Improvement of Sand Dunes with Enzyme-Induced Treatment to Control Hydraulic Erosion

Soil erosion is a destructive phenomenon that causes soil loss and the failure within structure built on it. Therefore, it is necessary to provide promising new approach to deal with it. In this paper, a new bio-inspired EICP technique has been used and the improvement of the erodibility parameters of silica sand has been evaluated using an erosion function apparatus device. Urease enzyme was extracted from watermelon seed kernel with an activity of 2.8 U/mL. In order to provide favorable environmental conditions and accelerate the deposition of calcium carbonate in the soil, a cementing solution containing 0.5, 0.75 and 1 M of calcium chloride and urea was used. Samples were treated with single and double injections (six days after the first injection) of enzyme and cementing solution with a treatment period of 14 days in an incubator at 50°C. The erodibility parameters of silica sand specimens treated with ten injection strategies were investigated. The best-performing treatment strategy produced a 98.55% reduction in erodibility and a six-fold increase in critical shear stress relative to untreated sand. These findings were confirmed by SEM, XRD and calcium carbonate titration tests. The results of titration test showed that in the best-performing treatment strategy, 18.7% of calcium carbonate was deposited in the soil compared to the control sample.