Mechanical recycling

Mechanical recycling is the processing of plastic waste into secondary raw materials or products, where the plastics' chemical compounds are not broken down. The waste is mechanically ground and melted by an extruder (often it is washed beforehand). It is then turned back into plastic pellets in the same process. This form of recycling is especially suitable for waste streams of one type of relatively clean plastic. In principle, all thermoplastics can be mechanically recycled with little or no loss of quality. However, plastic waste is often a contaminated mix of materials. Because the recycled plastic may contain contaminants, the quality of the final product ultimately decreases. For this reason, strict rules also apply to the use of granules in food packaging, for example. Read more about this under the piece Mechanical recycling challenges.

Extracting value from plastic waste 

Value can be extracted from plastic waste in several ways. A few decades ago, most waste was landfilled or incinerated. Now, about half of plastic packaging waste in the Netherlands is already recycled through mechanical recycling and the EU has ambitious plans to increase this percentage in the coming years. There is, however, a wide variety of plastic waste streams. Some streams, such as separately collected LDPE industrial waste and PET returnable bottles, are already almost completely successfully mechanically recycled. For the more mixed waste streams from households, however, that percentage is much lower.

Besides recycling targets, there are also ambitious goals on increasing the use of recycled raw materials. The entire chain is therefore looking into the possibilities of recycling as much as possible in a high-quality manner.

One way to do this is through mechanical recycling. Currently, more than 99% of the recycled volumes are mechanically recycled.

High-quality recycling means that after processing, a material returns as a raw material for the same product. This happens with PET bottles, for example. This makes them fully circular.

To achieve high-quality recycling, it is first of all important that plastic materials are easily recyclable. Next, it is necessary that the material streams are properly separated after use and collected separately. This can be done, for example, by the user himself (source separation), but automatic post-separation systems are also becoming increasingly accurate. Specialised recycling companies then process (e.g. grinding, washing and melting) the separated material streams back into raw materials. Ultimately, the packaging industry will have to demand recycled products and producers will have to be able to use recycled raw materials in new products.

When the waste streams of certain products can no longer be recycled into raw materials that can (can) be used again in similar products because, for example, it is too contaminated, mixed or discoloured, we soon speak of low-grade recycling, or downcycling.

What are the benefits of mechanical recycling?

Recycling in general has a lot of advantages. First, fewer new (fossil) raw materials are needed. In addition, it provides a solution to large quantities of waste. Recycling waste streams also creates fewer CO2 emissions than producing new raw materials. Plastic recycling has the potential to roughly halve environmental damage from emissions, according to the Central Planning Bureau (CPB).

These environmental benefits of replacing virgin raw materials with recycling outweigh the environmental impact of collection, sorting, transport and recycling activities. In addition, the cost of these necessary activities can be offset by revenue from the sale of recycled products.

Mechanical recycling challenges

There are, of course, challenges that the recycling industry faces. For example, according to the report 'Plastics as a secondary raw material' by the CPB, it is currently not yet socially profitable to recycle all household plastic waste. These streams consist of a 'mix' of materials with often high levels of contamination. The efforts around collection, sorting, washing and recycling and the high percentage of material loss involves huge costs and produces a raw material of limited quality. This makes it commercially unattractive to reuse the recycled raw materials from these streams in new products. In addition, the environmental gains from this mixed stream are also limited. Focusing on more sustainable product designs (such as using more mono-materials), better separation at source and technical developments around automatic sorting and, for instance, de-inking, does make mechanical recycling of these household waste streams more attractive.

However, there are also developments on chemical recycling, in which the contaminated mix as a whole is strongly heated and converted into, for example, oil, gas and other carbon-based raw materials, such as carbon black. The environmental impact of the various chemical recycling processes is currently many times higher than that of mechanical recycling, but the application potential of the raw materials produced is greater.

European Plastic Pact

With many European countries, including the Netherlands, signing the European Plastic Pact on 6 March this year, this may change. According to this pact, by 2025, all packaging plastic and single-use plastic should be designed to be reusable or recyclable. In addition, the pact sets a 20 per cent reduction in virgin plastics by 2025. Half of this 20 per cent reduction should come from a reduction in plastic use.

Ways to promote recycling

• Expansion of 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 currently exist and is unfortunately more difficult to achieve. Deposits generally ensure a very clean flow of plastic. Several studies, including a 2019 study by CE Delft, also show that the proportion of small bottles in litter decreases by 70 to 90 per cent due to deposits. In other countries where this system has already been introduced, the positive effects are already visible. In Norway, it ensures a 97 per cent collection rate. In Germany, 98 per cent of all PET bottles are recycled. And in America, the total volume of litter decreased by 33 per cent.

• Making minimum percentages of recycled materials mandatory in the production of new products

If a minimum percentage of recycled material in the production of new plastics is mandatory, companies will be forced to buy secondary plastics. This therefore increases the demand for secondary plastics and may reduce the cost of recycling by exploiting economies of scale. In addition, the value of recycled material becomes higher, making it more attractive for recyclers to recycle products instead of burning them in the incinerator.

The Dutch PlasticPact has agreed that by 2025 an average of at least 35 per cent recycled plastic per company should be used in the production of single-use plastic products. It is not the same as rules imposed by the government, but hopefully the 75 companies that signed the pact will commit to the rules and we will see the amount of recycled material in products increase significantly in the coming years.

Mechanical recycling of plastic film

KIVO, in partnership with KRAS Recycling set up a recycling plant in Kosovo under the name REKS. Here films mechanically recycled. REKS processes waste streams 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 offer the highest possible grades of transparent LDPE and LLDPE recycled raw materials from Post Consumer Recycled content (PCR) to produce.

Curious about recycling options for your plastic packaging?

If so, please feel free to contact us at 0299-398800 or the contact form below. Een of our experts are on hand to answer all your questions around mechanical recycling.