A revised model for microbially induced calcite precipitation: Improvements and new insights based on recent experiments

Abstract

The model for microbially induced calcite precipitation (MICP) published by Ebigbo et al. (2012) has been improved based on new insights obtained from experiments and model calibration. The challenge in constructing a predictive model for permeability reduction in the underground with MICP is the quantification of the complex interaction between flow, transport, biofilm growth, and reaction kinetics. New data from Lauchnor et al. (2015) on whole-cell ureolysis kinetics from batch experiments were incorporated into the model, which has allowed for a more precise quantification of the relevant parameters as well as a simplification of the reaction kinetics in the equations of the model. Further, the model has been calibrated objectively by inverse modeling using quasi-1D column experiments and a radial flow experiment. From the postprocessing of the inverse modeling, a comprehensive sensitivity analysis has been performed with focus on the model input parameters that were fitted in the course of the model calibration. It reveals that calcite precipitation and concentrations of NH

Investigating the Influence of the Initial Biomass Distribution and Injection Strategies on Biofilm-Mediated Calcite Precipitation in Porous Media

“…2.1. Figure 2 compares the order of magnitude of all rates (attachment, detachment, growth, decay) influencing the amount of attached biomass during the simulation of the column experiment D2 discussed in Hommel et al (2015). This figure shows that only during the initial injection of the cells into the column and the following 8-h batch period, the attachment rate is the highest rate.…”

“…Three sets of duplicate column experiments were carried out, including (1) initial attachment during injection, (2) attachment over an 8 h no-flow period, and (3) attachment and biofilm growth over 24 h. The six columns were constructed using clear PVC pipes of 61 cm length and 2.54 cm inner diameter, which were filled with 40 mesh quartz sand (0.5 mm effective filtration size, manufacturer information, Unimin Corp., Emmet, ID, identical to the sand used for the experiments described in Ebigbo et al (2012); Hommel et al (2015), packed under water and vertically positioned. They were inoculated simultaneously with 300 ml (two pore volumes) of cell suspension of identical cell concentration of S. pasteurii 3.2 × 10 7 CFU ml at a flow rate of 10 ml min in an upflow configuration.…”

“…Thus, prior to repeating the attachment experiments, a numerical study is conducted which investigates the influence of initial biomass distributions, representing attachment, on the model predictions of the resulting distribution of calcite and biomass. To this end, various scenarios were simulated using the numerical model proposed by Hommel et al (2015). In other words, this study aims at answering the question whether the initial amount and distribution of biomass (and thus the process of cell attachment) are prerequisites for modeling MICP or not.…”

Improving the Strength of Sandy Soils via Ureolytic CaCO<sub>3</sub> Solidification by <i>Sporosarcina ureae</i>

“…This has been seen to lead to a varied amount of CaCO 3 precipitation throughout the volume of a mould (van Paassen et al, 2009). Where cells are distributed more evenly to prevent clogging of this nature, nucleation may be beneficial for MICP (Hommel et al, 2015) and reveal a positive, linear relation between cell count and CaCO 3 precipitation. Collectively, this may work to explain why S. ureae with a near identical NH 3 -NH 4 + 630 activity to S. pasteurii did not outperform it on average in undrained, direct shear strength tests despite a higher colony total on average (p < 0.05).…”

The HPx software for multicomponent reactive transport during variably-saturated flow: Recent developments and applications

“…Biomass accumulation or biofilm production during microbiological reactions can also induce changes in hydraulic properties, which may potentially influence the coupled hydrological-physical-geochemical-biological processes operative in porous media and, consequently, such processes as flow paths, the performance of biofilters, and the transport of colloids (e.g., Bozorg et al (2015a), Bozorg et al (2015b), Carles Brangarí et al (2017), Or et al (2007), Rockhold et al (2002), Yarwood et al (2006)). The processes of precipitation and dissolution of minerals may be affected by microbiological processes, such as in the engineering practice of microbially induced calcium carbonate precipitation (Hommel et al, 2015;Martinez et al, 2014). Another process that can produce changes in porosity and the hydraulic properties is the migration of fines (solid mineral particles), which is influenced by both hydrodynamic and chemical factors (Bennacer et al, 2017;Mays and Hunt, 2007;Yu et al, 2013).…”