An Investigation of Techniques for Removal of Chromium from Electroplating Wastes

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Environmental Protection Agency, Water Quality Office, 1971 - Chromium compounds - 91 pages
 

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Page 29 - ... for varying periods up to 2 hours. Results, shown graphically in Figure 9 indicate that maximum adsorption occurred within the first 10 minutes and that increasing contact time beyond this point had very little effect. The effect of pH value on chromium adsorption is shown in Figure 10. The normal pH value of the synthetic waste solution containing 10-ppm chromium as dichromate using distilled water is 6.0. During this series of experiments, the pH value was varied from 2 to 12 by the addition...
Page 5 - FINISHING 1973 by Michael R. Watson Pollution Technology Review No. 5 Electroplating and other metal finishing waste streams are significant contributors to water pollution, either directly by their content of toxic and corrosive materials, such as cyanide, acids, and metals, or Indirectly through the deleterious effect these effluents exert on sewage treatment systems. Federal, state and municipal regulations fixing the allowable concentrations have been established and enforcement may be expected...
Page 81 - SECTION VII ACKNOWLEDGMENTS This research program was conducted during the period of April, 1968, through June, 1970. Battelle personnel participating in the program were AK Reed, TL Tewksbury, JF Shea, RG Brown, JG Price, MF Nichols, and GR Smithson, Jr. The cooperation and assistance of the following is gratefully acknowledged: Metal Finishers ' Foundation Pollution Abatement Committee : Walter V.
Page 83 - ... Metallurgical Soc. Conf., Vol. 24, "Precipitate Flotation — A New Metal Extraction and Concentration Technique", pp 659-679. (6) Grieves, RB, and Wood, RK , "Continuous Foam Fractionation: The Effect of Operating Variables on Separation", AICh.E. Journal Vol. 10, No. 4, p 456 (1964). (7) Grieves, RB, "Foam Separation Processes for Industrial Waste Treatment: Phenol, Phosphate, and Hexavalent Chromium", Proc. 21st Industr. Waste Conf., Purdue Univ. Engng. Ser. No. 121, p 192 (May, 1966). (8)...
Page 44 - Although there may at present be a certain laxity in legislation and enforcement, the day may come when every plater may be required to satisfy limits as low as 1 or 2 ppm of chromium. An acceptable liquid-liquid extraction process would have to be capable of achieving such limits. (2) Reagent recovery by stripping should be efficient. (3) The stripping operation should produce a greatly concentrated solution of the contaminant either for recovery or chemical destruction.
Page 1 - ... waste stream containing 100 ppm of hexavalent chromium. This was compared to an operating cost of about $7.00 for the conventional treatment method employing sodium bisulfite. Chromium loading capacities at this concentration were found to be in the range of...

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