Remediation technologies physical

Hydrocarbon materials, 20 180 Hydrocarbon propellants, 2 775 physical properties of, 2 776t Hydrocarbon raw materials, 23 686-687 Hydrocarbon release hazard, 20 627 Hydrocarbon remediation, technologies for, 23 112... 

Pollution of soils and waters by human activities is an important and widespread problem. This pollution by, organic and inorganic substances can affect individual organisms, human populations, and ecosystems, each in its own unique way. In particular former military installations, often used for weapons production and nuclear power plants represent a ongoing and substantial threat to environment and human health because of the specific pollutants that can be released Solvents, explosives, fuels, radionuclides, heavy metals, and metalloids all have been identified in the environment around these installations. Remediation technologies for these contaminated sites have been developed based on conventional systems utilising physical and chemical treatments, such as excavation and incineration, pump-and-treat methods, ultraviolet oxidation, soil washing, etc. 

This type of technology differs from most other remediation technologies is that the goal is to trap and immobilize contaminants within the existing medium, rather than trying to remove them via chemical or physical treatments. 

In a collection of synopses innovative site remediation technologies (43), technologies are categorized into bioremediation, chemical treatment, thermal treatment, vapor extraction, soil washing, solidification/stabilization, and other physical treatments. Here separation technologies are contained in the thermal treatment, vapor extraction, soil washing, and other physical treatment sections. Key technologies addressed are ... 

The efficient removal or permanent immobilization of metals achieved by current techniques such as physical extraction, chemical leaching, and vitrification results in both soil structure and fertility detriment. On the other hand, remediation technologies based on biological systems (bioremediation and phytoremediation) seem to be sound processes that enhance the natural response of soil to heavy metal contamination. In these cases, the slow rates of heavy metal removal in soil are strong drawbacks to scaling up the processes for technological applications. 

Electroreclamation (ER) is a soil remediation technology that uses electrokinetic effects to remove inorganic contamination. It can, for example, be used to remove heavy metals, all types of cyanides, arsenic, and other ionic or polar compounds. The basic principle involves applying a difference in potential, thus causing charged particles to migrate to the cathode or the anode. A special electrolyte system is used to both condition physical parameters around the electrodes and in the soil, and to remove the contaminants that have collected around the electrodes. 

Existing soil treatments offering solutions for most pollutants include physical, chemical, thermal, and biological techniques. Most physical treatment processes remove pollutants from the soil-water complex for further treatment or disposal in a more concentrated form. There are, however, some pollutants that are difficult to remove using conventional remediation technologies. Some of them are not only persistent or toxic but also have low solubility and strong adsorption to soil surfaces and organic matter in low-permeability clayey soils [5]. 

Adams, T. V. and Smith, G. J., 1998, DNAPL Remediation in Clay Till Using Steam-Enhanced Extraction In Physical, Chemical, and Thermal Technologies — Remediation of Chlorinated and Recalcitrant Compounds (edited by G. B. Wickramanayake and R. E. Hinchee), Battelle Press, Columbus, OH, pp. 103-108. 

Each project has its own unique characteristic physical, environmental, cultural, and regulatory setting. No single approach (technology, process, or cleanup standard) can be universally applied. The following sections discuss the key elements that impact the economic decisions of remediation projects and result in the most efficient, cost-effective restoration. 

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