The world is full of waste: according to the latest World Bank report What a waste 2.0: a global snapshot of solid waste management to 2050, if no action is taken to curb the phenomenon, by 2050 the amount of municipal waste produced will increase from the 2.01 billion tonnes recorded in 2016 to 3.14 billion. A 70 per cent increase attributed, again according to the report, to sustained demographic and economic growth.

High-income countries are responsible for 34 per cent of the waste generated worldwide and manage to send 31 per cent of it for recycling. Low-income countries, on the other hand, manage to recycle only 4 per cent of their waste, while more than 90 per cent ends up in landfill or is incinerated.

It should be noted that in recent years new technologies have been developed to make our economy more sustainable through waste recycling. Waste can in fact become a resource for producing new goods with a low CO2 impact: this is the idea behind the so-called Green Circular Districts model.

• What are Green Circular Districts
• What technologies for Green Circular Districts
  • Upcycling
  • Chemical recycling (waste to chemicals)
  • Circular hydrogen
• The environmental benefits of Green Circular Districts
• Projects in Italy

What are Green Circular Districts

A Green Circular District is a technological and industrial platform that integrates various green chemistry and circular economy technologies. The model contributes to the reconversion of traditional industrial sites, which rely on fossil sources, into new and more efficient low-emission chemical production processes. The aim is to produce, through waste recovery, recycled polymers together with low-carbon chemical products that can be used across various industrial supply chains.

At the same time, increasing the recycling rate means reducing recourse to incineration and landfill disposal. The concept of Green Circular Districts therefore goes hand in hand with that of circular economy: to achieve the set climate targets it is essential to preserve the planet's resources and avoid generating waste that is difficult to dispose of.

What technologies for Green Circular Districts

The technologies employed respond to decarbonisation objectives and focus primarily on the recycling of plastic waste and non-recyclable dry plastic residues. Indeed, every year in Europe approximately 25.8 million tonnes of plastic are produced, yet only 30 per cent is collected and sent for recycling, not to mention that Ispra reports that 15 per cent of unsorted waste consists of plastic.

Plastic waste that escapes separate collection and recycling often ends up being incinerated, though there is no shortage of instances of littering and illegal disposal in the environment. The quantity that ends up in rivers and lakes and from there in the sea is unfortunately enormous, as demonstrated by the concentrations of microplastics in water bodies.

Fortunately, solutions exist to prevent such problems. NextChem, a company specialising in technologies for the energy transition, has developed an integrated platform that includes green chemistry processes, upcycling — that is, quality mechanical recycling of plastic waste — chemical recycling of plastic residues and dry waste, and the production of green hydrogen from renewable energy sources via electrolysis.

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Mobilità sostenibile

Indipendenza energetica

Decarbonizzazione

Decarbonizzare i fertilizzanti

Cambiamenti climatici

Upcycling

How do Green Circular Districts work in practice? Typically, the process set in motion is capable of recovering value from plastic waste: this applies both to recyclable waste and to waste destined for landfill or incineration. A portion can be mechanically recycled: the aforementioned NextChem, for example, uses a proprietary technology called MyReplast Upcycling in order to obtain new high-quality recycled polymers.

The process includes a phase of careful sorting by polymer type and colour, volumetric reduction (involving the shredding of large plastic waste items into flakes) and the transformation of flakes into granules (pellets) of a specific colour and with specific physical characteristics.

Upcycling gives plastic waste a second life as secondary raw materials; the end products are capable of bridging the existing quality gap between recycled plastic and virgin plastic. The recycled polymers are used to manufacture new plastic objects (such as furniture, rigid packaging and automotive components) which, once their useful life cycle has ended, will once again become waste and can be recycled again.

Chemical recycling (waste to chemicals)

A technological solution for chemical recycling (waste to chemicals) makes it possible to obtain chemical products and "circular" fuels from non-mechanically recyclable plastic waste residues, such as the so-called Plasmix (the residue from the sorting process for plastic packaging collected through urban separate collection) and the so-called css (i.e. secondary solid fuel, a fraction of unsorted waste that has undergone qualitative selection).

Non-recyclable plastic waste can be chemically converted by recovering the carbon and hydrogen contained within it, through a process known as "partial oxidation". This process, without producing combustion, makes it possible to obtain a gas (in NextChem's case referred to as circular gas) which is used to generate new chemical products — such as circular hydrogen and ammonia — and low-carbon fuels, including circular methanol and circular ethanol, which are fundamental for industry and sustainable mobility.

Circular hydrogen

As mentioned, chemical recycling can also yield circular hydrogen. Circular hydrogen, together with "green" hydrogen produced by electrolysis and renewable energy sources, can be used as an industrial fuel and for public transport.

The economy of the future is placing great emphasis on hydrogen: in July 2020 the European Commission launched the European Hydrogen Strategy, in which it assigns the energy carrier a leading role in the European Union's energy transition pathway. Not only that: hydrogen is also set to power an increasingly significant share of public and private transport vehicles.

The environmental benefits of Green Circular Districts

A first and substantial benefit of these technologies is apparent in the industrial sector: replacing fossil sources in production processes (such as natural gas or hydrogen from methane) with circular gas or hydrogen, which have a significantly lower impact, contributes considerably to reducing CO2 emissions from industrial sites.

In the transport sector too, the CO2 footprint can be reduced thanks to circular fuels such as methanol, ethanol and ammonia produced through waste conversion and classified as "recycled carbon fuels", included in European renewable energy legislation, and in part as "advanced".

Beyond the environmental benefits, the Green Circular District model revitalises the local economy, creating new spin-off activities and new supply chains linked to synergies with other industries and with mobility.

Projects in Italy

The projects currently under study to implement the Green Circular District model concern immediately realisable green chemistry plants designed to support the energy transition. The aim is to obtain "circular" chemicals through the conversion of waste that could not be recycled by mechanical means. These chemicals could prove useful in industrial supply chains, in the low-carbon fuels and combustibles sector, or indeed for the production of new plastic materials. This is the principle underpinning the various Green Circular Districts now in the design phase: they are distributed from north to south across Italy, with different capacity scales and mixes of product outputs, including circular hydrogen, circular methanol, circular ethanol and circular gas.