Browsing by Subject "Soil remediation"
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Item Development of the electrode assisted soil washing process(Texas Tech University, 1997-05) Krishnan, RameshContaminants in soils containing a high percentage of silt- and clay-sized particles typically are strongly adsorbed onto the soil and are very difficult to remove. State-of-the-art technologies find it very difficult, if not impossible, to apply soil washing to these contaminated soils. However, a newly patented Electrode Assisted Soil Washing (EASW) process appears to be effective in removing petroleum hydrocarbons (gasoline, diesel, crude oil, etc.), chlorinated hydrocarbons (pentachlorophenol), and heavy metals (Pb, As, Cd, Zn) from contaminated soils made up of a high percentage of clay and silt. The EASW process produces a washed soil material that meets site-specific regulatory requirements which allow the washed soil to be returned to the site without further treatment. Furthermore, the contaminated water generated by the process can be treated with standard methods. The EASW process can be used alone, or it can be used in combination with other soil-washing methods. In the latter case, the EASW process is particularly effective in the treatment of contaminated fines streams generated by other soil-washing techniques. The EASW process has been developed to operate in a batch mode as well as in a continuous mode. Initially, laboratory contaminated soils (diesel and crude oil in Lubbock topsoil) were used to test the EASW process. Later, authentically contaminated soils from well documented sites in New Jersey (from a petrochemical loading dock) and the Gulf Coast were also washed using the EASW process. A complete anaylsis of the wastewater generated in the process was also done.Item Electrode-assisted soil washing(Texas Tech University, 1993-12) Krishnan, RameshSoil contamination has become a serious problem and has attracted much attention in the United States. In most cases the necessity to clean contaminated soil arises from a threat to our underground drinking water supply. There are many alternatives to solving this problem. One of the most viable alternatives for cleaning contaminated soil is Soil Washing. The state-of-the-art soil washing technologies are effective in cleaning large-grained soils (sands and coarse silts), but are ineffective with fine-grained soils (fine silts and flocculated clays). Usually, for successful soil washing, the soil should contain less than 25% of clays and silts. An innovative soil washing technology has been experimentally demonstrated, at the Chemical Engineering Department of the Texas Tech University, to clean contaminated soils that contain a very high percentage of fines (silts and flocculated clays). This technology is called the Electrode Assisted Soil Washing (EASW) technology. The laboratory scale EASW device has proved successful in washing contaminated soils carrying a greater percentage of fine silts and clays. The primary contaminants used to test the EASW device are a straight-run diesel fraction from the Fina refinery at Big Spring, Texas, and 26.2 API crude oil. The soil, these contaminants were tested on, is Lubbock top soil. To further strengthen the credibility of the EASW technology, authentic contaminated soils from the "real world" were washed successfully. Soils from the Gulf Coast and from an old petroleum product loading terminal in New Jersey were washed to below 100 ppm of the contaminant on the soil. A formal patent search has been made regarding the EASW process and no prior art was found. On this basis, a formal patent application has been filed and is pending, for the invention of the EASW process.