Treatment Technology Evaluation for Aqueous Metal and Cyanide Bearing Hazardous Wastes (F007)

As a result of recent developments In the area of hazardous waste management, the U.S. Environmental Protection Agency Is evaluating the performance of various technologies for the treatment and/or the destruction of certain wastes that are presently being disposed of In landfills and surface Impoundments. As a part of this program, the University of Cincinnati Is testing currently available treatment technologies that are applicable to metal- and cyanidebearing hazardous wastes at the U.S. EPA Test and Evaluation Facility In Cincinnati, Ohio. The following unit processes have been evaluated: alkaline chlorlnatlon, lime precipitation/ flocculation/settllng, multi-media filtration, anlon exchange, and cation exchange. Examination of several process configurations, utilizing the above-mentioned unit processes, did not produce any treatment train that could prevent codepositlon of cyanides and metals In the sludges when the feed stream contained mixed metals and complexed cyanides. It was also determined that special anion exchange resins are capable of removing the compiexed cyanides that are not destroyed by alkaline chlorlnatlon. Concentration of each of the metals in the final effluent from the cation exchange unit was less than 0.4 mg/L.