by Andy Grant and Peter Jones
5 minute read
Is the increase in recycling rejects in England due to an increase in the amount of contamination in recycling bins, caused by growing confusion amongst the public? Last month we identified a couple of other possibilities that would also explain the 184,000 tonne rise: better data capture, or better sorting at materials recycling facilities (MRFs). However, we didn’t attempt to assess which is the most plausible. In this article, we begin that tricky task.
We should also state a background assumption: any authority that collects a large proportion of its recycling co-mingled should, if it is reporting accurately, have a reject rate above 0%. A plausible minimum level of rejects is a matter for debate, but we think 5% would be low and 2% exceptional.
Kerbside sort systems, though, can plausibly give rise to very low levels of rejects. Indeed, under the outgoing WasteDataFlow reporting rules, reject counts were focused on primary MRFs rather than any subsequent sorting by reprocessors. This made it possible for some multi-stream authorities to correctly report 0% rejects, although this would have overstated the amount of material put to beneficial use.
Systematic analysis
The 51 authorities that are currently using kerbside sort-type systems have an overall reject rate of less than 1%. Comparing the 2011/12 and 2014/15 statistics, their reject rate has gone up by some 0.2%, with rejects rising from 5,027 to 13,872 tonnes; but the data reveals that most of this increase is accounted for by issues with waste wood and kerbside recycling in South Gloucestershire. Since the reject figures are consistently and explicably low for these authorities, we have excluded them from the analysis that follows.
Part of the explanation for the overall increase in rejects might be the increasing popularity of single stream and two stream collection systems. Over the period since 2011/12, Eunomia’s records indicate that more than 60 authorities have moved from multi-stream to single stream or twin stream systems – the exact number depends on how you count authorities in waste partnerships. Of these, 23 reported 0 rejects in 2011/12; only 6 did in 2014/15.
The total amount of reject material from councils that switched away from multi-stream collections accounts for 38,500 tonnes (13%) of the increase in rejects between the two years. But a couple of observations diminish the significance of “switching” as a contributing factor to the rise in rejects.
- The rise in rejects in these “switching” authorities is very similar to the overall average increase in rejects (about 575 tonnes per council).
- More than 15,000 tonnes of the switchers’ increase was garden waste rather than dry recycling. 14,300 tonnes of this was reported by the Dorset Waste Partnership. Excluding this outlier figure brings the average increase amongst “switching” authorities significantly below the national average increase in rejects.
MRFs have indicated that they tend to look favourably on material from councils that have recently switched from a kerbside sort to a co-mingled system. The data perhaps supports the idea that such councils’ recycling yields relatively low levels of rejects at least in the early years after the system change.
Because of the very small contribution to rejects from authorities that switched away from kerbside sort, we also exclude these figures from the analysis that follows and focus simply on the collection authorities and unitaries that collected some or all of their material co-mingled throughout the period 2011/12 to 2014/15.
Small change
Of these authorities, 157 saw their reject tonnage go up, while 47 saw it stay the same or decrease. But before we conclude that this reflects a widespread increase in public confusion, it’s worth looking at where the increase in rejects has taken place.
The chart below shows that 43 fewer authorities reported 0-2% rejects in 2014/15 than in 2011/12, while the number reporting 2-10% increased by 33. Where no authority reported a reject rate above 13% in 2011/12, eleven did in 2014/15.
Perhaps more significantly, the great majority of the tonnage increase in rejects is accounted for by councils that in 2011/12 reported 0-3% rejects, while the tonnage attributable to councils with 2011/12 reject rates above 10% has actually decreased, as shown in the chart below.
While the analysis above is not conclusive, it is suggestive. Around 13% of the 184,000 tonne increase in rejects appears to be associated with authorities that switched from source separated collection schemes that are more likely to separate out non-target material before they ever get into the system. Around 8% seems to be attributable to garden waste issues in Dorset in 2014/15. A few percent here and there are attributable to specific issues at individual authorities (some of which already had high rejects in 2011/12), which were explained in the BBC article that brought this issue to the fore – Greenwich using an “out of date” MRF, for example, resulting in a 3,000 tonne increase.
But most of the rest has occurred across a wide range of councils that formerly had improbably low rejects; many still have reject rates below 5%. Meanwhile, the authorities that had the highest level of rejects in 2011/12 have (taken as a group) seen their reject tonnage decrease.
Confused story
This is difficult to reconcile with the “confusion” explanation. Are we to understand that confusion has increased only in areas where formerly there was none, but where people were more confused in 2011 about what to recycle, matters have improved?
It is also a poor fit with one of the alternative theories we advanced: that the figures accurately report improved sorting of rejects by MRFs. In fact, the starting level of rejects in the councils where most of the increase has occurred was implausibly low.
It is, though, consistent with another theory – better reporting by councils (or by MRFs to councils) of an issue that has been there in co-mingled systems all along.
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