100 Area Hanford soil washing treatability tests

Soil washing laboratory tests performed at Hanford in support of 100 Area Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) feasibility studies included characterization of soils, physical separation, chemical extraction, and water treatment. Results to date show that < 20 % of the soil is finer than 0.25 mm (-40 mesh). The highest concentration of 60Co, 152Eu, and 137Cs contaminants is generally associated with fine soil particles. However, measurable concentrations of contaminants were found in all sizes of soil particles. In initial testing, attrition scrubbing was generally sufficient to treat soils to meet selected performance levels for 60Co and 152Eu. However, more intense attrition scrubbing, autogenous grinding, or chemical extraction was required to enhance removal of 137Cs. Additional tests and assessment of the feasibility of using soil washing techniques are in progress