"Project 12120 ERF." Includes bibliographical references (pages 109-114). Document for sale by the Superintendent of Documents, paper, $2.10. 4to.

Complex cyanides (forro- and forricyanide) in industrial waste water effluents impose a direct threat upon the environment. Methods to recover or destroy these compounds were evaluated in laboratory studies. The techniques tested include electrolysis, ozonation, chlorination and heavy metal ion precipitation. The study was conducted to determine the feasibility of using one or more of these methods to reduce the concentration of ferricyanide in both concentrated (10,000 to 100,000 mg/1) and dilute (10 to 100 mg/1) waste effluents. Numerous analytical procedures were developed to enhance the accuracy of sample analysis over the concentration range studied. Ferrocyanide can be oxidized to ferricyanide in overflow photographic color process bleaches using either electrolysis or ozone and the waste bleach recirculated for reuse in the process. Dilute concentrations of ferricyanide can be destroyed using ozone or chlorine under proper conditions of temperature, pH, and catalyst addition. A cost analysis is included for all methods that were judged acceptable for commercial demonstration. Cost data for each procedure is based upon an "average combined" photographic processor as defined in the report. This report was submitted in fulfillment of Project 12120 ERF, under the partial sponsorship of the U.S. Environmental Protection Agency Conclusions -- Recommendations -- Introduction -- Materials & apparatus -- Procedures -- Discussion of results -- Full scale ozone bleach regeneration and waste destruction installation -- Berkey photo -- Acknowledgments -- References -- Glossary -- Appendices.