The portable soil remediation unit is designed to remediate soil contaminated with non-recycled distillate petroleum hydrocarbons, including gasoline, jet fuel, diesel or #2 oil and heavier carbons, by rapidly volatilizing the petroleum contaminants from the soil and destroying the gases in a thermal oxidizer.
The unit consists of a rotary desorber equipped with alloy steel high-temperature section, with feed, discharge, and combustion control systems, a dust collector, and a modular thermal oxidizer with associated fuel and air delivery systems, all mounted on trailers for easy transport from site to site. The unit comes equipped with process fuel instrumentation and an 8′ x 12′ control room for safe, efficient, and dependable process operation.
The unit is capable of discharging soil having a total concentration of less than 20 ppm total petroleum hydrocarbon and less than 100 ppb each of toluene, ethyl benzene, and xylene, and less than 10 ppb of benzene, while meeting standard stack emission limits for VOC, opacity, and particulate loading.
Soil is loaded into a feed hopper. The hopper discharges soil onto a variable speed feeder belt equipped with a belt scale, which weighs the soil before it is fed into the rotary desorber. The belt scale provides soil feed rate and totalized weights. The belt feeds contaminated soil into a counterflow rotary desorber. Hydrocarbon compounds and moisture in the soil are evaporated with heat supplied by a direct-firing burner. Heat transfer to the soil in the rotary desorber is maximized by a veiling action of specially-designed lifting flights and patented combustion volume flights.
The evaporated hydrocarbons, water vapor, and dust released by the desorbing process are carried into a gravity settling chamber, where larger particles drop out of the gas stream. Fines are then collected by the baghouse. Gas containing hydrocarbon vapors from the baghouse is routed through an exhaust fan into a horizontal thermal oxidizer. Overall DRE (Destruction Removal Efficiency) is 97% or better.