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Landfills

The rules on waste management were first established by Presidential Decree 915 of 10 September 1982 on the disposal of waste. As well as introducing a number of principles for defining systems to limit waste production, this subdivided waste into four types: municipal, special, toxic and harmful. In February 1997, this decree was superseded by Legislative Decree 22 (the "Ronchi Decree"), which focuses on preventing and reducing the quantity and hazardousness of waste.
With Directive 1999/31/EC on the landfill of waste and the Italian transposing legislation (Legislative Decree 36/2003), a body of best practices was achieved in relation both to technical rules on the construction, management and post-management of the plants and to constraints on the acceptance of waste for landfill.
Subsequently, with the Decree of 3 August 2005, "Definition of acceptability criteria for landfill waste", the legislator defined the operational criteria and procedures for the acceptability of waste at landfills, in compliance with the provisions set forth by Legislative Decree 36/2003.
In April 2006, Legislative Decree 152 (the "Consolidated Environmental Act") came into force. This profoundly changed the legislative framework by introducing a wide range of innovations into the rules on environmental impact assessments and strategic environmental assessments, soil protection, water pollution prevention and water resources management, waste treatment and management, reclamation of contaminated sites, and pollution.
With Legislative Decree 205 of 3 December 2010, the legislator transposed into Italian law the indications of the European Union concerning the policies to be adopted with regard to the disposal of waste, and defined the priorities for waste management on the basis of what represents the best environmental option in planning policy.

 
 
  • Consequently, the disposal of waste in landfills represents the last level of the hierarchy in the integrated cycle of waste management, and plays an increasingly small role.
    The landfill system is used for the disposal of certain types of solid and sludge waste, both municipal and special.

    The legislation described above provides for 3 types of landfill:

    • inert waste;
    • non-hazardous waste (non-hazardous municipal and special waste);
    • hazardous waste (waste of mainly industrial and manufacturing origin).

    The system consists of the definitive storage of waste at a suitably prepared site, where it is compacted and arranged in strata for more efficient use of the surface area. At the end of each day, the refuse is covered with various types of material, such as geotextile fabric membranes or carbon foam sheets, excavated earth or other inert material, or the stabilised organic fraction (biostabilised or non-conforming compost) derived from the processing of the municipal waste itself.

    There are three types of landfill, according to the geo-morphological and hydrological characteristics of the site:

    • valley fill: created by filling old disused quarries or suitable ditches excavated on the land;
    • flat terrain: positioned on flat ground and enlarged upwards;
    • side hill: created by filling against the side of an incline, preferably with natural hollows or pits.

    To contain the entire mass of waste and prevent the diffusion and dispersion of leachates into the environment and the soil, protective barriers are created on the base and sides of the landfill, made from natural material (clay) and/or artificial material (polythene sheets).
    Landfill is undoubtedly the most impactful and least "productive" form of disposal.
    However, value can still be extracted even from this process, in the form of landfill gas.
    During decomposition, in addition to the production of leachates (sewage), which are drained off and sent to a purification plant for processing, biogas is produced. This consists mainly of methane and carbon dioxide, and is extracted by means of a system of pipes running through the interstrata of the waste. Once captured, the biogas is piped to suitable generators for the production of electricity. This operation also helps to prevent the spreading of foul odours through the air and makes it possible to lower emissions of methane (a greenhouse gas 20 times more potent than CO2) into the atmosphere, thus reducing the greenhouse effect in accordance with the principles of the Kyoto Protocol. The use of biogas for producing electricity also makes it possible to avoid the CO2 emissions produced by the combustion of conventional fossil fuels such as oil and coal. The positive effect is therefore twofold: there is a reduction in greenhouse gas emissions on the one hand, and an increase in the production of electricity from renewable sources on the other.
    In 2011, biogas was used to produce around 70 GWh of electricity, equivalent to the consumption of 22,500 families. Atmospheric emissions of around 33,000 tonnes of CO2 were also avoided.
    In addition to the above, the following measures for controlling emissions and environmental impacts are carried out every year: spot checks on electricity generator flues, wastewater, waste, soil, subsoil and air quality, at frequencies defined in the integrated environmental authorisation. These checks are carried out by certified laboratories.

     
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