uses boiling to be initiated on the surface of the particles. The violence of boiling being nucleated on particle surfaces directly dislodges contaminants from the particle surface. Such violent scrubbing of very small clay and silt particles can not be achieved by intense external mixing and shearing as practiced with other soil washing technologies. Intense mechanical shearing is not successful in washing small particles because the small particles move within the water film surrounding them during the mixing and shearing. In contrast, the EASW process initiates violent boiling on the particle's surface directly. Removal and destruction of a chlorinated hydrocarbon, pentachlorophenol. Boiling is nucleated on the particle surface by superheating the liquid water surrounding the particles. Superheating is achieved by the flow of electric current through the soil slurry being washed. The local intensity of energy release is increased by the geometry of electrodes and insulating orifices employed in the EASW soil washing apparatus. One such geometry that has been tested for continuous EASW soil washing is shown in Figure 1. The diameter of the central insulating orifice can be varied as desired to control the local intensity of energy release in its vicinity. The electrodes are connected to commercial 60Hz power via transformers. The present apparatus allows up to 400 volts to be applied across the electrodes. The process is self-regulating. When steam is present in the orifice the electrical resistance increases and the power input decreases. A patent (3) has been granted for this unique soil washing technology. Integration of EASW process into conventional soil washing processes The EASW unit is easily integrated into a conventional soil washing flowsheet as shown in Figure 2. The feed to the unit can either be whole soil, or just the contaminated fines stream from an existing soil washing process. Feeding only the contaminated fines st...
