AT A GLANCE:
How switching to commingled boosted Cambridge City’s static recycling level and the number of materials it could collect - and saved it £150,000 in its 2010 budget.
The once ferocious debate over source-segregated waste collections versus commingled has, thankfully, died down over the past year. With local authorities facing unprecedented budget cuts it seems industry has cut them some slack, recognising that the diminishing pot of money will dictate many local authority services now.
It has meant that more local authorities have moved to alternate weekly collections over weekly collections and therefore commingled collections rather than source segregated.
For Cambridge City Council, the main reason for swapping its collection system from source segregated to commingled, with help from waste contractor Viridor, was in fact to increase its recycling rates – an issue that previously would have been debated to the nth degree over which system provides the highest recycling rate.
But cost savings that have accompanied the changeover have been welcomed. “We saved £150,000 on the 2010 budget and we know that by the end of the financial year it will amount to more than this,” says Cambridge City council waste and street strategy manager Jen Robertson.
More cost-effective service
She admits the local authority was not responding to Government cuts when the decision to change recycling systems was made: “We were just looking for general savings as all local authorities always are. But we certainly felt that we could provide a better service to residents more cost effectively, while not losing anything we were gaining from our current system.”
Cambridge council swapped to commingled collections in 2009. The system was transformed from a kerbside sort system, which saw residents have two boxes – one for glass, paper and card and one for plastic bottles – picked up by kerber trucks, which have different collection points within them for each separate material. Refuse workers separated the glass into colours, as well as putting the correct material in the right section of the truck. It meant that the materials were already bulked up and so could be sold on easily by the waste contractor.
Robertson explains: “One of the things we found with the source segregated system was that we were limited in terms of the number of materials we could collect with our old system. We had already bolted on the second box for plastic bottles but we wanted to add more, in order to up our recycling rates.
“The boxes also added litter to the streets because they didn’t have lids. A survey also highlighted a barrier to the box that meant residents stopped recycling when the box was full and instead put materials into their residual waste.
“A big problem was the manual handling of the boxes which had got heavier and heavier over time as residents recycled more, making it harder for our refuse workers to lift. So, we became victims of our own success. But the recycling rate began to plateau.”
The limiting factor of kerbside-sort systems is a complaint Viridor comes across regularly. Cambridge Viridor regional operations manager Stuart Wood explains: “We are finding more and more people want to add materials to collections, while we find more end markets to put them in. For example, plastic bottles are only a recent addition to recycling collections really, as years ago it was rare to see them recycled, but now we’re more than happy to include and collect them.”
It was the residents’ call for the local authority to recycle more which made up Cambridge council’s mind about commingled collections.Now the residents have three bins to put their waste in: one for the recyclables; one for the residual waste; and one for their green waste. These are all collected on alternate weeks by the council’s in-house system as done previously. Standard refuse trucks then take the materials to Viridor’s MRF for bulking and selling.
And the results of the collection change have proven successful, with an extra 2,000-plus tonnes of recycling collected through the commingled scheme over the source segregated scheme. Meanwhile, the recycling for 2010/11 is predicted to be around the 22% mark, up from last year’s 17.9% rate.
“We did have some concerns,” Robertson admits. “At the top of the possible disadvantages to the system was the risk of contamination. We were very prepared for this to happen and we were very open to our residents about the potential for the quality of our recyclables to diminish. Although the kerbside-sort system was labour-intensive, the revenue we got back from the materials covered the increased cost of staff.”
Low contamination levels
For Cambridge, contamination levels have stayed extremely low at an average 1.9%. But it seems it may be the exception to the rule. “Cambridge has probably the best contamination level we deal with across the country,” says Wood. “They provide extremely clean material, which seems to be a result of the level of education the residents have about the recycling scheme.
“The contamination of material is not really a problem for the modern MRFs because they can deal with levels of 8% contamination. It’s just that that the cleaner the material is, the better the deal can be for the local authority.Contracts can be drawn up which allow for the specific value of the material to be accurately calculated, so the local authority can see the value of the material.
“It is possible to specifically target the value of each authority’s waste stream more accurately, which they then benefit from because their material stream is valued against a fixed index, which is reviewed every six months.”
Robertson believes the discipline that residents gained from knowing which materials to put into which box with the source segregated recycling system has continued into the commingled system, keeping contamination to a minimum. And so far, the feedback has been extremely positive.
“It’s so easy for the residents to put everything in one bin. And that’s the crucial thing. The easier we can make recycling, the better,” she says.
Although Cambridgeshire did not switch services for financial reasons, Wood believes it is a move many local authorities will be making in future to save money. “Commingled is something I believe more and more councils will be looking at because you get the best overall economic value with this type of collection when you put the material through a modern commingled MRF. And it makes it easier for the local authority to communicate to residents what they can recycle and the fact that it only has to go in one bin.
“We seriously believe it is less expensive than source segregated because you have one bin and one collection line rather than two or three vehicles collecting different materials. Although you have the MRF costs, which you didn’t have before, the overall expense of the commingled system is cheaper.”
The contract Cambridgeshire council is under with Viridor also encompasses neighbouring councils Huntingdon and Fenlon, which are rolling out a similar commingled system. Cambridgeshire is now looking at how to improve upon its system. Robertson adds: “We are hoping to add more materials to our collections in future. I think the thing is to examine all the factors involved to ensure we are carrying it out in the most cost-effective way possible.
“Residents have said they would like to recycle more plastic, so the particular materials we want to add are polypropylene and polystyrene. With an ambitious 2016 recycling and composting target of 50-55%, it seems Cambridge is most certainly on the right track to achieving it.”
Many in the recycling and waste management industry now seem to have accepted that the factors behind a successful recycling system are unique to each individual local authority, with a no one-size-fits-all approach available. With more emphasis on localism, will it be the residents driving the future of their recycling systems rather than industry? And will the commingled versus source segregated debate no longer matter?