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

聚氟烷基物质(PFAS)是一类合成化合物，50多年来广泛应用于各种工业应用和消费品中。由于这些化合物对人类健康和生态系统的负面影响，全氟辛烷磺酸是一个国家关注的问题。最近，在污水处理厂固体(污水污泥)中发现了PFASs，实验室和现场研究表明，PFASs可以从这些固体中浸出。由于土地应用这些固体，也称为生物固体，是施肥和改善土壤条件的常见做法，因此了解固体管理和处理做法如何影响生物固体中全氟辛烷磺酸的存在是很重要的。此外，对于生物固体中的全氟辛烷磺酸一旦应用到土壤中，暴露在自然环境中可能会对其潜在的淋溶产生怎样的影响，人们知之甚少。这项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做法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。该项目还将研究环境因素，如温度、降雨量和生物分解，这些因素可能会影响生物固体在土地应用后向环境中释放全氟辛烷磺酸。除了更好地了解全氟辛烷磺酸在生物固体中的命运外，该项目的结果可能会导致更好的污泥管理做法，将可能的全氟辛烷磺酸对土壤生态系统的暴露降至最低。该项目将包括为初中生、高中生和大学生提高对PFAS的理解和生物固体的土地应用的外展工作。这一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对污水衍生固体的解吸。这项拟议的研究将是第一次系统地确定控制污水固体中PFASs吸附能力的固相特征和水质因素。对污水产生的污泥，即二级和厌氧消化池污泥和生物固体的关注，提供了一种来源相同的固体，在其生产和使用过程中，其性质发生了重大变化。这项建议将结合PFASs吸附等温线和边缘实验，结合污水衍生固体和渗滤液的表征和微生物评估，以确定影响PFASs吸附的关键因素。本研究的中心假设如下：1)污水衍生固体的蛋白质含量将是影响PFASs吸附能力的关键固相特征，并且微生物处理通常会降低PFASs的吸附能力；2)增加溶解的多价阳离子浓度会增加PFASs的吸附能力，尤其是对较长链长的化合物；3)非生物顺序淋洗风化过程将耗尽生物固体的亲水性成分，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，帮助安全使用回收污水废物产生的生物固体，实现从国家污水处理过程中回收资源的可持续方法。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。

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.