Working scheme for safe management of construction and demolition wastes containing hazardous substances

Wastes from construction and demolition (C&D) are mainly composed of inert materials. A small proportion of C&D wastes contain substances which make them hazardous, for example, those wastes containing asbestos, mineral fibres, additives, some paints and resins, among others. On the other hand, in the manufacturing of several products used in the construction industry many hazardous substances are utilized. In most cases these materials are relatively safe while being used, but they become dangerous when they are broken, spilled or released in some way. There are other wastes groups which are not hazardous by themselves, but they can suffer reactions, producing toxic substances. These groups include, for example, some plastics or treated woods, which can emit toxic gases when they are burnt for energetic profit. In this work a scheme is presented for the safe management of construction and demolition wastes containing hazardous substances, starting from an inventory of hazardous wastes. This scheme takes into account different stages: i) selective extraction avoiding the mixture with no hazardous wastes, ii) characterization of hazardous substances contained in C&D, iii) feasibility evaluation of the reuse or recycle of the analyzed material and, iv) adequate treatment either for recycling or for safe final disposal. This constitutes the first step in the way of obtaining proper norms in this area, absent nowadays from the local regulations.