Hexavalent Chromium Removal in a Foam Flotation Pilot Plant

Abstract
Hexavalent chromium was removed from dilute simulated wastewater in a continuous flow pilot scale foam flotation plant. Cr(VI) was reduced to Cr(III) with ferrous sulfate, and the floc resulting on pH adjustment was then removed by precipitate flotation. Sodium lauryl sulfate was used as the carrier surfactant. Effluent Cr concentrations below 0.5 mg/L are easily achieved over the pH range 4.5 to 7.0. The effects of varying the hydraulic loading rate and the ferrous sulfate dose were studied.