An environmentally friendly soil improvement technology for sand and dust storms control
2019
Background: Dust storms occur when unchecked, strong, or turbulent winds combine with exposed
loose and dried soil surfaces. Sand and dust storms have a significant impact on society, economy, and
environment at local, regional, and global levels. The environmental and health hazards of such storms
cannot be permanently reduced, however, by taking appropriate measures, its impact can be reduced.
The present study aimed to investigate the effects of microbial precipitation of calcium carbonate
(CaCO3) as a biocompatible agent on soil stabilization and control of dust storms using ureaseproducing
bacteria (UPB) as a biological improvement technique, which were isolated, identified,
sprayed on the soil surface.
Methods: For this purpose, the erosion of bio-cemented soil samples was investigated experimentally
in a wind tunnel under the condition of wind velocity of 0 to 98 km.h-1 in two soil types with sandy and
silty texture in a completely randomized design with three replicates.
Results: The investigation of the threshold wind velocity of soil particles showed that soil particles
began to move at velocity of 8 and 10 km.h-1 in silty and sandy soils, respectively, but in all biological
samples (MICP), particles did not move until the wind speed reached 97 km.h-1. It was also revealed
that the weight loss of all MICP-treated samples at different wind velocities was significantly reduced
compared to the control group. Differences in the amount of soil loss among bio-cemented samples
and control treatments were even superior at higher velocities, so that at velocities more than 57 km.h-1,
soil losses increased significantly in the control group, while in soils treated with bacteria, soil loss was
very low (about 2.5 kg.m-2.h-1). Comparison of the bacteria used in this study also showed that Bacillus
infantis and Paenibacillus sp3 had high efficiency in controlling dust storms.
Conclusion: The formation of abrasion-resistant surface layers on soil samples treated by biocementation
showed that cementation by biological methods could be an effective way to stabilize
surface particles and control sand and dust storms.
Keywords: Urease, Dust storms, Bio cement, Soil loss flux
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