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    Item type:Publication,
    Sustainable Reduction of Soil Permeability through Microbial Bio-Clogging
    (2026-01-01)
    Kamchoom, Viroon
    ;
    Chaisarn, Sumetha
    ;
    Khattiwong, Thiti
    ;
    Laokhongthavorn, Laemthong
    Microbially induced bio-clogging presents a promising, sustainable alternative to conventional soil improvmeent methods for mitigating seepage in geotechnical applications. Despite its potential, uncertainties remain regarding the influence of bacterial concentration, culture medium application, and associated setting times under field-like conditions—factors which are critical to the effective deployment of this technology in practice. This study investigates the impact of bacterial bio-clogging on the hydraulic behaviour of coarse-grained soils, with particular emphasis on the system's performance during and following the cessation of culture medium supply. Laboratory experiments were conducted to assess the mechanisms of permeability reduction resulting from microbial colonisation and extracellular polymeric substance (EPS) production. Results demonstrate that bacterial adhesion and subsequent EPS accumulation lead to the progressive clogging of soil pores, causing a marked decline in saturated permeability. The observed reductions in permeability are comparable to those produced by traditional methods such as cement and bentonite grouting. This highlights the durability of the biofilm matrix and its ability to maintain hydraulic resistance in the absence of continued nutrient input. These findings contribute valuable insight into the viability of bio-clogging as a ground improvement strategy. By elucidating the relationship between bacterial activity, EPS production, and soil pore occlusion, this research advances the practical understanding required to optimise bio-mediated techniques for field-scale applications in sustainable geotechnical engineering.
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    Item type:Publication,
    Permeability and setting time of bio-mediated soil under various medium concentrations
    (2021-04-01)
    Treebupachatsakul, Treesukon
    ;
    Kamchoom, Viroon
    The bio-clogging using bacteria can be an eco-friendly and sustainable alternative to conventional grouting methods for seepage control. However, it remains unclear to date how the dilute concentration of bacterium and medium during field installation can affect the setting time of bacterium and its correlation with permeability reduction. In this study, the setting time of bacterium and its effectiveness in permeability reduction were addressed through experimental and theoretical investigations. A series of sand column was cultivated using different concentrations of Leuconostoc mesenteroides and culture medium. The distribution and composition of the bacterial product (i.e. dextran) were observed by refractometer, scanning electron microscope (SEM), and energy dispersive X-ray spectroscopy (EDS). Soil permeability was recorded using a constant head test. The results revealed that bacterium was effective to produce dextran at the setting time of about 5 d after installation. This dextran can reduce the permeability of bio-mediated soil by two orders of magnitude, even without culture medium supply. In general, the dextran production decreased proportionally with increase of bacterium and medium concentration. However, at 50% bacterium and medium concentration by weight, it still has a significant influence on permeability reduction with similar setting time, compared to 100% concentration.