AbstractStudies were made on treating a leachate from New Lyme, Ohio. The leachate was transported to Cincinnati, where a pilot‐sized rotating biological contactor (RBC) was used for a treatment evaluation. Biomass was developed on the RBC discs with primary effluent from the City of Cincinnati's Mill Creek Sewage Treatment Facility. Experiments were then conducted to determine the effectiveness of treating a hazardous waste leachate and to provide information on: the rate of organics removal; the final effluent quality; the fate of priority pollutants and specific organic compounds; and the loss of volatiles via stripping in the RBC. The results of these experiments and the applicability of an RBC to treat a hazardous waste leachate from a Superfund site are reporte