One aspect of the present invention relates to a method of treating municipal solid waste which includes landfilling a volume of solid waste, a substantial portion of which has been exposed to the atmosphere, adding moisture to the solid waste, compacting the moistened solid waste, and applying a daily covering material to the compacted solid waste. Alternatively, the method can be performed by adding moisture to the waste prior to landfilling. A further aspect of the present invention relates to a method of adding moisture to municipal solid waste which includes providing a fluid delivery system, exposing a substantial portion of a volume of solid waste to the atmosphere, and adding moisture to the volume of solid waste using the fluid delivery system, where such fluid delivery system includes an excavator having a movable arm and a fluid jet coupled to the movable arm, and means for delivering fluid, where such means for delivering fluid is coupled to the fluid jet of the excavator for delivery of fluid from a fluid source to the fluid jet.