Modelling work carried out by Zero Waste Scotland (ZWS) using real data found that applying the carbon metric to one scottish council’s recycling rate of 38% resulted in it falling to 28%.

Speaking at a 2degrees webinar yesterday (22 June), ZWS environmental analyst, Kimberley Pratt, said the large drop was due to the type of materials being prioritised and collected under the current weight-based target system.

“If [the council] is going to reach its 50% target by 2013 then there is still a bit of work to do,” she warned, adding that the council’s efforts needed to centre around materials with a higher carbon impact going forward.

“For that particular local authority, if they focus on carbon and increase textiles recycling to 90% and send 90% of food waste to anaerobic digestion, they could increase their carbon metric recycling rate to 65%,” she said.

Under the new metric system, tonnage-based targets will be weighted by applying a ‘carbon factor’ to the materials collected, which takes into account the environmental benefits of recycling them over sending them to landfill.

If councils go after materials with a higher weighted carbon ranking, such as textiles, cans, PET and small WEEE items, their recycling performance should improve.

The new measurement system is still very much a work in progress. A carbon metric technical steering group has been set up to gather new data and adjust the scheme if necessary. More understanding is also needed around end-of-life choices and the impact of reuse and energy-from-waste.

While the carbon metric will only apply to household waste initially, it is likely to eventually include the commercial and construction waste streams too.

Maxine Perella

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