Mound Laboratory activities on the removal of radionuclides from wastewater using bone char

Bone char, a natural product which is obtained from granulated cattle bone, was determined to be the optimum phosphate for large-scale removal of plutonium from wastewater. Particles in the 74 to 105 μ range gave the best combination of decontamination factors and flow rates. Small-scale pilot runs with two bone char columns in series were investigated both with and without pretreatment of the influent water. In the pilot runs thus far conducted, the capacity of bone char for ionic plutonium was never exceeded. However, partial regeneration (17 percent) of the bone char can be achieved using 1M Na2CO3 and 0.1M Na2HPO4. Studies were made using a bone char column (20 in. high and 10 in. in diameter) preceded by a 0.1 μ filter. Results from these pilot runs yielded effluent with less than 1 dis/min/ml at flow rates from 0.5 to 1.5 gal/min. High pressure drops (60 to 65 psig) were noted in these columns, but it was found that pressure drops could be lowered to less than 45 psig by washing the particles free of fines. At pH's higher than 9, flocculent evaluations showed that Purifloc A-23 and Nalco C-610 produced the best overall characteristics when floc size, settling rates, and solution clarity were considered. (auth)