Upscaling Calcium Carbonate Precipitation Rates from Pore to Continuum Scale Catherine Noiriel 1,2 , Carl I. Steefel 2,* , Li Yang 2 , Jonathan Ajo-Franklin 2 Geosciences Environnement Toulouse, UMR 5533 Universite Paul Sabatier/CNRS/IRD/CNES, 31400 Toulouse, France Earth Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 Catherine Noiriel Geosciences Environnement Toulouse UMR 5533 Universite Paul Sabatier/CNRS/IRD/CNES 14, avenue Edouard Belin 31400 Toulouse, France catherine.noiriel@get.obs-mip.fr (Tel: +33 5 61 33 25 68; Fax +33 5 61 33 25 Carl Steefel* (corresponding author) CISteefel@lbl.gov Li Yang lyang@lbl.gov Jonathan Ajo-Franklin JBAjo-Franklin@lbl.gov Earth Sciences Division Lawrence Berkeley National Laboratory 1 Cyclotron Road, Mail Stop 90-1116, Berkeley, CA 94720.

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Upscaling calcium carbonate precipitation rates from pore to continuum scale - eScholarship

Microbial induced calcium carbonate precipitation study using Bacillus subtilis with application to self-healing concrete preparation and characterization

The development of alternatives to soil stabilization through mechanical and chemical stabilization has paved the way for the development of biostabilization methods. Since its development, researchers have used different bacteria species for soil treatment. Soil treatment through bioremediation techniques has been used to understand its effect on strength parameters and contaminant remediation. Using a living organism for binding the soil grains to make the soil mass dense and durable is the basic idea of soil biotreatment. Bacteria and enzymes are commonly utilized in biostabilization, which is a common method to encourage ureolysis, leading to calcite precipitation in the soil mass. Microbial-induced calcite precipitation (MICP) and enzyme-induced calcite precipitation (EICP) techniques are emerging trends in soil stabilization. Unlike conventional methods, these techniques are environmentally friendly and sustainable. This review determines the challenges, applicability, advantages, and disadvantages of MICP and EICP in soil treatment and their role in the improvement of the geotechnical and geoenvironmental properties of soil. It further elaborates on their probable mechanism in improving the soil properties in the natural and lab environments. Moreover, it looks into the effectiveness of biostabilization as a remediation of soil contamination. This review intends to present a hands-on adoptable treatment method for in situ implementation depending on specific site conditions.

https://www.mdpi.com/2073-4352/11/4/370/pdf

State-of-the-Art Review of the Applicability and Challenges of Microbial-Induced Calcite Precipitation (MICP) and Enzyme-Induced Calcite Precipitation (EICP) Techniques for Geotechnical and Geoenvironmental Applications

Given that acid-rich rainfall can cause serious damage to heritage buildings in NW China and subsequently accelerate their aging problem, countermeasure to protect their integrity and also to preserve the continuity of Chinese culture is in pressing need. Enzyme-induced calcite precipitation (EICP) that modifies mechanical properties of the soil through enhancing the inter-particle bonds by the precipitated crystals and the formation of other carbonate minerals is under a spotlight in recent years. EICP is considered as an alternative to the microbial-induced calcite precipitation (MICP) because cultivating soil microbes are considered to be challenging in field applications. This study conducts a series of test tube experiments to reproduce the ordinary EICP process, and the produced calcite precipitation is compared to that of the modified EICP process subjected to the effect of higher MgCl2, NH4Cl, and CaCl2 concentrations respectively. The modified EICP subjected to the effect of higher MgCl2 concentrations performs the best, with the highest calcite precipitation. The enhancement mechanism of calcite precipitation is well interpreted through elevating the activity of urease enzyme by introducing the magnesium ions. Further, the degradation of calcite precipitation presents when subjected to the effect of higher NH4Cl concentration. The decreasing activity of urease enzyme and the reverse EICP process play a leading role in degrading the calcite precipitation. Moreover, when subjected to the effect of higher CaCl2 concentrations, the slower rate of ureolytic hydrolysis and the decreasing activity of urease enzyme are primarily responsible for forming the ‘hijacking’ phenomenon of calcite precipitation. The findings of this study explore the potential use of the EICP technology for the protection of heritage buildings in NW China.

Revealing the Enhancement and Degradation Mechanisms Affecting the Performance of Carbonate Precipitation in EICP Process

Concrete cracks have an adverse impact on the durability and safety of the concrete structures; and thus, repairing cracks to improve their mechanical properties is of great significance Recently, microbially induced carbonate precipitation (MICP) has been extensively studied to repair concrete cracks; however, few studies focused on the theoretical quantitively model to study the repair effects of MICP In this study, a theoretical calculation model with MICP was obtained by considering transport of solute, transport of suspended biomass, biofilm growth, geochemistry, ureolysis, and calcium carbonate (CaCO3) precipitation Moreover, the feasibility and practicability of the mathematical model were demonstrated by the crack repair tests The results showed that the calculated concentrations of suspended biomass in cracks gradually decreased during the tests; and the concentrations were larger for larger cracks The comparison between the calculated results and experimental results demonstrated the correctness of transport mode of suspended biomass The volume fractions of biofilm and solute concentrations were larger at the inlet, resulting in the increase of productive rates for CaCO3, which were consistent with experimental results For smaller cracks, the consumed concentrations of solutes were larger, eventually leading to smaller sonic time values; and the upper parts of cracks had smaller sonic time values, indicating better repair effects The proposed mathematical model represents a platform technology that leverages microbial metabolism and repair period to impart novel adjustive, sensing, biomineralization, and bioremediation multifunctionality to structural materials, which would lay a solid foundation for material remediation in civil engineering and material engineering fields

Theoretical quantification for cracks repair based on microbially induced carbonate precipitation (MICP) method

Application of enzymatic calcification for dust control and rainfall erosion resistance improvement.

Method for solidifying desert sands with enzyme‐catalysed mineralization

A low production rate for calcium carbonate with microbial solidification technology at low temperatures often restricts its application. For this reason, adding urea to the medium and the domestication of Bacillus megaterium at low temperature were proposed to produce more calcium carbonate based on an analysis of growth characteristics, urease activity, and the production rates for calcium carbonate under different conditions. Sand solidification tests were conducted to demonstrate improvements caused by the methods. The results showed that the higher the temperature, the faster the growth of Bacillus megaterium and the stronger the urease activity. Growth was fastest and urease activity strongest at a pH of 8. Adding urea to the medium and the domestication of B. megaterium at low temperature can both improve the production rate, effectively increasing calcium carbonate precipitation at low temperature. Combining the two methods resulted in greater improvement of the production rate for calcium carbonate. The two methods were also found to improve the effect of sand solidification. Therefore, our study provides a solid foundation for the actual engineering application of bio-cementation technology at low temperature.

Improvement of bio-cementation at low temperature based on Bacillus megaterium

Sandstorms are meteorological phenomena common in arid and semi-arid regions and have been recognized severe natural disasters worldwide The key problem is how to control and mitigate sandstorm natural disasters This research aims to mitigate their development by improving surface stability and soil water retention properties through soil mineralization The enzymatic induced carbonate precipitation (EICP) is proposed to solidify desert sands and form a hard crust layer on the surface of desert sands In contrast to micro-induced carbonate precipitation commonly used at room temperatures, EICP had high production efficiency and productivity at a broader temperature range (10–70 °C ±) and significantly improves material water retention properties, which was more suitable to desert environment Results demonstrate that the enzyme-catalysed mineralisation method can be better resistance to high winds as the number of spraying times increased

Linyu Wu

Papers

Theoretical quantification for cracks repair based on microbially induced carbonate precipitation (MICP) method

Application of enzymatic calcification for dust control and rainfall erosion resistance improvement.

Method for solidifying desert sands with enzyme‐catalysed mineralization

Improvement of bio-cementation at low temperature based on Bacillus megaterium

Enzyme-catalysed mineralisation experiment study to solidify desert sands.