Remediation in Challenging Environments: A New Approach for Accelerating Bioremediation in Cold Climates

在加拿大，联邦污染场地清单列出了超过2.1万个受污染或怀疑受到污染的场地。在约80%的受污染场地中，受到污染的是土壤环境，包括表层和地下土壤、沉积物和地下水。这些地点最常见的污染物是石油碳氢化合物，这是一种非水相液体，包括有毒和致癌的有机化合物。在加拿大的许多污染场地，碳氢化合物污染存在于寒冷气候的土壤环境中。寒冷地区的地面一年中有6到9个月处于半冰冻和冰冻状态，与温带地区相比，这大大缩短了活跃治疗期。在寒冷地区，目前的补救战略和现场活动，无论采用何种补救技术，往往只在夏季有效(每年只有2至4个月)。考虑到大量的受碳氢化合物影响的场地以及与有毒和致癌的碳氢化合物组分相关的环境风险，对寒冷气候下受碳氢化合物影响的土壤环境的更有效、更具成本效益和低能耗的修复技术的新的研究和开发有着强烈的需求。我最近的研究揭示了如何克服目前适用于寒冷气候地点的场地补救技术的局限性。在Discovery研究中，我将重点研究如何在短短的夏季加快生物修复，以及如何将生物修复扩展到非夏季月份。我的研究计划分为三个主题：1)评估生物修复可行性和选择有效策略的新方法；2)短夏季加速生物修复；3)在寒冷月份延长长期生物修复。相关的短期目标是：1.定量解释土壤颗粒中可生物利用的微区如何与提高生物降解活性和优化非冻水特性有关；2.开发冻融诱导的分离-溶解-生物降解(SDB)异地处理方法，在寒冷气候的短夏季期间应用；3.提高、测量和预测与非夏季月份碳氢化合物生物降解有关的微生物活动。从长远来看，我的研究将扩大到生产‘工程产品’。将利用主题1的结果开发一个可与联邦污染场地清单挂钩的更大规模的生物修复统计决策系统。主题2中开发的可持续发展方案进程将在实地扩大系统中进行测试，并将被视为一项可申请专利的技术。从主题3开始，将扩展所开发的微生物活动模型，使之成为掩埋在季节性冻融或冻土中的矿山废物适应气候变化的补救设计和管理的有效工具。这项研究的预期结果将扩大决策模型、补救策略和管理原则，将短短的夏季以外的时间包括在内，这显然将使加拿大公众、省和联邦污染场地计划以及能源、采矿和补救行业受益。总体而言，拟议的关于受自然资源开发和工业活动加剧影响的寒冷地区环境可持续性的研究将有助于满足加拿大今天的需求，并成为加拿大未来最重要的研究领域之一。因此，这项研究处于加拿大可持续发展和环境保护创新的前列。

In Canada, the Federal Contaminated Sites Inventory lists more than 21,000 sites that are contaminated or suspected of being contaminated. In about 80% of the total number of contaminated sites, it is the soil environments, including surface and subsurface soils, sediments and groundwater, which are contaminated. The most frequently identified contaminants at these sites are petroleum hydrocarbons, which are non-aqueous phase liquids that include toxic and carcinogenic organic compounds. In many of the contaminated sites in Canada, hydrocarbon contamination exists in cold-climate soil environments. The ground in cold regions remains semi-frozen and frozen for 6 to 9 months of the year, which greatly shortens the active treatment period compared to temperate regions. In cold regions, current remedial strategies and on-site activities, regardless of the type of remediation technology, have often been designed to be effective only during the summer months (only 2 to 4 months per year). Considering the large number of hydrocarbon-impacted sites and the environmental risks associated with toxic and carcinogenic hydrocarbon fractions, there is a strong demand for new research and development concerning more efficient, more cost-effective, and low-energy remediation technologies for hydrocarbon-impacted soil environments in cold climates. My recent research shed light on how to overcome the current limitations of site remediation technologies applied to cold-climate sites. In the Discovery research, I will focus on how to accelerate the bioremediation during short summers and how to extend the bioremediation to non-summer months. My research program is divided into three themes: 1) New Approach for Assessing Bioremediation Feasibility and Selecting an Effective Strategy; 2) Accelerated Bioremediation during Short Summers; and 3) Extended Long-Term Bioremediation during Cold Months. The associated short-term objectives are to: 1. Quantitatively explain how bioaccessible microsites in soil particles are related to the enhancement of biodegradation activity and to the optimization of unfrozen water characteristics; 2. Develop a freeze-thaw induced Separation–Dissolution–Biodegradation (SDB) ex situ treatment to be applied during short summers in cold climates; 3. Enhance, measure, and predict microbial activity related to hydrocarbon biodegradation during non-summer months. My research will be expanded in the long-term to produce ‘engineering products’. A larger-scale statistical decision-making system for bioremediation that can be linked to the Federal Contaminated Sites Inventory will be developed using the results from Theme 1. The SDB process developed in Theme 2 will be tested in scale-up systems in the field and will be considered a patentable technology. From Theme 3, the developed microbial activity model will be expanded to become an effective tool for climate change-adaptive remediation design and management for mine wastes buried in seasonally freezing and thawing or frozen ground. The expected outcomes of the research into expanding decision-making models, remediation strategies, and management principles to include periods beyond short summers will clearly benefit the Canadian public, provincial and federal contaminated site programs, and the energy, mining, and remediation industries. Overall, the proposed research related to the environmental sustainability of cold regions impacted by intensified natural resource development and industrial activities will contribute to meeting Canada’s needs today and become one of the most important research fields for Canada’s future. The research is thus on the frontline of Canada’s innovation for sustainable development and environmental protection.