EAGER: Assessment of Coupled Hydraulic Fracturing Fluid Mass Transfer and Biodegradation in Shallow Aquifer Systems

水力压裂液（HFF）是用于水力开采石油（水力压裂）的流体混合物。尽管实施了旨在在运行期间控制HFF的措施，但与运输、流体混合、注入、储存和井套管故障相关的意外释放已导致HFF污染饮用水供应。此类排放可能会影响土壤、地表沃茨和/或蓄水层，可能需要采取纠正行动以限制污染程度。此外，由于HFF是复杂的混合物，因此有必要了解混合物所有组分的环境命运，包括有机添加剂，表面活性剂，杀生物剂和盐。这项研究旨在更全面地了解影响环境中HFF的生物和化学反应。这些结果将有助于为监管决策提供信息，并为可持续管理和修复HFF向环境释放的战略提供技术基础。该项目还将通过让本科生参与实验室研究，在传统的课堂教学和学术出版框架之外纳入教育举措。这项研究也将有助于加强国家？通过招聘女性和代表性不足的少数民族科学和工程本科生和研究生，扩大人才库。最后，通过与环境咨询公司合作与从业人员分享，以及可能因水力压裂而负担过重的社区，结果将产生广泛的影响。先前的研究已经表明有机化合物的潜在易感性（例如，从水力压裂液（HFF）中的石油烃、胶凝剂和杀生物剂）到从深层页岩获得的现场样品和实验室规模的反应器中的自然衰减。 然而，环境中特定HFF组分的物理-化学质量转移和生物介导的转化反应在很大程度上是未知的，可能威胁受HFF释放影响的饮用水供应的安全性。研究的目标是在代表浅层含水层的条件下调查HFF，重点是HFF有机成分的生物转化（例如，萘和苯）。该研究计划围绕三项任务进行设计：（1）开发一种表征良好的合成HFF混合物，并表征现场衍生的返排，（2）测量HFF成分的吸附和解吸，作为土壤性质和盐度的函数，以及（3）量化HFF生物降解，微生物群落反应和分解代谢基因表达作为HFF暴露浓度的函数。这项研究的新方面包括微生物群落分析与有针对性的分子技术相结合，以评估结构和功能，以及使用先进的质谱技术来表征废水流和识别降解产物。这项工作的结果将提高对以下方面的理解：（a）影响复杂的高有机碳废物流中有机化合物反应性和副产物形成的自然衰减过程（物理-化学和生物），（B）天然地下微生物群落影响HFF传质（以及最终影响HFF成分寿命）的潜力，以及（c）可持续的低强度方法（即，自然衰减），用于修复和管理受HFF影响的场地。具体而言，从这项工作中得出的实验速率参数将有助于环境专业人员评估一系列环境相关条件下的自然衰减能力。此外，这些结果将为未来研究HFF在多维系统中的命运和运输的设计提供初步数据和技术基础，该奖项反映了NSF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。

Hydraulic fracturing fluids (HFFs) are fluid mixtures used for hydraulic extraction of petroleum (fracking). Despite the implementation of measures designed to contain HFFs during operation, accidental releases associated with transportation, fluid mixing, injection, storage, and well casing failures have led to contamination of drinking water supplies by HFFs. Such releases can impact soil, surface waters, and/or aquifers, potentially requiring corrective action to limit the extent of contamination. Further, as HFFs are complex mixtures, it is necessary to understand the environmental fate of all components of the mixture, which includes organic additives, surfactants, biocides, and salts. The proposed research aims to obtain a more complete understanding of the biological and chemical reactions impacting HFF in the environment. These results will help to inform regulatory decisions, and provide the technical basis for sustainable management and remediation strategies for HFF releases to the environment. The project will also incorporate education initiatives beyond the traditional framework of classroom instruction and scholarly publication, through the inclusion of undergraduate students in laboratory research. This research will also help to strengthen the Nation?s pool of talent through the recruitment of female and underrepresented minority science and engineering undergraduate and graduate students. Finally, the results will be broadly impactful through the sharing with practitioners through collaboration with environmental consulting firms, as well as to communities that may be disproportionately burdened by hydraulic fracturing. Previous studies have shown the potential susceptibility of organic compounds (e.g., petroleum hydrocarbons, gelling agents and biocides) in hydraulic fracturing fluid (HFF) to natural attenuation in field samples obtained from deep shale and in laboratory-scale reactors. However, the physical-chemical mass transfer and biologically-mediated transformation reactions of specific HFF components in the environment is largely unknown, potentially threatening the safety of drink water supplies impacted by HFF releases. The goal of the research is to investigate HFF under conditions representative of shallow aquifers, with an emphasis on biotic transformations of HFF organic constituents (e.g., naphthalene and benzene). The research program is structured around three tasks that are designed to: (1) develop a well-characterized synthetic HFF mixture and characterize field-derived flowback, (2) measure the sorption and desorption of HFF constituents as a function of soil properties and salinity, and (3) quantify HFF biodegradation, microbial community response and catabolic gene expression as a function of HFF exposure concentration. Novel aspects of this research include the coupling of microbial community analysis with targeted molecular techniques to assess both structure and function, and the use of advanced mass spectrometry techniques to characterize effluent streams and identify degradation products. Results of this work will improve understanding of: (a) natural attenuation processes (physical-chemical and biological) impacting organic compound reactivity and byproduct formation in a complex, high organic carbon waste stream, (b) the potential of native subsurface microbial communities to influence HFF mass transfer (and ultimately, HFF constituent longevity) and, (c) a sustainable, low-intensity approach (i.e., natural attenuation) for remediation and management of HFF-impacted sites. Specifically, the experimental rate parameters derived from this work will assist environmental professionals assess natural attenuation capacity for a range of environmentally relevant conditions. Further, these results will provide preliminary data and the technical basis for the design of future studies examining the fate and transport of HFF in multi-dimensional systems, and aid in the development mathematical models for improved management of HFF in shallow aquifer systems.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.