New Delhi / St. Gallen, July 2016: As part of the Sustainable Recycling Industries (SRI) initiative in India, a study was conducted on low-tech, low-cost methods to identify and segregate plastics containing hazardous additives.
Plastic recycling is an important economic activity in developing and emerging countries, involving thousands, if not millions, of people whose main activity is to create value out of plastic waste. This activity often takes place in the so-called informal sector, characterized by low levels of organization, technology and capital, as well as non-compliance to rules and regulations related to tax, minimum wages, workers safety and environmental protection.
Plastic recycling is by and large a sustainable activity: It avoids production of virgin plastics from fossil fuel, carbon dioxide emissions and landfilling. However, certain fractions of plastic waste such as those found in waste electrical and electronic equipment (WEEE) may contain hazardous substances and require specific treatment and, in some cases, destruction. Hazardous plastic additives include brominated flame retardants (BFRs) and heavy metals, exposure to which can have considerable health effects, such as cancer, damage to nervous and reproductive systems, and behavioural changes.
The SRI recycling initiative in India aims to remove plastics containing hazardous additives from secondary material cycles through an approach that includes applied scientific research, technological partnerships with informal and formal recyclers, market-based mechanisms and the design and implementation of effective rules and standards. A necessary first step towards the elimination of hazardous plastics from recycling processes is to develop methods that allow recyclers to identify and segregate those plastics from the mainstream. These methods should be simple and robust enough to be implemented in informal settings, where most plastic recycling occurs.
Scientists from Empa collected plastic samples from the informal recycling sector in New Delhi in order to analyse the content of hazardous materials and evaluate potential separation methods regarding their applicability, safety and efficiency in the informal sector. They observed that harmful additives, in particular BFRs, are found in concerning concentrations in some informal plastic recycling channels. With the current lack of awareness, technologies and incentives for more sound processes, those hazardous plastic fractions contaminate the mainstream and may end up in sensitive applications such as toys and food packaging.
Laboratory results show that very simple methods, such as using saltwater to separate plastics of different densities, are effective to segregate plastics containing BFRs. While some of these methods are already used by some informal recyclers, field observations and measurements suggest that separation could be further improved with trainings and simple tools.
This study therefore shows that it is technically feasible to remove BFRs from plastic streams in informal settings. Sufficiently simple techniques, applicable to the realities in developing countries, are available. The missing link seems to be rather organisational. SRI proposes the setup of a “buy-back” system which adequately remunerates recyclers to remove BFR-containing plastics from the recycling chain and provides a separated channel for adequate treatment of BFRs.
The report can be downloaded here.