Mechanical recycling of plastics is the best waste management option when considering climate change potential, depletion of natural resources and energy demand impacts according to the 2010 update of the “Environmental benefits of recycling” report by the UK’s Waste & Resources Action Programme (WRAP, Banbury / UK; www.wrap.org.uk). The analysis reinforces the conclusions of the report originally published in 2006 by highlighting that benefits of recycling are achieved mainly by avoiding production of virgin plastics.

WRAP’s review assessed 55 "state of the art" life cycle analyses (LCAs) on plastics, paper and cardboard, glass, aluminium, steel, wood and aggregates. It concluded that most studies show that recycling offers more environmental benefits and lower environmental impacts than the other waste management options. The decision to update the report was made following the emergence of new waste management options and new waste streams over the last three years. Over 200 LCAs published worldwide since 2006 were reviewed.

The key impact categories used for the assessment of the different waste management options for plastics were depletion of natural resources, climate change potential, cumulative energy demand and water consumption. End-of-life options considered were recycling, incineration with energy recovery, landfill and pyrolysis. The highly detailed 240 page report has 23 page and 19 page sections covering plastics and bioplastics respectively. In the plastics section, 22 cases were assessed, covering a total of 64 scenarios. The study selected seven publications when considering end-of-life alternatives for biopolymers.

The report concludes that the environmental benefits of mechanical recycling of plastics are maximised by collection of good quality material and by replacement of virgin plastics on a high, one to one, ratio. Recycling will become increasingly favoured as the UK moves to a lower-carbon energy mix, WRAP said. Incineration with energy recovery performs poorly in relation to climate change impact, but pyrolysis appears to be an emerging option considering all assessed indicators, although this was analysed in only two LCA studies, the study said. Landfill was confirmed as having the worst environmental impact in the majority of cases.

Biopolymers were considered in the review for the first time. Although biopolymers are only just emerging in various waste streams, data indicates good environmental performances of mechanical and chemical recycling with regard to energy demand, depletion of natural resources and climate change potential. However, for LCA studies that did not consider recycling as an option in the analysis, the data shows that incineration is a preferred option.

WRAP said that the updated report reinforces the key conclusion of its 2006 study that recycling of plastics and biopolymers provides more environmental benefits than other waste management options for most indicators assessed. It added that it is disappointing that there are very few LCAs which include an assessment of more innovative technologies such as gasification, pyrolysis and anaerobic digestion.

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WRAP’s 2010 update of the “Environmental benefits of recycling” report as a PDF document (2.15MB)