Deep cleaning method for highly contaminated soil

A cleaning method for contaminated soil, the method comprising:

• a feeding step including pouring the contaminated soil into a hopper and transported the contaminated soil to a washing machine;
• a washing step including adding water from a water tank to the washing machine and mixing the water with the contaminated soil;
• a first separation step including sending the contaminated soil that has completed the washing step through a vibrating sieve and separating the contaminated soil into stones and water with mud;
• a second separation step including receiving the water with mud from the first separation step, and sending the water with mud through a cyclone separator to separate the water with mud into sand water containing sand materials with particles larger than a predetermined particle size and mud water containing mud materials with particles smaller than the predetermined particle size, and delivering the mud water to a wastewater treatment unit;
• a countercurrent washing step including receiving the sand water that completed the second separation step, introducing the sand water into a countercurrent washing tank from the top, injecting water from the water tank into the bottom of the countercurrent washing tank to form a countercurrent washing state, discharging the washed sand from the bottom of the countercurrent washing tank, and over flowing mud washed from the sand by rising the water, and delivering mud water washed from the sand to the wastewater treatment unit;
• a wastewater treatment step including subjecting the mud water from the second separation step and the mud water from the countercurrent washing step that has been delivered to the wastewater treatment unit to sedimentation, separation, and press filtration to obtain a sludge cake and a filtrate including water and discharging the filtrate to the water tank.