A Study of a Combined Microwave and Thermal Desorption Process for Contaminated Soil

Abstract

In order to treat soil contaminated with high percentages of water and petroleum, the combined microwave and thermal desorption process was studied, which was composed of the consecutive connection of two pre-treatment processes. For the thickness of the contaminated soil layer on the transfer conveyor belt, the optimal total petroleum hydrocarbon (TPH) removal rate was studied with respect to the duration of microwave exposure in the consecutive process combined with thermal desorption. The TPH removal rate when the contaminated soil layer thickness was 1 cm at 6 kW of microwave power was 80%. The removals rates for 2 and 3 cm soil layer thicknesses were both 70%. Under identical experimental conditions, the TPH removal rate for the microwave pre-treatment, when considering the soil particle size, was over 70%. The lowest TPH removal rate was achieved with a particle diameter of 2.35 mm. For contaminated soil with 30% water content, 6 kW and a thermal desorption temperature of 600 o C were the optimal operational conditions for the removal of THP. However, considering the fuel consumption cost, 4 kW and a thermal desorption temperature of 300 o C would be the most economic conditions.

Removal of TPH, UCM, PAHs, and Alk-PAHs in oil-contaminated soil by thermal desorption

“…One previous study reported 94.7% of TPH removal after 15 min thermal desorption of petroleum oil-contaminated soil (initial concentration of 5133 ± 508 mg kg −1 ) at 200 °C in a rotary kiln [20]. In another study, the maximum TPH removal efficiency of about 98% was achieved at 500 °C after 15 min treatment of the combined microwave and thermal desorption processes [21].…”

Oil spill problems and sustainable response strategies through new technologies

“…97 Microwave energy has also been reported for rapid recovery of crude oil from soil. 97 Microwave energy has also been reported for rapid recovery of crude oil from soil.…”

“…The energy efficiency and therefore economic performance of thermal desorption especially in wet soils may be improved by pre-treatment using microwave heating to remove moisture and a proportion of petroleum contamination. 97 Microwave energy has also been reported for rapid recovery of crude oil from soil. It was recently reported 98 that microwave heating enhanced by carbon ber added as a microwave absorber was able to recover 94% of crude oil contaminants.…”

Remediation of hydrocarbon polluted soils using 2.45GHz frequency-heating: Influence of operating power and soil texture on soil temperature profiles and contaminant removal kinetics

“…For a full-scale application of MW remediation, a schematic design of a microwave heating system has recently been reported by Ha and Choi (2010), Barba et al (2011) or Chien (2012.…”