MOBILE SOIL TREATMENT APPARATUS AND METHOD

摘要

A mobile apparatus and method for treating contaminated soil is disclosed. The apparatus consists of three interconnected subunits, namely a fluidized bed reactor (10, 200) for segregating an aqueous soil slurry based on particle size; a metals extraction unit for removing heavy metals and other contaminants from the contaminated soil fraction; and a water treatment system utilizing a high density sludge process to remove metals from the contaminated aqueous phase. The fluidized bed reactor (10, 200) includes a relatively small first chamber (12, 202) and a relatively large second chamber (14, 204) which are partially separated by a baffle (16, 206). Pressurized gas is dispersed into the first chamber (12, 202) to create a turbulent mixture of raw soil and water, resulting in interparticle scouring of the soil surfaces to assist in the abrasion and removal of adsorbed contaminants. The soil particles are segregated into a first fraction containing relatively small, contaminated soil particles and a second fraction containing relatively large, uncontaminated soil particles. The first fraction is preferably withdrawn from an upper portion of the reactor (10, 200) as a foam. A soil slurry containing the relatively uncontaminated second fraction is continuously withdrawn from a lower portion of the reactor (10, 200). In one embodiment of the invention, the soil slurry may be circulated between the first and second chambers multiple times to increase the soil residence time in the reactor (10, 200). The soil slurry is dewatered downstream of reactor (10, 200) and the water filtrate is recycled. Gas vented from reactor (10, 200) may also be captured, cleaned and recycled.