Field-scale bio-cementation tests to improve sands

Abstract

Microbially induced calcite precipitation (MICP) is a bio-mediated cementation process that improves the geotechnical properties of soils through the precipitation of calcite at soil particle contacts. This study presents a field-scale, surficial application of MICP to improve the erosion resistance of loose sand deposits and provide surface stabilisation for dust control and future re-vegetation. Three test plots were treated with a bacterial culture and nutrient solutions at varying concentrations, and a fourth test plot served as a control. Improvement was assessed to a depth of 40 cm using dynamic cone penetration (DCP) testing and calcite content measurements. The most improved test plot received the lowest concentrations of urea and calcium chloride and developed a stiff crust measuring 2·5 cm thick, which exhibited increased resistance to erosion. DCP testing and calcite content measurements indicated improvement to a depth of approximately 28 cm near the targeted depth of 30 cm. The results suggest that further optimisation of solutions and techniques could render MICP viable for larger-scale applications.

Feasibility study for slope soil stabilization by microbial induced carbonate precipitation (MICP) using indigenous bacteria isolated from cold subarctic region

“…The MICP treatment can be achieved by stimulating the growth of indigenous bacteria in situ (bio-stimulation) or by augmenting ureolytic bacterial culture (bio-augmentation). Bio-stimulation is a process of modifying the in situ environmental conditions to enrich the existing microbial community with required urease capabilities [17,18]. Bioaugmentation largely differs from bio-stimulation and can be enabled by two ways: (1) bio-augmentation of indigenous bacteria: injecting enriched culture of indigenous bacteria isolated from native soil, and (2) bio-augmentation using exogenous bacteria: injecting enriched culture of specialized non-native bacterial strains (e.g.…”

Sand and silty-sand soil stabilization using bacterial enzyme–induced calcite precipitation (BEICP)

“…Even then, just growing and preserving the involved microorganisms under fieldlevel conditions would have its own set of complications. After two decades of active MICP research, therefore, it is noteworthy that relatively few large, meter-scale projects have yet been attempted within either lab or field studies using sand and natural soil systems (Burbank et al 2011;Gomez et al 2015;De Jong et al 2009;Nassar et al 2018;van Paassen et al 2009van Paassen et al , 2010a van Paassen 2011; Phillips et al 2016;van der Star et al 2011).…”

Global CO2 Emission-Related Geotechnical Engineering Hazards and the Mission for Sustainable Geotechnical Engineering

“…Recent studies have used an enzymatic reaction with calcium chloride instead of a direct injection of grown bacteria in an attempt to enhance the production rate of carbonate [111,112]. Other research has involved the removal of heavy metals [114], surficial application of MICP for erosion and dust control [115], and usage of seawater as a nutrient source to attain higher carbonate precipitation [116]. However, most MICP research so far has been conducted on the laboratory scale using coarse-grained soils in which the pores are relatively large, and shows applicability limitation for clayey soils [110].…”