Managing hazardous WEEE plastic additives in the Indian informal sector. A study on applicable identification and separation method
Plastic housings from waste electrical and electronic equipment (WEEE housings) contain hazardous substances such as heavy metals and certain brominated flame retardants (BFRs). The Stockholm Convention and national RoHS legislations severely restrict their further use in products. In many cases these plastics should thus not be recycled but safely disposed. In India, a majority of plastics is recycled in informal businesses, which characteristically do not follow work and environmental safety requirements, are not registered with the responsible government bodies, and do not pay taxes. Informal businesses are not limited by any laws and as such try to recycle as much material as possible. Plastics containing hazardous additives are thus reprocessed in unsafe working conditions and re-enter products without any control. This endangers workers and the public and leads to environmental contamination. Approaches of forceful formalisation and compliance with regulations have been tried widely but have mostly remained unsuccessful. Integrative approaches are far more likely to have a lasting impact. In the case of plastic recycling, this requires that the informal sector is given the technical capability and a targeted incentive system for not recycling certain materials in order to “clean the loop”. The first step towards this alternative system is the development of effective methods to identify and separate BFR-containing plastics.
In this context, this study aimed at answering the following questions: Which hazardous additives limit the recycling of high-quality plastics from e-waste such as housings? How can plastics containing these additives be identified and segregated in informal recycling units such as found in India? To answer these guiding questions, desk research and visits in Swiss and Indian WEEE recycling facilities were undertaken to identify possible technologies to identify and separate housing plastics containing hazardous materials. Several months were spent in Delhi to understand the informal plastic recycling system and assess the current fate hazardous plastics. Samples were taken from the informal sector. Pre-selected separation methods considered as applicable in the informal sector were tested to assess their removal efficiency.
Results indicate that the occurrence of hazardous additives varies greatly among different applications. WEEE housings generally do not contain heavy metals in harmful concentrations. Brominated flame retardants occur however in harmful concentrations, especially in some hotspots such as CRT casings. Both findings are in line with measurements conducted in Europe, with the exception that BFR concentrations in India are generally higher. This may be due to longer equipment lifetimes and later introduction of regulations on BFRs in India, which keep substances in circulation.
All observed or tested methods to separate BFR plastics had a high efficiency and were easy to apply. Of the surveyed methods, only density separation should be encouraged due to health concerns with the other methods. This method was shown to have a removal efficiency of above 95%, and 100% of the “clean” fraction (i.e., floating) complies with European standards for depollution of WEEE plastics, allowing these materials to be used in high-quality manufacturing.
Density separation is already used in the informal sector in addition to a plethora of simple and cost effective methods to segregate plastics. The introduction of density operations following detailed instructions with efficiencies verified in this study should thus be possible with a manageable effort. Informal actors in the recycling chains of developing and emerging countries already play an irreplaceable role in achieving high recycling rates. With some limited changes along the recycling chain, their operations and recycled products can be rendered safe.