Illegal and Sub-Standard Plastic Waste Treatment: When Recycled Plastics May Be Harmful for Consumers — and Why Black Plastics Are Unjustly Blamed
Authors: Kim Ragaert (Universiteit Gent), Arthur Schwesig (MGG Polymers Austria GmbH), Joost Duflou (KU Leuven), Margaret Bates (University of Northampton), Alberto de Andres Sanchez (Fundacion Tecnalia Research and Innovation), Stephane Arditi (European Environmental Bureau), Gergana Dimitrova (Fraunhofer-Gesellschaft zur Förderung der Angewandten Forschung e.V.), Elena D’Angelo (United Nations University), Violeta Nikolova (United Nations University); Copy Editor: Anna Megdell
Black plastics are commonly believed to represent a problem in Waste Electrical and Electronic Equipment (WEEE) recycling because, allegedly, they are “wrongly sorted” and end up in food-contact applications.[1]
However, we, the PolyCE[2] consortium — a Horizon 2020 project whose expertise lies in the development of advanced recycling and recovery solutions for high quality post-consumer recycled (PCR) plastics — propose arguments to counter such claims and offer expertise-based reasoning.
The following two arguments showcase why illegal and sub-standard plastic waste treatment, regardless of the plastic material color, are the main reasons harmful substances enter consumer products that contain plastics.
- Not just black, but also brightly colored WEEE plastics cannot be successfully sorted with only near infrared radiation (NIR) because the resulting plastics are poor quality and cannot be significantly improved by adding virgin plastics. Brightly colored WEEE plastics, sorted only by NIR, can only be used when the end user/manufacturer deliberately opts for recycled plastics with lower grades. Thus, also with bright NIR-recycled plastics, WEEE additives like Brominated Flame Retardants (BFRs) would enter consumer products. Any NIR-sorted WEEE plastic needs a density treatment at the very least.
- Black non-sorted plastic as well as any other non-sorted WEEE plastic stream is, in fact, useless given the poor quality due to the presence of a large variety of different non-miscible polymers. We can show here a typical composition of a non-sorted mixed stream from small domestic appliances (SDA)[3] and plastics from TV and monitor set back-cover housings from Cathode Ray Tube (CRT) and Flat Panel Displays (FPD):
This represents a non-miscible mixture of plastic types. Moreover, the content of PVC causes degradation of all polyesters. Note that the content of PS and ABS with Tetrabromobisphenol A is above 8%, which typically contributes to approximately 1–2% bromine content in the waste stream. The presence of Persistent Organic Pollutants (POPs) in SDA is negligible, though this is not the case for other waste streams with high market uptake, i.e. monitor housings.
Non-sorted streams from monitor housings are the main source of Polybrominated diphenyl ethers (PBDEs). If such a stream is not incinerated, but instead is compounded into virgin plastic to reduce cost, BFRs will again enter consumer products. Such operations constitute a criminal act in all signatory states, in case POP substances[4], such as Hexabromocyclododecan, Heptabromobisphenolether, etc., are reused. In the European Union, the law foresees that waste treatment operations (such as plastic recycling) can only be executed if they do not cause risk to water, air, soil, plants or animals[5].
BLACK PLASTICS SORTING
According to Turner (2018), “[black plastics are] not, however, readily recycled owing to the low sensitivity of black pigments to near infrared radiation used in conventional plastic sorting facilities.”[6]
It is true that NIR has no sensitivity to the color black and, in a NIR-only sorting plant, black products often end up in the ‘reject’ fraction. However, NIR is not the only sorting technology that separates plastic waste and other technologies. XPS (x-ray photoelectron spectroscopy), XRT (x-ray transmission spectroscopy), or density-based techniques can effectively separate materials containing concerning substances or brominated flame retardants, regardless of color. A best practice process, invented by A. Schwesig et al, combines density separation, electrostatic, and laser sorting, as described in the patent Processes and Requirements for the Recovery of Plastics from Durable Goods.
In fact, it is misleading to refer to plastic-sorting facilities as conventional, as there is no widespread or widely accepted definition of “conventional” in this context. Plastic sorting is a growing and quickly evolving activity that still has large potential for new technological developments.
Additionally, polymers with additives such as halogenated flame retardants and Sb2O3 need specific sorting technologies, such as density, XRT, or LIBS (Laser-Induced Breakdown Spectroscopy), regardless the type of polymer or color. Furthermore, there is no difference in the required treatment of black covers of TV sets and PC monitors, regardless if the color is dark or light.
ILLEGAL PLASTIC WASTE TREATMENT IN ASIA
NIR sorting is one of the dominant plastic waste treatment technologies in China, and is used by the SIR Group, Sun Hui Ltd., and others. On its webpage, SIR Group describes[7] how it combines NIR sorting with density separation and electrostatic sorting to achieve compliant and certified recycled plastics qualities. Such processes, operated by MGG Polymers or SIR Group, are cost intensive and companies that do not apply such intensive treatment steps to recover plastics make easier profits.
Sorting WEEE and other plastics is strongly regulated within the EU, especially for food-contact plastics. The only food-contact-to-food-contact application that has the approval of the European Food Safety Authority (EFSA) for 2018, and is industrially operational, is that of polyethylene terephthalate (PET) bottles. Any other recycled plastics sourcing, WEEE or otherwise, of food-contact application is currently illegal within the EU, implying that the source of such contaminations in food-contact products originates either outside the EU or from criminal actions (or both).
The PolyCE Consortium has reason to believe that most illegal use of plastic waste may occur in Asia, considering the fact that Asia has been the biggest buyer of plastic waste in the past and will likely to continue to be. Illegal waste treatment is, however, not limited to China and is still very common in Europe too. While high product standards enforced by REACH[8] do not likely lead to the reuse of plastic waste in products, illegal waste treatment is increasing due to China’s waste ban[9]. Reports from Poland, where plastic waste from all over Europe is illegally incinerated, for example in the city of Zgierz[10], provide evidence of the increasing environmental pressure caused by our plastic economy.
Typically, there are four stakeholders involved in the supply chain who could fail to provide compliant recycled plastics, namely:
● NIR-sorter companies that wrongly claim that their sorters can provide completely uncontaminated, clean plastics (which is maybe true for packaging waste, but not for WEEE treatment).
● Preprocessors of waste in Europe or the US who did not remove BFRs and heavy metals before they sell the preprocessed materials to non-European recyclers. They currently they sell to Vietnam and Malaysia from where the granulated material is shipped to China.
● Non-European recycling companies who are either ignorant about what they do with the installed machines or who abuse the machines to economize on treatment costs.
● Original Equipment Manufacturers (OEMs) who allow their non-European molders to change materials or who do not sufficiently control their products that are produced outside of Europe.
In conclusion, black plastics are not the reason for widespread pollution, but rather ignorance about best practices and criminal waste-treatment activities are. A misguided focus on black plastics would only lead to inefficient attempts to contain ongoing environmental pollution.
For 20 years now, electrostatic sorting has worked well with black plastics. Additionally, laser sorting has also produced satisfactory results. MGG Polymers, one of PolyCE’s consortium partners, patented several processes using electrostatic and laser sorting.
There is no need to keep black plastics in a closed loop within WEEE, considering that sorting technologies, other than NIR, allow sorting these plastics based on polymer type rather than color, a differentiation that is imperative when aiming for high-quality recycled materials. Likewise, additives that would constitute a food contact health risk are not limited to black plastics in WEEE. Thus, separating these would not actually solve a potential cross-section contamination. It is instead up to recyclers to adhere to regulations and to keep food contact and non-food contact materials separate.
Efficient and systematic quality verification methods are required and should become part of recycled polymer supply systems. Providing the technical means, standards, and economically viable operational procedures to help execute this vision are our contribution to further develop this sector. As long as the legal consequences for the illicit treatment and for the misuse of recycled materials remain low, this ratio of ‘high profits vs low risks’ will represent a driving factor for criminal groups and individuals to take advantage of this specific sector. Traceability, systematic checks, and severe penalties are likely to be key elements in the systematic development of the sector.
[1] Turner A. (2018), Black plastics: Linear and circular economies, hazardous additives and marine pollution published in Elsevier’s Environment International Journal on May 17th
[2] PolyCE, European Commission funded project under Grant Agreement number 730308. https://www.polyce-project.eu/
[3] Data about composition of WEEE plastic waste for incineration is provided by MGG Polymers, https://mgg-polymers.com
[4] Regulation (EC) №850/2004 on persistent organic pollutants
[5] EU Directive 2008/98/EC on waste, Article 13
[6] Turner A. (2018), Black plastics: Linear and circular economies, hazardous additives and marine pollution published in Elsevier’s Environment International Journal on May 17th
[8] Regulation (EC) No 1907/2006
[9] https://www.nationalgeographic.com/magazine/2019/06/china-plastic-waste-ban-impacting-countries-worldwide/
[10] 20.06.2018 Wirtschaftswoche: Die Müll Deponie Europas Polen kämpft gegen die Müll Mafia
