A novel strategy for containment of contaminated groundwater consists of a biologically produced extracellular polysaccharide (EPS) barrier, i.e. biobarrier, within a subsurface formation. To bring this technology closer to field scale, a PVC column (12 inch [30.5 cm] diameter x 48 inches [121.9 cm] high) was constructed to examine the effects of thick biofilms in porous media under radial flow...

Complex life cycles have evolved independently numerous times in marine animals as well as in disparate algae. Such life histories typically involve a dispersive immature stage followed by settlement and metamorphosis to an adult stage on the sea floor. One commonality among animals exhibiting transitions of this type is that their larvae pass through a 'precompetent' period in which they do no...

Original scientific paper Aerosol particle thickness measurements were performed at the "Politehnika" University in Timisoara (Romania) during March 2011 using a CIMEL SUN solar photometer, as part of the global AERONET network. The aerosol optical thickness (AOT) represents a parameter of optical visibility in an atmospheric air column from the instrument towards the sun, affected by the prese...

Resonant column tests were carried out on Hostun sand mixed with 5%, 10% and 20% non-plastic fines (defined as grains smaller than 0.075 mm) in order to quantify the combined influence of void ratio (e), anisotropic stress state σv′/σh′) content (fc) maximum small-strain shear modulus Gmax. A significant reduction Gmax increasing fc was observed. Using empirical model forwarded by Roesler, e σv...

The role of extracellular macromolecules on Escherichia coli O157:H7 transport and retention was investigated in saturated porous media. To compare the relative transport and retention of E. coli cells that are macromolecule rich and deficient, macromolecules were partially cleaved using a proteolytic enzyme. Characterization of bacterial cell surfaces, cell aggregation, and experiments in a pa...

Abstract A smoothed particle hydrodynamics code based on micropolar continua for geomaterials is developed problems involving large deformation and shear strain localization. Two typical geotechnical problems, i.e., biaxial compression test sand column collapse, are simulated using classical model to demonstrate the performance of newly proposed method. parameter study given scale effect in con...

The release of sludge-born bacteria and their further subsurface transport was studied. The migration of bacteria was investigated in column experiments which were carried out under the conditions corresponding to naturally occurring extreme rainfall. Coal fly ash as well as coarse and medium grained sand, whose properties are similar to the soils present in degraded areas, were used as column ...

– We present a simple model of a vibrated box of sand, and discuss its dynamics in terms of two parameters reflecting static and dynamic disorder respectively. The fluidised, intermediate and frozen (‘glassy’) dynamical regimes are extensively probed by analysing the response of the packing fraction to steady, as well as cyclic, shaking, and indicators of the onset of glassy behaviour are analy...

The treatment of perchlorate-contaminated groundwater was examined using two side-by-side pilot-scale fixed-bed bioreactors packed with sand or plastic media, and bioaugmented with the perchlorate-degrading bacterium Dechlorosoma sp. KJ. Groundwater containing perchlorate (77microg/L), nitrate (4mg-NO(3)/L), and dissolved oxygen (7.5mg/L) was amended with a carbon source (acetic acid) and nutri...