Evaluating the Performance of Bio-Clogging Additives for Sustainable Soil Permeability Reduction

Bio-clogging, facilitated by bacterial activity, offers a sustainable and environmentally friendly alternative to traditional grouting methods for controlling soil seepage. However, the influence of bacterial presence and the use of culture medium during field implementation on setting times and their correlation with permeability reduction remains uncertain, posing a challenge to the advancement of this technology. This study examines the effects of bacterially induced bio-clogging on soil permeability, with a specific focus on conditions during and after the removal of the culture medium. Laboratory experiments reveal that microbial activity, driven by bacterial adhesion and extracellular polymeric substance (EPS) production, significantly reduces soil permeability by clogging soil pores. The observed reductions in permeability are comparable to those achieved with conventional grouting techniques but are attained without the associated environmental impacts. Importantly, even after the removal of the culture medium, dextran—a byproduct of microbial activity—was retained, and the permeability reductions remained significant. This finding underscores the potential for sustainable permeability reduction through bio-clogging, demonstrating the robustness of microbial biofilms, which persist and continue to influence soil properties despite the withdrawal of external nutrients. This research contributes to a better understanding of how biofilm development and EPS production influence soil permeability reduction, offering a step toward refining bio-clogging techniques for practical use.

Keywords: Bio-clogging, Extracellular polymeric substances (EPS), Microbial ground improvement, Permeability reduction.