“…Improvement in strength of sand columns upon bacterial carbonates was also reported (Ferris and Stehmeier, 1992; De Jong et al, 2006; Whiffin et al, 2007). Recent research initiatives have shown that the calcite crystals form cohesive “bridges” between existing sand grains, increasing the stiffness of sand with limited decrease in permeability (Mitchell and Santamarina, 2005; De Jong et al, 2006; Whiffin et al, 2007; Ivanov and Chu, 2008; Van Paassen et al, 2010; Al Qabany, 2011) (Figure 4). Ureolytic driven MICCP has also been proposed to suppress dust, reduce permeability in granular media, improve soils, stabilize slopes and strengthen liquefiable soils (Gollapudi et al, 1995; Ferris et al, 1996; Whiffin et al, 2007; Bang et al, 2011; Burbank et al, 2011).…”