Remediation technique

The most commonly used remediation technique for the recovery of organic contaminants from ground water has been pump- and-treat, which recovers contaminants dissolved in the aqueous phase. In this regard, the application of carbon adsorption has found extensive, but not exclusive use. Vacuum extraction (also called soil venting) has also become popular for removal of volatile organic contaminants from the unsaturated zone in the gaseous phase. Both of these techniques can, in the initial remediation phase, rapidly recover contaminants at concentrations approximately equal to the solubility limit (pump-and-treat), or the maximum gas phase concentration of the contaminant (vacuum extraction). The... 

In the case of produced liquid hydrocarbons and other chemicals spilled during operations, subsequent remediation may be necessary. This section as well as Chapter 6, Environmental Considerations, details some remediation techniques currently employed. 

Hamby DM (1996) Site remediation techniques supporting environmental restoration activities—a review. Sci Tot Environ 191 203-224. 

Various soil remediation techniques such as incineration, soil washing, or biological soil treatment were applied in the past, but the microbiological degradation of TNT-contaminated soils is considered to be the most favorable technique as far as costs are concerned [414]. The following is a summary of these TNT remediation technologies ... 

An advantage of aquathermolysis is that the use of hot water as a remediation technique does not require the injection of potentially harmful chemicals. Additional advantages include the lower temperatures and pressures that are easier to produce and handle in the injection... 

The Arctic Foundations, Inc. (AFl), frozen soil barrier technology is constructed by artificially freezing the soil pore water. As the pore water freezes, the soil permeability decreases, thereby forming an impermeable barrier that surrounds and contains the contaminants. When properly installed, the frozen soil barrier prevents the migration of contaminants within groundwater and soil. Contaminants are contained in situ, with the frozen native soils serving as the containment medium. The contaminants are isolated by the wall until appropriate remediation techniques can be applied. 

The Ecolotree buffer uses phytoremediation, or plant processes, for environmental remediation purposes. Ecolotree buffers can be used to reduce the migration of subsurface water and surface runoff, while also acting as an in situ remediation technique for both organic and heavy-metal contaminants, including benzene, toluene, ethylbenzene, and xylene (BTEX) chlorinated solvents ammunition wastes and excess nutrients in soil or water. The technology is commercially available and has been used at landfill and waste treatment sites. 

Although vitrification of soils is a well-documented remediation technique, research into this particular technology ceased at an early stage, and little information is available about it. This technology is not commercially available. 

Horizontal drilling is a contaminant extraction technology designed to access areas that are difficult for vertical wells to reach due to surface obstructions such as buildings, landfills, and lagoons. The technique was originally developed as an oil extraction method. Environmental horizontal wells are used in correlation with other remediation techniques, such as pump-and-treat... 

The primary apphcation for this technology is the cleanup of heavily contaminated soils from abandoned herbicide and pesticide manufacturing sites and mixed petroleum wastes containing both hydrocarbon and heavy-metal contaminants. It also has potential as a remediation technique to restore fertility to agricultural soils suffering from overuse and salt buildup from irrigation. 

Some potential disadvantages associated with phytoremediation/plant-assisted remediation techniques include the following ... 

The heat of oxidation can benefit other remediation techniques. 

Abstract Proposed surfactant-based remediation techniques have the potential to be very... 

Dense nonaqueous-phase liquids (DNAPLs) are widespread at contaminated sites, where they are often distributed deep in aquifers due to their high densities [US EPA, 1993], Surfactant-based remediation techniques have the potential to be very effective at removing DNAPLs from contaminated sites (e.g., [Pennell, et al., 1994 Baran, et al., 1994 Pennell, etal., 1997 Zimmerman, et al., 1999]). However, one risk associated with surfactant-based remediation of DNAPLs is the potential for unwanted... 

The microbial reduction of chromium(VI) to chromium(ni) has been discussed as a possible remediation technique in heavily contaminated environmental media or wastes (Chen and Hao 1998). Factors... 

Kiister E, Dorusch F, Vogt C, Weiss H, Altenburger R. 2004. On line biomonitors used as a tool for toxicity reduction evaluation of in situ groundwater remediation techniques. Biosensors Bioelectronics 19 1711-1722. 

There is a general consensus (vide supra) on the environmental importance of catalytic reactions on the surface of many minerals. However, there is limited information in the literature about specific examples [9]. Systematic studies would allow the understanding of the dependence of the catalytic activity on mineral structure, mineral chemistry and surface reactivity. At the same time, this knowledge would be useful in designing remediation techniques based on minerals instead of synthetic catalysts. For example, sphalerite and ilmenite have been shown to be capable of degrading chlorinated carbon compounds via a photo catalytic mechanism [63]. 

Excavation in order to remove drums and highly polluted waste. If the most contaminated waste in the landfill body can be identified, excavation may be an efficient remediation technique. Partly corroded drums may be difficult to handle without contaminating the waste material this is for precautions and care. The excavated material may be removed for off-site treatment or may be re-landfilled in landfill sections established with landfill liners, leachate drainage collection, and treatment systems. 

Natural attenuation by itself, however, often is not sufficient to achieve a desired extent or rate of contaminant removal from an aquifer. In these instances, one remedial option may be to enhance the natural rate of biodegradation of pollutant chemicals in the aquifer. This strategy, called in situ bioremediation, is considered to be one of the most attractive remedial techniques from a cost perspective, because many of the high costs associated with pumping and treating groundwater or excavating contaminated aquifer material are avoided. Furthermore, the potential exposure of cleanup workers to pollutant chemicals is reduced if many of the contaminants are mineralized while still in the aquifer. 

In many cases, contaminated land can be treated in order to rehabilitate it for future use. The success of remediation techniques depends on the concentration, type and availability of the contaminants present, and on-site factors, such as soil texture, pH, availability of terminal electron acceptors (Section 4.6.5) and the age... 

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