Lasagna™ Process treatment zones

An innovative technology called the "lasagna" process is based on the electrokinetic phenomenon called electro osmosis. The lasagna process was created to treat difficult wastes in low permeabiUty, sdt- and clay-laden soils (40). The lasagna process is so named because it consists of a number of layered subsurface electrodes and treatment zones. These layers can be constmcted either horizontally where contaminants are forced to more upward or in vertical position where lateral contaminant movement is desired. 

Figure 12.14 illustrates a vertical flow arrangement, but other configurations are also possible. The process as illustrated in Figure 12.14 is being developed by Monsanto Company and is known as the lasagna process because of the layered structure of the treatment zones (Ho et al. 1993). 

Currently, the Lasagna process is a commercially viable soil remediation process that has been proven especially effective in treating chlorinated solvent contamination in low-permeabiUty soils. The use of DC electrical current to heat the soil and to mobilize pore water and contaminants directionally into degradative treatment zones makes in situ remediation possible. The process is a truly treatment in-place method since no contamination is brought aboveground. Transport and destruction take place within the soil mass. 

Field scale studies and projects were carried out by a consortium of industrial partners (Monsanto, DuPont, and General Electric), the USEPA and the DOE [1]. The electrokinetic process designed and operated for the removal of TCE at Paducah (KY, USA) was called the Lasagna process. It utilizes a DC electric field to move pore water and contaminants uniformly through the soil mass to treatment zones emplaced within the contaminated area. The treatment materials emplaced are typically irtMi, coke, and kaolin. The process results in little or no wastes. The system was operated over a 2-year period when the cleanup target ctmcentration of TCE (5.6 mg/kg) was met. The final results show an average TCE concentration of 0.38 mg/kg. 

---