Ureolytic Bacteria and Calcium Carbonate Formation as a Mechanism of Strength Enhancement of Sand

Abstract

Ureolytic bacteria have a great involvement in calcium carbonate precipitation for different applications starting from removing contaminants and surface coating of monumental estuaries to strengthening and improving the mechanical properties of sandy materials. Ureolytic bacteria hydrolyze urea to generate ATP by the efflux of ammonium ions through ATP-synthase, producing carbonate. In the presence of calcium ions in excess, calcium carbonate will precipitate. In-situ calcium carbonate precipitation is known as biocementation or BioGrout which is superior to the chemical cemented sandy materials in terms of resistance of weathering factors, conservation of permeability and insignificant decrease in porosity. The presented review emphasizes on bacterial calcium carbonate precipitation for the purpose of strength formation.