Six-phase soil heating

T0193 Current Environmental Solutions, L.L.C., In Situ Corona T0194 Current Environmental Solutions, L.L.C., Six-Phase Soil Heating T0197 Dames and Moore, Two-Phase Vacuum Extraction T0199 Dehydro-Tech Corporation, Carver-Greenfield Process T0200 Delphi Research, Inc., DETOX... 

T0194 Current Environmental Solutions, L.L.C., Six-Phase Soil Heating... 

TABLE 1 Cost Comparison for Six-Phase Soil Heating and Soil Vapor Extraction... 

A full-scale implementation of six-phase electrical heating technology was used in Sheffield (UK). Terra Vac Ltd. demonstrated how remediation timescales can be reduced from months/ years to weeks, with an electrical heating capable of remediation of soil in difficult geological conditions and in densely populated urban areas. TCE and VC were remediated by electrical heating up to 99.99 % [6]. 

ISOTEC was chosen to treat soils contaminated with dense non-aqueous-phase liquids (DNAPLs) at a Superfund site in Florida. With a projected cost of 340,000, ISOTEC was cheaper than the alternative technologies considered. The estimated cost for implementing six-phase heating at the site was 535,000, and the estimated cost for excavation and ex situ treatment was 835,000 (D21478I, pp. 10, 11). 

Sequential extractions (SSEs) were performed on the surface and subsurface soils, as Summarized in Table 8.2. The first six steps follow the method of Zeien and Briimmer,71 and Briimmer and Herms.72 The residual phase, that is, the phase that remained after step 6, was digested with a two-step microwave procedure. For the first step, 250 mg of sample were added to 4 ml of 65% HN03, 2.5 ml of 32% HC1 and 1 ml of 48% HF, and then heated for 5 min at 150 W and for 15 min at 350 W. For the second step the sample was cooled, and 10 ml of a 6% H3B03 were added and heated for 25 min at 250 W until a pressure of 15 bars was reached. No visible residues were left after this procedure. Extracted Zn was measured by atomic absorption spectrometry (Varian Spectra 220 Fast Sequential). The percentage of total Zn removed in each of the extraction steps is presented in Figure 8.4. The sum of all SSE steps was in good agreement with the total amount determined by XRF (+5%). 

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