REMOVAL OF URANIUM FROM WATER USING TERRESTRIAL PLANTS

Uranium (U) contamination of groundwater poses a serious environmental problem in uranium mining areas and in the vicinity of nuclear proces sing facilities. Preliminary laboratory experiments and treatability s tudies indicated that the roots of terrestrial plants could be efficie ntly used to remove U from aqueous streams (rhizofiltration). Certain sunflower plants were found to have a high affinity for U and were sel ected for treatment of contaminated water. almost all of the U removed from the water in the laboratory was concentrated in the roots. Bioac cumulation coefficients based on the ratios of U concentrations In the roots vs U concentrations in the aqueous phase reached 30 000. Rhizof iltration technology has been tested in the field with U-contaminated water at concentrations of 21-874 mu g/L at a former U processing faci lity in Ashtabula, OH. The pilot-scale rhizofiltration system provided final treatment to the site source water and reduced U concentration to <20 mu g/L (EPA Water Quality Standard) before discharge to the env ironment. System performance was subsequently evaluated under differen t flow rates permitting the development of effectiveness estimates for the approach.