Biostabilization of Desert Sands Using Bacterially Induced Calcite Precipitation

ABSTRACT

Sand storms have become a growing global environmental issue and there is an urgent need to explore cost-effective green technologies to stabilize the sands of desert regions. In this study, the performance of a ureolytic Bacillus sp. for stabilization of sands was evaluated. The Bacillus sp. could efficiently consolidate sand particles by hydrolysis of urea and the subsequent production of calcite and aragonite minerals. The biostabilized sands had a high resistance to erosion by a 33 m s⁻¹ wind speed even after 12-d exposure to freeze-thaw cycles. The compressive strength of biostabilized sands was dependent on the applied cell density and concentrations of Ca²⁺ and urea. High cell densities, urea and Ca²⁺ concentrations reduced the compressive strength. The optimal cell density, Ca²⁺ and urea concentrations were OD₆₀₀ 0.4, 15 mM and 20 g L⁻¹, respectively, when performance and cost were considered. This study shows that biostabilization of sand based on microbially induced carbonate precipitation (MICP) has potential for the prevention of sand storms and wind erosion of soil.

KEYWORDS:

• Consolidation
• microbial carbonate precipitation
• sand storm
• wind erosion
• ureolytic bacteria

Funding

This work was supported by National Natural Science Foundation of China (U1120302, U1403181 and 21177127). Partial funding for this research was also received from the Visiting Professor Program at King Saud University, Riyadh, Saudi Arabia.