Chrome Electroplating Waste BAT

During the past several years, waste produced by the electroplating industry has attracted attention due to the level of pollutants found in the waste stream, the difficulty associated with treatment, and the cost of waste disposal. EPA has enacted regulations to control the discharge from plating facilities and estimates that 140 million lb of metal pollutants will be prevented from being discharged to publicly owned treatment works. The current pretreatment regulations are oriented toward meeting standards using Best Practical Technology (BPT). These requirements can be normally achieved using cyanide oxidation, chromium reduction, and acid alkali neutralization. By July 1984, however, the second generation National Pollutant Discharge Elimination System (NPDES) permits for point source dischargers must be capable of treating toxic pollutants using Best Available Technology (BAT), as required by the Clean Water Act. The pretreatment standards for industrial users will also reflect BAT. The categorical standards for the electroplating industry were revised in August 1982 to include the metal finishing industry. The pretreatment standards for existing sources must be capable of meeting BAT standards by January 1984. The level of treatment to achieve BAT will probably include internal plant controls, flow reduction, resource recovery, and closed loop systems where economically achievable. Additionally, the Resource Conservation and Recovery Act (RCRA) regulates the disposal of sludges containing toxic materials. All sludges generated from the treatment of electroplating wastewater are listed hazardous wastes and must be hauled to a licensed landfill. Some industries have been successful with delisting electroplating sludge; however, this is not felt to be a long term solution to the problem. The conventional treatment of electroplating wastes using BPT produces a large volume of sludge. For example, chrome reduction produces 1.98 lb of dry solids using NaOH and 2.24 lb of dry solids using Ca(OH), for each pound of waste hexavalent chrome. In either case, the production of hazardous waste has been doubled through the treatment proWILLIAMSON P 04511