THE TRIPLE MULTIMINERAL BARRIER FOR HAZARDOUS-WASTE ENCAPSULATION

According to the present state of science and technology, the ultimate disposal of critical substances such as chemotoxic wastes, metal slur ries, radioactive substances, etc., as well as houshold waste, necessi tates enclosure within a multi-barrier system. The geology of the disp osal site plays an important role. The site itself defines the geologi cal barrier which has to fulfill at least two requirements: namely low permeability and retention, respectively retardation qualities. These can be achieved to a certain degree either by clay minerals, zeolites or an artificial product such as active coal. In order to increase th e imperviousness and retardation potentials of e.g. clayey geological barriers, technical barriers have to be added. One of them and the mos t important is the mineralogic barrier. It consists of clay dominated layers and according to the multimineral barrier concept the different layers have to meet different functions.