The characterization and modeling at different scales of the complex interplay between subsurface fluid dynamics, solute transport, mixing, and biogeochemical reactions, are fundamental to our understanding of subsurface processes occurring in contaminant transport and remediation in groundwater and the vadose zone, in the geological storage of energy, CO2 and H2, as well as in enhanced oil and gas recovery. This is particularly true for systems where complex single and multiphase flows, physical transport, chemical transformations, changes in media properties, as well as the dynamics of bacterial populations, occur in comparable time frames. Flow-through experiments have been widely used to study single and multiphase flow and solute transport in porous media. However, novel experimental approaches have been motivated by the increasing need to understand the evolution of coupled physical and biogeochemical processes in subsurface environments. Detailed investigation and experimental evidence of complex subsurface processes allow testing and validating new measuring techniques, and provide datasets with sufficient resolution to make the validation of coupled processes theories and numerical models possible.

The session will provide the opportunity for a multidisciplinary discussion based on recent advances in the characterization of single and multiphase flows, as well as conservative and reactive solute transport in porous media. It will focus on the investigation of coupled subsurface processes, including the dynamics of single and multiphase flows, NAPL dissolution and transport, mixing and mixing-controlled reactions, contaminant (bio)degradation, precipitation/dissolution reactions, bacterial dynamics and biofilm growth. We specially focus on contributions addressing the pore-scale and the intermediate-scale (i.e., centimeter to meter) in multi-dimensional flow-through systems, and aiming at the mechanistic understanding of coupled flow, transport and reactive processes. Experiments featuring high resolution measurements with novel sensor, analytical, and imaging techniques, will be addressed prominently.