Upscaling Effects of Soil Improvement by Microbially Induced Calcite Precipitation by Surface Percolation

Abstract

This study has contributed to the technology of soil stabilization via biocementation based on microbially induced calcite precipitation. The newly described method of insitu soil stabilization by surface percolation to dry soil under free draining environment is tested for its up-scaling potential. 2 m columns of one-dimensional trials indicated that repeated treatments of fine sand (< 0.3 mm) could lead to clogging closed at the injection end, resulting in limited cementation depth of less than 1 m. This clogging problem was not observed in 2 m coarse (> 0.5 mm) sand columns, allowing strength varying between 850 to 2067 kPa along the entire 2 m depth. Three-dimensional fine sand cementation trials indicated that relatively homogenous cementation in the horizontal direction could be achieved with 80% of cemented sand cementing to a strength between 2 to 2.5 MPa and to a depth of 20 cm.A simple mathematical model elucidated that the cementation depth was dependent on the infiltration rate of the cementation solution and the in-situ urease activity. The model also correctly predicted that repeated treatments would enhance clogging close to the injection point. Both experimental and simulated results suggested that the surface percolation technology was more applicable for coarse sand.

Urease active bioslurry: a novel soil improvement approach based on microbially induced carbonate precipitation

“…Similar heterogeneity of cementation distribution was also reported by Martinez et al (2013). More recently, Cheng and Cord-Ruwisch (2014) have developed a new treatment method that relies on surface percolation to apply a bacteria and cementation solution into unsaturated sandy soil, and a development of heterogeneity of cementation along a 2 m sand column (vertical direction) was observed during treatment.…”

“…For field applications, however, flushing can be carried out horizontally between the injection and extraction pipes, where the soil is fully saturated with the fluid, as proposed by van Paassen et al (2010). Downward vertical flushing using the surface percolation method can also be used, as explained by Cheng and Cord-Ruwisch (2014). After the injection was finished, the sand columns were kept at room temperature (25 ± 1°C) for 48 h to allow for a complete cementation reaction.…”

“…A uniform distribution of urease activity using the bioslurry approach does not seem to be restricted to the distance; however, many other factors can affect the outcomes of CaCO 3 content distribution, such as the concentration of cementation solution, flow rate, and preferential flow path (Cheng and Cord-Ruwisch 2014;Martinez et al 2013). …”

Bio-cementation of sandy soil using microbially induced carbonate precipitation for marine environments

“…calcium chloride) to form calcite that precipitates throughout the soil matrix. The microbially induced calcite crystals bridge the adjacent soil particles, and hence increase the shear strength and stiffness of soil while retaining high permeability (Van Paassen et al, 2010;Cheng & Cord-Ruwisch, 2014).…”

The Effect of Cell Immobilization by Calcium Alginate on Bacterially Induced Calcium Carbonate Precipitation

“…In recent years, microbially induced CaCO3 precipitation has emerged as an alternative approach to conventional CaCO3 extraction by mining. Bacterially induced CaCO3 precipitation has been successfully used for a wide range of applications including strengthening of sand and soil [1][2][3][4], removal of metal contaminants from the soil and groundwater [5], removal of calcium ions and polychlorinated biphenyls [6], remediation of monuments [7], CO2 sequestration [8], bio-deposition on porous materials such as limestone and brick [9,10], and, more recently, durability improvement of cementitious materials such as concrete [11][12][13].…”