Microbially Induced Calcite Precipitation (MICP) is a bio-mediated soil improvement process that can improve the engineering properties of granular soils through the precipitation of calcium carbonate on soil particle surfaces and contacts. Although bio-cementation has been investigated extensively in laboratory experiments (DeJong et al. 2006, Martinez et al. 2013, and others) and...
Microbially-induced calcite precipitation (MICP) is being widely researched as an emerging technology for subsurface engineering applications including sealing defects in wellbore cement and modifying the permeability of rock formations [1]. Our study team, including Montana State University’s Energy Research Institute and Center for Biofilm Engineering, The University of Stuttgart, Montana...
Fluid storage in the subsurface is important to reduce climate change (sequestration of CO2) or for energy storage (CH4, H2) to cope with the intermittent, unpredictable production of renewable sources like wind and solar. However, the fluids have the potential to leak through damaged cap rocks or wellbores. One method to remediate these problems is inducing calcium carbonate precipitation...
Strontium-90 (Sr-90), a toxic and carcinogenic radionuclide, is the product of uranium fission and is found in soil and groundwater at numerous DOE sites.1 Sr can also enter the environment through mine tailings leachate, produced water ponds (oil and gas extraction) or can occur naturally in rock formations.
A potential technology for groundwater remediation is the use of subsurface...
Low-field nuclear magnetic resonance (NMR) is a non-invasive measuring technique and an excellent tool for determining properties of materials with high magnetic susceptibilities such as rock cores and natural sediments. NMR is sensitive to parameters such as pore size, pore fluid changes, and permeability that are of interest to engineering applications such as subsurface fracture sealing and...
Several biochemical processes have been investigated to modify engineering properties of soil. Biomineral precipitation can increase strength and stiffness, and reduce porosity and permeability. Enzymatically induced calcium carbonate precipitation (EICP) is a biochemical process in which urea is hydrolyzed into ammonium and inorganic carbon, which promotes carbonate mineral precipitation....
Microbially driven calcite precipitation (via ureolysis) has shown great potential in a wide range of applications, including solid-phase capture, concrete crack remediation, soil stabilisation and carbon sequestration. Here, this process is investigated as a means of reducing the primary porosity and/or secondary fracture porosity of host rocks surrounding nuclear waste repositories in order...
When a solvent carries cations through a soil with fixed capacity for adsorption or ion exchange, the evolution of concentration fronts, which propagate through the soil at characteristic fractions of the solvent flow speed, is well described by classical theory. When the soil contains hydrophilic minerals such as iron oxyhydroxide, quartz, and clays which readily adsorb and desorb protons,...
Hydraulic fracturing (or fracking) is a well stimulation technique for unconventional oil and gas extraction [1]. Around 8-38 million cubic meters of fracking fluid containing water, chemicals, and sand are injected into the shale every day [2]. High-pressure injection of fracking fluids allows to create fractures and mobilize the gas and the oil towards the surface. Together with the gas, a...
Surface charge at solid-electrolyte interface is generally affected by the local physical and chemical properties in the solution such as ionic strength, pH and so on. In a system with concentration or pH variation, rather than the prevailing assumption of homogeneous surface change, it leads to a spontaneous inhomogeneous distribution of surface charge, which has been observed in geotechnical...
It is well known that the radionuclide-carrying colloids in ground water can facilitate the transport of contaminants in the subsurface. A set of column experiments under physically and chemically heterogeneous conditions was conducted. Pore velocity was maintained below 100 cm/d and solution of CsI and silica colloids (1 micron diameter) was injected through saturated columns. At the same...
A lattice Boltzmann method is applied for investigating the flow and convection diffusion processes in porous media with fractures and vugs at representative elementary volume (REV) scale. The structural parameters of porous media at pore scale are introduced into the generalized lattice Boltzmann equation (GLBE) to describe the relationship between permeability and porosity. A two-dimensional...
Zeolites have great potential in adsorption and separation of alkanes-olefins mixtures with similar properties due to its shape selectivity and huge specific surface area1. In our work, a series of zeolites were quickly screened to separate 1-chloropropane from 1-chloropropane/allyl chloride gas mixtures by the molecular simulation. The adsorption isotherm curves of simple component were...
With developments and applications of micro-reactors in the food, chemical and pharmaceutical industry, hydrodynamics and transport processes of drops in shear and extensional flows in micro-channels have attracted much attention from both academics and practitioners. Such systems specifically demonstrate potentials to enhance transport in micro-channels. The objective of this work is to...
In this presentation we present a numerical method for simulating fluid flow in highly anisotropic and heterogeneous porous media. To understand the behavior of the fluids at the scale of applications (the macro scale), the flow at the scale of pores (the micro scale) needs to be taken into account. In this case, standard numerical methods will either fail or become inefficient due to the...
