Study on the Impacts of Brominated Flame Retardants on the Recycling of WEEE plastics in Europe

Commissioned by EERA | Prepared by Sofies

Plastics account for around 25% of WEEE by weight and comprise a complex mixture of polymers and additives. Brominated flame retardants (BFRs) have been used in certain electrical and electronic equipment to meet fire-safety requirements, while some legacy BFRs, including certain PBDEs and HBCD, have subsequently been restricted.

Published in November 2020, the Study on the Impacts of Brominated Flame Retardants on the Recycling of WEEE Plastics in Europe examines how BFRs affect WEEE plastics recycling. It assesses material flows, treatment practices, recycling yields, recyclate quality and costs, and considers the implications of alternative flame retardants.

Brominated flame retardants in WEEE plastics

BFRs are used in selected plastics and components that require flame retardancy. The study estimates that around 90% of plastics from EEE are not brominated. Where plastics are intentionally brominated, bromine concentrations can be considerably higher, although average levels in mixed WEEE plastic streams are much lower.

The study distinguishes BFRs generally from legacy BFRs that have been restricted, including certain PBDEs and HBCD. Because electrical equipment can remain in use for many years, these substances can continue to enter recycling facilities through older WEEE. Restricted BFRs were found to represent a small and declining proportion of overall BFR content.

Bromine concentrations vary by WEEE category. The data reviewed found the highest average levels in screens, followed by small equipment, with lower levels in large household appliances and very low levels in temperature exchange equipment.

WEEE plastic flows in Europe

The study estimates that approximately 2.6 million tonnes of WEEE plastics were generated annually in Europe at the time of the analysis, but only around half entered official WEEE collection channels. Of approximately 1.3 million tonnes officially collected, around 1 million tonnes were sent to specialised WEEE plastics recycling facilities or, for epoxy resins in printed circuit boards, to integrated smelters.

Once material reaches specialised plastics recyclers, density separation and other sorting technologies are used to recover recyclable polymers. The study estimates that around 55% of WEEE plastics entering these facilities are converted into regranulates, principally PP, PE, ABS and PS.

The largest losses occur before specialised plastics recycling. The study estimates that around 60% of WEEE plastics arising in Europe do not reach specialised recycling facilities and concludes that less than a quarter of all WEEE plastics generated were effectively recycled at the time of the analysis.

How BFR-containing WEEE plastics are treated

Treatment is designed to separate bromine-rich plastics from fractions suitable for recycling. Specialised recyclers typically use density separation, often through sink-float processes, because plastics containing BFRs at functional concentrations generally have a higher density than the principal target polymers.

According to the study, density separation captures more than 95% of the original BFR content in a high-density fraction containing heavy plastics and additives. This fraction is generally unsuitable for conventional mechanical recycling. Bromine-poor material can undergo further sorting to recover polymers such as ABS, PS, PP and PE.

The WEEE treatment framework requires BFR-containing plastics to be segregated during treatment. Sorting technologies generally cannot distinguish restricted from non-restricted BFRs, so separation is based on total bromine content or physical characteristics such as density.

The 2,000 ppm bromine threshold

For relevant WEEE plastic fractions, the EN 50625 standards use 2,000 ppm total bromine as an operational threshold for BFR segregation. The threshold provides a practical alternative to analysing individual BFR compounds, which requires more specialised, time-consuming and costly laboratory testing.

The study questions whether the statistical assumptions underlying the 2,000 ppm threshold remain appropriate. It reports that the share of restricted BFRs within overall bromine content had declined substantially following restrictions on legacy substances.

Based on analytical data reviewed, the study estimates that around 2010 a total bromine concentration above approximately 2,500 ppm was likely to correspond to PBDE levels above 1,000 ppm, while data from 2015-2017 indicated an equivalent total bromine concentration of around 6,100 ppm.

The study therefore recommends reviewing the threshold and suggests that a higher level could reduce the quantity of plastics unnecessarily separated from recycling. The proposed 6,000 ppm figure is a study recommendation for consideration, not a new regulatory threshold.

Alternative flame retardants and recyclability

The study finds that replacing BFRs with alternative flame retardants would not necessarily increase WEEE plastics recycling yields. Polymers containing high concentrations of additives are already separated because additives can affect recyclate quality and consistency. Phosphorus-based and mineral flame retardants may also alter material properties or density and can therefore present their own recycling challenges.

Research reviewed in the study found that some phosphorus-based flame retardants can deteriorate during repeated processing, while some BFR-containing polymers maintained their properties for longer. Mineral flame retardants may require high loadings, potentially increasing brittleness.

The study therefore cautions against assuming that substitution automatically improves recyclability. Recycling performance depends on the combination of polymer, additives, material properties and available sorting technologies, and the effects of alternative flame retardants require further research.

Recommendations for policymakers, recyclers and producers

For policymakers

The study recommends better data on WEEE plastics flows and recycling performance, a review of treatment requirements for BFR-containing plastics, including the 2,000 ppm threshold, and greater harmonisation and stability across chemicals, waste and product legislation. A more predictable framework is presented as important for investment in recycling technologies.

For recyclers

Recyclers are encouraged to develop sorting and recycling methods capable of recovering a greater share of WEEE plastics, including polymers such as PC-ABS, PA and PBT. The study also recommends longer-term cooperation with producers so that recycling experience can inform product and material design.

For producers

The study recommends recycled-content targets to strengthen demand for WEEE plastic recyclates and greater exchange with recyclers on how polymer and additive choices affect end-of-life recyclability.

Key conclusions

• Most WEEE plastics are not brominated, and restricted legacy BFRs represent a small and declining share of the BFRs found in WEEE plastics.

• Density-based sorting can effectively separate bromine-rich material from the principal recyclable polymer streams.

• The largest losses occur before specialised plastics recycling, making collection and routing of WEEE plastics a major factor in overall recycling performance.

• Replacing BFRs with alternative flame retardants would not necessarily increase recycling yields.

• The study recommends reviewing the continued relevance of the 2,000 ppm bromine threshold.

Overall, the study identifies improved collection, technological innovation, stable regulation, stronger demand for recycled plastics and closer producer-recycler cooperation as priorities for increasing WEEE plastics recycling in Europe.

About the study

The Study on the Impacts of Brominated Flame Retardants on the Recycling of WEEE Plastics in Europe was published in November 2020 and prepared by Sofies. The study draws on available literature and data, stakeholder interviews and material-flow modelling.

Important note

The analysis and conclusions presented in the report are those of Sofies and do not necessarily represent the views of BSEF or its member companies. Readers should refer to the original publication for the full methodology, assumptions, references and context underlying its findings.

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