We take great pains to make sure our landfill has effective drainage and can minimize infiltration of leachate. Simply stated, leachate is any liquid material that drains from the landfill and contains significantly elevated amounts of undesirable material like toxins or special waste.
The leachate collection layer at AEL consists of a 24-inch drainage layer with a hydraulic conductivity greater than or equal to 1×10-3 cm/sec. The drainage layer diverts the leachate to 6-inch diameter perforated HDPE leachate collection pipes, which are bedded in granular media filled trench drains.
Through the collection pipes, leachate is collected in sumps, and pumped to the leachate storage pond. Electric submersible pumps equipped with liquid level pressure transducers are located in each sump and are programmed to automatically start as leachate depths within each sump reach a certain level. The leachate storage pond has a composite liner design, including a compacted low permeability soil liner overlayed by a 60-mil HDPE geomembrane.
AEL currently recirculates leachate over composite lined areas of the landfill as an interim measure while developing a long-term solution to leachate management. This process greatly accelerates decomposition resulting in the conversion of leachate into landfill gas for our waste to energy facility and the reduction of the overall volume of leachate for disposal.