Recycling, once seen as merely an environmentally friendly gesture, in an age where environmental awareness takes center stage, the necessity of addressing our planet's worsening waste crisis has become clearer than ever.

It is now a pivotal player in the pursuit of sustainability. As our consumption patterns escalate and landfills increase, the need to redefine our approach to waste management is becoming increasingly urgent. In this article, we delve into the complex world of recycling, explore innovative strategies, debunk myths, and advocate for a collective responsibility to protect the health of our planet.

Join us on a journey to uncover the multi-faceted layers of recycling, as we confront challenges, celebrate successes, and chart a course toward a greener, more sustainable future.

Once the separated waste enters the dedicated plants and a reusable material emerges from them, in what form does it return to our homes? It is not always so simple to reconstruct the genesis of any product, let alone one made of recycled material! In this second part we try to clarify an aspect that is little known to non-experts… and not only!

Recyclable materials and the main industrial waste transformation processes

The materials collected in a differentiated way which are most widely transformed to be placed back on the market in various forms are essentially:

• Paper and cardboard;
• Glass;
• Plastic;
• Wood;
• Metals (steel and aluminum);
• Electrical and electronic equipment;
• Batteries and accumulators;
• End-of-life tyres;
• Used vegetable and mineral oils;
• Organic;
• Textile waste;
• End-of-life vehicles.

The focus is on the need to reduce waste generation and reduce its risk, and the need to reuse products such as returnable bottles and containers, if reuse is not possible, recycle materials such as recycling paper, glass, plastic, organic materials, etc.

For materials that could not be reused and then recycled e.g. unsorted waste and bottom screen (i.e. dividing the waste into small indistinguishable and therefore non-recyclable pieces), there are two solutions for energy recovery through cold systems, such as bio-oxidation Aerobic, anaerobic, or heated systems, such as gasification, pyrolysis, incineration, or disposal in landfills.

Therefore, even in an ideal situation of complete recycling and recovery, there will be a percentage of waste remaining to be disposed of in a landfill or oxidized for disposal and energy recovery. Ideally, the use of incineration and undifferentiated landfills should be kept to a minimum.

As can be understood, the “integrated waste management system” is complex where, depending on the materials to be managed, specific supply chains and complex industrial structures (plants) are defined; based on these principles, the inevitability of regimes seems clear even if they are often unpopular with citizens.

To simplify we can say that separated wet (organic) waste can be mainly processed in two ways: in composting plants to produce soil amendments that can be reused in agriculture or to cover depleted landfills or in anaerobic biodigesters that, by extracting biogas, i.e. Methane gas resulting from the fermentation of waste, and through its combustion, electricity is produced; The finished material can become a soil improver.

Separated dry waste (paper, cardboard, plastic, glass, wood, etc.) if it is “clean” can be sent to special factories to return to the production cycle as raw materials or for energy production (as in the case of plastic in waste – to power plants), while if it is “ Dirty” can undergo a selection process before being sent to the final factories.

In selection mills there is a ‘preliminary separation', usually done by hand, of coarse materials that are considered foreign; Then, depending on the material to be processed, the systems can be equipped, for more thorough cleaning, with mechanical systems (vibrating plates, blows of compressed air, etc.) to divide paper and cardboard or separate plastic materials by color and electromagnets. Magnetic separators for ferrous metals (iron and steel) and induction systems eddy current separators for non-ferrous metals (aluminum and copper).

On the other hand, undifferentiated waste can undergo a preliminary selection process to separate ferrous and non-ferrous metals, which are sent for recycling, and subsequent mechanical treatment to separate the dry fraction.

Bulk materials, which mainly consist of materials with high calorific value (paper, cardboard, plastic, wood) in fractions too fine to be separated, can be sent after an additional refining process, to recover energy when converting waste into energy. Stations in the form of fuel produced from waste, so-called CDR, from which heat and electricity are obtained.

From the bottom screen, composed of low-quality organic matter because it also contains non-separable foreign matter, biogas can be extracted and electricity produced through the anaerobic biodigestion process; Once biogas generation is exhausted, the material becomes stabilized, loses its bacterial load, and can be used to cover depleted landfills.

For bulky items and waste electrical and electronic equipment, we continue the process of selection and relative disassembly; The obtained parts (metal, wood, plastic, glass, etc.) are divided and the materials return to production as raw materials.

In any case, all of these processes produce waste that can no longer be refined, but which, depending on its calorific value, can be sent for energy recovery in waste-to-energy plants to produce heat and electricity or in landfills; The more efficient the systems are, the less waste is produced, thus reducing the use of landfills and waste-to-energy plants.

Recycling and repair

Paper and cardboard are recyclable materials, as the cellulose they contain can be exposed to repeated uses. However, the process of recycling paper and cardboard consumes a lot of energy: to make one ton of paper from virgin cellulose, 15 trees, 440,000 liters of water, and 7,600 kWh of electricity is needed, but starting from waste paper fibers, what Approximately 95% to new paper; Compared to other products, the pulping process results in significant savings in energy, water, and wood.

Paper mills, in addition to consuming large amounts of natural gas to produce the energy needed to convert materials, also generate waste that in countries like Germany and Sweden ends up in mills built near paper mills for energy. Recovery (waste-to-energy plants) produce electricity that is reused by the paper mills themselves while in Italy, as happens in the Lucca region, the largest sector of the national paper sector, it ends up in a landfill because there is no waste. For power plants planned in the region.

Paper recycling includes different types of products: newspapers, magazines, books, notebooks, brochures, bags, cardboard packaging, food and detergent boxes or shoes, paper tapes from yogurt and beverage packages, etc. In some cases, the collected waste paper is sold separately abroad (China or Germany).

Thanks to its nature, glass can be remelted countless times to produce new bottles or flasks, allowing significant savings in energy and raw materials. Glass packaging (bottles, cans, etc.) ends up in glass factories and undergoes a sorting process in a specialized processing plant.

The primary treatment consists of various sorting operations (manual or mechanical), separation by color (white, green, red), crushing, screening, and disposal of all foreign materials with special attention to the ceramics which, if they remain in the mixture, are decomposed. Able to weaken the final product. Finally, glass sand resulting from secondary waste treatment, which is not suitable for the production of glass containers, is recycled in the ceramic industry and other glass sectors (e.g. fiber or abrasive paper).

The most common plastic materials in the consumer products market are:

• Polyethylene and polyethylene: bags, detergent bottles, toys, films and other packaging;
• PP, polypropylene, with very different uses: furniture pieces, food containers, detergent and detergent bottles, carpets, garden furniture;
• PVC, polyvinyl chloride: egg trays, films, pipes;
• And also indoors, in windows, in tiles;
• PET, polyethylene terephthalate: beverage bottles, synthetic fibers, cassette tapes;
• PS, polystyrene: food trays, cutlery, plates, hats.

After the separate collection phase, the plastic is taken to the first selection and treatment plants; it is then separated with general mechanical and optical procedures from other fractions and impurities, and then divided by type of polymer.

In particular, PET and PE, low and high density, are selected. Thus, after some shredding phases, flakes or granules are obtained which will be used for the production of new objects. The material obtained is better the more homogeneous the starting plastic is.

If the different types are divided homogeneously, secondary raw material is obtained, i.e. with technical and chemical characteristics of the recycled material very similar to the initial ones.

Some examples of products:

1. Recycled PET and/or PP: new containers (non-food), buckets, fruit, and vegetable crates, fibers for padding, sweaters, ‘fleece', carpets, yarns and furnishing fabrics, car interiors, sheets for various packaging, frames of glasses, body parts of household appliances, reusable bags, quilts, chairs, tables, trolleys, and trolleys for shopping in supermarkets, flower pots;
2. Recycled PVC: pipes, rainwater drains, fittings, cable glands, products for the construction sector and irrigation in agriculture;
3. Recycled PE: detergent containers, caps, waste bag films, packaging films, and household goods.

If different types of plastic are treated together, heterogeneous recycled plastic is obtained and used for example for the production of benches, playgrounds, fences, street furniture, road signs, components for cars or scooters, design objects (lamps), pallets, and brooms.

Plastic not sent for recovery can be destined for waste-to-energy, exploiting the possibility of energy recovery; finally, if subjected to a specific treatment, it can give rise to alternative fuels, which can be used in cement kilns and for the production of thermoelectric energy.

The wood used by recycling companies mainly comes from:

1. packaging;
2. waste from first and second wood processing;
3. waste resulting from construction and demolition processes;
4. bulky waste, such as furniture and fixtures, coming from urban waste collection.

Wood recycling is essentially oriented toward the production of chipboard panels; Furthermore, other types of panels, blocks for pallets, cellulose pulp for paper mills, and wood-cement blocks for construction are produced.

Not all wooden packaging is transformed into panels: this is the case of pallets which, following their use and/or disposal if repairable, are reconditioned to allow them to be put back on the market, extending their life cycle.

Aluminum has excellent characteristics for recycling: it can be 100% recycled and reused infinitely to create new products every time. Aluminum packaging is usually collected together with other types of materials (e.g. glass or plastic, ferrous packaging), from which, in special first treatment plants, they are separated using a separator that works on eddy currents generated by the magnetic field present to be then pressed into bales and sent to foundries.

Steel packaging (boxes, cans, jars, caps, food lids, buckets, drums, and cans…) is also collected together with other types of materials (for example glass or plastic, non-ferrous packaging), from which, in special first treatment plants, they are separated using magnetic systems (electromagnets). Steel packaging is pressed into bales and sent to steel mills where it is melted in furnaces to produce new steel. Even steel, like aluminum, can be reused endlessly.

In the first case, ‘compost' (fine compost) is produced, obtained from organic waste selected at the source which is an excellent fertilizer and is used in horticulture, fruit growing, industrial crops, nursery gardening, creation of public green areas, and areas of naturalistic interest and ‘compost of controlled quality (FOS stabilized organic fraction) obtained from waste not selected at the source and finds valid use in the environmental restoration of exhausted quarries, polluted areas, exhausted landfills and as a material for various technical uses such as the arrangement of areas of respect for motorways and railways (embankments) and the creation of large green areas (public parks, golf courses, football fields, etc.).

In the second case (TMB) the following are produced:

1. recyclable components, such as paper, metals, plastics and glass, and other components that can only be sent to landfill;
2. ‘biogas' usable as fuel;
3. a ‘solid digestate' that can be exploited to improve the agricultural properties of the soil.

In the third case, only biogas and solid digestate are produced.

WEEE, Waste from Electrical and Electronic Equipment, i.e. refrigerators, air conditioners, washing machines, dishwashers, televisions, PCs, neon lamps and tubes, and small household appliances in general (mobile phones, food grinders, hairdryers, etc.), once collected, are transported to specific plants where they are dismantled both manually and mechanically to obtain glass, plastics, ferrous metals (iron and steel), non-ferrous metals (copper, zinc, tin, aluminum) and precious metals (gold, palladium) which are reintroduced into the industrial cycle of production.

The same goes for batteries and accumulators from which Lead, Nickel, Cadmium, Zinc, and Mercury are obtained, as well as plastics.

Once collected, used oils can be transformed into lubricants through a regeneration process (mineral oils) or into biodiesel, surfactants, and soaps (vegetable oils).

Textile waste finds its destination in reuse (68%), in recycling in the textile industry (25%), and in landfill disposal (7%).

Tires (rubber, steel), vehicles (glass, metals, rubber, plastics, lubricants), and inert construction and demolition waste (sand, gravel, cement) are also practically completely recycled.

There are also plants capable of treating street-sweeping waste from which organic matter, sand, gravel, and metals can be obtained.

In conclusion

Recycling stands as a powerful catalyst for positive environmental change. As we navigate the challenges of a rapidly evolving world, the imperative to embrace sustainable practices becomes increasingly evident. Recycling not only conserves precious resources but also mitigates the harmful impacts of waste on our planet. The collective effort to recycle, whether through individual actions or community initiatives, contributes to a healthier and more sustainable future for generations to come.

By understanding the interconnectedness of our actions and their environmental repercussions, we empower ourselves to make informed choices that benefit both the planet and its inhabitants. The journey towards a circular economy, where materials are reused and repurposed, is a shared responsibility that requires ongoing commitment from individuals, businesses, and governments alike.

In fostering a culture of recycling, we not only reduce the burden on landfills but also diminish our reliance on finite resources. The economic, social, and environmental benefits of recycling are manifold, offering a holistic solution to some of the pressing challenges we face in the 21st century.

As we reflect on the positive strides made in recycling practices, it is crucial to acknowledge that there is still work to be done. Continuous innovation, education, and advocacy are essential components in amplifying the impact of recycling efforts. By championing sustainable living and responsible consumption, we can create a ripple effect that extends far beyond our immediate surroundings.

In the grand scheme of environmental conservation, recycling emerges as a beacon of hope, showcasing the potential for positive change when individuals and communities unite with a shared purpose. Through the simple act of recycling, we contribute to a greener, cleaner, and more resilient world one where waste is minimized, resources are maximized, and the delicate balance of our planet is preserved for future generations.