Development of a Scaled Repeated Five-Spot Treatment Model for Examining Microbial Induced Calcite Precipitation Feasibility in Field Applications

Microbial induced calcite precipitation (MICP) has been heavily investigated in laboratory experiments with few forays into field-scale implementation. Conventionally, MICP refers to an alternative technology for improving the geotechnical properties of soils via microbially mediated urea hydrolysis inducing conditions for calcite precipitation at particle contacts. The study presented herein focuses on up-scaling the conventional treatment process to more realistic volumes through the development of a scaled repeated five-spot treatment model. Commonly used in oil recovery applications, the repeated five-spot well pattern provides for a flow symmetry condition allowing for improved laboratory model feasibility. A conventional MICP two-phase treatment technique resulted in improvement in the target treatment (0.5 m by 0.5 m by 0.15 m) zone with small spatial variation. Sensors, including bender elements and sampling wells, provided valuable insight into the evolution of biological, chemical, and mechanical changes spatially and temporally during treatment. Overall, the scaled repeated five-spot treatment model was successful at capturing a complex treatment scenario involving a bio-mediated soil improvement technology and demonstrated the potential to capture complex scenarios of soil improvement.