THERMAL-TREATMENT OF FUEL OIL-CONTAMINATED SOILS UNDER RAPID HEATING CONDITIONS

Batch samples (similar to 50 mg) of 63-125-mu m particles of a U.S. EPA synthetic soil matrix, neat or contaminated with 4 or 7 wt% of no. 2 fuel oil, were subjected to preselected temperature-time histories. Effects of heating rate; final temperature, heating time, and contamination level on extents and apparent global rates of contaminant removal were studied. At 1000 degrees C/s, the percent fuel oil removal approached 100% in about 0.7 s (final temperature congruent to 700 degrees C). Most of the oil can also be eliminated by heating the sample to final temperatures of 300 and 500 degrees C at 1000 degrees C/s and then continuing heating for about 25 s, Heating rate affects the details of oil release but heating to 300 degrees C at 200 or 1000 degrees C/s each gave oil decontamination efficiencies that approached 100% in about 25 s. For the same peak temperature and heating rate, soils with initial contaminant levels of 4 or 7 wt% required about the same total heating time for essentially complete removal of the oil. Products generated during the heating of selected soil samples were collected and analyzed. The results imply that significant chemical transformations of the fuel oil probably occur during higher temperature, e.g., 500 degrees C, thermal treatment.