Cutting the Carbon Impacts of Waste

A clearer picture of how waste can be managed to reduce its impacts on climate change emerges in new research published today.

The reports anticipate the greenhouse gas effects of the UK’s main waste streams between 2005 and 2031¹, and assess the different ways of dealing with household garden and food waste^2,3.

Welcoming the reports, Local Environment Minister Ben Bradshaw said:

“To reduce the environmental impact of our rubbish, UK waste management is already moving away from reliance on landfill towards minimisation, re-use, recycling and energy recovery, with the aim of moving as far up the waste hierarchy as is sensible in each case.

“This latest research provides valuable information on how to reduce the cost and maximise the benefits of this shift. It will enable us to build on current learning and lead the way in developing systems that minimise our impact on the environment and on dangerous climate change”.

The ERM report shows that recycling has significant benefits over landfill, particularly in terms of reduced greenhouse gas emissions, for:

• non-ferrous metals such as aluminium;
• plastics;
• textiles;
• paper and card; and
• food and garden waste (particularly by anaerobic digestion, which produces heat and power).

Glass was not specifically covered as it is a small proportion of the total waste streams with relatively high recycling rates. However, other recent research has found significant environmental benefits from recycling glass, particularly back into containers⁴.

For waste wood:
• The research established that both energy recovery and recycling bring environmental benefits. In general energy recovery is shown to offer a greater reduction in greenhouse gas emissions than recycling. However the extent of the benefit will be dependent on the type of wood waste, the level of contamination, and whether reuse options are available.

For paper and card:
• Recycling brings the greatest environmental benefits. This is consistent with other recent published work^4,5. The net impacts projected for different options in the future will depend on what assumptions are made about technological change and energy use.

For garden and food waste:
• All three reports show that minimising the amount of these materials going to landfill is better, both in terms of environmental impact and, increasingly, cost. Anaerobic digestion in particular, but also composting, brings about a net reduction in greenhouse gas emissions, although there is uncertainty over the scale of the reduction that can be attributed to composting. This uncertainty will be addressed in a further Defra-funded study to be published in the next 18 months.

• The Eunomia research shows that there can be real cost and environmental gains from collecting garden and food waste separately from each other. This enables the processing costs to be minimised and can increase the amount of food collected. In terms of environmental impact, anaerobic digestion of food waste in particular performs best.

• The Eunomia Food waste report³ report suggests that if the 5.5 million tonnes of food waste in the UK were targeted for separate collection and anaerobic digestion, between 477 and 761 GWh/year of electricity would be generated – enough to meet the needs of up to 164,000 households.

There is clear evidence that to achieve the lowest financial and environmental costs, decision makers need to take a whole system approach, which considers options for treatment together with those for collection systems. The research results will contribute to Defra’s revised Waste Strategy, due for publication this Spring.

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^{1. Carbon Balances and Energy Impacts of the Management of UK Wastes. ERM and Golder Associates report for Defra.}

^{2. Managing Biowastes from Households in the UK: Applying Life-cycle Thinking in the Framework of Cost-benefit Analysis. Eunomia Report for WRAP [due for publication late March]}

^{3. Dealing with Food Waste in the UK. Eunomia Report for WRAP.}

^{4. Environmental benefits of recycling. WRAP 2006, available from www.wrap.org.uk} 

^{5. Paper and cardboard - recovery or disposal? Review of life cycle assessment and cost-benefit analysison the recovery and disposal of paper and cardboard. EEA Technical report No 5/2006}