Gas-enhanced in situ thermal treatment for rapid site remediation

加拿大有成千上万的废弃工业地产，土壤和地下水受到有害有机化学品的污染。这些布朗菲尔德的重新开发对周围社区在经济和环境上都是有益的。然而，再开发往往受到清洁技术去除污染物的能力的限制，特别是当存在石油燃料、氯化溶剂和煤焦油等非水相液体时。被称为原位热处理（ISTT）的一类处理技术可用于在其他技术失败的条件下就地积极处理这些化学品。ISTT技术加热地下水，使地下水沸腾，并使污染物蒸发，然后在真空下以气体形式去除。气体的产生和捕获对于有效的清洁至关重要，但是关于ISTT期间这些气体的形成和行为或关于操纵气体以提高处理效率的方法知之甚少。这项研究将进行详细的实验室实验，以研究在电阻加热（ERH）过程中产生的气体，这是一种常用的ISTT技术。将评估天然气生产率及其在地下的分布情况，并将开发促进天然气开发和加速污染物清除的技术。还将进行实验，以评估ERH对生物修复的影响，以及微生物在此过程中产生气体的潜力。除了实验之外，还将开发计算机程序来模拟气泡的形成和移动，因为地下被加热，并模拟温度对生物修复的影响。该研究将由大学研究人员，环境工程顾问，行业合作伙伴和监管机构组成的团队指导，并将由四名硕士和两名博士研究生进行。研究结果预计将通过改进的修复系统设计立即使合作伙伴受益，并帮助场地所有者，房地产开发商和市政当局快速修复难以处理的布朗菲尔德场地。

There are tens of thousands of abandoned industrial properties in Canada where soil and groundwater have been contaminated by hazardous organic chemicals. Redevelopment of these brownfield sites is economically and environmentally beneficial to the surrounding communities. However, redevelopment is often limited by the ability of clean-up technologies to remove contaminants, particularly when non-aqueous phase liquids (NAPLs) such as petroleum fuels, chlorinated solvents, and coal tars are present. A class of treatment technologies referred to as in situ thermal treatment (ISTT) can be used to aggressively treat these chemicals in place under conditions where other technologies fail. ISTT technologies heat the subsurface to boil the groundwater and vapourize the contaminants, which are then removed under vacuum as gases. The creation and capture of gases is critical to effective clean-up, but little is known concerning the formation and behaviour of these gases during ISTT or about methods to manipulate gases to increase treatment efficiency. This research will conduct detailed laboratory experiments to study gases that are created during electrical resistance heating (ERH), which is one commonly employed ISTT technology. Both the rate of gas production and its distribution in the subsurface will be assessed, and techniques will be developed to promote gas development and accelerate contaminant removal. Experiments will also be conducted to assess the impact of ERH on bioremediation, and the potential for microbes to produce gases during this process. In addition to experiments, computer programs will be developed to simulate gas bubble formation and movement as the subsurface is heated, and simulate the effect of temperature on bioremediation. The research will be guided by a team of university researchers, environmental engineering consultants, industry partners, and regulators, and will be conducted by four Masters and two Doctoral graduate students. The research results are expected to immediately benefit the partners through improved system design for remediation and help site owners, property developers and municipalities to rapidly remediate difficult-to-treat brownfield sites.