Biofilm addition improves sand strength over a wide range of saturations.

Bio-mediated ground improvement is an attractive alternative to traditional admixtures for strength improvement of shallow surfaces because it is environmentally friendly. Since biofilms contain extracellular polymeric substances (EPS), they can be considered as an alternative to current technologies to improve soil strength. EPS containing biofilms are porous materials with charged surfaces, and therefore adsorption and capillary condensation can result in water retention.