CRI releases study on impact of single stream recycling
The Container Recycling Institute (CRI) has undertaken
a study of the impact of single stream collection of
residential recyclables. CRI selected Clarissa Morawski,
principal of CM Consulting, to research the issue. Morawski
reviewed 60 previously published studies, reports and
articles in trade publications. The report finds that
there are many negative downstream impacts of contaminated
stock due to the mixing of the materials at curbsite.
“Basically, the report confirms that you can’t unscramble
an egg,” explained CRI executive director Susan Collins.
“Once the materials are mixed together in a single-stream
recycling system, there will be cross contamination of
materials and glass breakage. These issues then result
in increased costs for the secondary processors.”
The report describes the evolution of single-stream recycling
in the United States, the recent downturn in the scrap
market for all recyclable materials, and explains factors
affecting collection costs. The real purpose of the study,
however, is to examine the impacts of single stream recycling,
as compared to other methods, on every step of the recycling
Initial ease of collection and collection costs;
Contamination rates and overall material yield at
material recovery facilities (MRFs);
Impacts on material yield at paper mills;
Impacts on yield at plastics processors;
Impacts on paper mills, on quality, quantity, equipment
maintenance and costs;
Impacts on aluminum processors on contamination
levels, resulting equipment shutdowns, and profit
Impacts on glass, including color mixing, suitability
for certain end-uses, and increased operating costs;
Impacts on plastic quality and costs.
Recycling’s real purpose is remanufacturing and end use.
Most lay people, and perhaps most local officials, assume
that all recycled items go to their best use. They are
shocked to learn that the materials they dutifully put
in a recycling bin may in fact wind up in a landfill.
The key to achieving the environmental and economic benefits
of recycling is to keep the material circulating for
as many product lives as possible. This is the closed
loop that reduces the need for virgin materials, thus
avoiding the energy consumption and greenhouse gas emissions
associated with primary materials extraction, transportation
Ensuring that secondary recovered recyclables are utilized
for the highest possible end-use is a critical part of
successful diversion. For plastic, high-end uses can
have ten to twenty times the environmental benefit in
terms of the replacement of virgin materials and those
avoided upstream impacts. Using glass to make containers
saves much more energy than using recycled glass for
The historical focus of residential recycling (in the
1990’s) has been on keeping materials out of landfills.
This led to creating systems that could collect the greatest
volume of material, with less of a focus on final end-use
of the materials.
In an effort to increase recycling volumes and reduce
high recycling collection costs, the waste management
sector created single stream recycling collection, which
increases efficiencies by collecting more material with
less labor and less distance traveled. Automated single
stream collection can reduce the number of employees,
improve route efficiency, and reduce workers compensation
costs. Single stream can encourage residents to place
more material in their recycling bin by giving them a
larger bin and by simplifying the system.
Glass is the material most affected by the amount of
breakage in each type of collection system.
In single-stream programs, it is virtually impossible
to prevent glass from breaking as it goes to the curb,
is dumped in the truck, gets compacted, gets dumped on
the tipping floor of the MRF, is driven over by forklifts,
and is dumped on conveyor belts to be processed by the
MRF. On average, 40 percent of glass from single-stream
collection winds up in landfills, while 20 percent is
small broken glass used for low-end applications.
Only 40 percent is recycled into containers and fiberglass.
About one third of the non-recyclable glass is broken
glass, too small to separate for recycling, some of which
can be used for sandblasting base, aggregate material,
or Alternative Daily Cover (ADC). These ―down-cycled
uses do not have the same savings in terms of energy
conservation and avoided emissions. In contrast, dual-stream
systems have an average yield of 90 percent, and container-deposit
systems yield 98 percent glass available for use in bottlemaking.
In general, the final commodities from single stream
programs will be more contaminated than those that are
collected in a dual-stream system or sorted at the curb.
This contamination increase often results in the commodity
being worth less than cleaner material, and can create
problems at paper mills, leading to equipment failure,
lost productivity and expensive repairs. In other words,
the cost savings for a municipality from single-stream
collection show up as cost increases for the processors
and remanufacturers. The contaminants are thrown away
by the paper mills. So an item, such as a plastic bottle
that was recyclable when it was placed at the curb, becomes
trash by the time it is sorted as a contaminant by the
A study conducted in 2002 by Eureka Recycling (of St.
Paul, Minnesota) compared five different collection methods,
and found that single-stream collected 21 percent more
material than the baseline method. However, the study
did not ultimately recommend a single-stream system,
because the lower collection costs were outweighed by
higher processing costs and lower material revenues.
In another study, Daniel Lantz of Ontario, Canada-based
Metro Waste Paper Recovery analyzed recovery rates for
three single-stream and four dual-stream programs in
that province. The study found that a drop in collection
costs sees a commensurate rise in processing costs. In
a recent article, Lantz concluded that the supposed benefits
of single-stream systems over dual-stream do not outweigh
―In summary, with increased processing costs and lost
revenues in total far exceeding collection savings in
most instances (and zero under alternating-week collection),
overall single-stream recycling does not show the cost
advantage that was originally anticipated. As well, the
expected increases in capture rate are also not apparent.
Overall, dual-stream recycling still appears to be more
In spite of these challenging conditions and their impact
on the current demand for recyclables, recycling continues
to be a vital component of a national strategy to conserve
resources, supply the manufacturing base and reduce greenhouse
gas emissions, toxics and waste going to landfills and
Manufacturers of new glass, metal, plastic and fiber
products continue to encourage clean collection so that
they can use secondary feedstock instead of virgin material
for remanufacturing. While manufacturers will continue
to invest capital into their systems to increase recycled
inputs, these investments will remain contingent upon
a regular supply of clean material.
The upstream environmental benefit of remanufacturing
materials is 10 to 20 times greater than downcycled or
More simply put, when a product is made from recycled
material, the use of virgin materials is not required.
Therefore, all the upstream energy and associated environmental
impacts from the extraction, transport and processing
of those virgin materials are not required, or ―avoided.