The third law of thermodynamics states that the Universe's entropy is constantly increasing. The Entropy is a scientific and extremely complex concept which, translated in simpler terms, represents the level of "Disorder" of a given system. It is impossible to reduce the Universe's Entropy but it is possible to reduce the contribution that human beings give to entropy's increase.
In the solid waste sector, the Disorder (Entropy), with which the waste is returned/given, represents one of the main problems that hinders the possibility of increasing the level of recyclable materials. The mix of different materials makes it difficult to recycle them.
To increase order, that is to reduce Disorder and so the Entropy's level with which the waste is returned/given, means that it would be possible to increase the level of recyclable materials. It is possible to pursue efficient actions of recycling through waste fluxes divided by category, product group, materials’ homogeneity.
To enhance the level of order in waste management, and so to reduce Entropy, two main pilot activities will be carried out:
- Separate collection. At present separate collections are growing both in quantity and in quality. However the cooperation between citizens and urban hygiene firms should be increased in order to further improve the service. For this reason TSA will start in two pilot collection routes some actions aimed at enhancing citizens’ responsibility. The actions consist in the combined use of information campaigns and computerized systems aimed at the correct recognition of the behaviour of the single citizen. In this way any non-virtuous attitudes could be recognized and supported with the aim of reaching a more efficient " At-source Selection" of waste by citizens. The aim is to change from an "At-source Separated" collection to an "At-source Selected" collection.
- Mechanical treatment. The amount of waste collected in mixed way, such as multi-material collected waste or residual waste from originally separate collection, will be processed in a dedicate facility with advanced technologies. GESENU will start many pilot campaigns aimed at optimizing the extraction of recyclable materials in these fluxes. The optical sensors with NIR technology and ballistic/inertial separator will be the advanced technologies used for this aim. In other words, the mechanical selection will be able to return less muddled waste fluxes, that is with less Entropy than in the input ones. Besides, the characteristics of the residual flux coming from these treatments will be assessed in order to consider the possibility of using the residual flux as SRF and so reaching a global recovery of the material.
- Biological treatment. During the project campaigns of analysis and experimental tests for the aerobic-anaerobic integrated treatment of the organic fraction from originally separated collection will be realized. The aim is to demonstrate how this type of treatment could improve the compost's agronomic quality and produce renewable energy. Many recent studies show how the suitable sequence of anaerobic and then aerobic processes leads to a final compost richer in organic carbon. The organic carbon is an important element for soil fertility. The carbon-depleted soils are areas at risk of desertification. Often higher attention is paid to using fertilizers in agricultural soils and lower attention is paid to returning organic carbon to the soils. Intensive agricultural practices, energy-crops, extraction of fossil fuels are activities that lead to deprive the world of carbon. The compost could play an important role in the reconstruction of the so called “carbon-sink”, that is the world's carbon source.