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

Abstract

This study proposes and describes a novel approach for cementing sandy soils in marine environments by modifying the promising technique of microbially induced carbonate precipitation (MICP). In contrast to the usual MICP technique described in the literature, the method proposed herein relies on the calcium ions dissolved in seawater as the sole source of calcium for calcite formation. This proposed method involves flushing high-salinity-tolerant, urease-active bacteria followed by a mixture of urea and seawater through a porous sandy soil, leading to bacterial carbonate release from the urease reaction and precipitation of insoluble and semi-soluble carbonate salts including calcium carbonate and magnesium carbonate trihydrate. This precipitation method resulted in a physical stabilisation of sand that reached an unconfined compressive strength of up to 300 kPa, which is about two-fold higher (with same amount of crystals produced) than that of the MICP treatment in which highly concentrated calcium and urea solutions are used. Permeability was retained at about 30% for all MICP-treated samples, suggesting good drainage ability. This new exploration of MICP technology provides a high potential for using bio-cementation in marine environments, for applications such as mitigation of submarine sediment liquefaction and prevention of beach sand erosion and cliffs scouring.

A Reactive Transport Model for Biogrout Compared to Experimental Data

“…In order to control the process, a reliable predictive model is needed. The Biogrout process is based on microbially induced carbonate precipitation (MICP) (Bang et al 2001;Cheng et al 2014;DeJong et al 2006) and is a bio-mediated soil improvement method (DeJong et al 2010(DeJong et al , 2013Ivanov and Chu 2008). The proposed variant of Biogrout is urea-based.…”

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].…”

Biomineralization Mediated by Ureolytic Bacteria Applied to Water Treatment: A Review

“…The use of ions present in seawater for crystal formation mediated by ureolytic bacteria, specifically Bacillus sp. DSM23526 strain MCP-11 [60] was first described by Cheng et al [57]. Bacillus sp.…”

“…Bacillus sp. induced calcite crystals formation, additionally the presence of magnesium carbonate trihydrate (MgCO 3 ·3H 2 O) was detected, which is a consequence of the high concentration of magnesium ion in seawater (above 50 mM), which is five times more than the calcium concentration (10 mM) [57].…”