Treatment of Photographic Ferrocyanide-Type Bleach Solutions for Reuse and Disposal

Complex cyanides (ferrocyanide and ferricyanide) 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/l) and dilute (10 to 100 mg/l) waste effluents. — Ferrocyanide can be oxidized to ferricyanide in overflow photographic color process bleaches using either electrolysis or ozone and the regenerated waste bleach recirculated for reuse in the process. Dilute concentrations of ferricyanide can be destroyed using ozone or chlorine under the proper conditions of temperature, pH and catalyst addition. A cost analysis was made for the methods that were judged acceptable for commercial use. Cost data for each procedure are based upon an “average combined” photographic processor.

Print ISSN

0361-4573

Published

1973-09

Content type

Original Research

DOI

10.5594/J06948