Comparison of energy consumptions between ultrasonic, mechanical, and combined soil washing processes

Vigorous physical effects including micro-jet and micro-streaming can be induced in heterogeneous systems by acoustic cavitation. This can be useful for the removal of pollutants from contaminated soil particles. In this study, the diesel removal efficiencies in ultrasonic, mechanical, and combined soil washing processes have been compared considering the electrical energy consumptions for these processes. The combined process showed synergistic effects for both removal efficiency and effective volume also has the advantage of a short operation time compared to the sequential processes. Thus the ultrasonic soil washing process with mechanical mixing is considered a promising technology for industrial use.

► The use of ultrasound in mechanical soil washing processes was investigated.
► The combined process was effective in terms of removal efficiency, operation time, and energy.
► Mechanical mixing increased the exposure of ultrasound to soil particles.
► Ultrasound enhanced the removal of contaminant effectively.
► Removal of the contaminant from the pores required very high energy.