More Like this

1. Trace organic contaminants in field-scale cultivated alfalfa, soil, and pore water after 10 years of irrigation with reclaimed wastewater

   https://doi.org/10.1016/j.scitotenv.2020.140698  

   Sharma, Priyamvada ; Poustie, Andrew ; Verburg, Paul ; Pagilla, Krishna ; Yang, Yu ; Hanigan, David ( November 2020 , Science of The Total Environment)

   null (Ed.)
2. Contributions of Pore‐Scale Mixing and Mechanical Dispersion to Reaction During Active Spreading by Radial Groundwater Flow

   https://doi.org/10.1029/2019WR026276  

   Neupauer, Roseanna M. ; Sather, Lauren J. ; Mays, David C. ; Crimaldi, John P. ; Roth, Eric J. ( July 2020 , Water Resources Research)

   Spreading and mixing are complementary processes that promote reaction of two reactive aqueous solutes present in contiguous plumes in groundwater. Spreading reconfigures the plume geometry, elongating the interface between the plumes, while mixing increases the volume of aquifer occupied by each plume, bringing the solute molecules together to react. Since reaction only occurs where the two solute plumes are in contact with each other, local mechanisms that drive flow and transport near the interface between the plumes control the amount of reaction. This work uses local characteristics of the plumes and the flow field near the plume interface to analyze the relative contributions of pore‐scale mixing and mechanical dispersion to instantaneous, irreversible, bimolecular reaction in a homogeneous aquifer with active spreading caused by radial flow from a well. Two solutes are introduced in sequence at the well, creating concentric circular plumes. We allow for incomplete mixing of the solutes in the pore space, by modeling the pore space as a segregated compartment and a mixed compartment with first‐order mass transfer between the two compartments. We develop semi‐analytical expressions for concentrations of the solutes in both compartments. We found that the relative contribution of mechanical dispersion to reaction increases over time and also increases due to increases in the Peclet number, in the relative source concentration of the chasing solute, and in the mass transfer rate from the segregated compartment to the mixed compartment of the pore space.

    

   more » « less
3. Direct Pore-Level Visualization and Verification of In Situ Oil-in-Water Pickering Emulsification during Polymeric Nanogel Flooding for EOR in a Transparent Three-Dimensional Micromodel

   https://doi.org/10.1021/acs.langmuir.1c02029  

   Zhang, Yandong ; Geng, Jiaming ; Liu, Junchen ; Bai, Baojun ; He, Xiaoming ; Wei, Mingzhen ; Deng, Wen ( November 2021 , Langmuir)
4. Simulated dynamics of soil water and pore vapor in a semiarid sandy ecosystem

   https://doi.org/https://doi.org/10.1016/j.jaridenv.2017.11.004  

   Pedram, S. ; Wang, X. ; Liu, T. ; and Duan, L. ( November 2017 , Journal of arid environments)

   Understanding dynamics of soil water content (SWC) and pore air relative humidity (RHpa), as influenced by wetting-drying cycles, is crucial for sustaining fragile ecosystems of desert lands across the world. However, to date, such an understanding is still incomplete. The objective of this study was to examine such dynamics at a typical desert site within the Horqin Sandy Land, located in Mongolian Plateau of north China. The results indicated that vaporization primarily occurred at a depth of around 10 cm below the ground surface. The diurnal variations of the SWC and RHpa in the top 10 cm soils were much larger than those in the soils at a deeper depth. For a non-rainy day, the SWC and RHpa were mainly determined by the relative magnitude of atmospheric temperature over soil temperature, whereas, for a rainy day, the SWC and RHpa were primarily controlled by the rainfall pattern and amount. The retardation role of the top dry soil layer, which is about 10 cm thick and exists most time at the study site, can effectively prevent the beneath moist soils from being further dried up, and thus is beneficial for sustaining the desert ecosystem. 

   more » « less
5. Membrane aging effects on water recovery during full-scale potable reuse: mathematical optimization of backwashing frequency for constant-flux microfiltration

   Cogan, N ; Ozturk, D ; Ishida, K ; Safarik, J ; Chellam, S ( April 2022 , Separation and purification technology)

   One tool in efforts to tackle the ever growing problem of water scarcity is municipal wastewater reclamation to produce drinking water. Microfiltration (MF) is a central technology for potable reuse because it is highly effective in removing pathogenic protozoa, bacteria, and other colloids and for reverse osmosis pretreatment. However, as microfiltered materials accumulate at the membrane surface, its productivity is reduced requiring periodic removal of foulants. A mathematical model of MF is described in the context of hollow fiber filtration that focused on optimizing constant flux operation with backwashing. Design curves were also proposed for determining backwash timing. The model analysis is evaluated against real-world MF fouling for membranes that range in age from a few weeks to three years, observed at the world’s largest water reuse facility operated by the Orange County Water District. The presented model compares well with the full-scale operational data, and model parameters accurately capture variations in fouling kinetics with membrane age, providing clues to changes in optimal regeneration timing and frequency as membrane performance declines over long time scales. 

   more » « less