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2011 | Buch

Kapitel lesen Erstes Kapitel lesen

Subsurface Solute Transport Models and Case Histories

With Applications to Radionuclide Migration

verfasst von: Vyacheslav G. Rumynin

Verlag: Springer Netherlands

Buchreihe : Theory and Applications of Transport in Porous Media

Enthalten in: Springer Professional "Wirtschaft+Technik" , Springer Professional "Technik"

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Über dieses Buch

The book addresses the development of the basic knowledge of the subsurface solute transfer with a particular emphasis on field data collection and analysis coupled with modeling (analytical and numerical) tool application. The relevant theoretical developments are concerned mainly with the formulation and solution of deterministic mass-transport equations for a wide range of engineering issues in groundwater quality assessment and forecasting.

The book gives many computational examples and case studies drawn from the conducted field investigations. The analyzed problems are as follows:

investigation and prediction of groundwater contamination by industrial contaminants and solutions (radionuclides, chloride and nitrate brine) with special focus on the effect of (a) aquifer heterogeneity, anisotropy, and dual porosity, (b) density contrast existing between industrial waste and groundwater, or in density-stratified artesian and coastal groundwater systems; (c) physicochemical interactions that play a major role in retarding (e.g. adsorption) or enhancing (e.g. interactions between dissolved species and mobile colloids) contaminant transport;prediction of the effects of pumping on groundwater quality at wellfields;groundwater dating using stable and radioactive isotopes for prediction and assessment of contamination potential;field and laboratory tests’ design and analysis, and monitoring data interpretation;partitioning of surface and subsurface flows using isotope techniques.

One of the most essential topics addressed in the book is the migration and fate of radionuclides. Model development is motivated by field data analysis from a number of radioactively contaminated sites in the Russian Federation: near-surface radioactive waste disposal sites and deep-well radioactive waste injection sites. They play a unique role in the advancement of knowledge of the subsurface behavior and fate of many hazardous radionuclides and can be considered as field-scale laboratories.

Thus, the book, along with theoretical findings, contains field information, which will facilitate the understanding of subsurface solute transport and the development of a methodology for practical applications to groundwater hydrology.

Inhaltsverzeichnis

Frontmatter

The Essentials of Dissolved Species Transport in the Subsurface Environment: Basic Definitions, Fundamental Mechanisms and Mathematical Formulation

Frontmatter

Chapter 1. Advection and Dispersion of Dissolved Species in Aquifers

Abstract

The transfer of chemical components that, when in solutions, have no effect on the physical properties of aquifer materials and groundwater, is inseparable from the groundwater flow. Their advective transport involves micro- and macrodispersion processes, which control the extent of solute dispersion in homogeneous and heterogeneous aquifers. In this chapter, we will consider the migration models that describe the motion of solutions miscible with groundwater in homogeneous aquifers. The solute migration processes in heterogeneous (stratified and fracturedporous) systems will be discussed in separate chapters.

Vyacheslav G. Rumynin

Chapter 2. Water Movement and Solute Transport in Unsaturated Porous Media

Abstract

The unsaturated zone, also termed the vadose zone, is the portion of the subsurface above the groundwater table. It contains air as well as water in the pores. This zone is also high in organic matter and clay, which promotes sorption, biological degradation and transformation of contaminants. In industrial or agricultural areas, where the ground surface is contaminated by hazardouswastes or fertilizers and pesticides, the unsaturated zone may be thought of as a buffer zone, which provides protection to the underlying aquifers. Unsaturated zone is often regarded as a filter removing undesirable substances before they affect aquifers, and the hydrogeologic properties of unsaturated zone are the most important factor for groundwater deterioration induced by surface contamination (Stephens 1996; Selker et al. 1999).

Vyacheslav G. Rumynin

Conceptual Models for Regional Assessment of Solute Transport (Under Homogeneous Liquid Flow Conditions)

Frontmatter

Chapter 3. One-Dimensional Hydrodynamic Mixing Models for Regional Flow Systems Under Areal Recharge Conditions and Their Application to the Interpretation of Isotopic Data

Abstract

Vyacheslav G. Rumynin

Chapter 4. Profile (Two-Dimensional in Vertical Cross-Section) Models for Solute Transport in Regional Flow Systems

Abstract

Vertical concentration gradients in natural systems can be rather large, often created by contaminant release near the water table as occurs in case of non-point contamination sources formed under the areal recharge conditions. Therefore the regional horizontal flow models discussed in the previous chapter have some serious limitations: neglecting the real redistribution of pollutants over the aquifer depth, such models allow one to calculate only vertically averaged concentration profiles. For example, such formulation of the problem is too coarse when migration processes are studied on the basis of hydrogeological monitoring data from wells penetrating thick (tens of meters) water-bearing strata. The propagation velocities of concentration fronts in individual profile zones can also differ from the averaged estimates. The prerequisites for the formation of contrast hydrogeochemical zonality are (a) the infiltration character of phreatic-water pollution and (b) the nonuniform distribution of rock permeability.

Vyacheslav G. Rumynin

Chapter 5. Models for Assessment of Transverse Diffusive and Advective Transfer in Regional Two-Layer Systems

Abstract

In many groundwater systems, the porous media have near-horizontal layered structures that have been formed by natural sedimentology processes. Diffusive transfer of solute mass between layers differing in hydraulic conductivity is a key smoothing mechanism of concentration profiles in such stratified groundwater systems. A result of this process is the higher rate of mass transfer in layers with lower permeability and its lower rate in layers with higher permeability.

Vyacheslav G. Rumynin

Chapter 6. Analytical Models for Solute Transport in Saturated Fractured-Porous Media

Abstract

Analysis and prediction of solute transport in fractured reservoirs is usually based on the dual porosity (mobile-immobile domain) concept. Matrix diffusion and equilibrium adsorption in the matrix influence dramatically on dissolved contaminants’ retardation in the fracture-matrix system (Neretnieks 1980; Sudicky and Frind 1982; Mironenko and Rumynin 1986; Rasmuson and Neretnieks 1986a; Maloszewski and Zuber 1993; Zuber and Motyka 1994; Moench 1995; Callahan et al. 2000; Zhou et al. 2007). Matrix diffusion not only causes a delayed solute arrival time but also additional dispersion (due to rate-limited mass transfer between fractures and porous blocks) of the advanced solute front. On the other hand, fracture/matrix exchange kinetics causes the tailing effect that is a well-known limitation of pump-and-treat remediation systems wherein high concentrations of fracture domain contaminants are removed relatively quickly, followed by an asymptotic approach to a sustained period of much lower concentration related to the slow release of contamination from the matrix back to the fracture solution (Valocchi 1986; Cosler 2004). Matrix block porosity and size/length, fracture spacing, and matrix diffusivity along with the chemical identity of the contaminant are the parameters that most strongly govern the degree to which matrix diffusion prolongs the aquifer restoration process and control the length of time the aquifer will be decontaminated (Mutch et al. 1993).

Vyacheslav G. Rumynin

Chapter 7. Flow and Transport Through Unsaturated Fractured-Porous Rocks

Abstract

The models discussed in the previous chapter can potentially be expanded to study hydrological processes in the unsaturated zone presented by fractured formations. The dual porosity models are of primary interest for describing infiltration and solute transport. In these models the matrix acts as a source or sinks for water imbibition and dissolved component diffusion between the adjacent fractures, and it is more often assumed that solutes cannot move globally through matrix by advection. However analysis of flow and transport in partially saturated media may require incorporating a dual porosity–dual permeability modeling concept. In the dual permeability matrix diffusion models, the solute can transport globally through matrix by advection as well as diffusion (Gerke and van Genuchten 1993a; Ho 2001a, b; Mathias et al. 2005; Gerke 2006a, b; Houseworth 2006).

Vyacheslav G. Rumynin

Solute Transport Processes Induced by Recharge and Discharge Wells

Frontmatter

Chapter 8. Models for Tracer Test Analysis and Interpretation

Abstract

A common approach to characterizing aquifer mass transfer properties is the use of tracer tests. Our focus is mostly on tracer tests that employ a forced flow field induced by injection and/or withdrawal wells. Such tests offer advantages for estimating transport properties in porous and fractured media over natural gradient tracer tests (Hydraulic and tracer testing…, 1996). We also will focus on the analysis of models describing the vertical movement of natural saltwater–freshwater interface in thick groundwater systems. The interpretation of the latter process also results in useful information about solute transport properties of systems featuring natural hydrogeochemical stratification. Those models are next modified to account for density difference between the fluids in contact (see Secs. 12.3 and 14.2).

Vyacheslav G. Rumynin

Chapter 9. Models for Prediction of Effects of Pumping on Groundwater Quality at Well-Fields

Abstract

Traditionally, hydrogeological research into the effects of changes in groundwater quality has focused on the influence of industrial and/or agricultural near-surface sources of contamination on the subsurface environment. However, in water supply systems (wellfields), the change in hydraulic conditions due to pumping can, on its own account, become a hazard to the water quality. Thus, water withdrawal from a well or a well cluster creates a potential for vertical (upward or downward) migration of water with specific ion or isotope composition through or from neighboring hydrogeological units to the water-producing aquifers, resulting in degradation of the pumped groundwater quality. The relevant analytical models, describing the shift in the depth stratification of water quality in interconnected aquifers (leaky aquifer systems) under the influence of groundwater withdrawal, supplement a set of models predicting the saltwater upconing towards the pumping wells due to freshwater abstraction (see Sects. 8.5, 12.3, and 14.2.3). Water quality degradation within the aquifers where vertical leakage is induced by hydraulic-head differences was observed in many wellfields under exploitation all over the world (Goode et al. 1993; E1-Bihery and Lachmar 1994; Foster and Chilton 2003; Marandi and Vallner 2010).

Vyacheslav G. Rumynin

Lumped-Parameter Models for Flow and Solute Balance in Coupled Surface-Water/Groundwater Systems

Frontmatter

Chapter 10. Conceptual Lumped-Parameter Models for Coupled Transient Flow and Solute Transport in Catchments

Abstract

The major objective of this chapter is to determine the effect of runoff–infiltration partitioning on hydrochemical or isotopic response of a catchment (Fig. 10.1) under conditions of variable rainfall rate and transient flow process. The lumped-parameter formulation of the flow problem significantly simplifies the search of solute transport problem that makes practically possible the long-range prediction of chemical component distributions between the near-surface domain and the aquifer system relying on a restricted number of hydrogeological parameters.

Vyacheslav G. Rumynin

Chapter 11. Unsteady-State Hydrogeological Model of Evaporation-Induced Sedimentation in a Surface Reservoir

Abstract

As shown in a number of publications of fundamental character (Sonnenfeld 1984; Wood and Sanford 1990; Wood 2002; Ingebritsen et al. 2006; Kohfahl et al. 2008), the major processes determining the degree of concentration of natural solutions in isolated water areas (such as lagoons or continental lakes) include evaporation from water surface and the inflow of seawater and river water. Natural groundwater systems also often play an important role in the hydrological balance of surface water bodies such as lagoons or lakes (Fujinawa et al. 2009). Such processes result in the formation of thick strata of salt deposits (evaporates). However, the studies of evaporative sedimentation basins focus mostly on the equilibrium stage of the process; they often involve some simplifying assumptions, for example, the evaporation rate from the water surface may be assumed constant (the dependence of evaporation rate form salt concentration in the solution is not taken into account), which is only true in a certain range of water mineralization values.

Vyacheslav G. Rumynin

Variable-Density Flow and Solute Transport: Physical Phenomena and Mathematical Formulation

Frontmatter

Chapter 12. Dynamic Equilibrium of Freshwater–Saltwater Interface

Abstract

In this chapter, idealized groundwater flow systems containing two liquids, namely freshwater and saltwater, of different density separated by an abrupt interface are considered under steady-state conditions. Classical approaches to the determination of the shape of the interface at equilibrium related to the two benchmark problems, seawater intrusion in a costal aquifer, and saltwater upcoming beneath a partially penetrating pumping well, are reviewed. In particular, it is shown that Ghyben–Herzberg approximation for Dupuit–Forchheimer-based models provide practically valuable insight into the behavior of the groundwater systems under consideration.

Vyacheslav G. Rumynin

Chapter 13. Dynamics of Saltwater–Freshwater Interface

Abstract

The displacement of a fluid by another one of different density and viscosity represents a problem of fundamental interest. It finds applications in situations ranging from enhanced oil recovery and the spreading of pollutants in groundwater reservoirs, to processes accompanying CO₂ sequestration in the deep geological formations. In the first part of this chapter (Sect. 13.1) the linear (unidirectional in the horizontal plane) and radial movement of the interface between displacing and displaced fluids in a confined homogeneous aquifer is analyzed. In the second part of the chapter (Sect. 13.2) we will examine how some ideas of the two-phase flow theory can be used to model the migration of brine in fresh water aquifer systems.

Vyacheslav G. Rumynin

Chapter 14. Studying Subsurface Density-Induced Phenomena Using Numerical Modeling

Abstract

This chapter examines the influence of density-induced flow phenomena on solute transport in hypothetical groundwater systems taking into account different scenarios of leakage of industrial waste from surface reservoirs, as well as a scenario of upward saltwater movement from a deeper saltwater zone into the freshwater zone in response to pumping into a well using different modeling technique. Numerical modeling emerged here as one of the primary tools used to understand the most important physical processes that occur in systems containing mobile freshwater–saltwater interface. The major difficulties of density-induced subsurface transport simulation are due to the fact that the density of the water and the concentrations of chemical species dissolved in the water can vary substantially throughout the modeled area, affecting the flow pattern, and the latter, in turn, affects the change in concentration field. Thus, the flow and transport problems are coupled.

Vyacheslav G. Rumynin

Case Histories of Subsurface Contamination by Industrial and Environmental Brines: Field Data Analysis and Modeling of Migration Processes

Frontmatter

Chapter 15. Radioactive Brine Migration at the Lake Karachai Site (South Urals, Russian Federation)

Abstract

The Lake Karachai site plays a unique role in the advancement of knowledge of the subsurface behavior and fate of many hazardous radionuclides. It is located within one of the South Ural provinces in Russian Federation (Drozhko and Glagolenko 1997; Drozhko et al. 1997a, b, c; Petrov et al. 1994; Solodov et al. 1994, 2005). The site is connected with Mayak Amalgamated Industry (MAI), a plant, producing radioactive materials for military and civil needs.

Vyacheslav G. Rumynin

Chapter 16. Modeling of Seawater Intrusion in Coastal Area of River Andarax Delta (Almeria, Spain)

Abstract

The problem of groundwater quality preservation in coastal regions faces almost all countries that have marine water areas, in particular, insular states. This problem is aggravated by the fact that coastal areas are commonly most habitable and industrially developed, and groundwater serves as a major source of drinking water supply to the population. Indeed, freshwater resources in the coastal aquifers are likely to experience disastrous and irreversible impacts due to overexploitation and ingress of seawater into freshwater aquifers. The latter process leads to a decrease in groundwater quality at water supply systems located within the coastal areas. Therefore, the management of groundwater resources in coastal aquifers requires special attention to minimize the extent of seawater intrusion into aquifers and upconing of seawater near pumping stations. Numerical modeling that treats density-dependent flow and miscible salt transport (Bear 1999; Zhang et al. 2004; Gingerich and Voss 2005; Giambastiani et al. 2007) can help in creating a basis for the relevant hydrogeological investigations and forecasting. This section is an example of model analysis of seawater intrusion into coastal aquifers, which naturally discharge into the Mediterranean Sea at a resort coastal zone in Almeria province (Spain).

Vyacheslav G. Rumynin

Chapter 17. Studying and Modeling of Uncontrolled Discharge of Deep Brine into Mine Drainage Systems at the Korshunovsky Iron Ore Mine (Eastern Siberia, Russian Federation)

Abstract

A large number of case studies related to mining areas demonstrate that extensive mining activities may affect the groundwater chemistry by lowering the base drainage level and promoting the upconing of brackish groundwater contained in deeper layers of groundwater systems in upper freshwater aquifers (Sherwani 1980; Banks et al. 1997; Mironenko and Rumynin 1999; Nonner 2002). First of all, the upconing process influences the quality of the pumped water. Salinization of well systems and drainage water arises many acute environmental problems in mining areas. Thus, the discharge of highly mineralized mine water into streams deteriorates downstream water quality dramatically.

Vyacheslav G. Rumynin

Chapter 18. Light Wastewater Injection into a Deep Geological Formation Containing Brine (“Volzhsky Orgsintez” Deep-Well Disposal Site, Central Russia Region)

Abstract

Deep-well disposal (injection) of hazardous chemical waste (DWWD) has been widely practiced around the world for many years (Tsang 1996; Clark et al. 2005; Tsang et al. 2008). It was proved that in many cases the DWWD technology is the only disposal option that effectively removes waste from the biosphere.

Vyacheslav G. Rumynin

Physicochemical Description and Mathematical Formulation of Sorption Processes

Frontmatter

Chapter 19. Conceptual Models for Sorption Under Batch Conditions

Abstract

In equilibrium, the amount of a dissolved component, N, adsorbed on soil or aquifer material and the concentration of this component in the liquid phase, C, at a given temperature and pressure satisfy a unique relationship N = f(C), referred to as the (single-component) sorption isotherm (model). Empirical coefficients of the sorption isotherms are determined by the energy of the different adsorption sites and the nature of liquid/solid interactions (Venitcianov and Rubinshtein 1983). Under certain conditions, sorption processes are only partially reversible, so the desorption parameters may differ, in one direction or another, from the sorption parameters. This is a manifestation of sorption hysteresis (Sect. 19.1.3).

Vyacheslav G. Rumynin

Chapter 20. Conceptual Transport Models for Adsorbable Solutes

Abstract

In order to study non-conservative contaminant transport, it is essential to couple physicochemical phenomena with flow and transport models. The analytical solutions presented here combine equations for groundwater flow along streamlines with equations for sorption (both linear and nonlinear, equilibrium and first-order kinetic) processes and first-order decay. A simplified radionuclide transport model accounting for the effect of the presence of stable trace components in the formation water on sorption is also considered.

Vyacheslav G. Rumynin

Experimental and Modeling Study of Adsorption–Desorption Processes

Frontmatter

Chapter 21. Radon Site for Near-Surface Disposal of Solid RW

Abstract

Radon Enterprise, as a regional repository for RW processing and disposal, is a member of the Northwestern Center of Nuclear Energy. The Center is located in Sosnoviy Bor Town (Fig. 21.1). The distance from the Radon site to the shoreline of the Gulf of Finland (Koporskaya Bay) is about 1 km.

Vyacheslav G. Rumynin

Chapter 22. Study of Physical, Mechanical, Flow, and Solute Transfer Properties of Clay Formations with Respect to the Design of Underground Storage Facilities for RW Disposal

Abstract

Clay formations are widespread in the Northwestern part of Russian Federation. In St. Petersburg region southeast of the Gulf of Finland and Ladoga Lake, they occur close to the surface (Fig. 22.1). The sediments are represented by two formations, which formed in Vendian and Cambrian geological periods ( ∼ 650-500 Ma). The degree of the clayey sediment consolidation is rather high and therefore they can be also referred to the mudstone lithological type of rock (Arnould 2006). In the northwestern Russian Federation, Vendian and Cambrian clays have local names, Kothlin (associated with a geological suite) and Blue (associated with the characteristic color), respectively.

Vyacheslav G. Rumynin

Chapter 23. Tomsk-7 and Krasnoyarsk-26 Sites for Deep-Well Injection Radioactive Waste Disposal, and Lake Karachai Site of Near-Surface Disposal of Radioactive Brine

Abstract

This experimental study was motivated by the need to carry out a safety assessment focused on the scientific understanding and measurement of the consequences of operations with radioactive waste (RW) at two chemical plants in Western Siberia. The industrial cycles of these plants are aimed at the production of nuclear weapon components and isotopes for medical and research needs. Both sites are associated with two systems of injection wells, which are used for disposal of low-level (LLW) and intermediate-level (ILW) radioactive wastes in deep geological formations. The solute transport properties of these formations are of special interest for long-term radionuclide migration forecasting.

Vyacheslav G. Rumynin

Colloid-Facilitated Solute Transport in Aquifers

Frontmatter

Chapter 24. Colloidal Systems and Equilibrium in Such Systems

Abstract

In this chapter, primary factors controlling the stability of colloidal systems and adsorption-related interactions of colloidal particles with dissolves chemical species are considered. Governing equations for sorption equilibrium and kinetics are formulated. A number of case study researches elsewhere illustrating the presence of colloids in groundwater at different locations and their role in the trace element (in particular radionuclides) binding and capture within this environment are examined. All this creates a basis for the further development (Chaps. 26 and 27) of colloid-facilitated transport models.

Vyacheslav G. Rumynin

Chapter 25. Experimental Study of Radionuclide Interaction with Colloids with Respect to Tomsk-7 Deep-Well RW Disposal in a Geological Formation

Abstract

Colloid-facilitated transport is still an issue in a division of contaminant hydrology related to radioactive solution migration in the subsurface environment. Sophisticated phenomenological transport models are available, but progress is required to fully understand mechanisms and parameters. This study focuses on this experimental direction.

Vyacheslav G. Rumynin

Chapter 26. Models of Sorption Type for Colloid-Facilitated Transport in Aquifers

Abstract

This chapter considers sorption-based numerical models simulating 1D migration of chemical species in the presence of mobile reactive colloids. One of the model extensions includes a module for simulating the migration of a colloid mixture characterized by heterogeneous distributions of particle size and sorption properties. The modeling analysis is accompanied by simple analytical assessments based on characteristic solutions. The simulation and analytical results indicate that species binding to colloids may lead to a considerable enhancement of the colloid-mediated solute migration. The differences in the kinetic constants for sorption and desorption as well as sorption irreversibility appreciably affect the transport rate at local and regional scales.

Vyacheslav G. Rumynin

Chapter 27. A Thermodynamics-Based Conceptual Model for Colloid-Facilitated Solute Transport

Abstract

As mentioned above (Sect. 19.1.2), changes in the physicochemical conditions in the system over space and time, which take place in unsteady-state migration flows, reduce the potential of the above-considered sorption isotherm-based models with time-invariant coefficients, in particular, models describing colloid-facilitated transport. Their empirical nature does not allow them to be applied outside of the specific parameters of the contaminated site. Therefore, thermodynamics-based approach, describing sorption as a series of specific reactions between dissolved ions and surface sites, can be more productive for analyzing solute transport under field conditions.

Vyacheslav G. Rumynin

Backmatter

Titel: Subsurface Solute Transport Models and Case Histories
verfasst von: Vyacheslav G. Rumynin
Verlag: Springer Netherlands
Electronic ISBN: 978-94-007-1306-2
Print ISBN: 978-94-007-1305-5
DOI: https://doi.org/10.1007/978-94-007-1306-2