Presentation materials
Viruses are generally found as aggregates in the environment. The aggregation is a natural process which helps viruses to survive in soil and sediments and provides them resistance to disinfection, when they are suspended in water. Aggregation distinguishes between homogeneous and heterogeneous. In the former viruses agglomerate among themselves; whereas in the latter they nucleate around a...
Microbes in natural and engineering systems are often found as aggregates consisting of microbial communities, organic and inorganic matters, and water. Such bio-aggregates play important roles in shaping biogeochemistry of soil and groundwater environments, clogging of porous media, biofilm formation, and human lung infections [1 – 3]. In addition, aggregated cells are reported to have...
Bacterial motility is central to processes in agriculture, the environment, and medicine. While motility is typically studied in bulk liquid or on flat surfaces, many bacterial habitats—e.g., soils, sediments, and biological gels/tissues—are complex porous media. Here, we use studies of E. coli in transparent 3D porous media to demonstrate how confinement in a heterogenous medium...
A meter-scale tank test simulating two-dimensional plane strain conditions was performed to evaluate the effectiveness of microbially induced desaturation & precipitation (MIDP) through denitrification for ground improvement applications in stratified soils. The process stimulates indigenous nitrate-reducing bacteria through the injection of a solution containing nitrate, calcium and a...
Key functions of soils, such as permeability or habitat for microorganisms, are determined by structures at the microaggregate scale (< 250
Although advanced imaging techniques now allow snapshots even down to the nanoscale, the evolution of elemental distributions and dynamic processes still can often not be assessed experimentally. So mechanistic models operating at the pore scale...
Seawater flooding, is a widely used improved oil recovery technique in oil reservoirs. Due to presence of sulfate (SO42-) in seawater, this technique can be associated with two side effects. The first side effect is the formation of various types of scale (e.g. BaSO4, CaSO4, and SrSO4) due to the incompatibility of seawater and formation brine that reduces permeability both in the reservoir...
In the present era marked by the desire to build a bio-economy, plant biomass has a vast potential as a source of renewable and environmentally friendly molecules of interest. Deconstruction of biomass by a cocktail of enzymes is relevant at an industrial scale. However, achieving a better understanding of the intimate relationship between synergistic enzymatic activity and deconstruction of...
Enzymatically Induced Carbonate Precipitation (EICP) can be used to engineer the properties of porous media in situ. By targeted precipitation within the pore space, EICP reduces porosity and, more importantly, also affects the hydraulic properties of the porous medium: its intrinsic permeability as well as its relative-permeability and capillary-pressure-saturation relations. While the change...
Microbial induced calcium carbonate (
Microbially induced calcite precipitation (MICP) is believed to have a great potential to provide eco-friendly solutions to a wide range of geotechnical problems, e.g. mediation of contaminations, improvement of soft underground, erosion control and so forth. Recently, plenty of experimental and numerical investigations have been conducted by many researchers to get a better insight into the...
During hydraulic fracturing, preferential flow paths are created to extract hydrocarbons from shale reservoirs, typically with large amounts of produced water. The water is often rich in hydrocarbons and sulfate, providing ideal nutrients for promotion of sulfate reducing bacteria (SRB) growth and biosouring. Bacteria growth may clog fracture pathways and decrease hydrocarbon production, while...
