Polymeric flocculants solution strengths

Four types of colloids were considered in the WIPP program intrinsic actinide colloids, mineral colloids, microbes, and humic acid colloids (US DOE, 1996). Intrinsic actinide colloids, consisting of polymerized hydrated actinide hydroxides, are not stable in the neutral to moderately basic pH conditions expected in the WIPP, and were assumed not to contribute to the total actinide concentrations in solution. Mineral colloids are destabilized and tend to flocculate in the high-ionic-strength WIPP brines (Kelly et al., 1999). In the performance assessment calculations for the WIPP, a highly conservative value of 2.6 X 10 mol actinide per liter, for each actinide, was assumed to be bound to mineral colloids and to contribute to the mobile fraction. Actinides sorbed onto microbes and humic acids were estimated to contribute significantly to the concentration of mobile actinides in WIPP brines as discussed above (Section 9.06.3.2.2). 

---