The aggregate extraction industry generates large amounts of residues that are basically in the form of
sludge. These are the result of the cleaning process, with water, in which the materials extracted from the
soil are subject to. In fact, this water, used in order to free the aggregates from the smallest fractions that
they have, are driven to a raft in where the particles that are in suspension are decanted. The result of this
decantion is, on one hand; the production of large volume of sludge that rest stored, and on the other
hand; the significant water flows that are returned to the aquifer of where they have been previously
pumped. Therefore, the result of the aggregate treatment in industrial plants is the generation of sizeable
volumes of sludges that are deposed in rafts
