Eluate analysis

Analysis method, which uses liquids or gasses to leach out soluble substances from solid materials to be inspected. Subsequently, the liquid or gaseous phase is separated from the solid matter by filtration, sedimentation, or centrifugation. The eluate obtained in this way can be analyzed for the wanted substances. 
Assessment and logging of such substances (type and mass) provides information about impairments or hazards to waters that are likely to occur if the materials are stored or disposed of (s. Disposal site) in such a way that they get in contact with water.

However, under real landfill conditions, the values determined by eluate analysis are generally only reached after very long periods or not at all. And what is more, the values obtained from eluate analysis are not conclusive enough to define the harmfulness of the material disposed or to be disposed. Therefore, additional criteria must be taken into account for sound evaluation of the expected disposal behavior and disposal conditions required for protection of ground and surface water. These include e.g. the ratio of leachable proportions to overall content of a substance in dry sludge residues. Identification of leachability of a substance using water is specified in the German standard methods for the examination of water, waste water and sludge according to DIN 38 414-4.