On-off cycles of production wells, especially in bank filtration settings, cause oscillations in the local water table, which can deliver significant amounts of dissolved oxygen (DO) to the shallow groundwater. The potential for DO introduced in this manner to oxidize manganese (Mn), mediated by the obligate aerobe Pseudomonas putida GB-1, was tested in a column of quartz sand fed with anoxic i...

On-off cycles of production wells, especially in bank filtration settings, cause oscillations in the local water table, which can deliver significant amounts of dissolved oxygen (DO) to the shallow groundwater. The potential for DO introduced in this manner to oxidize manganese(II) (Mn(II)), mediated by the obligate aerobe Pseudomonas putida GB-1, was tested in a column of quartz sand fed with ...

Bacterial chemotaxis enables motile cells to move along chemical gradients and to swim toward optimal places for biodegradation. However, its potentially positive effects on subsurface remediation rely on the efficiency of bacterial movement in porous media, which is often restricted by high deposition rates and adhesion to soil surfaces. In well-controlled column systems, we assessed the influ...

Department of Defense operational ranges may become contaminated by particles of explosives residues (ER) as a result of low-order detonations of munitions. The goal of this study was to determine the extent to which particles of ER could migrate through columns of sandy sediment, representing model aquifer materials. Transport experiments were conducted in saturated columns (2 × 20 cm) packed ...

The direct deposition of polyethyleneimine (PEI), a weak polycation with large content amino groups, onto sand fractions different sizes (F70, F100, F200, and F355), resulted in versatile core-shell sorbents for water cleaning. Herein, PEI the polyanion poly(acrylic acid) (PAA) were directly precipitated as an nonstoichiometric polyelectrolyte complex ([PEI]:[PAA] = 2:1) surface followed by cro...

Ethylenediaminotetraacetic acid (EDTA) occurring in groundwater aquifers complicates the prediction of nanoparticle movement in the porous medium. This paper demonstrates an approach combining Triple Pulse Experiments (TPEs) and numerical modelling to quantify the influence of EDTA on the deposition and retention of polymer nanoparticles in a water-saturated column packed with iron-oxide-coated...

Transport of colloids with transient wetting fronts represents an important mechanism of contaminant migration in the vadose zone. The work presented here used steady-state saturated and transient unsaturated flow columns to evaluate the transport of a fluorescent latex microsphere (980 nm in diameter) with capillary wetting fronts of different solution surface tensions and ionic strengths. The...

The removal of microplastic from wastewater collected a plastic recycling facility was investigated, using laboratory scale sand-filter. Wastewater samples were before and after the onsite sand-filter, for characterization different polymer types, sizes, shapes. A considerable difference in characteristics concentrations microplastics observed sand-filtration, demonstrating differences source a...

Laboratory tracer experiments were conducted to investigate solute transport in 12.5-m long, horizontally placed soil columns during steady saturated water flow. Two columns having cross-sectional areas of 10 x IOcm’ were used: a uniformly packed homogeneous sandy column and a heterogeneous column containing layered, mixed, and lenticular formations of various shapes and sizes. The heterogeneou...