In recent months, mixed glass prices have dropped dramatically. In particular, mixed glass has dropped to less than £5 a tonne, whereas colour-separated glass has remained relatively stable. Packaging recovery notes (PRNs) are also in decline, and glass recycling firm Recresco lowered its mixed glass prices down to £8.50 a tonne in December 2010 in response to the PRN’s decreasing value.
Recresco is well positioned to capitalise on the fact that colour-sorted glass continues to command higher prices, feeding these benefits back to the market, because it sorts recycled glass by colour. Most recycled glass is no longer sorted like this on the doorstep because it is understood that asking consumers to separate glass by colour discourages them from recycling at all.
Most MRFs do not sort by colour either. The result has been an increase in the amount of mixed colour glass in the waste stream. Only limited amounts of mixed cullet can be used to produce new glass packaging, so instead more is used in the production of aggregate for road building. That is one reason why prices for mixed cullet have suffered.
Until now there has only been one MRF processing glass in south Wales. This has meant that much of the material recycled in the region has been ‘exported’ to the north of England
UK glass manufacturers produce very little green glass - most of it comes from wine bottles which are imported - hence weak prices for green glass. But demand for brown and clear cullet, which is used by the UK glass industry, remains strong, explaining their relatively resilient prices.
Figures last month show brown glass coming in at £24-£27 per tonne and clear glass coming in at £27-£30 through December. Mixed glass fetched a maximum of £5 per tonne, with some instances of it being accepted free of charge.
Until now there has only been one MRF processing glass in south Wales. This has meant that much of the material recycled in the region has been ‘exported’ to the north of England. As transport prices increase, this has become less and less practical. At the same time, increasing recycling rates mean that there is now enough demand in south Wales for further glass recycling infrastructure and so, earlier this month, Recresco opened a plant in Cwmbran to process glass.
Sorting glass by colour is not a simple job, but the result (higher value) is worth the time and effort. As with all sorting, the glass is also cleaned and everything that is not glass needs to be removed, such as paper, bottle tops, plastic bags, stones or other impurities. If these contaminates are not removed before being melted, they would appear embedded into the finished bottle.
Recresco uses the latest glass sorting technology. Some of it has been designed and built in-house where it was not already available. This means that the Cwmbran site can now use high-specification optical sorting equipment to process 10 tonnes of glass every hour by colour. The glass cullet produced is of such high quality that bottle manufacturers can use a much higher percentage of the glass material than they normally would - which is why they will pay more for it, creating a truly sustainable recycling model.
The value of mixed glass is expected to remain low, so the benefits of spending time and money to separate glass into its colours are outweighing any negatives there may be. Not only does it produce a higher quality glass cullet that commands a higher value, but it is more easily melted down to reproduce new glass bottles with less waste.
As the demand for mixed glass declines, the payback for colour-separated glass will increase.
Tim Gent is a director at Recresco