Abstract: A soil washing process includes mixing water and contaminated soil in a log washer, separating the soil and water mixture into a first stream of wet soil and a second stream of water and floating organic materials, dewatering the first stream of wet soil to form a cleaned soil stream, dewatering the second stream to separate out the organic materials and form a water stream, separating the water stream into a stream of non-colloidal particulates and a stream of colloid-containing water, dewatering the stream of non-colloidal particulates, and adding the stream of colloid-containing water to the soil and water mixture. The method may further include returning a first portion of the colloid-containing water to the log washer, and drawing off a second portion of the colloid-containing water to filter out the colloids before returning a clean water stream to the log washer.

Abstract: A soil washing process includes mixing water and contaminated soil in a log washer, separating the soil and water mixture into a first stream of wet soil and a second stream of water and floating organic materials, dewatering the first stream of wet soil to form a cleaned soil stream, dewatering the second stream to separate out the organic materials and form a water stream, separating the water stream into a stream of non-colloidal particulates and a stream of colloid-containing water, dewatering the stream of non-colloidal particulates, and adding the stream of colloid-containing water to the soil and water mixture. The method may further include returning a first portion of the colloid-containing water to the log washer, and drawing off a second portion of the colloid-containing water to filter out the colloids before returning a clean water stream to the log washer.