Small islands are extremely valuable in terms of environment and culture, but at the same time they present fragile ecosystem structures. In fact, their small size limits the capacity of these micro-ecosystems to absorb any impacts and regenerate their services.
In this context, waste management policies play an important role. In fact, the economy of the islands mainly lives on tourism, a phenomenon that generates an "accordion effect" on the population of the islands: in the high season months the number of inhabitants triples, with higher peaks during the central weeks of August. Therefore, these seasonal peaks require an elastic organization of the urban hygiene service, whose planning can not be based on production data of resident inhabitants (as in reality), as with the increase of the presences during the summer period the production per capita is much higher than expected.
In the small islands there is now a clear awareness of the importance of providing a correct and modern management of the urban hygiene service and of how it constitutes a qualifying element of the image of its territory. Awareness that has resulted in an increase in separate waste collection, of 14,853t, with 37.2% growth. Out of 34 municipalities present in the small italian islands, 9 have exceeded 50% of separation, reaching peaks of 73% in the municipality of Sant'Antioco and 69% in La Maddalena (Sardinia), 66% in Procida (Campania).
However, despite the growth trend, the level of separate collection still remains low: in fact, 20 municipalities do not exceed 40%, 11 of which do not reach 20%.
Surely, an increase percentage in separate waste collection would allow significant economic savings: we are talking about 3M€ a year, and also higher revenues (for example, recycling paper and cardboard would result in overall economic benefits of around 2.4M€ a year.
Therefore, the allocation of treatment plants for the organic fraction in the islands would considerably reduce the number of transfers to the mainland, thus obtaining savings in terms of transport (up to 1 M € / year), and energy recovery through the revenue of compost and biogas / biomethane.
Waste represents one of the greatest opportunities for sustainable growth for our country and for Europe. To this end, the direction taken by the European Union is shown by a series of provisions and regulations concerning integrated waste management: with the Waste Framework Directive 2008/98/EC, a minimum threshold for waste recovery equal to 50% is imposed on the Member States through separate collection.
Furthermore, the Directive inserts a hierarchy of actions to be carried out in waste management, also known as the "Four R Rule", namely: Reduction of waste produced; Waste Reuse; Recycling with the conversion of waste into useful products; Recovery of other types (eg waste-to-energy with energy production).
With the Dlgs. 205/2010, Italy has implemented this Directive, 6 months before the deadline set by the EU.
On 2 July 2014, the European Commission, with its Communication "Towards a circular economy", adopted a package of proposals on circular economy, including the guidelines to be followed to increase waste recycling and more efficiently use of the resources, limiting dependence on uncertain supply sources, reducing waste and preventing the loss of valuable materials, with the aim of creating jobs and reducing environmental impacts.
Therefore the Communication pushes to move from the economic model of linear economy (in which resources are extracted, used and thrown away) to that of a more circular economy (in which resources must be re-circulated so that they can remain in use as long as possible).
The use and consumption of resources and the production of waste and waste are considered as aspects of the same problem; it is no longer acceptable that substantial quantities of potential "secondary raw materials" still end up in landfills today, without being recovered and recycled. In this regard, Europe aspires to be a "zero waste" continent, where all that is produced and consumed must then be re-introduced into the productive-economic cycle.
Depending on the type of waste to be treated, various technologies have developed over time. Regarding the recycling of waste, the current landscape can be divided into already consolidated supply chains (glass, paper, metal, wood, plastic, organic) and expanding supply chains, such as those for electronic equipment.
The term "hydrometallurgy" includes all the chemical and chemical-physical techniques of liquid-phase treatment of residues deriving from industrial processes or wastewater of various kinds, aimed at recovering the metals present in them. These technologies find a field of application with enormous potential for expansion, for example in the recovery of critical materials (rare earths, precious metals, etc.) from WEEE.
This procedure can be distinguished in two different moments: a) dissolution of the solid, called leaching, which consists in the solid / liquid extraction process that occurs by reacting the solid to be treated with an appropriate solution capable of dissolving some (or all) the components and make them stable in the solution itself; b) separation and purification of the metal: from the leaching process a solution containing metal ions and many other impurities is obtained. The recovery and purification operations can be completed by operations of: precipitation / cristrallization; ion exchange; solvent extraction; electrodeposition.
Composting is an aerobic biological process, accelerated and controlled, which leads to the production of compost from organic residues through the action of bacteria and fungi. Compost is then used as a soil improver in agriculture and in nursery gardening. It is a technique that is occupying a prominent place in the treatment of waste: in 1993 there were about 10 industrial composting plants, while in 2008 there were 290 plants, with the forecast for 2019 of the addition of another hundred.
The industrial composting plants are subdivided into continuous cycle plants (where the material is daily loaded) and in batch systems (where the material is loaded in batches, technically in biocells, and remains closed for just over a week before ending the process in plate). Parallel to the composting plants, anaerobic digestion systems of the organic fraction have been developed, plants in which gas is extracted (typically methane) and consequently it is possible to access the contributions related to renewable or similar sources. The digested material is then sent to composting plants.
The plastics of urban waste are made of polymeric materials and classified as thermoplastic resins and thermosetting resins: only the first ones are recyclable.
The recycling process can take place mechanically (in order to obtain the starting macromolecule) or chemically or thermally (to obtain the monomer or other raw materials): in the first case, applicable to the thermoplastic resins, the manufactured products are selected by type of polymer, washed, dried by centrifugation, shredded and subjected to molding by extrusion or molding. The success of the process depends on the degree of separation and purity of the starting polymer, which allows the macromolecules to reconstruct the original structure, guaranteeing the mechanical properties of the final product. Chemical recycling takes place through the action of a solvent or by thermal means, through that of heat.
Interesting are the new technologies that are developing over the years, in order to remove plastic from the oceans. One of these projects is "The Ocean Cleanup", created in 2011 by the then 16 year old Boyan Slat. It is a system made up of a floating polyethylene tube, a resistant and recyclable material. Together with the screen (which captures the sub-surface debris), it has the function of capturing and concentrating the collected plastic through an anchoring system that allows the collection of debris present beyond the first meters of depth. The pipe is in fact flexible enough to follow the waves of the sea, and rigid enough to maintain its "U" shape. The debris thus retained by the system is subsequently collected by the support vessel, brought to the mainland and recycled.
Another interesting project is the Seabin, conceived by two Australian surfers Andrew Turton and Pete Ceglinski. The project consists of a "basket" of marine waste, which is placed in the water and thanks to a pump fixed to a jetty, it sucks in a trash the floating garbage. In addition, a purifier can also be placed inside that filters out traces of oil and fuel from the water. Made from 70 to 100% recycled polyethylene with the natural fiber waste collection network, it certainly represents an excellent ecological initiative.
Most of the smaller Italian islands have, to date, organized the separate waste collection with the door-to-door system, which allows you to prevent waste being left on the street and a more efficient collection, thanks also to the condominium contraventions system in case the organic materials are not separated. Among the small islands, the most virtuous municipality is Pantelleria, which has reached the quota of 65% of separation, starting from just under 20 points in 2014.
Another important milestone was reached by the Municipality of Lampedusa: thanks to the intervention of Esper Spa, the on-site treatment of mowing and pruning and the re-use for soil nourishment is now planned. In fact, due to the desertification of the island territory, the restoration of the land can only pass through actions of reforestation and soil fertilization. The project foresees that the residues of grassy mowing and pruning that are produced daily in the municipal territory, will be treated, transformed and reused in the same island, thus creating a circular process with returns both from an environmental and economic point of view. Before, the same waste was transferred to Sicily with huge costs for the Municipality both in terms of transfer and treatment. Also on the island of Lampedusa, the door-to-door waste collection service was reorganized and introduced the punctual pricing in the Municipality of Lampedusa and Linosa, involving a reduction in the total quantity of urban waste produced (10-20%). An organization which has also been supported by an information campaign, towards the development of a conscious and ecologically sustainable consumption.
Offshore the Indian Ocean, there is an island well known to tourism, and attentive to sustainability: Mauritius. The treatment of solid waste is organized in a composting plant in the La Chaumiére area; the process and technology is provided by an Indian company, Excel Industries (India) Ltd. Thus, the plant receives about 300 tons of solid waste per day, which are treated in compost, and then the same compost is sold as fertilizer. The remaining waste material that can not manage the La Chaumiére plant is transported to the Sea Chicose landfill, where it is then buried. The good news is that, after the start of the La Chaumiére plant, the transportation of the material destined for landfill has been considerably reduced, as the Government envisaged a waste recovery plan for 180,000 tons / year for the next 20 years. The compound product, once matured, is sold in bags of 5 to 25kg under the Ferrich brand, which is addressed to large producers of sugarcane and vegetables as the main compost market for mass sales. Furthermore, regular customers is also a hotel with a golf course.
An important initiative is also found off the Pacific Ocean. Thanks to the commitment of SPREP, in December 2005 in Samoa the transformation of the Tafaigata landfill was completed, through the "Fukuoka" method of the homonymous University in Japan. The aforementioned method provides for the treatment of waste through an "aerobic" process (which takes place by ventilating the waste itself, in order to guarantee the correct supply of oxygen), which allows to obtain the compost (as a final product) and to carry, therefore, to the regeneration of the soil that in doing so is transformed into a green area.
The project of the University of Jena, Germany, in collaboration with the Universities of Quintana Roo (Mexico) and the Litoral of Argentina, deals with the matter of waste management starting from the question "how can sustainable waste management be created by providing a improvement at the social and environmental level". The project concerns the island of Cozumel, the third largest island in Mexico, 95,000 residents and a strong flow of tourism, focusing the study in Las Fincas, an area outside the city of San Miguel. Since 2003, the Mexican government has introduced a waste recycling policy; however, each state has its own specific laws. It is still a study, but of fundamental importance as it is aimed at encouraging the reuse of waste material, since less than 20% is currently recycled in Mexico (unlike in Germany, which flies on recycling 60%).