Enhanced in situ thermal treatment of soil and groundwater: high temperature treatment and combined remedies

清理受污染场地是一个数十亿美元的问题。 不清理城市地区受污染的土壤和地下水，限制了可持续城市发展所需的布朗菲尔德的再开发，并威胁到人类和生态健康。 许多最难处理的场地具有复杂的地质情况，并受到非水相液体（NAPL）的污染，这是一类危险的工业液体，包括石油燃料，杂酚油，煤焦油和氯化溶剂。 原位热处理（ISTT）技术用于在复杂场地处理这些化学品，通过加热土壤和地下水来蒸发和去除污染物。 ISTT技术通常用于需要在短时间内进行清理的情况，以及基于注入的清理技术失败的情况。 然而，ISTT应用可能是昂贵的和能源密集型的，需要新的研究来开发缩短操作时间并确保在一系列污染物上的性能的方法。 这项研究将使用实验室实验和数值模拟相结合，以缩小与ISTT相关的知识差距，从而开发改进的概念模型，操作策略和模拟工具。 二维流动池实验将用于研究在高于水沸点的温度下沸腾的污染物的去除，以及开发优化的提取方案以减少加热时间和能源使用。 一维和二维实验将用于研究互补的，低能量的，后加热技术，包括热增强生物修复和反应物混合热对流。 使用两种不同的数值方法的模拟将进行比较的实验结果和对方，以评估模型的能力和开发技术的关键ISTT过程的准确模拟。 这项研究将由一个大学研究人员小组和一个行业合作伙伴进行，并将在四年内培训七名HQP，掌握与清理复杂污染场地有关的技术和专业技能。

The clean-up of contaminated sites is a multi-billion-dollar problem. Failure to clean up contaminated soil and groundwater in urban areas limits the redevelopment of brownfield properties required for sustainable urban development, and threatens human and ecological health. Many of the most difficult-to-treat sites have complex geology and are contaminated with non-aqueous phase liquids (NAPLs), a class of hazardous industrial liquids that includes petroleum fuels, creosote, coal tar and chlorinated solvents. In situ thermal treatment (ISTT) technologies are used to treat these chemicals at complex sites by heating the soil and groundwater to vapourize and remove contaminants. ISTT technologies are often used when clean-up is required over short timeframes, and under conditions where injection-based clean-up technologies fail. However, ISTT applications can be costly and energy-intensive, and new research is needed to develop approaches to shorten operation times and ensure performance over a range of contaminants. This research will use a combination of laboratory experiments and numerical modelling to close identified knowledge gaps related to ISTT, leading to the development of improved conceptual models, operation strategies, and simulation tools. Two-dimensional flow cell experiments will be used to investigate the removal of contaminants that boil at temperatures higher than the boiling point of water, as well as to develop optimized extraction schemes to reduce heating times and energy use. One-dimensional and two-dimensional experiments will be used to investigate complementary, lower-energy, post-heating technologies, including thermally-enhanced bioremediation and reactant mixing by thermal convection. Simulations using two different numerical approaches will be compared to the experimental results and to each other, to assess model capabilities and develop techniques for accurate simulation of key ISTT processes. This research will be conducted by a team of University researchers and an industry partner, and will train seven HQP over four years on technical and professional skills relevant to the clean-up of complex contaminated sites.