Groundwater contamination problem

Gaily, R. M. and Gorelick, S. M., 1993, Design of Optimal, Reliable Plume Capture Schemes Application to the Gloucester Landfill Groundwater Contamination Problem Ground Water, Vol. 31, No. 1, pp. 107-114. 

The disposal of chlorinated solvents in landfills and their leakage from storage tanks have caused extremely expensive groundwater-contamination problems that have not yet been solved. Substitutes for chlorinated solvents are now widely used, and care in their disposal is required. 

One of the immediate applications of this model is to simulate advection and dispersion of contaminants in soil columns with low permeability and strong retention mechanisms. In these cases, the contaminant would not be expected to travel to the lowest layers of the soil profile very soon. In this chapter, results from two common contaminant-input conceptualizations were simulated. The first scenario consisted of a localized contaminant load (point source) located at the center of the topsoil column layer (point-source contaminant inputs may simulate localized leakages of chemicals on the surface of the earth). The second simulation consists of a linearly distributed contaminant load (line source) over the top surface of a soil column. Line sources are commonly used in groundwater contamination problems (e.g., see Mulligan and Ahlfeld, 2001). Additionally, a two-point source simulation is included for purposes of comparison. 

The applications of separation science to environmental restoration are centered on the cleanup of contaminated groundwaters and soils. The extent and complexity of the groundwater contamination problem continues to present formidable technological obstacles to cleanup. The most important factors that contribute to this complexity are the large number of contaminated sites, the wide diversity of the contaminants present in those sites, the Inherent complexity of the subsurface chemistry of the contaminants, and the difficulty in interpreting existing regulations to establish compliance and properly prioritize site remediation efforts. 

The MTBE reactive distillation process was patented several decades ago, and the process was widely used in the petroleum industry. Many reactive columns were installed around the world to produce MTBE, which was blended into gasoline. This process was probably the largest application of reactive distillation in terms of the number of columns and total production capacity. Because MTBE presents groundwater contamination problems, it is gradually being phased out of use in gasoline. 

Although many environmental and safety problems can be avoided using UCG, there is some concern about groundwater contamination as a result of the process (see Groundwatermonitoring). 

For question 9, the municipal landfill has had public relations problems with the community. There has been concern over both odor issues and possible groundwater contamination. Taking these concerns into consideration, can you develop addional arguments that make the investment more finacially attractive ... 

Air, soil, and water are vital to life on this planet. We mnst protect these resonrces and nse them wisely— onr snrvival as a species depends on them. Despite recent impressive strides in improving the environment, evidence is overwhelming that more effective action mnst be taken to address snch critical issnes as acid rain, hazardons waste disposal, hazardous waste landfills, and groundwater contamination. It is also vital that we assess realistically the potential health and enviromnental impacts of emerging chemical products and technologies. The problems are clearly complex and demand a broad array of new research initiatives. 

Considerable work has been done on the behavior of pollutant species at air-water and air-soil interfaces. For example, wet and diy deposition measurements of various gaseous and particulate species have been made over a wide range of atmospheric and land-cover conditions. Still, the problem is of such complexity that species-dependent and particle-size-dependent rates of transfer from the atmosphere to water and soil surfaces are not completely understood. There is much to be learned about pollutant transfer at water-soil interfaces. Concern about groundwater contamination by mineral... 

Apart from its application to the specific problem of groundwater contamination, this procedure offers a potentially valuable procedure for simulating bioremediation of contaminated soils. 

The collective evidence suggests the variable recalcitrance of MTBE under aerobic conditions, a degree of recalcitrance anaerobic conditions, and that the presence of the putative degradation product tert-butanol cannot necessarily be construed as evidence for biodegradation (Landmeyer et al. 1998). Bioremediation of groundwater contaminated with MTBE is clearly beset with problems for its practical implementation. 

Subsurface drains function like an infinite line of extraction wells, and can be used to contain and remove a plume or to lower the groundwater table (Figure 16.12). They are more cost-effective than pumping for shallow contamination problems at depths of less than 12 m (40 ft). Depths may be increased if the site is stable, if the soil has a low permeability, and if no rock excavations are encountered. 

Many times in geochemical modeling we want to understand not only what reactions proceed in an open chemical system, but where they take place (e.g., Steefel et al., 2005). In a problem of groundwater contamination, for example, we may wish to know not only the extent to which a contaminant might sorb, precipitate, or degrade, but how far it will migrate before doing so. 

Vanloocke, R., DeBorger, R., Voets, J. P, and Verstraete, W., 1975, Soil and Groundwater Contamination by Oil Spills Problems and Remedies International Journal of Environmental Studies, No. 8, pp. 99-111. 

Zoller U. (1993). Groundwater contamination by detergents and polycyclic aromatic hydrocarbons—a global problem of organic contaminants Is the solution locally specific Water... 

CESAR was developed to address the problem of locating, characterizing, and removing dense non-aqueous-phase liquids (DNAPLs) from contaminated aquifer systems. The process is particularly suited to remediating groundwater contaminated with chlorinated solvents, such as trichloroethylene (TCE), tetrachloroethene (PCE), trichloroethane (TCE), and carbon tetrachloride (CCE). According to the vendor, CESAR can also be applied to sites contaminated with creosote, polychlorinated biphenyls (PCBs), Freon 113, volatile organic compounds (VOCs),... 

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