CAREER: Stabilization of Mining and Energy Related Byproducts using Bio-Mediated Soil Improvement

这笔学院早期职业发展(CALEAR)补助金将开发可持续的方法，利用自然生物过程稳定采矿和能源相关的副产品材料。为满足物质和能源需求而开采会产生大量的副产品材料，如矿尾矿、火山灰和油砂尾矿，这些材料必须储存数百至数千年。通常，对产生的副产品的管理是该行业最困难的挑战之一。安全地储存这些副产品材料是维护社会和环境安全的必要之举。当这些遏制系统失效时，它们有可能成为一场灾难性的灾难。这项职业资助将使用生物中介的方法来稳定副产品材料，以防止遏制系统的故障和副产品材料的传播。生物介导的土壤改良方法将利用材料的生物地球化学来提高副产品材料的机械稳定性，并固定材料中的任何微量元素。这笔拨款还将重点向公众解释生物介导的土壤改良的处理过程和好处，以使其成为一种可行的土地改良替代方案。该教育计划的目标是就地球系统的可持续性，特别是与采矿和能源有关的副产品的储存，教育不同的受众，包括K-12学生、大学生、普通公众和州立法机构。在学术界招聘和留住女性工程师也将是教育计划的重点。这项职业资助的总体目标是开发生物中介治疗方法，以改善采矿和能源相关副产品的性能。副产品储存系统具有固有的工程问题，特别是：1)储存材料因剪切强度不足而失效，2)储存材料因风或地表水的侵蚀而扩散，3)有毒痕量元素渗入附近的地表水和地下水水源。这项职业资助将通过使用生物中介的改进方法来解决这些问题。将使用尿素分解驱动的微生物诱导碳酸盐沉淀(MICP)方法来提高储存副产品的剪切强度和结构稳定性，减少风和地表水的侵蚀潜力，并固定可能渗入附近水源的微量元素。剪切强度的提高将在排水和不排水的简单剪切加载条件下进行评估，侵蚀的减少将使用撞击射流进行评估。将使用实验和化学平衡建模技术来评估将微量元素固定在副产品材料中的能力。此外，还将探索替代的生物代谢途径，如铁和硫酸盐还原，这可能会导致改进生物矿化稳定技术。由于副产品材料的储存寿命比典型的工程项目长几个数量级，因此还将评估处理技术的持久性。这项职业资助的结果将促进对生物介导性土壤改良的理解。特别是，将调查微生物代谢过程和地质材料的物理和化学方面对由此产生的材料行为的影响。这种更好的理解将为利用一种新的生物中介方法储存采矿和能源相关的副产品材料提供指导。这一结果还将推动生物介导性土壤改良技术适用于许多其他地质环境，包括受污染的土壤、可液化的中间土壤和缺氧沉积物。这项职业资助还将提供对生物介导性改良的持久性的洞察，这对所有生物介导性土壤改良的田间应用将是重要的。

This Faculty Early Career Development (CAREER) grant will develop sustainable methods to stabilize mining and energy related byproduct materials using natural biological processes. Mining for material and energy needs generates large volumes of byproduct material, such as ore tailings, coal ash, and oil sand tailings, and these materials must be stored for hundreds to thousands of years. Often it is the management of the generated byproducts that is one of the most difficult challenges for the industry. Safely storing these byproduct materials is a necessity to keep society and the environment safe. When these containment systems fail, they have the potential to be a catastrophic disaster. This CAREER grant will use biologically mediated methods to stabilize the byproduct materials to prevent the failure of the containment systems and the spread of the byproduct materials. The bio-mediated soil improvement methods will harness the bio-geochemistry of the materials to improve the mechanical stability of the byproduct materials as well as immobilize any trace elements within the materials. The grant will also focus on explaining to the public the treatment process and benefits of bio-mediated soil improvement in order for it to become a viable ground improvement alternative. The objective of the educational plan is to educate various audiences, including K-12 students, university students, the general public, and the state legislature, on sustainability in geo-systems, specifically the storage of mining and energy related byproduct materials. The recruitment and retention of female engineers in academia will also be a focus of the educational plan.The overall objective of this CAREER grant is to develop biologically mediated treatment methods to improve the performance of mining and energy related byproduct material. Byproduct storage systems have inherent engineering concerns, specifically: 1) failure of the stored material due to inadequate shear strength, 2) spreading of the stored material due to erosion from wind or surface water, and 3) leaching of toxic trace elements into nearby surface and ground water sources. This CAREER grant will address these concerns by using bio-mediated improvement methods. Ureolytic-driven microbial induced carbonate precipitation (MICP) methods will be used to improve the shear strength and structural stability of the stored byproducts, reduce the potential of erosion due to wind and surface water, and immobilize trace elements that may potentially leach into nearby water sources. The improvement in shear strength will be evaluated under drained and undrained simple shear loading conditions, and the reduction in erosion will be assessed using impinging jets. The ability to immobilize trace elements within the byproduct material will be evaluated using experimental and chemical equilibrium modeling techniques. In addition, alternative biological metabolic pathways, such as iron and sulfate reduction, will be explored that may result in improved bio-mineralization stabilization techniques. Since the storage life of the byproduct material is orders of magnitude longer than typical engineering projects, the permanence of the treatment techniques will also be assessed. The results of this CAREER grant will advance the understanding of bio-mediated soil improvement. In particular, the influence of microbial metabolic processes and the physical and chemical aspects of the geo-materials on the resulting material behavior will be investigated. This improved understanding will provide guidance for the storage of mining and energy related byproduct materials, using a novel bio-mediated approach. The results will also advance bio-mediated soil improvement technology to be applicable for many other geo-environments, including contaminated soils, liquefiable intermediate soils, and anoxic sediments. This CAREER grant will also provide insight into the longevity of bio-mediated improvement, which will be important for all bio-mediated soil improvement field implementation applications.