Mechanical recycling is the processing of plastic waste into secondary raw materials or products, where the chemical compounds of the plastics are not broken down. The waste is mechanically ground and melted by an extruder (often washed). Then, in the same process, plastic granules are made from it again. This form of recycling is particularly suitable for waste streams of one type of relatively clean plastic. In principle, all thermoplastics can be mechanically recycled with little or even no loss of quality. However, plastic waste is often a contaminated mix of materials. Because the recycled plastic can contain contaminants, the quality of the end product eventually decreases. For this reason, strict rules also apply to the use of granulate in, for example, food packaging. Read more about this in the section Challenges of Mechanical Recycling.
Value from plastic waste
There are various ways to obtain value from plastic waste. A few decades the biggest part of our plastic waste was dumped or incinerated. Now in the Netherlands about half of the plastic packaging waste is already recycled through mechanical recycling and the EU has ambitious plans to increase this percentage in the coming years. However, there is a wide variety of plastic waste streams. Some streams, such as separately collected LDPE industrial waste and PET deposit bottles, are already almost entirely successfully mechanically recycled. For the more mixed waste streams from households, however, the percentage is much lower.
In addition to recycling targets, there are also ambitious targets for increasing the use of recycled materials. The entire chain is therefore looking into the possibilities of recycling as much as possible in a high-quality manner.
One way of doing this is through mechanical recycling. Currently, more than 99% of the quantity materials recycled are mechanically recycled.
High-quality recycling means that after processing, a material will be used for the same product again. This happens, for example, with PET bottles. These are therefore completely circular.
In order to be able to recycle at high quality, it is first of all important that the plastic materials are easy to recycle. Above that, it is necessary that the material flows are properly separated and collected separately after use. This can be done, for example, by the user himself (source separation), but the systems for automatic post-separation are getting increasingly accurate. Specialized recycling companies process (e.g. grinding, washing and melting) the separated material flows into raw materials. Ultimately, there will be a demand for recycled products in the packaging industry and producers must be able to use recycled materials in new products in a high-quality way by then.
When the waste flows of certain products can no longer be recycled into materials that can be (re)used in similar products, because they are too polluted, mixed or discolored, for example, we speak of low-grade recycling, or downcycling.
What are the advantages of mechanical recycling?
Recycling in general has many advantages. Firstly, fewer new (fossil) raw materials are needed. In addition, it offers a solution for the large amounts of waste. Recycling waste streams also produces less CO2 emissions than producing new raw materials. According to the Netherlands Bureau for Economic Policy Analysis (Centraal Planbureau), recycling plastic has the potential to roughly halve the environmental damage caused by emissions.
These environmental benefits of replacing new raw materials by recycling outweigh the environmental impact of collection, sorting, transport and recycling activities. In addition, the costs of these necessary activities can be offset by revenue from the sale of recycled products.
Mechanical recycling challenges
Of course, the recycling industry also faces challenges. For example, according to CPB’s report ‘Plastics as a secondary raw material’, it is not yet socially viable to recycle all household plastic waste. These streams consist of a ‘mix’ of materials, often with a high degree of pollution. The efforts surrounding collection, sorting, washing and recycling and the high percentage of material loss involve enormous costs and produce a raw material of limited quality. This makes it commercially unattractive to re-use the recycled raw materials from these streams in new products. In addition, the environmental benefits of this mixed stream are also limited. Focusing on more sustainable product designs (such as the use of more mono-materials), better separation at source and technical developments in automatic sorting and de-inking, for example, does make the mechanical recycling of these household waste streams more attractive.
However, there are also developments in the field of chemical recycling. In that process the polluted mix as a whole is strongly heated and converted into, for example, oil, gas and other carbon-containing raw materials, such as carbon black. The environmental impact of the various chemical recycling processes is currently much higher than that of mechanical recycling, but the potential applications of the raw materials produced are greater.
European Plastic Pact
Now that many European countries, including the Netherlands, signed the European Plastic Pact on 6 March this year, things may change. According to this pact, by 2025 all packaging plastic and single-use plastic must be designed to be reusable or recyclable. In addition, the pact aims for a 20 percent reduction in newly made plastics by 2025. Half of this 20 percent reduction must come from a reduction in the use of plastic.
Ways to promote recycling
- Expansion of the deposit system
For PET bottles, extending the deposit system is a good way to ensure a higher collection rate. A deposit system for other types of plastic does not yet exist and is unfortunately also more difficult to implement. In general, deposits ensure a very clean flow of plastic. Several studies, including one conducted by CE Delft in 2019, also show that the share of small bottles in litter due to deposits is declining by 70 to 90 per cent. In other countries where this system has already been introduced, the positive effects are already visible. In Norway it accounts for a collection rate of 97%. In Germany, 98% of all PET bottles are recycled. And in America, the total volume of litter decreased by 33 percent.
- Mandatory minimum percentages of recycled material in the production of new products
If a minimum percentage of recycled material is required in the production of new plastics, companies are forced to purchase secondary plastics. This therefore increases the demand for secondary plastics and can reduce the cost of recycling by exploiting economies of scale. In addition, the value of recycled material increases, making it more attractive for recyclers to recycle products rather than incinerate them in the incinerator.
In the Dutch PlasticPact it has been agreed that by 2025 an average of at least 35% recycled plastic must be used per company in the production of disposable plastic products. This is not the same as the rules imposed by the government, but hopefully the 75 companies that signed the pact will commit themselves to the rules and we will see the amount of recycled material in products increase considerably in the coming years.
Mechanical recycling of plastic film
KIVO, in cooperation with KRAS Recycling, has set up a recycling plant in Kosovo under the name REKS. In this plant films are mechanically recycled. REKS processes waste flows from Europe and the Balkan region. By manually separating unprinted transparent LDPE films without labels, films with labels, stretch films, lightly printed films and heavily printed/coloured films, REKS is able to produce the highest possible qualities of transparent LDPE and LLDPE recycled raw materials from Post-Consumer Recycled content (PCR).
Curious about the recycling possibilities for your plastic packaging?
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