Collaborative Research: WERF: Determining the role of organic matter quality on PFAS leaching from sewage sludge and biosolids

聚氟烷基和全氟烷基物质（PFASs）是一类合成化合物，已广泛应用于各种工业应用和消费产品超过50年。由于这些化合物对人类健康和生态系统的负面影响，全氟辛烷磺酸已成为全国关注的问题。最近，在污水处理厂的固体（污水污泥）中发现了全氟磺酸，实验室和现场研究表明，全氟磺酸可以从这些固体中浸出。由于这些固体（也称为生物固体）的土地应用是施肥和改善土壤条件的一种常见做法，因此了解固体管理和处理做法如何影响生物固体中全氟磺酸的存在是很重要的。此外，人们对暴露于自然环境如何影响生物固体中全氟辛烷的潜在浸出知之甚少，一旦它们被施用于土壤。该研究项目将与污水处理厂合作，通过实验确定污水污泥管理措施对最终进入生物固体的全氟辛烷磺酸的数量和类型的影响。该项目还将研究在土地施用生物固体后可能影响全氟磺酸向环境释放的环境因素，如温度、降雨和生物分解。除了更好地了解PFAS在生物固体中的命运之外，该项目的成果可能会带来更好的污泥管理实践，从而最大限度地减少PFAS对土壤生态系统的影响。该项目将包括开展外联工作，以提高中学生、高中生和大学生对全氟辛烷磺酸和生物固体的土地应用的了解。这个合作研究项目的主要目标是了解固体特性和水质如何影响PFAS从污水来源的固体中解吸。拟议的研究将是系统地确定控制污水固体中全氟磺酸吸附能力的固相特征和水质因素的第一次努力。侧重于污水产生的污泥，即二次和厌氧消化池污泥和生物固体，提供了一种相同来源的固体，其生产和使用在性质上发生了重大变化。该提案将结合全氟烷烃吸附等温线和边缘实验，与污水来源的固体和渗滤液特性和微生物评估相结合，以确定控制全氟烷烃吸附的关键因素。本研究的中心假设如下：1)污水源固体蛋白质含量将是影响PFASs吸附能力的关键固相特征，并且随着微生物的处理，吸附能力一般会降低；2)溶解多价阳离子浓度的增加会增加PFASs的吸附能力，特别是对链长较长的化合物；3)非生物序贯淋溶风化过程会耗尽生物固体中的亲水成分，使剩余的生物固体具有更强的疏水性，从而增加PFASs的吸附能力。如果成功，该项目将提供有价值的信息，有助于安全使用由回收污水废物产生的生物固体，使国家废水处理过程中资源回收的可持续方法成为可能。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Poly- and perfluoroalkyl substances (PFASs) are a class of synthetic compounds that have been widely used in a variety of industrial applications and consumer products for over 50 years. PFASs are a national concern due to the negative effects of these compounds on human health and ecosystems. Recently, PFASs were found in wastewater treatment plant solids (sewage sludge), and laboratory and field studies indicate that PFASs can leach from these solids. Since land application of these solids, also known as biosolids, is a common practice to fertilize and improve soil conditions, it is important to understand how solids management and treatment practices affect the presence of PFASs in biosolids. Additionally, little is known about how exposure to natural environments may affect the potential leaching of PFASs from biosolids once they are applied to soil. This research project will work with wastewater treatment plants to experimentally determine the effects of sewage sludge management practices on the amount and types of PFASs that end up in the biosolids. This project will also study environmental factors, such as temperature, rainfall, and biological decomposition, that may impact the release of PFASs into the environment following land application of biosolids. In addition to better understanding the fate of PFAS in biosolids, the outcomes of the project will likely lead to better sludge management practices that minimize possible PFAS exposure to soil ecosystems. The project will include outreach efforts to improve the understanding of PFASs and land-application of biosolids for middle school, high school, and university students.The main objective of this collaborative research project is to understand how solid characteristics and water quality affect PFAS desorption from sewage-derived solids. The proposed research will be the first effort to systematically identify solid phase characteristics and water quality factors that govern PFASs sorption capacity in sewage solids. The focus on sewage-derived sludge, namely secondary and anaerobic digester sludges and biosolids, provides a same-sourced solid that substantially changes in character over its production and its use. This proposal will combine PFASs sorption isotherm and edge experiments, conducted in concert with sewage-derived solid and leachate characterization and microbial assessments, to identify the critical factors governing PFASs sorption. The central hypotheses in this study are as follows: 1) sewage-derived solids protein contents will be the key solid phase characteristics that affects PFASs sorption capacity, and that sorption capacity will generally decrease with microbiological processing; 2) the presence of increased dissolved polyvalent cation concentration will increase PFASs sorption capacity, particularly for the longer chain length compounds; and 3) the abiotic sequential leaching weathering process will deplete the hydrophilic components of the biosolids, rendering the remaining biosolids with a more hydrophobic character and thus increased PFASs sorption capacity. If successful, this project will provide valuable information that will aid in the safe use of biosolids produced from recycling sewage waste, enabling a sustainable method of resource recovery from the Nation's wastewater treatment processes.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.