Collaborative Research: Characterizing Biodegradable and Recalcitrant Distillates used during Hydraulic Fracturing: Rates, Risks, and Microbial Metabolic Processes

CBET 1336326/1336702 Paula Mouser/Desiree Plata俄亥俄州立大学/杜克大学水平钻井和水力压裂技术的进步最近使从煤层和甲烷页岩地层中提取大量能源成为可能。目前，页岩能源开发的速度超过了监管政策和对这些技术的潜在环境和健康影响的研究。公众关注的问题包括压裂和返排液处理不当可能对饮用水资源造成的污染(例如井漏、地面泄漏)，以及在地下深处仍未回收的注入液的命运。研究项目的目的是确定水力压裂过程中使用的部分芳香族和脂肪族化合物的生物降解率，以便更好地确定在天然含水层条件下可能对生态或人类健康构成风险的可降解或顽固成分。精选的化学类别代表了经常使用的潜在有毒化合物，这些化合物通常是化学制造商在水力压裂液添加剂中未披露的。为了实现这一目标，研究人员将表征具有代表性的压裂液中存在的低分子和高分子芳烃和脂肪族馏分，并使用高分辨率分析技术识别风险成分的子集，包括带有火焰离子化检测的气相色谱(GC)、GC-MS和多维GC。将进行使用本地微生物种群和精选细菌分离株的实验室实验，以调查化学成分如何在一系列物理和化学条件下生物降解，这些条件代表着浅层淡水含水层、较深的盐基岩以及页岩地层压力和温度。将使用高通量生物技术工具监测微生物动态，包括对16S rRNA基因进行焦化处理，这使得可以在广泛的生物物种之间进行比较。研究结果将被用于开发风险矩阵，该矩阵概述了沿压力、温度和盐度范围存在或不存在潜在有毒有机成分的情况。可降解组分与微生物之间的关系将为理解导致压裂液中馏分油化合物生物转化的特定微生物代谢机制提供一个起点。该项目将显著提高我们对压裂液馏分油如何被本地微生物生物降解的理解，并将识别可能限制或促进环境中高风险化合物降解的关键物理化学因素。这项研究的结果包括更好地量化生物降解率，以及更好地对这些系统的流动和运输模型进行参数化。它还将进一步深入了解化合物的持久性，以便在环境友好的钻井作业中改善化学层。研究成果将通过EnergyExplained向学生和更广泛的公众传达！在当地各种场所(图书馆、博物馆和/或小学)举办讲座，突出诸如稀缺性、安全性、可行性以及天然气和可再生技术对环境的影响等问题。调查人员还将通过俄亥俄州立大学S地下能源中心和推广办公室领导的定期研讨会和工作组会议，向阿巴拉契亚地区的非营利组织、监管机构、学者和其他利益相关者传播有关关键页岩能源问题的知识。

CBET 1336326/1336702Paula Mouser/ Desiree PlataOhio State University/Duke UniversityAdvancements in horizontal drilling and hydraulic fracturing techniques have recently made it possible to extract large volumes of energy resources from coal bed and methane shale formations. Currently, shale energy development is occurring at a rate that is outpacing both regulatory policies and research on the potential environmental and health effects of these techniques. Public concerns include the potential contamination of drinking water resources through the mishandling of fracturing and flowback fluids (e.g. borehole leaks, surface spills), as well as the fate of injected fluids that remain unrecovered in the deep subsurface. The objective of the research project is to determine biodegradation rates for select aromatic and aliphatic compounds that are used during the hydraulic fracturing process in order to better define the degradable or recalcitrant constituents that may pose risk to ecological or human health under natural aquifer conditions. The select chemical classes represent frequently used, potentially toxic compounds that are often undisclosed by chemical manufacturers in hydraulic fracture fluid additives. To realize this objective, the investigators will characterize low and high molecular weight aromatic and aliphatic distillates present in a representative fracturing fluid and identify a subset of risk constituents using high resolution analytical techniques, including gas chromatography (GC) with flame ionization detection, GC mass spectrometry, and multi-dimensional GC. Laboratory experiments employing indigenous microbial populations and select bacterial isolates will be performed to investigate how chemical constituents are biologically degraded across a range of physical and chemical conditions representative of shallow freshwater aquifers, deeper saline bedrock, and shale formation pressures and temperatures. Microbial dynamics will be monitored using high-throughput biotechnology tools, including pyroseqeuncing of the 16S rRNA gene, which allows comparison across a broad range of biological species. Research findings will be used to develop a risk matrix that outlines the presence or absence of potentially toxic organic constituents along a pressure, temperature, and salinity spectrum. Associations between degradable constituents and microorganisms will provide a starting point for understanding the specific microbial metabolic mechanisms responsible for distillate compound biotransformation in fracturing fluids.The project will significantly improve our understanding of how fracturing fluid distillates are biodegraded by indigenous microorganisms and will identify the key physicochemical factors that may limit or enhance the degradation of higher risk compounds in the environment. Outcomes from this research include better quantification of biodegradation rates and better parameterization of flow and transport models of these systems. It will also provide further insight into the persistence of compounds in order to improve chemical formations in environmentally friendly drilling operations. Research findings will be communicated to students and the broader public through EnergyExplained! lectures, highlighting such issues as scarcity, security, feasibility, and environmental impacts from natural gas and renewable technologies at a variety of local venues (libraries, museum, and/or grade schools). Investigators will also disseminate knowledge on key shale energy issues to non-profits, regulatory agencies, academics, and other stakeholders in the Appalachian region through regular workshops and workgroup meetings led by Ohio State University?s Subsurface Energy Resource Center and Extension Office.