10 May 2010
Independent research has challenged support for kerbside-sort collection and claimed that it equals or outperforms single stream co-mingled collection.
The research, a four-month study conducted by WYG Environment, found that 26 of the top 30 English dry recycling local authorities use co-mingled collections and that WasteDataFlow information for 2008/09 showed local councils who used co-mingled collection performed significantly better than those using kerbside-sort collections; diverting on average 25% more tonnage even after allowing for materials recycling facility rejections. It also found that using alternate week collections of residual waste and co-mingled dry recyclables from wheeled bins, plus weekly food waste collections and chargeable garden waste collections, can produce recycling and composting rates of 70%. The report also concluded there is anecdotal evidence that co-mingling can improve operational health and safety, street cleanliness and that recyclates from co-mingled collections meet the specifications of reprocessors in the UK and abroad.
According to Greenstar UK CEO Ian Wakelin, a long-term advocate for co-mingled collections: “I think the deck has been stacked against co-mingling. Now there is new, important and impartial evidence about co-mingling and other collection options.
“Given the great pressure we all face to cut waste and to recycle more, I would hope the relevant authorities will give this evidence equal emphasis when considering collection alternatives.”
Echoing Wakelin’s view, Roger Edwards, managing director of municipal services provider, Verdant, which handles recycling and refuse collections for over 20 local authorities, said: “Some have said that kerbside-sort is the only ‘real’ collection system, which frankly denigrates the many scores of councils and millions of people who find that co-mingling is their reality and a very effective one too.
“Because of their greater diversion performance, co-mingled collections will become cheaper relative to kerbside-sort as disposal costs rise in the future.”
In the past WRAP has claimed that single-stream co-mingling is more expensive than the kerbside variety.
However, the WYG study indicated that one system can be cheaper or more expensive than the other due to variable factors such as recyclate sales, the cost of containers and collections, MRF gate fees and locations, tonnage diverted and so on.
In particular, WYG’s research found that where kerbside-sorted collection is deemed cheaper, its cost differential with co-mingling narrows if all true total costs are considered. According to Greenstar and Verdant, these include the additional financial benefit that comes from the proven ability of co-mingling to divert more tonnage from landfill and therefore reduce associated operational and tax costs.
“This can make a telling difference,” added Wakelin, whose company operates eight MRFs across the UK, “Over time, these savings could become even more significant as gate fees and haulage costs reduce as more MRFs are built.”
WYG’s investigation of contamination rates at MRFs said official Environment Agency estimates of 10.85% average rejection rates were overstated. The study found an average rejection rate of around 4% and said modern plants that accept a wider range of dry recyclables and use newer technology achieve even lower rates.
In the study, MRF operators told WYG that there are sometimes “unrealistic expectations” regarding recyclate quality. Wakelin said that as more MRFs are built and more are upgraded with modern technology, so rejection rates should fall.
Greenstar’s CEO added: “Quality of processing is important, but so is recycling volume. I will continue to support co-mingling as a proven way of substantially lifting domestic and commercial recycling tonnages. But as I have always said, co-mingling is not and should not be, the only way.”
The WYG research report on kerbside collection recycling systems is available as a free download from www.wyg.com/recyclingreview