In Situ flushing of contaminated soils from a refinery: Organic compounds and metal removals

This article demonstrates the applicability of in situ flushing for the remediation of soilcontaminated with petroleum hydrocarbons at a Mexican refinery. The initial average total petroleum hydrocarbon(TPH) concentration for the demonstration field test was 55,156 g/kg. After six weeks of in situ flushing with alternate periods of water and water/surfactant, an averageconcentration of 1,407 mg/kg was reached, achieving a total removal efficiency of 98 percent. At the end ofthe process, no hydrocarbons such as diesel; gasoline; benzene, toluene, ethyl benzene, and xylene(BTEX); or petroleum aromatic hydrocarbons (PAHs) were found. Iron washing achieved aremoval efficiency of 70 percent, and for vanadium, the removal efficiency was 94.4 percent. The volume of soiltreated was 41.6 m 3 (38 m 2 ), equivalent to 69.5 tons of soil. A roughcalculation of the process costs estimated a total cost of $104.20/m 3 ($114.00/m 2 ). Our research indicates that there are a few studies demonstratingin situ flushing experiences under field conditions where both organic (TPH, diesel, gasoline, PAHs,BTEX) and metal (iron and vanadium) removals are reported. © 2004 Wiley Periodicals,Inc.