Abstract
It has become increasingly common for consumer product and their packaging to be advertised as being ‘recyclable’ or ‘compostable’, signalling their environmental compatibility. However, it is important to question whether these products are truly available for recycling and, even if so, will such items actually be recycled in the real waste management systems in place today.
Unfortunately and upon closer inspection, many sustainability promises fall short. The term ‘recyclability’ often only refers to materials that could theoretically be recycled, focusing merely on the composition of the new product and/or its packaging. But this is far from being recyclable in practice. Practical recyclability is far more complex. It includes the ability of labourers and sensors in sorting systems to detect and effectively separate recyclables from a material flow. Furthermore, the consumer of recyclable materials must have suitable processes to beneficially use the separated recyclables as a secondary material.
The current discussion on recyclability is largely focused on packaging and, in particular, to plastic packaging. However, in Austria, plastic packaging waste only represents 3.7% of municipal waste and a mere 0.25% of all waste. Despite this, plastic products, and in particular plastic packaging, have not achieved the same recycling rates as materials like metals, glass and paper. It is evident that plastic still has significant room for improvement in terms of its recyclability.
Reducing the discussion to plastic products, however, is too simplistic. To enhance overall recycling rates, we must improve the recyclability of all products that will become waste. Improved recyclability should be a general requirement for all products, but nowadays legal requirements for recyclability, expressed through collection and recycling quotas, only apply to certain products or their waste streams. There is a growing need for Extended Producer Responsibility regulations and laws to build into products the ability to reduce the impacts of their use at the end of their life.
From a waste management perspective, ‘recyclability’ refers to the ability of a product to be recycled after separate collection and waste processing. Recyclability can be determined for all physical products as an individual attribute and a gradual indicator of producer responsibility. This assessment is essentially determined by two parameters: the nature of the products and the actual recycling routes available after use. Properly understood, recyclability is not a theoretical property but represents the material suitability of a product to contribute to closing material cycles within established collection and recycling structures.
But we have to distinguish between three levels of recyclability of products: theoretical, technical and real recyclability.
An example of ‘theoretical recyclability’ involves PET bottles with full-body sleeves. Although the bottles themselves are collected separately (as is common in larger European cities) and are ideally recyclable, they often cannot be detected by the state-of-the-art Near Infrared (NIR) sensors because the sleeves prevent the PET from being detected. Consequently, these bottles are not sorted out and thus not recycled. The matter becomes more complex as some sleeves can be ‘invisible’ to certain NIR sensors. Therefore, detectability not only depends on the type of sleeve but also on the decision algorithm of the sorting machine. If the sensors are suitable and the algorithm is correctly programmed, some bottles could still be detected and recycled.
A second example concerns the ‘bioplastic bag’ as an alternative to the conventional plastic bag. Despite common belief, in most cases these bags are only compostable under specific laboratory conditions not found in conventional composting plants. As a result, they are often classified as contaminants by composting plant operators and sent for thermal recovery in most European countries. After the separate collection of the plastic packaging waste (‘yellow bin’ in Europe), the bioplastic bag is sent to the sorting plant. The crucial question then becomes whether these bags can be identified and sorted as a mono-fraction ‘bioplastic’. Unfortunately, there is a wide variety of bio-based plastics, and current treatment plants lack the sensor-based sorting machines that can identify these bioplastics. Given their small proportion in the bulk material, retrofitting them would be economically unfeasible for the foreseeable future. Consequently, bioplastic bags are directed into the high calorific value fraction, processed into solid recovered fuel and used to produce energy. However, on the positive side, incineration of bio-based residues is largely considered climate-neutral, the ‘spirit of recycling’ remains a distant prospect, still under research.
Alternatively, if a bioplastic bag ends up in residual waste, it will be thermally treated or (if still allowed and/or if a waste-to-energy (WTE) plant is not available) landfilled, rendering ‘composting’ and ‘recycling’ labels misleading. Therefore, replacing plastic bags with bioplastic ones offers no significant waste management advantages, and true waste reduction at the top of the hierarchy is the only sensible approach.
‘Theoretical recyclability’ tests products in their original state, usually based on material composition. Classification as recyclable does not guarantee that the product is actually recyclable after use by consumers.
After use, if the product has become waste, its technical detectability with suitable sensors and its sortability in real sorting systems as well as the existence of recycling processes must be checked. These factors allow us to determine the ‘technical recyclability’, meaning the product could technically be recycled.
Finally, in real-world waste management systems, additional factors must be considered, including the behaviour of waste generators, the presence and influence of the collection system, the actual levels of pollution of the collected material, as well as regional aspects such as the availability of suitable sorting systems and the existence of markets for the secondary raw materials. Adequate funding for collection, sorting and recycling must also be available and effectively utilized in a region. When all these elements are considered, we can speak of the ‘real recyclability’ of a product.
From scientific point of view, the term ‘recyclability’ should be redefined and sharpened. Detectability, sortability, suitability of real collection systems and existing markets must be taken into account. The recyclability of any material that bears such a claim should also be supported by experimental and pilot tests.
An important product procurement policy measure would be to give preference to recyclable products through licensing fees for collection and recycling systems. It is logical that real recyclability (not just theoretical) should be favoured in licensing fees. Products and packaging found not to be recyclable in practice should fall into a significantly (and painfully) more expensive licensing category. This ‘ecomodulation’ can influence producers and retailers. Giving priority to real recyclability in products and making non-recyclable products more expensive can be seen as a crucial consumer steering measure.
If more and better recyclable products are found in waste management plants in the future, the technical capacity to separate and recycle them will also improve. Legislators are called upon to create the appropriate framework conditions and incentive systems to privilege recyclable products.
Dear reader: This year, a new edition of the Recy & DepoTech conference will be celebrated, which promises engaging discussions on a range of topics critical to the advancement of circular economy practices, one of them being the topic of this editorial. We extend a warm invitation to all interested parties to participate in this year’s edition and also in the upcoming conference editions and contribute to the vital discussions surrounding the circular economy.
The present Special Issue showcases a selection of works presented during the last Recy & DepoTech conference, highlighting the diverse and innovative research being conducted in this field. We are grateful to Waste Management & Research for providing us with the platform to showcase these selected articles. We hope these selected contributions inspire and inform the journal’s readership, aiding them in their own work and fostering further advancements in sustainable practices in our field.
