Biological clogging of soils under radial flow

Abstract Biofilm growth on grain surfaces and at pore throats can significantly reduce the hydraulic conductivity of soils. However, most studies on microbially induced soil clogging have been conducted under one-dimensional flow conditions, which often suffer from inlet clogging and deviate from radial flow conditions typically encountered in the field. This study presents an extensive compilation of published results, micromechanical analyses, pore-scale experiments, and macro-scale radial flow experiments. Results show that (1) the presence of bacteria has minimal impact on fluid viscosity, (2) biofilm growth on solid surfaces is constrained by flow velocity within pores, (3) bioclogging in coarse silts and fine sands can reduce hydraulic conductivity by two to three orders of magnitude, (4) bioclogging does not occur under high velocity flow in the near-field of the well, and (5) clogging develops at a characteristic radial distance determined by pore size and flow rate. The presented results provide insight into microbially induced bioclogging in porous media and a unique dataset to further develop novel bioclogging solutions for subsurface hydraulic conductivity barriers and seals.