Hazardous Waste Minimization at a Brass Wire Mill

To eliminate hazardous hexavalent chromium from a brass wire-mill waste, hydrogen peroxide was examined In place of chromic acid for pickling, first in bench-scale tests and then in plant tests. Nthough the elimination of chromic acid requires more rigid control of the ~ wastewater treatment operation and increases the zinc content of the waste-treatment effluent, the economic benefit of substituting peroxide outweighs these disadvantages. Neutralization with caustic soda and membrane ultrafiltration results In an effluent with acceptable concentrations of copper, zinc, lead and nickel.