Investigating the biological treatment effect on fine-grained soil resistance against wind erosion: An experimental case study

Abstract

Wind erosion occurs in arid and semi-arid regions and causes surface erosion, dust and environmental threats. Despite research on the formation of biological surface crust on coarse-grained soils via the MICP process, as an alternative method to prevent and reduce desertification and dust, a few studies have been conducted on clay soils. The current research adopted the biological dust control technique using the Bacillus pasteurii microorganism in silt and clay soils in Meighan Wetland, Iran, which consists of specific salt and minerals. The treated soil specimens were exposed to a wind tunnel for 7, 14, 28, 56 and 140 days in order to measure surface erosion. To determine the effect of the amount of bacteria on the MICP method, the bacteria concentrations of 50 % and 100 % and amount of bacteria on the surface 1 and 2 lit/m² were investigated. To further investigate the effect of soil modification with bacteria on the specimens, cone penetration, acid washing, scanning electron microscopy, and X-ray diffraction tests were carried out. The results showed that according to the conditions of the study area, the use of MICP method and the creation of biological crust in the scope of the current study was an effective and environmentally friendly procedure. By using this method, the surface resistance of silt and clay samples in the region has increased by 95 % and 80 %, respectively. In addition, the use of the MICP method leads to the reduction of wind erosion of silt and clay samples by 90 % and 98 %, respectively.