THE RECYCLING OF INERT WASTE FROM CONSTRUCTION, DEMOLITION AND INDUSTRIAL ACTIVITY: TECHNICAL CHARACTERIZATION AND POSSIBILITIES OF REUSE OF THE RECYCLED INERT WASTE

Industry is more and more interested in adopting manufacturing processes that permit a more contolled use of natural raw materials and a minimum production of waste, both for economic and environmental reasons founded on the principle of sustainable development. In this context, research into the recycling and re-use of waste materials resulting from the demolition of buildings is highly relevant. Materials of this kind, if treated by specially designed equipment and subjected to specific quality controls, enable the inert material to be regenerated and reintroduced into the manufacturing processes of the same production sector. An increase in the willingness to use these regenerated elements would bring the following environmental advantages: - reduction of the amount of waste produced and a consequent lower level of danger, - re-use, recycling and regeneration of the maximum quantity of waste possible, - reduction of the amount of waste sent to the refuse dump and correct disposal of the residual waste that cannot be regenerated, - prevention and repression of illegal dumping and other illicit behaviour that causes damage to the environment and to citizens’ health, - improvement in the quality of the inert material recycled. The treatment and recycling techniques used for waste from building construction and demolition (from now on termed as C&D waste), consisting for the most part in inert materials, rubble, excavation soil and rocks, enable the production of recycled aggregates with qualitative characteristics comparable to those of natural inert aggregates. From a normative standpoint, both national and European legislation emphasize the need to provide incentives for the advantageous exploitation and regeneration of C&D waste. The same legislation recommends that the methodological approach of Life Cycle Analysis (LCA) should be adopted for the evaluation of environmental impact related to the re-use of waste. However, in Italy the inert waste recycling sector is still having difficulty in taking off because the profit margin is often poor. This is due to the relation existing between the costs connected with the disposal and regeneration operations and the costs correlated to mining activities. This results in the recycling operation being anti-economical and therefore of no interest to operators. To give an example, in certain realities there exists an abundant availability of natural inert materials at moderate prices and this leads to the profit margin of recycling being too low. In fact, throughout Europe C&D waste recycling varies greatly from country to country. In the present study we report the results of research aimed at the evaluation of the technical characteristics of inert material produced from the recycling of both C&D waste and other waste from specific industrial sectors (steel plant and foundries slags, municipal solid waste incineration, , etc.). The characterization of the recycled inert material is carried out by laboratory tests, such as particle size analysis, strength testing (point load test, compression test, R.I.H.N. test) and leaching tests. The whole point behind establishing a technical characterization of these materials is to be able to evaluate their effective introduction into certain technical applications where they can replace natural inert material that has to be mined, with the same guarantee of identical performance and cost levels and with considerable advantages from an environmental standpoint.