Sludge Generation from Ferrous/Sulfide Chromium Treatment.
Abstract
The reaction pH and reduction chemical can drastically effect the volume of wastewater treatment sludges produced in chromium treatment. Experiments at the Air Force Engineering and Services Laboratory have shown that mixing sodium sulfide and ferrous chloride (9:1 ratio) at pH 8.0 rapidly reduced hexavalent chromium and produced approximately one-fourth the sludge (on a dry weight basis) as the standard acidic reaction using only ferrous sulfate. The mechanism involves an oxidation of the sulfide to sulfate with the ferrous ion acting as a catalyst. This catalytic effect is possible because the large sulfide overdose shifts the ferrous and sulfide ion equilibrium to the molecular form. The electron transfer then occurs on the sulfide side of the molecule. An additional benefit of the process is that there is no need to reduce the pH of the influent wastestream prior to chromium reduction. Likewise, the caustic required for raising the pH to precipitation levels is also limited. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1984
- Accession Number
- ADA146600
Entities
People
- J. R. Aldrich