、氮和磷的质量平衡。HTL实验的结果将为流程模块的开发和验证提供信息和指导，这些模块将被纳入QSDSAN(卫生和资源回收的量化可持续设计)，这是一个开源建模框架，用于优化从废水和废弃生物质中回收资源。在破坏全氟辛烷磺酸的同时优化资源回收的模型预测随后将用从几个WRRF获得的污泥和消化的生物固体进行验证。该项目的成功完成有可能通过开发和验证一种新技术来产生变革性的影响，该新技术可以解决污泥全氟辛烷磺酸污染问题，同时促进有价值的产品的回收。为了实施该项目的教育和外展活动，首席调查员(PI)计划利用科罗拉多矿业学院(CSM)现有的REU计划，通过招收以前没有参加过本科研究的学生来扩大对STEM教育的参与。此外，PIS计划1)举办虚拟研讨会，以支持和扩大水研究社区对QSDSan建模的使用；2)为将参加CSM阅读障碍儿童夏令营的K-6学生开发从废流中回收资源的夏令营活动。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Per- and polyfluoroalkyl substances (PFAS) are fluorinated organic chemicals that are used in numerous consumer products and industrial applications. During the last decade, PFAS have emerged as priority pollutants due to increasing concerns about their persistence, stability, and toxicity to humans and other living organisms as they accumulate in the environment. The increasing detection of PFAS in sludge and biosolids from water resource recovery facilities (WRRFs) has raised serious concerns about using these solids in agriculture and farming as soil amendments, and sources of organic matter and nutrients. The goal of this collaborative project is to evaluate the use of hydrothermal liquefaction (HTL) as a platform technology to advance the simultaneous destruction of PFAS and recovery of liquid fuel and nutrients from sludge. The HTL process uses high temperature (250-350°C) and high pressure (100-250 bar) to break down PFAS-in sludge from WRRFs in a specially designed reactor. The proposed research will evaluate the effectiveness of HTL to remediate PFAS-laden sludges while producing liquid fuel and nutrients. The successful completion of this project will benefit society through the development of new fundamental knowledge and technology to advance the cost-effective remediation and management of PFAS-laden sludges from WRRFs. Additional benefits to society will be achieved through outreach and educational activities including the mentoring of a graduate student at Colorado School of Mines and a graduate student at the University of Illinois at Urbana-Champaign.The detection of PFAS in agricultural fields and farms where sludges were applied to the land has raised serious concerns about the land application of sludge, a farming practice commonly used to improve soil quality and crop yields. The goal of this collaborative research is to evaluate and advance the application of hydrothermal liquefaction (HTL) as an alternative technology for managing PFAS-laden sludges from water resource recovery facilities (WRRFs). This goal will be advanced through a combination of experiments and modeling efforts with a focus on two critical objectives: (1) identify HTL process conditions that ensure destruction of PFAS that accumulate in sludges from WRRFs; and (2) develop and apply a system modeling framework to optimize sludge valorization through the recovery of fuel and valuable products (e.g., nutrients) while safely destroying the PFAS contaminants. The proposed experiments will evaluate the destruction of PFAS and track the mass balances of the carbon, nitrogen, and phosphorus that are generated during sludge HTL. The results of the HTL experiments will inform and guide the development and validation of process modules that will be incorporated into QSDsan (Quantitative Sustainable Design for sanitation and resource recovery), an open-source modeling framework for optimizing resource recovery from wastewater and waste biomass. Model predictions that optimize resource recovery while destroying PFAS will then be validated with sludges and digested biosolids obtained from several WRRFs. The successful completion of this project has the potential for transformative impact through the development and validation of a new technology that addresses sludge PFAS contamination while advancing the recovery of valuable products. To implement the education and outreach activities of the project, the Principal Investigators (PIs) plan to leverage an existing REU program at Colorado School of Mines (CSM) to broaden participation in STEM education by recruiting students who have not previously participated in undergraduate research. In addition, the PIs plan to 1) conduct virtual workshops to support and broaden the use of QSDsan modeling by the water research community and 2) develop summer camp activities on resource recovery from waste streams for K-6 students that will participate in a summer camp for children with dyslexia at CSM.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.