mohamraz

• Razbani, Mohammad Amin; Røyne, Anja & Jettestuen, Espen (2024). A One-Dimensional Reactive Transport Model for Microbially Induced Calcium Carbonate Precipitation (MICP) in Phreeqc. Geomicrobiology Journal. ISSN 0149-0451. s. 1–11. doi: 10.1080/01490451.2024.2425295. Fulltekst i vitenarkiv Vis sammendrag

  Microbially induced calcium carbonate precipitation (MICP) is a geotechnical solution with a low ecological footprint. Conducting MICP inside a porous medium can be used for biocementation. Despite many models and tools being published for simulating MICP, a computationally light, easy-to-use, and freely-available simulation tool is lacking. In this work, we present a reactive transport model using the native capabilities of the Phreeqc software (a free and open-source geochemical solver). We model MICP inside a column packed with sands and inoculated with bacteria. Our model is a one-dimensional representation of the column that accounts for the kinetics of precipitation and ureolysis as well as porosity change. We verify our model by simulating previously published MICP experiments to show our model gives reasonably well predictions. Sensitivity analysis of our model’s input parameters and discussions around their range are presented. Additionally, we calculate the supersaturation of calcite as a function of space and time—a feature that could be important for precipitation, but it is commonly ignored in MCIP modeling. Our scripts developed for running simulations are accessible publicly. Due to the low computational effort required for the simulations, our Phreeqc scripts can be used to design and test different treatment recipes for conducting MICP.

• Razbani, Mohammad Amin; Jettestuen, Espen & Røyne, Anja (2023). Direct Pore-Scale Numerical Simulation of Microbially Induced Calcium Carbonate Precipitation. Water Resources Research. ISSN 0043-1397. 59(1), s. 1–14. doi: 10.1029/2022WR032988. Fulltekst i vitenarkiv Vis sammendrag

  Microbially induced calcium carbonate precipitation (MICP) is a promising method for eco-friendly solutions in geotechincal engineering. MICP involves highly coupled processes in geochemistry and bacterial metabolism that take place in a porous medium. Advancement of these processes drives calcite crystal growth which leads to a decrease in porosity and permeability of the medium. Mathematical models are being developed and used to predict the fate of system at different conditions. Micro-scale and local bio-geochemical evolution and its role on the overall macroscopic fate of MICP needs further investigation. In this work, a pore-scale reactive transport model of MICP for biocementation is developed in a closed system. MICP is simulated in a sample porous geometry in 2D using a native geochemical solver and a lattice Boltzmann solver that handles diffusive transport. We present reactive-transport factors to up-scale pore-scale effects and quantify the efficiency of MICP at different stages of the process. Our results show that pore-scale effects on the average concentration of urea and calcium are not significant after the initial 20% of urea have been consumed. On the other hand, the pH evolution in the system is significantly affected by pore-scale effects. We also explored effects of biomass density and biomass distribution on the reactive transport factors, as well as the effect of the urea to calcium ratio on the resulting crystallization patterns. We found that a higher ratio of rate of ureolysis to rate of precipitation leads to more nucleation sites and more uniform calcite precipitation in the geometry.

Se alle arbeider i NVA

• Razbani, Mohammad Amin; Zehner, Jennifer Simone; Jettestuen, Espen; Røyne, Anja; Sikorski, Pawel & Malthe-Sørenssen, Anders (2019). A pore-scale model of microbially induced calcium carbonate precipitation. Fulltekst i vitenarkiv
• Zehner, Jennifer Simone; Karlsen, Emil; Razbani, Mohammad Amin; Jettestuen, Espen; Malthe-Sørensen, Anders & Wentzel, Alexander [Vis alle 9 forfattere av denne artikkelen] (2019). The quest for bio-concrete: crossing disciplinary boundaries and wrangling bacteria to enable cleaner construction. Fulltekst i vitenarkiv
• Razbani, Mohammad Amin; Jettestuen, Espen; Røyne, Anja & Malthe-Sørenssen, Anders (2018). Modelling of dissolution and precipitation during microbially induced calcium carbonate cementation process using lattice Boltzmann method. Fulltekst i vitenarkiv

Se alle arbeider i NVA