Work undertaken by the Waste & Resources Action Programme reviewed life cycle analyses of additional materials from the previous report carried out in 2006, including food waste, garden waste, textiles and biopolymers. Other materials also looked at in Environmental Benefits of Recycling - 2010 Update were wood, plastics, paper and cardboard. Pyrolysis, gasification, anaerobic digestion, composting and energy from waste technologies were additionally examined.
WRAP environmental policy manager Keith James said: The interesting message was that recycling materials saves more energy than energy facilities actually gain from the materials.
Assessing paper and cardboard, incineration through energy from waste was revealed as being a satisfactory end of life option for paper and card, due to the electricity and heat that can be generated from it. Although recycling is better in general regarding energy demand and waste consumption, when juxtaposed with incineration they are comparable for climate change. WRAP asserted that it is difficult to establish a relative preference because of inconsistencies between the studies. These results are less stable than the previous report where recycling had a slight advantage. This is believed to be a result of the development of more improved incineration facilities which generate electricity.
Results also showed that the type of paper and card has a significant influence on what is the best end use. In one study it showed that due to corrugated cardboards short fibre length and therefore bad quality, it is the worst type of paper for recycling. It is therefore, more environmentally beneficial to recycle high quality products such as office paper.
Recycling of plastics was found to be the best option in respect of climate change potential, depletion of natural sources and energy demand impacts. But new technology pyrolysis is the preferred and promising option regarding all indicators assessed. Incineration actually came out to be worse than landfill regarding climate change. However, incineration may be preferable for dealing with waste plastic arising from electronic and electrical equipment of end of life vehicles because pre-treatment of this material for recycling means they use a similar amount of energy. The report found quality plastics also provided environmental benefits.
The report stressed that, In order to maximize the environmental benefits of recycling it is thus essential to develop the domestic recycling capacity.
Analyses of biopolymers found composting is not advantageous for energy demand or depletion of natural resources, although many biopolymers are marketed as suitable for composting.
James explained: For biopolymers, it was interesting that recycling came out as preferable to composting. We were not anticipating that result. However, the issue there that there is not enough biopolymers in the waste stream to make it viable to have its own recycling system. So well have to wait until there is enough tonnage in the stream to make recycling viable.
Those studies which did not consider recycling as an option showed that incineration was the preferred option. Anaerobic digestion also had an advantage over composting due to the recovery of biogas produced.
For the same reason, AD seemed to come out on top for food and garden waste, even though less than half the studies included this technology. Incineration was also seen as a preferred option even though food waste has a relatively low heating value. However, regarding home composting, the report highlighted that there is some concern that if there is not enough air in the composter, the process will produce more methane and contribute significantly to climate change. Therefore home compost bins must be properly managed
There were shortcomings, added James. When the report was commissioned we wanted to know more about gasification and pyrolysis but there wasnt a lot of information about these new technologies. Many of them are being trialled at the moment.
WRAP also found there was little information regarding the LCA of textiles and wood. Recycling came out to be the best option for wood regarding human health, climate change and ecosystem quality but it actually presents a larger contribution of damage to resource due to the use of fossil fuels. Incineration therefore seems to be more favourable when analysing energy consumption. Again, results showed the higher the quality the wood, the better the environmental impact.
Textile recycling is also seen to be significantly better for the environment than other options. But the report found that UK recycling excluding reuse, is limited due to the lack of technologies and making new garments from used clothing is very marginal. Therefore, WRAP believes fibre separation technologies need to be developed.