Impact of dissolved organic matter on colloid transport in the vadose zone: Deterministic approximation of transport deposition coefficients from polymeric coating characteristics

Evaluating the effects of variable water chemistry on bacterial transport during infiltration

“…Pseudomonas fluorescens UPER-1 has been modeled using a range of attachment kinetics, including first order, second order and intermediate order, when transporting in saturated sand columns with different types and concentrations of salt (Deshpande and Shonnard, 1999). The presence of natural organic matter may also reduce bacterial deposition due to additional repulsive interaction energy (Franchi and O'Melia, 2003;Morales et al, 2011). Solution composition affects bacterial deposition by altering the surface charge of both the bacteria and the collector.…”

Water Transport, Retention, and Survival ofEscherichia coliin Unsaturated Porous Media: A Comprehensive Review of Processes, Models, and Factors

“…In coherence with Pang (2009), reduced colloidal attenuation rates with distance was observed as organic waste, manure and sewage sludge was applied to 4 cm long mini-columns (k remx ≈ 20-80/m), 50 cm long undisturbed columns (k remx ≈ 20-40/m), and in a field scenario of 450 cm (k remx ≈ 2/m) (Unc et al, 2012). One hypothesis is that organically contaminated filters increase aggregation, which cause deposition rate time-and depth-dependency, since the presence of humic acid in the transporting solution has been found to induce colloidal flocculation (Morales et al, 2011). Tong et al (2010 reported that the presence of E. coli extracellular polymeric substances, which has been associated with cell-cell interactions and bioclogging (Kim et al, 2010;Or et al, 2007b), enhances the hyper-exponential shapes of the deposition profiles.…”

“…This has been attributed to increased double layer thickness and decreased ζ -potential (Morales et al, 2011;Wan and Tokunaga, 2002), as well as macromolecule conformational changes that increase the cell separation, called pHassociated electrosteric stabilization (Kim et al, 2009a). Morales et al (2011) found that the ionic strength had higher effect on retention than pH in the absence of humic acid (dissolved organic matter); however, pH had large importance in its presence.…”

“…This has been attributed to increased double layer thickness and decreased ζ -potential (Morales et al, 2011;Wan and Tokunaga, 2002), as well as macromolecule conformational changes that increase the cell separation, called pHassociated electrosteric stabilization (Kim et al, 2009a). Morales et al (2011) found that the ionic strength had higher effect on retention than pH in the absence of humic acid (dissolved organic matter); however, pH had large importance in its presence. Nevertheless, the pH of groundwater and manure slurry is approximately neutral (Schijven and Hassanizadeh, 2000;Unc et al, 2012) and groundwater and sewage water generally have low ionic strengths that are less than 10 mM (Powelson and Mills, 2001;Wang and Zhou, 2010;Yang et al, 2007).…”

Effects of dissolved organic matter on the co-transport of mineral colloids and sorptive contaminants

“…In natural subsurface environments, mineral colloids, NOM, and contaminants often co-exist. Studies have shown that NOM not only enhances mobility of mineral colloids (Akbour et al, 2002;Kretzschmar et al, 1995;Morales et al, 2011;Specht et al, 2000), but also changes equilibrium and kinetics of contaminant adsorption to minerals (Bouby et al, 2011;Kraemer et al, 2002;Lippold and Lippmann-Pipke, 2009;Saiers, 2002;Ticknor et al, 1996). Therefore, it is expected that colloid-facilitated contaminant transport will be affected by NOM.…”