I’ve been recycling since I was in grade school in the late 1950s. As a school project, we collected and sorted newspapers and magazines. In college, we recycled aluminum cans. By the mid-1970s, I was separating and recycling paper, aluminum and glass. The sorting was not very difficult, but it did require me to have separate containers in my garage.
More recently, we’ve seen the advent of comingled recycling. In dual-stream recycling, all types of cans and bottles are in one container and all types of papers in the next. In single-stream recycling, everything you want to recycle is collected in one container. With both of these approaches, non-recyclables (i.e., garbage) are collected separately and go straight to the landfill).
Suspecting that recycling is a marginal business, I have worried that these comingled approaches must be less profitable, since a lot of sorting must be done off-site. The advantage is that a lot more people will participate if they don’t have to sort their materials. By one estimate, recycling rates go up 50% in the switch from dual-stream to single-stream recycling (Fitzgerald et al. 2012). Greater recycling means there is less demand for land-fill space. Single-stream recycling can also reduce the number of trucks that make the weekly trip to your neighborhood, each using diesel fuel and emitting CO2 to the atmosphere. Switching from dual- to single-stream recycling is estimated to reduce CO2 emissions by 0.71 tons per ton of collected material.
Unfortunately, people tend to be lazy, so garbage is found in single-stream recycling bins, which contaminates the collected materials and increases the amount of material that must be diverted to the landfill. Even if done properly, glass bottles tend to contaminate the collections of newspaper and card-board, reducing its value as a recycled material. On April 23, 2015, the Wall Street Journal ran a story on how glass contaminants were increasing the costs of recycling, potentially driving some contractors out of business. Glass is valued as a recycled commodity, but marginal in value.
An analysis by Pressley et al. (2015) gives us some useful statistics on the recycling business. I was somewhat surprised to find that the cost per ton to pull useful materials out of mixed garbage (i.e., no sorting of any kind) was about the same as the cost to process the same weight of either single- or dual-stream materials collected for recycling ($23.4 to $24.9 per metric ton). The difference is that about 76% of the material in mixed garbage goes to the landfill, versus only 10-11% for comingled collections.
With old-fashioned pre-sorted recycling, about 35% of the total waste stream is collected for recycling and 65% is garbage that goes to the landfill. For the recycled materials only 2% remains after processing. So, the overall amount going to landfill is about 67%.
In programs with dual-stream recycling, 65% of the total waste stream is garbage that is directly land-filled, but about 90% of the comingled materials are recycled, so the overall landfill rate is about 69%. With its higher levels of participation, single-stream recycling results in a landfill rate of about 55%. So, sorting makes only a small difference, which is easily exceeded if people are willing to recycle 50% more material in comingled form.
The recycling rate in the U.S. varies among materials: more than 95% of lead-acid batteries are recycled, 55% of beverage cans, and about 30% of various types of plastic bottles. Recycled materials reduce the use of energy needed to mine new materials from the Earth, with the associated disruption that mining causes to land and water. The recycling industry operates with narrow margins between the costs of collection and separation and the value of the materials that can be sold for reprocessing.
At all costs, we should pursue collection regimes that preserve the profitability of this business. Otherwise, recycling will fall back onto municipalities, where it is not likely to compete favorably against the host of other public services that people demand, and not likely to survive in the face of the increasing conservative pressures to privatize public activities.
Environmental Protection Agency. 2014. Municipal sold waster generation, recycling, and disposal in the United States: facts and figures for 2012. US-EPA-530-F-14-001, Washington, DC
Fitzgerald, G.C., J.S. Krones, and N.J. Themelis. 2012. Greenhouse gas impact of dual stream and single stream collection and separation of recyclables. Resource Conservation and Recycling 69: 50-56.
Pressley, P.N., J.W. Levis, A. Damgaard, M.A. Barlaz, and J.F. DeCarolis. 2015. Analysis of material recovery facilities for use in life-cycle assessment. Waste Management 35: 307-317.