In-situ thermal conductive heating (TCH) for soil remediation: A review

This paper provides a comprehensive overview of research works on in-situ thermal conductive heating (TCH), including heat transfer in soil, desorption behavior of pollutants, and mass transfer mechanism within the site. Each stage influences the effectiveness of subsequent stages. Comparison of simulation and experimental results demonstrates that heat transfer and temperature rise in soil are related to the hydrogeological conditions, wells layout and pollutants contents. Thermal desorption of pollutants from soil particles can be influenced by four aspects: energy input, pollutant properties, soil characteristics, and the binding state of pollutant in soil. The exponential decay kinetic model exhibits better applicability for fitting thermal desorption processes. After desorption, the pollutants migrate in soil driven by high temperature and extraction pressure, while hydro-geological conditions of the site determine the actual migration path and rate. Applying convection-dispersion model allows for quantitatively describing the complex migration behavior of pollutants in heterogeneous sites. Future research should focus more on the composite effects of multiple factors in TCH and develop multi-field coupling models through the combination of numerical simulation and in-situ experiments. Accurate characterization and prediction of entire TCH process can improve remediation efficiency, reduce energy costs, and achieve sustainable low-carbon remediation.