September 9th, 2013

Material differences: collection methods, quality and export

8 minute read

by Andy Grant


Why is it that we export recyclate? The Daily Mail’s outrage regarding exports back in April may have been fuelled by the mistaken belief that much of the material is landfilled, but to some the fact that we ship recyclate overseas is quite outrageous enough: Doretta Cocks was reported as calling the practice “shameful”.

It can be argued that our use of commingled collection and MRF sorting is a major reason for exports. True, commingled MRF outputs are typically more contaminated than some other sources of recyclate. Further, the economics and reprocessing equipment abroad are often more favourable to handling contaminated material, and (until recently) many overseas buyers were content to receive it.

But I think this is too simplistic. The contamination issue is a can of worms and broad generalisations don’t really explain why some material is reprocessed here, and why some goes abroad. In truth, contamination matters more for some materials than others; and in some cases, commingled actually results in material reprocessors prefer. Let’s look at the commonly collected materials.


Testing their metal

Bales of steel cans sorted by MRFs typically are more contaminated than those sorted at the kerbside – but buyers are not particularly concerned about it. The reprocessing system can cope just as well with 5% contamination as with 2%; it just results in a bit more slag and some extra gas emissions. Theoretically, buyers will adjust prices down if they’re receiving less target material than expected, but this doesn’t always happen in practice.

Contamination is of more concern to aluminium buyers, for the obvious reason that the price of aluminium is so much higher. But at its huge Warrington plant the leading closed loop reprocessor, Novelis, has experienced quality problems with aluminium cans from all types of UK sources. The incorporation of “widgets” and other plastic fittings into cans has been a particular challenge. It is always keen to promote high quality and separate collection, whether through award schemes or its support for the Campaign for Real Recycling. But recycling through Novelis isn’t the only beneficial use of aluminium, and material that falls short of their standards still finds its way onto the scrap market to be melted down.


Polymer math

Plastics are a quite different case: UK plastic packaging recyclers buy the majority of their materials from MRFs and find kerbsorted plastics, unless they’re collecting bottles only, generally to be ‘lower grade’. A recycler aims to sort plastics into distinct polymer and colour grades, which command very different prices. HDPE and PET are valuable, and are often reprocessed into flake here, while less valuable polymers may be sold on.

To work efficiently, the sorting process needs inputs with compositions that match the overall sorting design of the plant and feed sufficient valuable material through to reprocessing processes. A MRF can readily produce an output that is, say, 80% PET and 20% other polymers. This needs further sorting – but it produces predictable amounts of target material. Kerbside sort material can be taken, but, particularly if they are from mixed plastic schemes, yields of valuable polymers are relatively low per tonne of input. But if all systems resulted in perfectly sorted MRF output, that wouldn’t be appealing either – it would render the reprocessors’ expensive sorting technology redundant.


Fibre, glass

‘Fibres’ such as paper and card are widely thought to be much better quality when separated rather than commingled. However, you can make beneficial products from most MRF fibre products – commingling and contamination are not the end of the world. Granted, the product commonly won’t be newsprint made in the UK, and some of the contamination will have to be sent down a non-recycling route such as landfill or energy from waste. But commingled collection and contamination in paper do not seem to pose a fundamental problem.


MRF Material

In the mix: MRF materials ready for sorting. Photo by Alex Foster, via Flickr.


The views we hear reported in the recycling press are predominately those of the UK newsprint industry (who struggle to use commingled material). I suspect the views of Far East reprocessors might be more nuanced. When the Chinese started favouring material from the USA over the UK on quality grounds this certainly wasn’t a choice between prevailing collection methods: the majority of recovered municipal fibre in the USA is collected commingled.

Glass is a bigger issue. First, including glass in a commingled mix has a detrimental effect on the quality of the materials that are collected with it. Secondly, the process by which MRFs remove glass tends to produce material that at best is mostly suitable for reprocessing as aggregate. MRF glass is therefore almost certainly less environmentally beneficial than kerbsorted, which is more likely to be turned back into glass. However, this doesn’t translate into a lower likelihood of export. There is plenty of domestic demand for aggregate, and little MRF glass is exported. High quality colour-sorted glass is far more likely to makes its way overseas to be turned back into bottles in countries that have large wine industries.

This brief tour of the material streams shows that the relationship between collection method, quality and export is far from simple. I don’t doubt that reprocessors report commingled recycling is more contaminated, and that’s almost certainly true for all bar plastics. But does it matter in relation to the export of material?


Sorting the arguments

The key question regarding contamination is whether it is economically or environmentally detrimental. For the most part we are talking about degrees of impact, and there is a need to balance contamination against other pertinent issues that favour or disfavour each collection method.

Reprocessors may argue that commingling and contamination hinder investment in UK capacity. Indeed, anyone who objects to exporting recyclate faces the problem that the UK has nowhere near enough reprocessing capacity to handle the material we already collect, let alone to cope with more. Today, to recycle we have to export.

It seems unlikely that contamination is the major obstacle stopping us building more recycling infrastructure. Most contamination issues can be addressed through technology. Harder to tackle are costs such as disposal, land, labour and energy, which may compare unfavourably with cheap shipping costs. Finally, there is the broader international trade issue: we import very many of the products that become our waste, and simply manufacture too little to find indigenous uses for all of our recycling.

So long as commodity values are favourable, a well-configured kerbside sort system will often have a lower net cost than commingled collection while providing employment for a larger local workforce. It is logistically more complex, but operational problems can usually be overcome given enough local operational expertise. Commingled collections are sometimes marginally more expensive, but easier to operate from both service user and collection operator points of view.

Containers are divisive: householders whose properties are suited to them often like the convenience of the wheeled bins typically used for commingled collection, while those that lack space for them may complain of ‘bin blight’. Boxes are easier where space is limited, but inconvenient when heavy, especially if you have a long walk to your set out point, and can lead to litter problems. If source separation schemes are to prevail, better containment solutions are needed so that the debate can move on from whether the containment is not big, convenient and secure enough to whether it is right to expect service users to do some sorting/separation themselves.

There is no simple answer to whether kerbside sort or commingled collection is the right approach. It’s a very complex issue, and depends on local circumstances. I have sympathy for the purist “clean is right” argument that favours kerbside sort, but I think there are material mixes and situations where it is better to run a commingled approach.


Collection Pie

In the vast stream: single stream commingled collections are now the most popular with councils. Source: Eunomia.


As technology develops, something of a compromise will be found: a reasonable two or three stream system that caters for most of the dry materials. Cans and plastics are easily separated. Paper is a diminishing part of the waste stream and it may not be long before the economic logic of basing recycling systems on the production of newsprint comes into question. Glass remains a problem if mixed with other materials and needs to be kept separate – advice we may yet see included in Defra’s guidance on the Waste (England and Wales) Regulations 2012.

This result will not delight reprocessors wedded to maximum separation. Nor will it please those who prioritise making recycling simple for residents. But I expect to see local authorities that need to minimise costs responding to the market and moving in this direction.

And when it comes to outrage regarding exporting materials to the Far East or elsewhere we need to remember the likely fate of such material. There is a high probability that it will soon be reborn as packaging for goods in a shipping container that’s heading back to Europe or North America.


Andy Grant


Andy Grant Principal Consultant


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