A study was conducted on treating a simulated leachate that contained high concentrations of ammonia-nitrogen ranging between 20 and 1000 mg/L. A pilot sized rotating biological contractor (RBC) was used to treat a surrogate leachate composed of primary effluent that was adjusted with glucose and ammonium chloride to achieve various concentrations of dissolved organic carbon and ammonia-nitrogen. Experiments were conducted to determine: The rate of ammonia conversion; The drop in pH at high ammonia concentrations; The effect of low pH on ammonia conversion; The effect of high ammonia levels (1000 mg/L) on ammonia conversion, and The effect of temperature on the reaction rate constant. The results from these experiments and the applicability of a RBC to treat leachates containing high concentrations of ammonia-nitrogen are reported.