Evaluation of Bacillus Brevis in Microbial-Induced Calcite Precipitation of Threshold Friction Velocity and Crust Thickness for Wind Erosion Control of Aeolian Soil

An eco-friendly method of soil improvement known as Microbial Induced Calcite Precipitation (MICP) has received significant recognition in the past decade. This study presents a report on the capability of MICP in modifying the threshold friction velocity (TFV) and soil crust thickness of aeolian soil bio-treated at various suspension densities of a ureolytic microorganisms – Bacillus brevis (B. brevis) and cementation reagent of varying concentration. The B. brevis suspension densities and cementation reagents used to trigger the MICP process are 0, 0.5, 2.0, 4.0, 6.0 and 8.0 McFarland standards (i.e., 0, 1.50 × 108, 6.0 × 108, 1.20 × 109, 1.80 × 109 and 2.40 × 109 cells/ml and 0.25, 0.5, 0.75 and 1.0 M, respectively. The results at various B. brevis suspension densities and cementation reagent concentration indicated improvement in threshold friction velocity (TFV) and soil crust thickness of aeolian soil bio-treated. Bio-treatment of aeolian with 6.0 x 108 cells/ml – 0.75 M mix ratio improved the critical threshold friction velocity (TFV) of natural aeolian soil from 13.6 m/s to 18.2 m/s similarly, the soil crust thickness of the bio-treated aeolian soil specimens with 6 x 108 cells/ml – 0.75 M and subjected to the maximum wind speed load of 20 m/s improved from the natural powdery form with no crust thickness to 90 mm. these parameters contributed significantly in improving wind-induced resistance.