Stabilizing Highly Erodible Sands against Wind Erosion Using Two MICP Pathways: Aerobic Denitrification and Nonsterile Ureolysis

Document Type

Article

Publication Date

11-17-2025

Department

Department of Civil, Environmental, and Geospatial Engineering

Abstract

Stabilizing soils against wind erosion is a critical challenge, particularly in regions with loose, sandy soils, such as dune sands. This study explores the potential of microbially induced calcite precipitation (MICP) to enhance the stability of poorly graded dune sands at the southern shores of Lake Superior against wind erosion. Two MICP pathways, i.e., ureolysis (U-MICP) and aerobic denitrification (D-MICP), were investigated using microorganism communities cultivated under nonsterile conditions from activated sludge. The nonsterile methods used to cultivate the required bacteria communities reduce the cost and facilitate the bacteria cultivation process required for future large-scale field applications. Furthermore, as denitrification is typically assumed to only occur under completely anoxic conditions, the application of this pathway is usually not considered for shallow ground improvement projects such as improving the wind erosion resistance of sand dunes. In this study, the ability of microorganism communities cultivated from activated sludge to perform denitrification in the presence of oxygen was confirmed using batch experiments. The cultivated microorganisms were then used to stabilize dune sands through D-MICP in the presence of oxygen. The spray method was used for both U-MICP and D-MICP treatments of dune sands. A series of laboratory wind tunnel tests were conducted on treated and untreated samples to evaluate the effectiveness of MICP in enhancing the wind erosion resistance of the soils. Additionally, sand column treatments and lab-scale cone penetration tests were performed to assess the effect of MICP treatments on soil strength as a key factor against wind erosion using the constant-head infiltration method. The results revealed the differences in the performance of the two MICP pathways, emphasizing the influence of the number of treatment cycles on soil stabilization. Particularly, it was shown that six cycles of aerobic D-MICP and one cycle of U-MICP significantly increased wind erosion resistance. The results also revealed that excess (unused) calcium chloride used in U-MICP treatment could precipitate within the treated samples and significantly impact soil stabilization against wind erosion.

Publication Title

Journal of Geotechnical and Geoenvironmental Engineering

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