Systems and processes for treating, reducing and/or disposing of leachate created by a landfill system by aerating, spraying and/or stripping leachate in a controlled environment to promote evaporation of a water component of the leachate, to strip a portion of ammonia from the leachate and/or to promote biological decomposition of the leachate. The reduced or concentrated leachate produced by the system or process, whether liquid, solid or slurry, can be disposed of as allowed or desired at a cost benefitted by the reduced volume and/or treated condition of the leachate.