Thermovalorization: new technologies, impacts and mitigation strategies [Termovalorizzatori: analisi e confronto tra nuove tecnologie, impatti e strategie di mitigazione]

In recent decades the quantity (in weight and volume) of solid waste is grown so rapidly to become a real problem especially in densely urbanized areas. The disposal of Municipal Solid Waste by incineration with energy recovery (WtE) is recognized as the most suitable system to process non-recyclable waste. However in several countries there are still concerns from experts and local communities about the environmental impact of incinerators. Epidemiological studies, developed since the 80s, are still the subject of controversial discussion because the results of research often refer to old incinerators--built a few decades ago--and therefore more impactful. In fact inadequate levels of gas cleaning and combustion process control in these facilities tended to risk the health of plant workers and local environment. This situation furthermore contributes to increase public risk perception and the spread of the NIMBY (not in my backyard) syndrome while siting this unwanted but necessary facilities. Actually, new strategies as advances in emission control designs and very stringent new governmental regulations, have resulted in large reductions in the amount of emissions. So the first aim of this work has been to understand if these high perception of risk have a reason to exist also in modern and new municipal waste incinerators. The second aim is to discover if the law, the new technologies and the mitigation strategies can really set a limit on the negative impacts on human health and on environment and if is it possible to improve or increase these strategies. Work has been divided into two parts. The first part focuses on analysis of waste environmental impact regulations, of plant operation systems and of epidemiological studies results. The second part involves the examination of the actual use of regulatory instruments, the most advanced technologies and the strategies for mitigation in the most effective new concept incinerators plants. For this verification has been analyzed in detail some different incineration plants recently created or rehabilitated in the last decade. The case-studies showed that the preliminary evaluation tools and the constant control of the waste incinerator are very effective. Moreover the comparison between the maximum emission limits, the BAT and the analysis of the actual emission of the cases study has shown the effectiveness of the depuration systems currently used. The emissions are in fact much lower than these limits. By the comparison we also identified the most efficient strategies and the best policies to inform and to involve people. Success in siting an unwanted but needed facility requires that authorities fully involve the public with openness and integrity in all aspects of the planning process. Starting from these result and in order to exploit what is already effective, some proposals where outlined and aim to be the basis for further approaches to design waste disposal plants.