Single-stream recycling, now entering its second decade in Canada, seems to be gaining momentum. More and more municipalities are looking to single-stream recycling for its promise as a low cost, high-diversion solution to their waste diversion goals.
But should they?
In this, they’re being influenced by our neighbours to the south who are introducing single-stream programs at a rapid rate, rather than the European diversion leaders who tend to stay away from single-stream collection.
Earlier this year, a new report from the UK’s 4R Environmental Ltd. entitled Procurement Outcomes for Waste Collection Systems in the UK Market April 2008-February 2012 analyzed the results of more than 65 recycling collection tenders between 2008 and 2012. The report identifies that of the 65 tenders, 51 per cent of all procurement for recycling collection services resulted in curbside sort, with 28 per cent awarded to single-stream co-mingling and 21 per cent to two-stream (dual) systems.
However (notably), 29 request for bids did not prescribe the type of collection system, but left it open to the competitive marketplace. Interestingly, in those situations 90 per cent (26 of 29) of the winning bids offered curbside sort or two-stream collection, while only 10 per cent, (3 of 29) offered single-stream collection.
Commenting on the findings, Andy Bond (author of the report), said, “Senior managers at local authorities who are considering their procurement options might be surprised by these findings and that they will almost certainly benefit from allowing the most open procurement system rather than prescribing this at the outset.”
Single stream a low cost?
For the past six years, the largest Ontario-based single-stream and two-stream recycling programs have been closely analysed. During this time, single-stream has always been more expensive, and this year is no different.
The analysis includes only curbside collection and processing costs, subtracting total revenues for the program. When you include “extraneous costs” associated with operating depots, transferring and administration, the cost differential between the two collection systems is more pronounced: single-stream costs 60 per cent more than two-stream collection.
(Note: 2011 data comparison includes Halton Region as one of the four single-stream programs; the same four two-stream systems as used historically; costs are from the annual Waste Diversion Ontario datacall.)
After accounting for approximately two per cent inflation per year, overall, the average program net cost for single-stream has increased by $1.67 (1.1 per cent) per tonne or $3.66 (12.8 per cent) per household. (See Table 1.)
Again, after accounting for inflation, the average two-stream program actually decreased in net cost by $9.41 per tonne (–6.5 per cent) or $1.42 (–5.2 per cent) per household. (See Table 2.)
So the difference in net cost between single stream compared to two stream is a $21.49 per tonne and $6.13 per household premium. (See Table 3.)
The single-stream premium escalates after accounting for economies of scale, maintenance and the paper fibre premium provided to two of the single-stream programs. The “fibre premium” is the net increase in average revenue paid by the end-market and is approximately $5.25 to $6.25 per tonne to those programs. (This premium does not relate to the program type, but rather to the economy of scale of newspaper available from those programs.)
Three of the single-stream programs operate over two shifts per day while the two-stream programs only operate over one. The ability to operate the facility two shifts per day means that the equipment is monetized over the larger number of tonnes, providing an economy of scale. Economies of scales would provide a decrease in cost of between $4.50 and $7.50 per tonne for two-stream programs. Adding the extra maintenance would increase two-stream costs by $2.25 to $3.00 per tonne. (See Table 4 for adjusted costs.)
With these adjustments, the cost differential widens to between $28 and $33 per tonne in favour of two-stream recycling. Comparing all costs including collection, processing and administration, the cost of single-stream recycling is approximately 22 per cent to 26.5 per cent higher than two-stream programs. Finally, single-stream programs even show a $13 per tonne lower average basket of goods revenues.
Single stream collects more?
Advocates of single-stream recycling regularly argue that offering a “more convenient” collection option to residents will result in higher diversion rates. But this, too, may not be so.
Initially, if one includes all municipalities in both program types, single-stream programs appear to capture approximately 204 kg/hh in 2011, while two-stream programs captured approximately 191 kg/hh (6.3 per cent less). But the data show two municipalities with a substantial decrease in recovered quantities per household. By removing these outliers, the data shows that two-stream programs recovered about 10 kg/hh more than single-stream. (See Table 5 for a comparison of quantities recovered.)
It’s worth noting that single-stream programs capture approximately 22 kg/hh more newspaper than two-stream programs. This is not unreasonable to expect considering the size and number of newspapers available in these programs. But one must bear in mind that quantities recovered per household does not provide information on actual recovery rates. For that, quantities generated would have to be made available. Therefore, no real conclusions can be drawn from available data that one type of program is better than the other for newsprint.
The list of materials managed is not identical in all municipalities but, for the most part, matches up reasonably well, i.e., does not favour single-stream or two-stream programs.
The mounting evidence against mixing all recyclables together is compelling. Consequently, some municipalities have decided not to make the shift to single-stream.
Ottawa, as an example, operates a two-stream collection system. Faced with the possibility of converting to single-stream, the city conducted a public survey to see what residents would prefer. The community supported maintaining the existing system, which collects containers and fibres separately on alternating weeks. By maintaining the separate collection system and reducing garbage collection to once every two weeks, the city is expected to save taxpayers $9 million annually over the next six years, and will preserve the life of its landfill.
In 2006, the City of London, Ontario undertook a comprehensive review of their recycling system, with key goals being to reduce program cost, increase the capture of recyclable materials and add new materials. London had a two-stream system where fibres are kept separate from containers. The analysis concluded that a two-stream collection system would be the most appropriate for London compared with single-stream collection, as it would reduce processing costs, produce better quality material for final markets, capture more recyclables (i.e., less recyclables going to residue or mixed with the end product) and have minimal impacts on collection. Limited to zero savings were expected from single- stream collection as the city expected to continue to have a dedicated blue box collection vehicle and not co-collect recyclables with garbage or source-separated organics.
The new state-of-art two-stream MRF has been operating for 15 months. The program has reduced London’s processing costs by about 10 per cent and, on average, the price paid for recyclables from London exceeds the StewardEdge Composite Price by 15 per cent per tonne.
In Europe, there are a few examples of communities that have actually switched
back to two- stream collection (sometimes called “un-mingled” there). The town of Torbay, Northampton, and Cheshire West and Chester in the UK all recently decided to “un-mingle” their collection programs.
Closer to home, Auburn, Maine also un-mingled its collection; Berkley California, Walpole and Boylston, Massachusetts, Fryeburg and Concord, New Hampshire and Roseville, Minnesota are all examples of communities that chose to keep their two-stream programs after a thorough review of the benefits that single-stream proposed to offer.
The cost differential between the two systems not only continues to favour two -stream recycling, but it appears the gap is widening. The ever-more pronounced premium paid for single-stream comes without any real diversion benefits, or revenue benefits. Looking at Toronto’s latest processing tender results shows single-stream recycling is about to substantially increase this disparity even more. With an ever-increasing list of materials to be managed in the future, it’s easy to see that single-stream approaches will not control costs compared to two-stream.
Separation of fibres and containers from a single, mixed stream of materials is reasonably possible. However, add in flexible packaging, and the task becomes more than challenging. Flexibles (e.g., pouches, films, etc.) act similar in air to single sheets of fibre and create operational challenges when using rotating screens (which are commonly used in single-stream to separate fibres from containers). In two-stream programs, the flexibles could be added to the container stream and removed with a combination of trommels and air, leaving the rigids to be processed with magnets, eddy currents and optical sorters.
Consider the changing fibre stream and the dramatic decrease in newspaper in the mix (less than half what was generated just ten years ago). Less and less processing of fibres will be necessary in future. MRFs will simply remove OCC using an inexpensive OCC screen and bale the rest. (The last City of Toronto and Region of Durham RFPs required only OCC and mixed paper to be generated. ONP is no longer a recognized marketable commodity.)
So why “force” the sorting of 100 per cent of the recyclables, when only the container stream now requires any significant infrastructure? A recycling system where fibres and containers are separated at the curb means much less overall infrastructure and, ultimately, much lower overall costs. Alternating weekly collection of fibres and containers or split carts (for those looking for cart collection) can ensure collection costs are on par with single-stream.
Lower costs, similar diversion, much more flexibility to add more materials in a more cost effective manner…
Going single stream? Cheque please!
Clarissa Morawski is Principal of CM Consulting in Peterborough, Ontario. Contact Clarissa at firstname.lastname@example.org
Dan Lantz is VP Operations at Cascades Recovery Inc. in Toronto, Ontario. Contact Dan at email@example.com