First trial of recycling used insecticide treated nets by pyrolysis for safer environment: The RINSE project

Thanks to the large-scale distribution of long-lasting insecticide-treated nets (LLINs), several hundreds of millions of cases, and malaria related mortality, were averted these last decades. However, disposing of the used, and discarded nets, made of non-biodegradable plastics, and impregnated with insecticides, and usually burned or buried, raises significant, physical and chemical, environmental and health concerns. This study explores the first application of pyrolysis to recycle, and repurpose, discarded LLINs, with tests conducted in Lombok, Indonesia.

Pyrolysis was tested on Royal Sentry® LLINs, made from polyethylene and impregnated with alpha-cypermethrin. A special equipment was prepared to make this pyrolysis, following the same protocol as the one currently used for treating plastic waste at large-scale in the factory Geo Trash Management (Lombok).

The pyrolysis yielded 81.3 % high-quality oil, 5.65 % oil residue, and 5 % carbon residue. Gas Chromatography-Mass Spectrometry (GC-MS) analysis identified 36 hydrocarbons, 7 alcohols, and 1 acid, without harmful chemicals like polychlorinated biphenyls (PCBs). Unexpectedly, the nets contained Nonacosane, a mosquito attractant, and Citronellol, a natural repellent, raising questions about their effects on mosquito behaviour.

Polyethylene LLINs are suitable for pyrolysis, offering an innovative solution to the environmental impact of discarded nets. The Recycling used Insecticide-Treated Nets for Safer Environment (RINSE) project plans to transfer this technology to malaria-endemic countries, establishing recycling structures and promoting sustainability. This approach supports global efforts to combat plastic pollution, create a circular economy, and sustainably manage LLIN disposal. Further research is recommended to explore the behavioural implications of detected compounds.