Single stream recycling means that recyclables are not sorted by customers and are collected in one fell swoop by recyclers. An example of single stream recycling would be if you have one bin in which you put your office paper, newspaper, plastics, cans, glass, and metal. This is probably the most common form of recycling that Margaret and I have seen in the US.
Dual or multi stream recycling means that some materials are sorted by customers and/or collected separately by recyclers. For instance in some places papers are collected separately from plastics, glass, and metals. In Bellingham, newspaper is collected in one bin, office paper in another, and plastics, metals, and glass in another.
With single stream recycling you usually save on collection costs. Only one truck is needed to collect the items and it can use a compactor so it can collect a lot more on a single run. In dual or multi stream recycling, you might need a separate truck for some materials or you have partitions in a single truck to keep everything separate, which makes it a lot harder to compact the materials, meaning more trips to gather the same amount of material.
The trade-off is that with single stream recycling your transportation cost savings result in a lower-grade product that recyclers can sell because they have a more difficult time sorting the materials into separate categories. The more materials are mixed together the harder a recycling facility has to work to produce a clean, pure product. Dirty products with lots of contaminants in them are hard to sell.
When we were visiting with GreenBlue in Charlottesville, Virginia, I got the impression that single stream was going to be the wave of the future. Nina Goodrich, the executive director, told us that didn’t think the US would ever move back towards dual or multi stream recycling. Nina was also convinced that we have the technology to effectively sort commingled materials.
Scott Horne, VP of Government Relations and General Counsel for the Institute of Scrap Recycling Industries (ISRI) didn’t think that single stream was the solution. While shredder technologies (for recycling things like cars and major appliances) have advanced by leaps and bounds, Scott thought that the technology for sorting single stream materials really wasn’t advanced enough to be efficient, and he couldn’t say when it would get there.
It seems to me that the trend towards commingled collection of recyclables is being powered by a desire to make recycling easy, and perhaps by the relatively high prices recyclables have commanded in the last decade. For myself, I think we are better off the more we sort. It doesn’t take too much time to keep your paper separate from your glass (glass shards are almost impossible to remove from paper, but ruin paper-making machinery). If we have the opportunity to keep our materials separate it seems to make the most sense to separate.