Article
Engineering, Environmental
Mengfan Dai, Ni Yan, Mark L. Brusseau
Summary: This study focuses on the impact of bacteria on the retention and transport of per- and poly-fluoroalkyl substances (PFAS) in soil and groundwater. The results show that the presence of bacteria significantly hinders the transport of PFAS and the biomass of bacteria plays a key role in this process. It highlights the need for further research on the effect of bacteria on PFAS transport in soil and groundwater.
Article
Engineering, Environmental
Justine E. F. Abraham, Kevin G. Mumford, David J. Patch, Kela P. Weber
Summary: This study investigated the transport of PFOS, PFOA, and 6:2 FTS individually and in binary mixtures in the presence of a trapped gas phase using column experiments. The adsorption at the air-water interface significantly retarded their transport, and the competition between PFOS and PFOA for adsorption also affected their transport.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2022)
Article
Environmental Sciences
Chengcheng Gong, Peter G. Cook, Rene Therrien, Wenke Wang, Philip Brunner
Summary: Groundwater models that simulate only saturated flow use groundwater recharge as an input parameter. However, variably saturated subsurface flow models require climate data such as precipitation and potential evapotranspiration instead of recharge. Despite the challenges in defining groundwater recharge in these models, variably saturated subsurface flow models can still provide crucial information for water resources management.
WATER RESOURCES RESEARCH
(2023)
Article
Environmental Sciences
Mark L. Brusseau
Summary: The objective of this study was to determine the most representative methods of measuring air-water interfacial area for the retention and transport of PFAS and other interfacially active solutes in unsaturated porous media. Comparing multiple measurement and prediction methods, it was found that all methods produced coincident results for the interfacial area of glass beads, validating the aqueous interfacial tracer-test methods. The differences in interfacial areas measured for sands and soil were shown to be due to method-dependent contributions of solid-surface roughness.
SCIENCE OF THE TOTAL ENVIRONMENT
(2023)
Article
Green & Sustainable Science & Technology
Mauro Giudici
Summary: The sustainable exploitation of groundwater resources is a complex problem that involves water flow in soils and sediments. Modeling water flow using partial differential equations is an effective approach, which assumes that the change in water content is balanced by the net water flux and that the flux is related to the matric potential. Different equations can be used to express the relationship between these physical quantities, and the choice of boundary conditions is also important.
Article
Environmental Sciences
Mattias Sorengard, Sofia Bergstrom, Philip McCleaf, Karin Wiberg, Lutz Ahrens
Summary: This study investigated the transport and distribution of PFAS in an urban groundwater aquifer affected by PFAS contamination. The military training site was identified as the main source of PFAS contamination in drinking water extraction areas. Transport variations and dilution from adjacent aquifers were found to impact PFAS concentrations in the groundwater.
ENVIRONMENTAL POLLUTION
(2022)
Article
Environmental Sciences
P. A. Novak, S. D. Hoeksema, S. N. Thompson, K. M. Trayler
Summary: This study assesses PFAS contamination and identifies the major drainage sources to the Swan Canning Estuary in Perth Western Australia. The results show that PFAS concentration and composition in the estuary vary significantly with season and spatially. Historical AFFF use on a commercial airport and defence base is likely responsible for the elevated PFAS levels from three major catchment sources. It is also found that the influence of multiple PFAS sources on the estuary depends on various factors such as historical usage timeframe, groundwater interactions, and surface water discharge.
MARINE POLLUTION BULLETIN
(2023)
Article
Environmental Sciences
Gwynn R. Johnson, Mark L. Brusseau, Kenneth C. Carroll, Geoffrey R. Tick, Candice M. Duncan
Summary: A meta-analysis of PFAS concentrations in groundwater across 20 countries showed distinct differences in concentration ranges between sites, with soil generally having higher PFAS levels. Reported presence of PFAS in all media in various regions highlights the potential impact on water resources and ecosystems. The study underscores the importance of considering background PFAS concentrations in risk assessments due to their ubiquitous distribution and potential health implications.
SCIENCE OF THE TOTAL ENVIRONMENT
(2022)
Article
Engineering, Environmental
John F. Stults, Youn Jeong Choi, Charles E. Schaefer, Tissa H. Illangasekare, Christopher P. Higgins
Summary: Predicting the transport of PFAAs in the vadose zone is crucial for cleanup and risk mitigation. This study introduces a novel experimental method to estimate the chemical partitioning parameters of PFAAs in unsaturated soils, and reevaluates previous research to discover transport nonidealities in unsaturated systems that were previously overlooked.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2022)
Article
Engineering, Civil
Liqiong Yang, Jia Kang, Xijuan Chen, Steven A. Ripp, William P. Johnson, Jie Zhuang
Summary: This study utilized a noninvasive, real-time bioluminescent imaging technique to investigate the transport and retention of bioluminescent Escherichia coli strain 652T7 under different pore water velocities and saturations. The results showed that under unsaturated flow conditions, bacterial migration was slow due to modestly unfavorable attachment conditions at interfaces. The non-invasive bioluminescence method provided real-time quantitative observation of bacterial distribution and revealed contrasting transport behaviors previously obtained via more laborious methods.
JOURNAL OF HYDROLOGY
(2021)
Article
Engineering, Environmental
Yifan Ji, Ni Yan, Mark L. Brusseau, Bo Guo, Xilai Zheng, Mengfan Dai, Hejie Liu, Xin Li
Summary: The presence of sodium dodecyl sulfate (SDS) affected the adsorption of perfluorooctanoic acid (PFOA) at solid-water and air-water interfaces, with lower SDS concentrations showing similar retardation factors to those without SDS, but higher concentrations leading to increased retardation and enhanced adsorption at the interfaces. The model accurately predicted the transport behavior of PFOA and SDS, showing differential transport during the experiments and increased surface activity of PFOA in the presence of higher SDS concentrations.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2021)
Article
Environmental Sciences
Annesh Borthakur, Brian K. Cranmer, Gregory P. Dooley, Jens Blotevogel, Shaily Mahendra, Sanjay K. Mohanty
Summary: This study examined the effects of flow interruption on PFAS transport in porous media. The results showed that after flow interruption, the PFAS concentration did not decrease, potentially due to enhanced release of colloid-associated PFAS. Colloids may play a disproportionate role in the transport of PFAS in conditions that release colloids from porous media.
ENVIRONMENTAL POLLUTION
(2021)
Article
Engineering, Civil
Abdelkrim Aharmouch, Brahim Amaziane
Summary: The multi-dimensional mass conservative numerical method is developed for solving transient variably saturated groundwater flow problems, which is particularly suitable for limited computational resources. The method discretizes the Richards equation spatially with a finite element method and temporally with an implicit Euler scheme, using mass-conservative and mass-lumping techniques to ensure stability. The method also approximates stiffness and mass matrices to reduce computational effort, achieving reliable results in benchmark tests and real field case problems.
JOURNAL OF HYDROLOGY
(2021)
Article
Physics, Fluids & Plasmas
M. J. Johnson, W. A. Maza, V. M. Breslin, D. R. Boris, T. B. Petrova, S. G. Walton
Summary: This study investigates a plasma driven with high-voltage pulses for degrading PFOS in water and finds that the contact time between the plasma reactor and the solution is the main factor determining PFOS loss. The most energy efficient operating parameters for PFOS degradation come from minimizing the duration and frequency of the high-voltage pulses to reduce power consumption.
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2022)
Article
Environmental Sciences
Brian R. Pinkard, Shreyas Shetty, Derek Stritzinger, Christopher Bellona, Igor Novosselov
Summary: Effective technologies, such as supercritical water oxidation (SCWO), are needed for the destruction of PFAS. This study found that destruction and defluorination efficiencies of PFOS via SCWO were influenced by temperature and residence time, with a maximum 70.0% PFOS destruction and 78.2% defluorination achieved at 500 degrees C after 60 minutes of reaction.
Article
Water Resources
Jicai Zeng, Bo Guo
Summary: PFAS fate and transport in the environment are not well understood, with recent modeling studies suggesting long-chain PFAS remain in the shallow vadose zone. Heterogeneities in the subsurface can lead to accelerated leaching of PFAS, especially in preferential flow pathways. Surfactant-induced flow has minimal impact on long-term PFAS leaching in the vadose zone.
ADVANCES IN WATER RESOURCES
(2021)
Article
Engineering, Environmental
Sidian Chen, Jiamin Jiang, Bo Guo
Summary: This study introduces a novel upscaling framework for deriving macroscopic phase behavior formulations in complex nanopore networks in organic-rich shale, allowing a better understanding of the effects of nanoconfinement in shale reservoirs.
CHEMICAL ENGINEERING JOURNAL
(2021)
Article
Engineering, Environmental
Yifan Ji, Ni Yan, Mark L. Brusseau, Bo Guo, Xilai Zheng, Mengfan Dai, Hejie Liu, Xin Li
Summary: The presence of sodium dodecyl sulfate (SDS) affected the adsorption of perfluorooctanoic acid (PFOA) at solid-water and air-water interfaces, with lower SDS concentrations showing similar retardation factors to those without SDS, but higher concentrations leading to increased retardation and enhanced adsorption at the interfaces. The model accurately predicted the transport behavior of PFOA and SDS, showing differential transport during the experiments and increased surface activity of PFOA in the presence of higher SDS concentrations.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2021)
Article
Engineering, Civil
Tianyuan Zheng, Bo Guo, Haibing Shao
Summary: This study introduces a novel hybrid framework that couples a multilayer dynamic reconstruction model and a full-dimensional model to simulate CO2 injection in geological formations with local heterogeneities. The hybrid model maintains the accuracy of conventional full-dimensional models while significantly reducing computational costs.
JOURNAL OF HYDROLOGY
(2021)
Article
Engineering, Environmental
Mark L. Brusseau, Bo Guo, Dandan Huang, Ni Yan, Ying Lyu
Summary: PFAS transport in unsaturated porous media is affected by surfactant-induced flow and nonlinear air-water interfacial adsorption. Experimental results show that AWIA is linear when the input concentration is sufficiently below the critical reference concentration.
Article
Water Resources
Bo Guo, Jicai Zeng, Mark L. Brusseau, Yonggen Zhang
Summary: This study developed a simplified analytical model for quantifying long-term PFAS leaching in the vadose zone and validated its accuracy and efficiency.
ADVANCES IN WATER RESOURCES
(2022)
Article
Geosciences, Multidisciplinary
Chao-Zhong Qin, Xin Wang, Mahmoud Hefny, Jianlin Zhao, Sidian Chen, Bo Guo
Summary: Spontaneous imbibition is important in various subsurface and industrial applications, but the pore-scale wetting dynamics and its scaling to the Darcy model are still unresolved. It is found that pore-scale heterogeneity significantly affects the entrapment of the nonwetting fluid, and wetting dynamics deviates capillary pressure and relative permeability from their quasi-static counterparts. A nonequilibrium model for wetting permeability is proposed, which incorporates flow dynamics well. The implementation of the nonequilibrium model in two-phase Darcy modeling successfully predicts sharp wetting fronts in good agreement with experimental observations.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Engineering, Civil
Jicai Zeng, Mark L. Brusseau, Bo Guo
Summary: PFAS, as emerging contaminants, tend to accumulate at solid-water and air-water interfaces in the vadose zone. Various factors influence their long-term retention in the vadose zone, with adsorption at these interfaces playing a crucial role. Chain length and porewater ionic strength impact the retention strength, while nonlinear adsorption decreases retention at higher concentrations.
JOURNAL OF HYDROLOGY
(2021)
Article
Environmental Sciences
Beatrix Becker, Bo Guo, Ivan Buntic, Bernd Flemisch, Rainer Helmig
Summary: This paper presents an efficient compositional model for simulating underground gas storage in porous formations. The model extends the concept of vertical equilibrium and combines a compositional VE model with a compositional full-dimensional model, resulting in improved simulation accuracy and computational efficiency.
WATER RESOURCES RESEARCH
(2022)
Article
Environmental Sciences
M. L. Brusseau, B. Guo
Summary: This research focused on the relationship between soil porewater concentrations and soil concentrations of PFAS, based on a comprehensive model. The model was validated using measured parameters and literature data, showing accurate predictions of concentration ratios. Numerical simulations demonstrated the importance of air-water interfacial adsorption for the distribution of longer-chain PFAS. It was found that PFAS soil porewater concentrations can vary from ng/L to mg/L depending on soil concentrations and site conditions.
Article
Engineering, Environmental
Bo Guo, Hassan Saleem, Mark L. Brusseau
Summary: A mathematical model is presented to predict interfacial tension and fluid-fluid interfacial adsorption for mixtures of PFAS and/or hydrocarbon surfactants. The model is validated using various interfacial tension data from the literature.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2023)
Article
Geosciences, Multidisciplinary
Jicai Zeng, Bo Guo
Summary: Per- and polyfluoroalkyl substances (PFAS) are contaminants that are strongly retained in vadose zones due to adsorption. The leaching of PFAS through vadose zones poses a great risk of groundwater contamination. Previous studies have underestimated the impact of preferential flow caused by soil heterogeneities on PFAS transport. Our numerical simulations show that longer-chain PFAS experience accelerated leaching due to reduced accessible air-water interfacial areas along preferential flow pathways. It is critical to characterize soil heterogeneities to accurately predict the leaching of long-chain PFAS in vadose zones.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Environmental Sciences
Sidian Chen, Bo Guo
Summary: Air-water interfacial adsorption greatly affects the transportation of per- and polyfluoroalkyl substances (PFAS) in vadose zones. Determining the accessibility of PFAS to all thin-water-film air-water interfaces and understanding how mass-transfer limitations in thin water films control PFAS transport in soils are still unknown. In this study, a pore-scale model is developed to examine the impact of mass-transfer limitations in thin water films on PFAS transport in sand medium.
WATER RESOURCES RESEARCH
(2023)