Catalytic Oxidation of Mixed Wastes Containing High Organic Content—Emission Reduction and the Effect of Steam

To resolve mixed organic and radioactive waste disposal problems, Lawrence Berkeley National Laboratory (LBNL) initiated a treatability study using the catalytic chemical oxidation (CCO) system to oxidize a mixed-waste stream and to confine tritium as part of LBNL's pollution prevention program. LBNL has also adopted a legal approach by seeking an equivalent waste-treatment determination for the CCO process, and by petitioning the United States Environmental Protection Agency (EPA) to delist F-coded treatment residues. The results of this study demonstrate that (1) the CCO process can treat aqueous wastes containing a broad range of organic chemicals and achieve more than 99.999% destruction efficiency; (2) greater than 99.9% trapping efficiency for tritiated water can be achieved using an emission-reduction system that also confines the vapor of hydrochloric acid or nitric acid to the liquid residue; and (3) neutralized treatment residues can be disposed of as low-level radioactive waste at a permitted facility after EPA has approved LBNL's petitions, or the tritium in the residues can be recycled. The high oxidation efficiency of the CCO process is mainly due to the optimized operating conditions of the CCO process and the combined effect of steam reforming in the oxidation cell and the catalytic oxidation of organic mixtures and CO in the Pt/Al₂O₃ catalyst bed.

Keywords::

• Catalytic chemical oxidation
• Steam reforming
• Mixed wastes
• Emission reduction
• Delisting petition.

ACKNOWLEDGMENTS

Li-Yang Chang is supported by the Environmental Management and Office of Science (SC) programs through the U.S. Department of Energy Contract DE-AC03-76SF0098 with the University of California. Chit Than, Hiromi Morimoto, and Philip G. Williams are former LBNL researchers. The regulatory and legal supports on our petitions to EPA were provided by Nancy Ware, LBNL's environmental legal counsel. We appreciate the support of colleagues from the DOE complex, LBNL and other laboratories, our communities, environmental professional organizations, universities, and biomedical research institutes. We are also grateful for the editing of Theresa Duque and comments of the paper's reviewers.

Notes

*Verified by an independent commercial laboratory, per EPA protocols (methods 8015, 8260, and/or 8270). For the compounds listed in Method 8260, the detection limits are 0.5 ppb (μ g/L). Depending on the sample volume, for the compounds listed in Method 8270, the detection limits could vary from 50 to 500 ppb, and for the compounds listed in Method 8015, the detection limits could vary from 100 to 200 ppb. Also, see Table 3.

^#More than 50 chlorinated compounds were analyzed with Methods 8015, 8260, and 8270. The 18 listed in this table are included in 40 CFR 261 Appendix VIII.

*For the 11 compounds tested by Method 8260, the detection limits are 0.5 ppb (μ g/L). By contrast, for the 12 compounds tested by Method 8270, the detection limits vary from 20 to 200 ppb (depending on the volume of sample analyzed); and for the 5 compounds tested by Method 8015, the detection limits vary from 100 to 200 ppb.