Recirculation of leachate through landfilled solid wastes offers potential advantages in reducing the volume of liquid by surface evaporation, and reducing the strength of leachate by crude anaerobic treatment within the landfill. Increasing the moisture content of the fill is also reported to give rise to a more rapid stabilization of solid wastes, and to enhance gas (methane) production.
Results of research using 7 m3 lysimeters essentially confirmed these benefits and produced a predicted volume of low strength leachate within 18 months. A full-scale study at a lined landfill at Seamer Carr, North Yorkshire, has shown that on a large scale these benefits are more difficult to obtain, although this three-year study has proved successful in considerably reducing the volume and organic strength of leachate.
It is concluded that recirculation by itself cannot provide a lasting solution for leachate management, although significant reductions in the volume and strength of leachate can be obtained. Careful control is required and, in particular, it is necessary to consider the hydrology of a landfill and how this is affected by use of (final and intermediate) cover material.