A Lagrangian stochastic model is proposed as a tool that can be utilized in forecasting remedial performance and estimating the benefits (in terms of flux and mass reduction) derived from a source zone remedial effort. The stochastic functional relationships that describe the hydraulic "structure" and non-aqueous phase liquid (NAPL) "architecture" have been described in a companion paper (Enfield, C.G., Wood, A.L., Espinoza, F.P., Brooks, M.C., Annable, M., Rao, P.S.C., this issue. Design of aquifer remediation systems: (1) describing hydraulic structure and NAPL architecture using tracers. J. Contam. Hydrol.). The previously defined functions were used along with the properties of the remedial fluids to describe remedial performance. There are two objectives for this paper. First, is to show that a simple analytic element model can be used to give a reasonable estimate of system performance. This is accomplished by comparing forecast performance to observed performance. The second objective is to display the model output in terms of change in mass flux and mass removal as a function of pore volumes of remedial fluid injected. The modelling results suggest that short term benefits are obtained and related to mass reduction at the sites where the model was tested.
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http://dx.doi.org/10.1016/j.jconhyd.2005.08.004 | DOI Listing |
Sci Rep
January 2025
USDA, ARS, Sustainable Agricultural Water Systems (SAWS) Unit, UC Davis, 239 Hopkins Road, Davis, CA, 95616, USA.
This study explores innovative drywell designs for managed aquifer recharge (MAR) in agricultural settings, focusing on smaller diameter and deeper drywells, including the repurposing of dried or abandoned wells. Numerical simulations assessed the impact of drywell diameter (5-120 cm), depth (15-55 m), screen height, and subsurface heterogeneity on infiltration (I) and recharge (R) volumes over a one-year period under constant head conditions. Results indicate that smaller diameter drywells can effectively infiltrate and recharge significant water volumes.
View Article and Find Full Text PDFWarming associated with climate change is driving poleward shifts in the marine habitat of anadromous Pacific salmon ( spp.). Yet the spawning locations for salmon to establish self-sustaining populations and the consequences for the ecosystem if they should do so are unclear.
View Article and Find Full Text PDFEnviron Pollut
January 2025
College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China.
Sludge landfilling is widely used in China, accounting for approximately 65% of total sludge disposal, due to its simplicity and cost-effectiveness. However, with increasing land scarcity and stricter environmental regulations, the Chinese government has emphasized reducing sludge landfilling. Despite these efforts, sludge historically disposed of in landfills continues to pose risks, including heavy metal leaching and contamination of groundwater and soil.
View Article and Find Full Text PDFSci Bull (Beijing)
December 2024
Laboratory of Nuclear Energy Chemistry, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China. Electronic address:
Tailored design of organic linkers or metal nodes can introduce desirable functionalities into metal-organic cages (MOCs), significantly expanding their potential applications. In this study, we present a viable approach for engineering acyl-type metal nodes to create interior oxygen-rich sites within MOCs, enabling specific recognition of metal ions, including radioactive contaminants, while maintaining the structural integrity of the MOCs. A novel MOC featuring a uranyl-sealed calix[4]resorcinarene (C[4]R)-based multisite cavity, referred to as UOC, is synthesized as a prototype.
View Article and Find Full Text PDFAWWA Water Sci
March 2024
Department of Civil, Construction, and Environmental Engineering, North, Carolina State University, Raleigh, North, Carolina, USA.
Per- and polyfluoroalkyl substances (PFAS) occur widely in drinking water, and consumption of contaminated drinking water is an important human exposure route. Granular activated carbon (GAC) adsorption can effectively remove PFAS from water. To support the design of GAC treatment systems, a rapid bench-scale testing procedure and scale-up approach are needed to assess the effects of GAC type, background water matrix, and empty bed contact time (EBCT) on GAC use rates.
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