Electrode-assisted soil washing

Soil 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.