The simplest type of leachate recirculation system design is a pump which is placed in a sump at the base of the landfill into which leachate drains from the landfill. An automatic level detection device then sets a pump to run whenever adequate leachate is available in the sump. The pump delivers leachate into a pipe which conveys the leachate to the top of the active landfill cell and the leachate is allowed to trickle out over the top of the waste until it seeps back into the surface of the landfill.
Over a period of time the leachate that seeps into the top of the waste will percolate downward and arrive at the bottom of the lined landfill cell, from which it will be recirculated again.
In high rainfall areas the amount of leachate on the surface of the open landfill cell can cause problems for the movement of vehicles, so landfill operators may excavate soakaway trenches to reduce surface saturation of the waste, and some operators favor construction of horizontal pipes laid in the waste below the capping restoration layer and discharge leachate into those.
In wet locations, and at some point in the life of a landfill leachate recirculation systems have a habit of biting-back by producing an ever increasing volume of water recirculating through the waste. At some point the operator will need to move on to a new cell, or start to remove leachate from the recirculation cycle by methods such as off-site tankerage of waste or on site treatment and disposal of leachate to a local watercourse, once all absorptive capacity has been utilized in the waste.
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Leachate Recirculation System Design
Related terms: Leachate Collection Pumps, Leachate Recycling, Leachate Water, Landfill Leachate Collection. Design, Leachate Tank, Leachate Collection Systems, Leachate Evaporation Systems, Leachate Pumping Systems