Pilot Scale Ferrous and Sulfide Metals Treatment in Wastewater Cleanup
Metal finishing operations generate large volumes of hazardous aqueous wastes containing metals and organics. End-of-pipe treatment usually involves coupled processes to precipitate metals followed by organic degradation. Large volumes of metal bearing sludges are generated during the treatment and are classified as RCRA regulated hazardous wastes. A two-stage treatment process was developed and piloted which reduced the volume of the waste sludge generated during wastewater cleanup. The two stages involve: 1) treatment with alkaline ferrous sulfate and sodium sulfide to reduce hexavalent chrome and precipitate all of the hazardous metals, and 2) biodegradation of the organic components. Aspects regarding the hexavalent chromium reduction, metals precipitation, metals flocculation, filtering, and the related chemistry are discussed.
KeywordsFerrous Sulfate Hexavalent Chromium Sulfide Concentration Chromium Reduction Sodium Sulfide
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