Upscaling Microbial Induced Calcite Precipitation in 0.5m Columns: Experimental and Modeling Results

Microbial induced calcite precipitation (MICP), involving microbial urea hydrolysis by the bacteria Sporoscarcina pasteurii to prime conditions for calcite precipitation, offers an environmentally conscience solution to a wide range of civil engineering problems. MICP has been shown to improve the undrained shear response of soils at the element scale and offers potential benefits over current ground improvement techniques that are highly energy intensive and may pose health risks. The objective of this study is to identify effective means of achieving uniform distribution of precipitate in a one-dimensional flow, 50 cm long laboratory sand column experiments. The approach involves comparing two injection methods and investigating a numerical model of MICP developed previously (Barkouki et al. 2010). Results demonstrate that the stopped-flow injection of a urea- and calcium-rich solution produces a more uniform calcite distribution as compared to a continuous injection method. Statistical analysis on the regression parameters used show that more, higher quality data is required to achieve a unique solution to calibrating MICP.