Abstract: Many industries produce a waste-water stream high in heavy metals. Disposal of sludge from these wastewater treatment plants has become increasingly difficult and expensive in the US due to passage of the Resource Conservation and Recovery Act's 'land disposal ban' for hazardous wastes. Innovative methods can be found for dealing with such wastes. For example, in performing a mandated clean-up under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), Asarco's California Gulch water-treatment plant in Colorado meets CERCLA clean-up goals while using a waste water treatment sludge as a smelter feedstock, recovering incidental saleable metals, and producing non-hazardous products. In this plant, Asarco treats acidic mine-drainage water having high metal concentrations and uses the waste sludge generated as a lime replacement in lead smelting operations. -Author