A 3-D numerical method is developed to investigate the spatial distribution of surface fluxes over heterogeneous surfaces in (semi-)arid regions. Quantifying the effects of changes in the momentum, thermal and moisture roughness lengths on the airflow and fluxes in the ABL is important for water resources management and local climate studies. The governing equations and turbulence models are modified to include the effects of atmospheric stability conditions on the airflow. The turbulent airflow in ABL is simulated based on the Unsteady Reynolds-Averaged Navier-Stokes (URANS) approach to understand the air flow over the non-homogeneous surfaces from dry land through the water surface and vice versa. The model can be used to study airflow in neutral and non-neutral ABL over complex and non-homogeneous surfaces. The model results were used to investigate the flow parameters and (heat) flux variations over small water surfaces considering its surrounding conditions.
This chapter investigates the three aquifer storage and recovery (ASR) facilities in Southwest Florida to understand water–rock geochemical interactions during the ASR process. Mobilization of metals from the Floridan Aquifer System (FAS) matrix during ASR activities is apparent and is likely due to a complex interaction of geochemical processes. The chemically heterogeneous aquifer contains metal-rich phases in sufficient amounts to become mobilized by oxidation or other processes to yield concentrations in recovered waters that may exceed maximum contaminant levels (MCLs). Arsenian pyrite is among the sources of arsenic and other trace metals in the aquifer; however, preliminary sequential extraction studies and work by other researchers suggest that phases such as organics contain As and other metals. Moreover, organic material may contain uranium, which is also thought to be associated with carbonate minerals in the Suwannee Limestone. Water-quality data from more than 15 cycle tests from three ASR facilities in Southwestern Florida indicate significant mobilization of metals into stored and recovered water during ASR.
This chapter extends the coupled Markov chain (CMC) to three-dimensional (3-D) to better suit the model for many practical problems. The CMC model is very convenient to implement for stochastic simulation, because the CMC model requires neither parametric fitting of a semivariogram model nor cumbersome indicator cokriging techniques. In the Markovian framework, the conditional distribution of any future state is independent of the past history if the present state is given. As an illustration of the applicability of the CMC model, an example based on data from the Alabama MADE Test Site on unconsolidated coastal plain sediments is considered. Based on the developed 3-D CMC model, a single realization can be generated. Monte Carlo simulations show that this model is stable for most cases. The 2-D application on the MADE site shows that the model has promise for delineating the complex geological structure of an aquifer, even with only sparse data.
This chapter describes the development of a 3D high-resolution model of Injection Area 18, a disposal site at the Siberian Chemical Complex, to study the impact of heterogeneity on the subsurface spreading of waste. The new feature of this model is the ability to describe in detail the site formation's internal 3D architecture, using a Markov's chain for modeling binary lithological heterogeneity. Numerical studies of transport at this site show that the problem of selecting the best model for predicting long-term regional-scale waste transport at this site still exists. The effective macro-dispersion model and dual-porosity model are competitive approaches for such predications. The simulation of 40 years of injection history, up to the present, to obtain 3D distributions of injected wastes within the studied formation, shows that today, the main mass of waste is predominantly distributed within the sand. The modeling results did not show any significant upward waste movement during 40 years of injection through preferential flow paths that could be formed in such a heterogeneous system. This fact indicates that the anisotropy of effective correlation scales, which leads to the hydraulic anisotropy of the system, prevents vertical migration of injected waste.
From 1960 into the 21st century, deep-well injection of liquid radioactive wastes has played a significant role in preventing environmental contamination. Deep-well injection of liquid radioactive waste in a freshwater horizon at Tomsk-7 and Krasnojarsk-26 was begun in 1960, when the Soviet government granted a permit for using this horizon. Scientists involved in deep-well injection projects envisaged observation wells in which measurements and sampling of underground waters would be conducted. Deep-well injection is considered a temporary measure, to be changed through the technology of waste solidification. At the same time, continued developments show that it is reasonable to combine solidification of specific waste categories with liquid-form disposal, if favorable geological conditions are present for those purposes. Forecast accounts and modeling were carried out to support the continued deep-well disposal of liquid radioactive wastes up to 2010–2115. The continuation of deep-well injection of liquid radioactive wastes, at operational sites, will help avoid the significant economic expenses associated with the application of alternative technologies and will simultaneously ensure safe waste disposal.
This chapter explains the long-term experiences in modeling and reservoir survey for the injection of brine from cavern leaching into deep saline aquifers. New technical solutions have to be adopted for disposal-well completion to ensure an optimal injection process and avoid corrosion. New technological innovations are necessary to build a cavern storage facility in the interior of a country without the option of using brine industrially on site, discharging the brine into rivers, or building a pipeline to the open sea. The exploration work was not only performed at the Kraak salt dome but also simultaneously extended, with the same scope of investigations, to the injection formation. Suitable geological structures for brine disposal were found in an area north of the Kraak salt dome in Mesozoic sandstones of the Aalen (Middle Jurassic) and Rät (Upper Triassic) formations. Prognosis calculations with the simulation model have shown that the leaching process and the brine injection in the aquifer can be extended as planned, without reaching critical pressure values in the reservoir. Simulation models provide good evidence to ensure economical and safe brine injection into deep aquifers under long-term conditions.
This chapter investigates the effect of the human-caused impact on changes in the absorbing capacity of rocks in deep, acidic liquid radioactive waste (LRW) repositories. Acidic radioactive waste is injected into the underground repository in batches. The process of acidic-waste injection is conducted in three phases. Disposal of acidic LRW into deep underground repositories leads to the formation of a nonequilibrium, geochemical system. Complex physicochemical interactions directed towards attaining a state of equilibrium developed within the system. This effect could explain the continuous increase in radionuclide sorption with the increased interaction time of waste with the rock under hydrothermal conditions. Experiments demonstrated the possibility of creating two barrier types. The first is associated with the formation of solid phase iron and chromium hydrous-oxide compounds; amorphous silica and the transformation products thereof form the second. Formation of both ensures the reliable localization of various radionuclides, including the most environmentally hazardous actinides.
Publisher Summary This chapter quantitatively evaluates the adsorption-related reactions with respect to natural attenuation, sorption, and desorption kinetics and equilibrium under different geochemical, temperature, and pressure conditions with application to radioactive waste disposal sites in the Russian Federation. An analysis of the experiments with sand, clay, and metavolcanic rock core samples indicates that the adsorption isotherms for 90Sr and 137Cs are of the Freundlich type. All described batch and diffusion experiments revealed hysteresis in radionuclide adsorption. Alterations in the chemical composition of the solution and the secondary mineral phase of the rock transformation might also lead to hysteresis in adsorption. A rapid drop in radionuclide concentration in solution, which is caused by its sorptive uptake, is modified by a gradual increase in the corresponding concentrations. Experiments showed that temperature noticeably affects the intensity of radionuclide adsorption. The results of these experiments could affect the direction of the theoretical study of subsurface radionuclide migration, modeling activity, and numerical code developments.
This chapter explains the bacterial diversity studied in water collected from the S15 monitoring well, located near to the Borehole Radioactive Waste Injection Site Tomsk-7 in Siberia, Russia. Results presented in this study indicate that the structure of the bacterial communities at the S15 monitoring site is rather complex and diverse. Interestingly, about 75% of the sequences of the S15A 16S rDNA library shared extremely high identity at the level of species with the 16S rRNA genes of already cultured bacterial strains. Many of the retrieved 16S rDNA sequences were related to the 16S rRNA genes of bacterial strains that are involved in different interactions with metals, such as geothrix fermentans H5, sinorhizobium sp 9702-M4 etc. Culturing bacteria from heavy-metal-polluted and other extreme environments is, however, very important because it gives one the opportunity to study novel, not-yet-described metabolic pathways and properties of life that can help in understanding the biogeochemical processes on the Earth. In addition, some of the isolates can serve as templates for developing in situ bioremediation procedures, as in the case of the uranium mining waste isolate bacillus sphaericus JG-A12, which was used for construction of biological ceramics for cleaning the drain waters of uranium wastes.
This chapter outlines the historic legal interpretations and tries to make the explanation in the context within which general principles may affect geologic sequestration (GS) of CO2 projects. The preponderance of case law presented here suggests that surface and mineral owners will have a legitimate claim on subsurface strata used for GS projects. Many actors will have real interests in GS projects, including the injector, owner of injected material, surface property owner, mineral owner, mineral lessee, neighboring surface and mineral owners, and neighboring mineral lessees. Because of the large size of many proposed GS projects, care needs to be taken to ensure that adjacent mineral rights owner's holdings are not compromised. Because mineral rights have been found to trump both storage uses and surface holdings, any GS project needs to carefully examine mineral, water, and surface uses of the land that will be influenced by an injection project. Mineral extraction in adjacent strata could compromise the formation's storage integrity. Likewise, pressure increases in the substrata could affect lateral movement of waters in the subsurface and affect groundwater quality.
This chapter discusses the use of deep geologic horizons for liquid waste disposal at power complexes in Central Russia. The results from studies of deep geological formations in European Russia, as well as injection experience and expertise, show that liquid salt wastes from nuclear power plants can be successfully injected into deep geological formations. The existence of a favorable geological structure is a necessary condition for the application of deep-well injection. In the central part of European Russia, known geologically as the Russian Platform, vast territories of the big sedimentary basin are characterized by favorable conditions for deep-well injection of liquid industrial waste. Liquid waste for injection is created by the equipment for demineralization of natural water used for replenishment of technological systems in the first and second loops of the nuclear reactor. The volume of liquid wastes that is suitable for injection at atomic power plants can be increased through the use of new effective sorption materials developed by the Russian Federation. By applying these materials in the preprocessing of liquid radioactive waste, total radioactive activity can be reduced to levels below those established for radioactive wastes.
