Separate collection and Recycling

Glass recycling

Glass waste is mainly made up of green, brown or transparent bottles and containers, and to a lesser extent glasses and plates.

Collection in roadside bins only for glass has over the years ensured best results in terms of “purity” of the collected material, as it minimizes contamination from other waste materials. Residual impurities are removed in glass recycling plants equipped with advanced technology for the selection and separation of glass from foreign matter.

At this point it is considered “ready for the oven” and is sent to glass factories to be recast together with raw materials, to obtain new products.

Almost all recycled glass is used to make new bottles and containers (on average each new glass item contains 30% of recycled material), while a small amount is used to produce fiberglass .

Paper recycling

Paper and cardboard waste mainly comes from separate collection of municipal solid waste. The first step in recycling separately-collected material consists in separating paper from cardboard by weight and consistency.
According to the norm (norma UNI EN 643:2002) the cellulosic materials selected take the name of pulper and are categorized in 5 groups, from that of “ordinary quality” to that of “special quality” according to the physical-chemical properties.
After being pressed and packaged in bales, pulper is sent to paper mills, where it is reduced to a paste before being mixed with virgin cellulose pulp, to produce new items in recycled paper.
Paper cannot be recycled indefinitely, as the treatments reduce its quality due to the degradation of cellulose fibers: on average, it tends not to be recycled more than 5 times.

Plastic recycle

The recovery of plastic waste is particularly difficult, when compared to that of other materials. This is due to the heterogeneity of the polimers that make up packaging. What is normally considered as “plastic” is in fact a very large and heterogeneous set of different chemical compounds.
The mechanical recycling process involves shredding, washing, drying, extrusion and granulation, leading to the production of recycled plastic in the form of flakes or granules. In practice, the uses for the polymers obtained from recycling are limited by costs and the qualitative characteristics of recycled plastic: part of the recovered material is not suitable for use in the production of original packaging, but is used for less valuable items (e.g. urban furnishing objects).
In addition to mechanical recycling, there are several recovery technologies for plastic packaging: Chemical recycling, still not widespread, and energy recovery.

Chemical recyclingo involves the decomposition of polimers to rerturn to the original monomers which can be re-injected into the production cycle of plastics or petrochemical products. There are several processes through which chemical recycling is carried out: hydrogenation (degradation by oxygen and heat), pyrolysis and gasification.

Waste from the plastic recycling process generally goes to a energy recovery, but can also be used in steelworks as an SRA (Secondary Reducing Agent) i.e. as a reducing agent during furnace oxidation reactions, replacing up to 20 % of the coke normally used for this purpose.

Aluminum recycling

Aluminum is very suitable for recycling because it can be subjected to an infinite number of cycles without suffering significant loss of quality: secondary aluminum is therefore equivalent to primary metal.

There are also numerous environmental benefits from recycling aluminum: the production of 1 kg of secondary aluminum requires 5 % of the energy consumption necessary for the production of metal from the mineral (bauxite). For the same reason, aluminum recycling is cost-effective.

The recycling process involves an initial phase of selection and separation from foreign materials and then sending the aluminum to a foundry to be subjected to fusion and formed into ingots.

Steel recycling

Steel in urban solid waste is normally present in the form of cans and containers, and its use has been decreasing as a result of the increase in aluminum cans and plastic containers.

The initial step of the recovery process involves magnetic separation of ferrous materials, which are subsequently shredded in order to facilitate separation from foreign materials.

For steel packaging it is necessary to remove tinplate. In this way the materials obtained can be recycled in steel mills/foundries in the production of new steel.

Wood recycling

Almost all recycled wood is used for the production of chipboard panels for the furniture industry.
It can also be used to produce cellulose pulp for paper mills.

After the removal of foreign materials, the wood is shredded, dried, glued, pressed and finished.

Wood residues can be sent to waste-to-energy plants to produce electrical and thermal energy.