scholarly journals Building conceptual models of field-scale uranium reactive transport in a dynamic vadose zone-aquifer-river system

2008 ◽  
Vol 44 (12) ◽  
Author(s):  
Steven B. Yabusaki ◽  
Yilin Fang ◽  
Scott R. Waichler
Keyword(s):  
Vadose Zone ◽  
Reactive Transport ◽  
Conceptual Models ◽  
River System ◽  
Field Scale

Performance Assessment of Low-Level Waste Disposal Facilities Using Coupled Unsaturated Flow and Reactive Transport Simulators

2002 ◽  
Vol 713 ◽  
Author(s):  
Diana H. Bacon ◽  
B. Peter McGrail ◽  
Vicky L. Freedman ◽  
Giancarlo Ventura ◽  
Piero Risoluti ◽  
...  
Keyword(s):  
Waste Disposal ◽  
Vadose Zone ◽  
Reactive Transport ◽  
Unsaturated Flow ◽  
Filler Materials ◽  
Release Rates ◽  
Glass Waste ◽  
Shallow Subsurface ◽  
Low Level ◽  
Reactive Chemical Transport

ABSTRACTRecent advances in the development of reactive chemical transport simulators have made it possible to use these tools in performance assessments (PAs) for nuclear waste disposal. Reactive transport codes were used to evaluate the impacts of design modifications on the performance of two shallow subsurface disposal systems for low-level radioactive waste. The first disposal system, located at the Hanford site in Richland, Washington, is for disposal of lowlevel waste glass. Glass waste blocks will be disposed in subsurface trenches, surrounded by backfill material. Using different waste package sizes and layering had a small impact on technetium release rates to the vadose zone. The second disposal system involves a hypothetical repository for low-level waste in Italy. A model of uranium release from a grout waste form was developed using the STORM reactive transport code. Uranium is predicted to be relatively insoluble for several hundred years under the high-pH environment of the cement pore water. The effect of using different filler materials between the waste packages on uranium flux to the vadose zone proved to have a negligible impact on release rates.

scholarly journals Conceptual Models of Flow through a Heterogeneous, Layered Vadose Zone under a Percolation Pond

2004 ◽  
Author(s):  
Kristine Baker ◽  
Larry Hull ◽  
Jesse Bennett ◽  
Shannon Ansley ◽  
Gail Heath
Keyword(s):  
Vadose Zone ◽  
Conceptual Models ◽  
Flow Through

Investigation of Underground Bio-Methanation Using Bio-Reactive Transport Modeling

2021 ◽  
Author(s):  
Denis Sergeevich Nikolaev ◽  
Nazika Moeininia ◽  
Holger Ott ◽  
Hagen Bueltemeier
Keyword(s):  
Carbon Dioxide ◽  
Reactive Transport ◽  
Transport Model ◽  
Porous Media Flow ◽  
Potential Candidate ◽  
Field Scale ◽  
Reactive Transport Model ◽  
Demand Fluctuations ◽  
Gas Fields ◽  
The Impact

Abstract Underground bio-methanation is a promising technology for large-scale renewable energy storage. Additionally, it enables the recycling of CO2 via the generation of "renewable methane" in porous reservoirs using in-situ microbes as bio-catalysts. Potential candidate reservoirs are depleted gas fields or even abandoned gas storages, providing enormous storage capacity to balance seasonal energy supply and demand fluctuations. This paper discusses the underlying bio-methanation process as part of the ongoing research project "Bio-UGS – Biological conversion of carbon dioxide and hydrogen to methane," funded by the German Federal Ministry of Education and Research (BMBF). First, the hydrodynamic processes are assessed, and a review of the related microbial processes is provided. Then, based on exemplary field-scale simulations, the bio-reactive transport process and its consequences for operation are evaluated. The hydrogen conversion process was investigated by numerical simulations on field scale. For this, a two-phase multi-component bio-reactive transport model was implemented by (Hagemann 2018) in the open-source DuMux (Flemisch et al. 2011) simulation toolkit for porous media flow. The underlying processes include the transport of reactants and products, consumption of specific components, and the related growth and decay of the microbial population, resulting in a bio-reactive transport model. The microbial kinetic parameters of methanogenic reactions are taken from the available literature. The simulation study covers different scenarios on conceptional field-scale models, studying the impact of well placement, injection rates, and gas compositions. Due to a significant sensitivity of the simulation results to the bio-conversion kinetics, the field-specific conversion rates must be obtained. Thus, the Bio-UGS project is accompanied by laboratory experiments out of the frame of this paper. Other parameters are rather a matter of design; in the present case of depleted gas fields, those parameters are coupled and can be chosen to convert fully hydrogen and carbon dioxide to methane. Especially the well spacing can be considered the main design parameter in the likely case of a given injection rate and gas composition. This study extends the application of the previously developed code from a homogeneous-2D to the heterogeneous-3D case. The simulations mimic the co-injection of carbon dioxide and hydrogen from a 40 MW electrolysis.

scholarly journals A case study of field-scale maize irrigation patterns in western Nebraska: implications for water managers and recommendations for hyper-resolution land surface modeling

2017 ◽  
Vol 21 (2) ◽  
pp. 1051-1062 ◽  
Author(s):  
Justin Gibson ◽  
Trenton E. Franz ◽  
Tiejun Wang ◽  
John Gates ◽  
Patricio Grassini ◽  
...  
Keyword(s):  
Vadose Zone ◽  
Land Surface ◽  
Spatial Scales ◽  
Crop Model ◽  
Zone Model ◽  
Field Scale ◽  
Maize Production ◽  
Operational Forecasts ◽  
Local Water ◽  
Model Benchmark

Abstract. In many agricultural regions, the human use of water for irrigation is often ignored or poorly represented in land surface models (LSMs) and operational forecasts. Because irrigation increases soil moisture, feedback on the surface energy balance, rainfall recycling, and atmospheric dynamics is not represented and may lead to reduced model skill. In this work, we describe four plausible and relatively simple irrigation routines that can be coupled to the next generation of hyper-resolution LSMs operating at scales of 1 km or less. The irrigation output from the four routines (crop model, precipitation delayed, evapotranspiration replacement, and vadose zone model) is compared against a historical field-scale irrigation database (2008–2014) from a 35 km2 study area under maize production and center pivot irrigation in western Nebraska (USA). We find that the most yield-conservative irrigation routine (crop model) produces seasonal totals of irrigation that compare well against the observed irrigation amounts across a range of wet and dry years but with a low bias of 80 mm yr−1. The most aggressive irrigation saving routine (vadose zone model) indicates a potential irrigation savings of 120 mm yr−1 and yield losses of less than 3 % against the crop model benchmark and historical averages. The results of the various irrigation routines and associated yield penalties will be valuable for future consideration by local water managers to be informed about the potential value of irrigation saving technologies and irrigation practices. Moreover, the routines offer the hyper-resolution LSM community a range of irrigation routines to better constrain irrigation decision-making at critical temporal (daily) and spatial scales (< 1 km).

A model-based analysis of the reactive transport behaviour of 37 trace organic compounds during field-scale bank filtration

2020 ◽  
Vol 173 ◽  
pp. 115523 ◽  
Author(s):  
Alicia Sanz-Prat ◽  
Janek Greskowiak ◽  
Victoria Burke ◽  
Carlos A. Rivera Villarreyes ◽  
Julia Krause ◽  
...  
Keyword(s):  
Organic Compounds ◽  
Reactive Transport ◽  
Bank Filtration ◽  
Field Scale ◽  
Trace Organic Compounds ◽  
Model Based ◽  
Transport Behaviour ◽  
Trace Organic ◽  
Model Based Analysis

scholarly journals Reactive Transport of Manure‐Derived Nitrogen in the Vadose Zone: Consideration of Macropore Connectivity to Subsurface Receptors

2019 ◽  
Vol 18 (1) ◽  
pp. 1-18 ◽  
Author(s):  
Syed I. Hussain ◽  
Steven K. Frey ◽  
David W. Blowes ◽  
Carol J. Ptacek ◽  
David Wilson ◽  
...  
Keyword(s):  
Vadose Zone ◽  
Reactive Transport
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