The leachate recirculation rate will depend upon the amount of leachate which appears at the base of the landfill.
In wet climates the quantity of leachate which the landfill produces may cause excess ponding on the top of the cell when pumped up for recirculation, and rapidly exceed the available absorptive capacity of the waste in the landfill.
In such cases the leachate recirculation rate will need to be reduced and an early installation of a leachate treatment plant, or off site tankerage to a suitable leachate treatment facility, may be required.
The prudent landfill operator with an installed landfill gas collection and utlization plant will always take care to limit the leachate recirculation rate below the point that wastes within the landfill at any level within the landfill builds and and saturates the waste. Once saturated the landfilled waste will cease landfill gas production in the parts which become saturated. It is thought that waste material that has become saturated seldom returns to any significant landfill gas production once it is drained. Introducing cold water may have a significant cooling effect on the waste which has also been reported to effectively stop landfill gas production.
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