Reciclagem. Crédito: PxHere/Jilbert Ebrahimi/Unsplash

Mechanical, energy or chemical? The different types of recycling work

Everything starts by properly collecting and separating your waste, but making the most of residues works different ways. Learn the importance of every single recycling step to ensure valuable materials do not end up at the landfill

The world recycling industry enters a new stage in 2018. After China’s decision to forbid the import of certain solid waste, many nations that relied on the Asian country now have to find alternatives to get rid of their waste. The new Chinese law forbids purchasing 24 types of residues, which can be grouped into four distinct categories: plastics, unsorted paper, slags from certain ore and textile scraps. The measure is part of China National Environmental Protection Plan. As a result, many recycling plants were closed, especially across the provinces of Canton, Zhejiang and Shandong, as well as in coastal regions featuring major ports that are gateways to goods, including waste.

This global recycling market turnover poses a big challenge for plastic waste. In 2016, according to Comtrade, a UN database, China imported 7.35 million tons of plastics; this accounts for 55.3% of the global production. If this includes waste that entered the country through Hong Kong, those numbers round up to 10.2 million tons: nearly 70% of the total.

Every plastic material is potentially recyclable, but, for many countries, recycling is still a challenge. Not all countries are financially capable of investing in cutting-edge recycling technologies. In Brazil, for instance, recycling is mainly supported by investments from private initiatives and follows the recycling market logic: new recycling models are adopted when companies see a potential for financial returns.

In 2010, the National Solid Waste Policy (PNRS) was put into effect, though with a very poor outcome. A report by the Brazilian Ministry of Environment showed that only 12 Brazilian states complied with the policy by developing their own solid waste plans, and that 60% of Brazilian cities do not have appropriate landfills. In 2015, the Brazilian Ministry of Environment stated again that Brazil still had 3 thousand active garbage dumps.

Today, the country recycles only 3% of its nearly 80 million tons of waste produced, an economic loss of BRL 120 billion a year. The last big Brazilian recycling investment was made in 2013, when the federal government allocated BRL 220 million for this purpose. A rather poor investment compared to company activities. The Coca-Cola Company announced a BRL 1.6 billion subsidy for a five-year program designed to reuse two-thirds of all packaging marketed in Brazil until 2020.

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Three Types of Recycling

Here are the three main types of recycling: mechanical, energy and chemical. Every single type is subdivided into minor categories, but understanding them gives us a great idea of how the world processes most of its recyclables. 

Any of these three main recycling types involves three basic steps. They are collection and separation of waste, i.e., sorting residues by type of material and cleaning level; residue reuse, when the separated material goes through one of the three above-listed procedures and is reverted back into raw material; and waste transformation, the final stage, when this raw material becomes a finished product again.

Mechanical Recycling

Globally speaking, mechanical recycling is the most used method to give residues new usages, whatever they are. Through this method, plastics - whether obtained from industrial scrap or domestic or commercial disposal - are mechanically transformed without changing their chemical structure, so they can be used to produce new materials. Today, mechanically recycled plastics are used to make new packages, garbage bags, floors, hoses and car parts, among others. This is the most widely used technology for Polyolefins (PE and PP).

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Energy Recycling

Energy recycling consists of converting plastic into both thermal and electric energy by leveraging, through incineration, the heat power released by these materials in the form of fuel.  Energy recycling is important due to its ability for diversifying the energetic matrix and optimizing the space available in heavily populated cities with little room for landfills. This solution is widely used in Europe and Japan, but requires heavy investments and the engagement of public authorities, since it isn’t financially sustainable.

On the other hand, energy recycling has settled itself as an environment-friendly solution. As with cars, waste incineration plants for energy recycling use catalyzers to withhold emissions. “Energy recycling used to be negatively seen because of the emissions it produced, but that was then, back in the 70’s and 80’s. Today, clearer rules have been set for incineration equipment to work properly and ensure emissions are more environment-friendly,” says Miguel Bahiense, Plastivida’s CEO, the Social and Environmental Institute for Plastics. 

reciclagem energética

Chemical Recycling

Of these three, chemical recycling is the most complex process. With this method, plastics are reprocessed and their chemical structure modified so they can be used as raw material for different industries or as a basic input for manufacturing new plastic products. However, chemical recycling is more expensive and requires large amounts of plastic to be economically feasible.  

According to Miguel Bahiense, Plastivida’s CEO, it’s too early to talk about the potential of chemical recycling because it is still under development.  “Chemical recycling is probably out there in order to propose alternative solutions for something not easily retrieved by energy or mechanical means, instead of replacing those methods,” says Bahiense. “Chemical recycling is still in its childhood. It exists in a lab, but nothing we could refer to as a real-world thing. Chemical recycling is more complex and requires greater technology developments", he says.

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Different Types of Recycling For Each Product

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There is no such thing as a recycling template better than all others. Your ideal choice depends on the case and is mainly determined by the type of waste and local economy aspects. Energy recycling, for instance, is widely used in well-developed countries such as the US. Mechanical recycling, in turn, is more used in developing countries such as Brazil.

For Bahiense, one of the major challenges of recycling is to overcome misinformation on the different types available and their related benefits and impacts. For example, it is said that energy recycling will fully replace mechanical recycling, and that this replacement will be the end of informal garbage collector cooperatives, as well as of millions of jobs. “People think that [by adopting energy recycling] local governments will no longer need to make selective collections and that everything will be sent for incineration. However, this is something totally impossible, because the content of organic compounds in waste disposals makes it economically and technically inviable for most countries,” he explains. 

Actually, the three techniques complement each other. “None of them is capable of providing a 100% waste recycling. Even when you effectively sort and collect your waste, it’s not possible to ensure all plastics will be clean and ready enough to be mechanically recycled,” says Bahiense. “The portion that is not mechanically recycled can be energetically recycled. That’s why these procedures are complementary,” he says. 

The German Model

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Luis Tercero Espinoza, Coordinator of the Business Unit for Systemic Risks at the Fraunhofer ISI (Institute for Systems and Innovation Research), a German independent research institute, says that Germany is a great example of how the different types of recycling complement each other. According to the World Economic Forum, Germany boasts the world’s highest recycling rates: nearly 56.1%. “Different types of recycling happen in Germany. Many products are submitted to mechanical and chemical treatments. Products range from paper and carton to end-of-life vehicles,” explains Espinoza. 

Here, the mechanical procedure is the first step of a process that can be complemented by other types of recycling. “For example, when a vehicle is recycled, the first step is removing and discarding all its fluids; the acid-lead battery has to be removed and recycled apart before the vehicle can be crushed. The resulting residue consists of many portions of steel, non-ferrous metal, ore and a small portion of plastic, textile and other materials. A technical challenge posed by mechanical recycling is to minimize the loss of so-called critical raw material, such as precious metals,” explains Espinoza. At this step, the chemical recycling method presents itself as the most appropriate one, capable of complementing the whole chain.

The Challenge of Selective Collection and Informality

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Today, one of the greatest challenges for both Germany and the world is to expand their selective collection. “Electronic components and other specific material are normally kept in home shelves or exported as second-hand or non-declared products,” considers Espinoza. He thinks it is paramount to stop treating recycling as an informal activity and start registering its whole chain in more formal channels. For him, this makes the process more efficient and truly sustainable, both economically and socially speaking.

Miguel Bahiense thinks the need for Brazil to overcome informality is even greater. “At its very beginning, recycling appeared here as a heavily social activity. Consider, for example, the soda can pickers, who, due to social issues, found a way to top their incomes with this activity. But that is not a formally registered job, there is no guarantee of stability and pickers are often submitted to unhealthy conditions,” he explains.

Informal workers are the majority when it comes to recycling in Brazil. According to the National Movement of Recyclable Material Pickers, Brazil has 800 thousand active workers, in charge of separating nearly 90% of all recyclable waste produced in the country (data provided by IPEA, the Applied Economics Research Institute).

Regulating and certifying both workers and the whole recycling chain can also provide economic benefits to Brazil. It is estimated that the country produces annually 100 thousand tons of electronic waste stuffed with noble metals. Recovering noble elements like gold and lead from those recycled materials could yield profits of nearly BRL 2.5 billion. On a global level, the figures are even more impressive: every year the world produces 45 million tons of electronic waste, but recycles only 20%. In other words, we have a trillionaire dollar industry that is little explored.

To achieve that, one should start from the baseline by focusing on selective collection. “The key here is to ensure an optimal selective collection. One of the main recycling bottlenecks, if not the greatest, is to perform a proper selective collection,” says Bahiense. The first step is to separate recyclable from organic waste at home.

Plastic and Garbage: Reusing or Recycling Them?

Reutilização de resíduos. Crédito: Roman Kraft/Unsplash

Plastic, glass, aluminum and other non-biodegradable waste are known as garbage villains; however, the majority of waste found in Brazilian landfills is of organic nature. “We should also strive to avoid wasting food. Today, 70% of all domestic garbage produced consists of food waste [according to data from the Brazilian Ministry of Environment: “organic waste accounts for over 50% of total solid urban waste produced in Brazil”]. If avoided, this would contribute to not overload the waste treatment chain, including its logistics, transportation, final destination and the recycling process itself,” concludes Plastivida’s CEO.

Thus, recycling should not be disconnected from other equally sustainable initiatives. Besides avoiding food waste, supporting the reuse of materials would be a critical action. 

Waste reuse does not require any physical, chemical or biological transformation but only a change of behavior: for example, using a jam glass as the container for a homemade sauce, or using the ice cream plastic vessel as a container, or even drinking water or coffee in the same disposable cups more than once.

When a product or package is no longer useful, it is time to put recycling into play - also, if you are aware that selective collection is a must, this reasoning should prevail. The key is to build a truly sustainable mindset and also a behavior engaged in avoiding waste, by supporting the reuse of materials and, of course, recycling residues.