James Conca, James, Elizabeth Strietelmeier, Ningping Lu, Stuart D. Ware, Tammy P. Taylor, John Kaszuba1, and Judith Wright, Treatability Study of Reactive Materials to Remediate Ground Water Contaminated with Radionuclides, Metals and Nitrates in a Four-Component Permeable Reactive Barrier, Groundwater Remediation of Trace Metals, Radionuclides, and Nutrients, with Permeable Reactive Barriers, eds. D.L. Naftz, S.J. Morrison, J.A. Davis, and C.C. Fuller, Academic Press, p. 221-252 (2002).
The treatment of a shallow multicontaminant plume of 239,240Pu, 241Am, 90Sr, nitrate and perchlorate in Mortandad Canyon, Los Alamos, NM, was investigated in the laboratory using a multiple permeable reactive barrier consisting of four sequential layers. These layers include a polyelectrolyte-impregnated porous gravel for flocculating colloids, an Apatite II layer for plutonium, americium, and strontium immobilization, a layer of pecan shells as a biobarrier to nitrate and perchlorate, and a limestone gravel layer for any anionic species that may slip through the other layers, especially those of americium-carbonate. These layers can perform multiple functions, e.g., the pecan shells also sorb strontium very well and the Apatite II also remediates nitrate and perchlorate very well. Nitrate, perchlorate, plutonium, americium, and 90Sr concentrations were reduced to below their maximum concentration limits (MCL) and usually to below detection limits in laboratory studies. The materials for this particular multiple barrier are inexpensive and readily available.