The bed of the Fox River is contaminated with PCB (polychlorinated biphenyls) over a distance of almost 19 miles. The project involves processing about 3 million m3 of contaminated dredged material. A large part of the clean sand extracted from the sediment will be re-used on site as well as in other local projects. Tetra Tech Inc. is the main contractor for the clean-up of the Fox River. Boskalis process the contaminated dredged material, using a desanding and dewatering plant. Boskalis, with her subsidiary Dolman, specializes in soil and sediment treatment, and designed and built the completely new desanding and dewatering plant for this project in just eight months. Never before has a plant of this kind been built on such a large scale and in so little time.