Biogeochemical Changes During Bio-cementation Mediated by Stimulated and Augmented Ureolytic Microorganisms

Abstract

Microbially Induced Calcite Precipitation (MICP) is a bio-mediated cementation process that can improve the engineering properties of granular soils through the precipitation of calcite. The process is made possible by soil microorganisms containing urease enzymes, which hydrolyze urea and enable carbonate ions to become available for precipitation. While most researchers have injected non-native ureolytic bacteria to complete bio-cementation, enrichment of native ureolytic microorganisms may enable reductions in process treatment costs and environmental impacts. In this study, a large-scale bio-cementation experiment involving two 1.7-meter diameter tanks and a complementary soil column experiment were performed to investigate biogeochemical differences between bio-cementation mediated by either native or augmented ( Sporosarcina pasteurii) ureolytic microorganisms. Although post-treatment distributions of calcite and engineering properties were similar between approaches, the results of this study suggest that significant differences in ureolysis rates and related precipitation rates between native and augmented microbial communities may influence the temporal progression and spatial distribution of bio-cementation, solution biogeochemical changes, and precipitate microstructure. The role of urea hydrolysis in enabling calcite precipitation through sustained super-saturation following treatment injections is explored.

Biocementation Mediated By Stimulated Ureolytic Microbes From Brahmaputra Riverbank For Mitigation of Soil Erosion

“…Similar observations were made at Graddy et al 30, where the majority of the isolated strains (47 out of 57) from bio-stimulation soil tank were found to be strains of the Sporosarcina genus. It is worth noting that the soil enrichment media for stimulation was rich in urea, similar to Gomez et al 44 . The initial pH of the growth media is kept at 7.5.…”

Bioprecipitation of calcium carbonate mediated by ureolysis: A review

“…For biocementation to be economically feasible, two important criteria need to be addressed, namely minimizing the costs of bacterial production cementation treatment [103]. Stimulating indigenous ureolytic microorganisms through injection methods may help eliminate the need for bacterial cultivation and reduce the treatment cost [104]. Interestingly, a recent review paper by Rahman et al [105] presented a detailed cost assessment and environmental benefit of MICP technology using three scenarios: only paver blocks treated with MICP, pavers and sub-base layer treated with MICP, and pavers and subgrade treated with MICP.…”

Reducing Compressibility of the Expansive Soil by Microbiological‐Induced Calcium Carbonate Precipitation

“…is calcium carbonate precipitation can not only fill the pores between the soil particles but also form glue on the surface of the soil particles to make the soil particles adhere to each other. When calcium carbonate precipitates and solidifies, a relatively high-strength calcium carbonate crystals are formed, which improve many engineering properties of the soil [15][16][17]. e chemical reaction process of calcium carbonate precipitation induced by microorganisms can be simplified as shown in the following:…”