Safety case for proposed novel cementitious lechate barriers

The purpose of this document is to establish the safety case for the construction of a novel cementitious barrier as a landfill liner. It is intended for submission to the Environment Agency and describes the work that has been carried out since 1998 to establish the safety of the barriers. It is anticipated that the document will evolve in discussion with the EA.\nThe safety case is developed on the basis of predictive models which are validated by site trials. These trials have taken place at the Risley landfill site in Cheshire. Three trial cells have been constructed containing a total of 70 m3 of concrete. The data used in the models has been derived from laboratory experiments with permeability (high pressure through flow) and diffusion tests.\nThe principal intended benefits of the new barrier are:\n- Low permeability combined with high cation exchange capacity to give improved containment.\n- Construction from waste materials which would otherwise go into landfills.\n- A relatively hard concrete surface to permit operation of vehicles and to prevent damage from large items of waste compacted onto it.\n