TABLE 7.1-BASIC CHARACTERISTICS OF AIR-CLEANING EQUIPMENT USED IN NUCLEAR-PROCESS TABLE 7.2-APPROXIMATE COMPARATIVE COSTS FOR CLEANING OF RADIOACTIVE OFF-GAS STREAMS' oxide Machining of uranium and Normal and enriched uranium Reverse-jet filter its alloys Reactor cooling air: pre- Nonradioactive atmospheric Bonded 1 to 3μ fiber glass in deep-bed units Same as above plus AEC cellulose-asbestos or glass web 99.95 350 50 dusts, etc. units Ventilation air from process Sand or fiber glass in deep-bed vessels Nonradioactive atmospheric Oil-coated filters, fiber glass mats to electrostatic precipitators dust 99. 7->99.9 2860-5500 400 units <10-90 5-550 0. 40 Radioisotopes and inert dusts Bonded fiber glass and AEC cellulose-asbestos or glass web 99.98 200-800 100 units *Based on power costs of $0.015 kw-hr and 10% depreciation only. REFERENCES 1. S. K. FRIEDLANDER, L. SILVERMAN, P. DRINKER, and M. W. FIRST, 2. M. H. WILKENING, Natural Activity as a Tracer in the Sorting o 4. P. DRINKER and T. HATCH, Industrial Dust, 2nd ed., McGraw- 5. L. SILVERMAN, Economic Aspects of Air and Gas Cleaning for Nucle 6. R. DENNIS, M. W. FIRST, and L. SILVERMAN, Dust Collectors 7. C. J. STAIRMAND, Design and Performance of Cyclone Dust S Trans. Inst. Chem. Engrs. (London), 29: 356 (1951). 8. M. W. FIRST et al., Air Cleaning Studies: Progress Report for Fe 1950, to January 31, 1951, USAEC Report NYO-1581, Harvard U School of Public Health, June 30, 1951. 9. M. W. FIRST et al., Air Cleaning Studies: Progress Report for Fe 1951, to June 30, 1952, USAEC Report NYO-1586, Harvard U School of Public Health, Dec. 16, 1952. 10. G. A. JOHNSON, S. K. FRIEDLANDER, R. DENNIS, M. W. FIRST, and L MAN, Performance Characteristics of Centrifugal Scrubbers, Ch Progr. 51: 176–188 (1955). 11. R. DENNIS, G. A. JOHNSON, M. W. FIRST, and L. SILVERMAN, Pe of Commercial Dust Collectors (Report of Field Tests), USAE NYO-1588, Harvard University School of Public Health, Nov. 2, 12. A. G. Blasewitz, and B. F. Judson, Filtration of Radioactive Ae Glass Fibers, Air Repair, 4: 223 (1955). 13. L. SILVERMAN, Control of Radioactive Air Pollution, in Radiation Handbook, H. Blatz (Ed.), pp. 22–1 to 22–45, McGraw-Hill Book C Inc., New York, 1959. 14. L. SILVERMAN, Laboratory Design for Handling Radioactive Materia Discussion, BRAB Conference Report 3, for conference held Nov 28, 1951. (Available from Building Research Advisory Board, Research Council, Washington, D.C.) 15. R. DENNIS, G. A. JOHNSON, M. W. FIRST, and L. SILVERMAN, H Collectors Perform, Chem. En. 59(2): 196–198 (February 1952). 16. C. E. BILLINGS, M. W. FIRST, R. DENNIS, and L. Silverman, L Performance of Fabric Dust and Fume Collectors, USAEC Repor 1590, Harvard University School of Public Health, Aug. 31, 1954. REMOVAL OF RADIOACTIVITY BY WATER-TREATME PROCESSES The waterworks profession has had the most extensive experience any group in treating, economically, large volumes of liquid mater to remove low concentrations of contaminating or polluting materi Waterworks operators handle large quantities of chemicals in tre ment and are familiar with sludge-disposal problems. In additi many have knowledge and experience in removing toxic and ot nuisancelike substances and therefore are in an excellent position cope with the newer problems facing them as a result of the introd tion of radioactive materials into surface waters. It is reasonable therefore to consider the experience of this indus and to evaluate the various treatment processes for the removal small quantities of radioactive materials contained in large volur of liquid wastes. An evaluation of water-treatment processes is important beca much of the low-level liquid waste currently produced is relea directly or through sewerage systems to water environments. Si many communities use rivers and wells as sources of water sup and utilize some form of water-treatment process before the wate consumed by the public, information is needed on how effective th processes are in the removal of radioactive materials. This chapter describes laboratory and pilot-plant investigations the removal of radioactive materials by conventional water-treatm processes, by nonconventional processes that could easily be ind porated into conventional facilities, and by full-scale facilit particularly for the removal of weapons-test debris (fallout). 8-1 CONVENTIONAL PROCESSES Conventional water-treatment processes of interest in terms removal of radioactive materials include chemical coagulation sedimentation, filtration, lime and soda-ash softening, and exchange. Chemical coagulation involves the destabilization, aggregation, & binding together of colloids. These colloids form chemical flocs t adsorb, entrap, or otherwise bring together suspended matter, m particularly, finely divided suspended matter.' Commonly u 155 |