Study on Pb and PAHs Emission Levels of Heavy Metals- and PAHs-Contaminated Soil during Thermal Treatment Process

The objective of this study was to use thermal treatment to treat soil contaminated with heavy metals and polycyclic aromatic hydrocarbons (PAHs). The emissions of lead (Pb) and PAHs during the thermal treatment process were evaluated. The parameters included pretreatment, temperature, and speed of the rotary kiln. Cadmium (Cd) had a higher mobility in thermally treated contaminated soil slag than other heavy metals because the primary fraction of Cd was the exchangeable fraction (90%). Of the temperatures tested in this study, the highest emission concentration of Pb occurred at 700 degrees C. The Pb emission concentrations in the gas phase and solid phase were 44 mu g/N m(3) and 138.35 mu g/N m(3), respectively. In PAHs emissions, naphthalene, acenaphthene (Acp), and fluorene were the main species in the gas phase, at different operating temperatures. The concentrations of these species ranged from 615.5 to 2,002.3 mu g/N m(3). Acp and chrysene were the main species in the solid phase at different temperatures, and the concentrations of these species ranged from 25.5 to 113 mu g/N m(3).