Contamination Challenges

Producers’ and consumers’ assumptions are hurting single-stream recycling.

Bryan Staley, President

September 11, 2014

4 Min Read
Contamination Challenges

The ultimate goal of recycling is minimizing the need for raw resources in the production of products. Reductions in the mining of raw materials and the production of virgin products often result in substantial energy and emissions savings—as well as cost savings from avoided environmental compliance practices.

Global markets readily gobble up recovered commodities for the manufacturing of new products. Often manufacturers look to recovered materials for cost savings, marketability of an eco-product or to meet emissions compliance requirements. In the late 1990s, the growing number of markets for recovered commodities was reinforced with new opportunities to reduce collection costs and the industry’s desire to increase recovery efficiencies, resulting in the single-stream collection strategy for recyclables.

However, challenges remain for single-stream collection, which initially received impetus from the notion that heightened convenience would directly result in greater participation curbside. The challenges relate primarily to 1) a lack of consideration in the design of materials that are destined to be discards, such as packaging materials and containers, and 2) the issue of contamination that occurs as a part of recycling collection activities. Recycling contaminants are generally defined as unrecyclable materials that must be separated from recyclable materials or problematic materials, such as plastic films and broken glass, which jam equipment or create excessive wear and tear at material recovery facilities.

Indirectly, contamination residuals also threaten to reduce commodity prices. Optimized profitability of the materials recovery business requires reduced operational costs for collection and processing, and increased commodity prices. There has been a lot of concern about the long-term economic sustainability of this commodity-price-driven revenue model. Residuals increase operational costs for collection and processing, and potentially negatively affect commodity prices. Two studies published by the Resource Association and the State of Oregon Department of Environmental Quality reviewed recycling commodity prices and found that materials sourced from commingled collection systems, especially paper, was valued lower than recovered material sourced from dual-stream or multi-stream collection systems. This suggests that the increased volume gained with single-stream must be evaluated against the reduced quality of the recovered material and the lower revenue per ton that may result.

Another big issue is awareness. The general public is unaware of the recovery business’s intricacies. Most people assume that if an item is accepted at one location then it’s accepted at any location, which may be the root of the plastic film problem. Since grocers accept plastic bags, people tend to assume that plastic bags are recyclable. Also, many people don’t understand the differences in resins. Plastic is plastic, people figure, so if a soda bottle is recyclable, then a drinking straw should be recyclable as well.

Ultimately, contamination issues lead back to producer responsibility. Product manufacturers need to understand better how the packaging they produce is managed at end-of-life and the supply-and-demand issues with specific recyclables. For example, there is a higher demand for #1 and #2 plastics than for #3, #4, #5, #6 and #7 plastics. There are also regional differences in what can be recycled, and resulting labeling issues. For example, some areas recycle #6 plastic, but others do not, yet many #6 plastics have an SPI code enclosed in the universal recycling symbol, which is confusing. Thus, educating the general public and upstream manufacturing sectors is a key aspect in minimizing contamination in the long run.

Some cities have even coupled enforcement activities with education, such as Longview, Wash., which experienced a contamination rate of 45 percent at one point. In response, the city initiated a program of random recycling inspections conducted at curbside. If non-recyclables are found in a recycling bin, an educational notice is attached to the bin detailing items that are acceptable for recovery, and a random follow-up inspection is conducted. If non-recyclables are found again, the recycling bin is removed and the occupant’s billing status is changed to garbage-only with a $10 rate increase per month for six months.

Providing better education to the general public and improving the dialogue between the manufacturing and waste industries is critical to increase waste management efficiency in the long run. 

Bryan Staley, P.E., Ph.D., is president of the Environmental Research and Education Foundation (, a nonprofit foundation that funds and directs scientific research and educational initiatives to benefit industry participants and the communities they serve.

Heather Troutman recently graduated with a bachelor’s degree in environmental science from North Carolina State University. She will soon begin a Master of Science program in resource efficiency in architecture and planning at HafenCity University in Hamburg, Germany, with a focus on lifecycle design in products and urban systems.

About the Author(s)

Bryan Staley

President, Environmental Research and Education Foundation

Bryan Staley, P.E., is president of the Environmental Research and Education Foundation, a non-profit foundation that funds and directs scientific research and educational initiatives to benefit industry participants and the communities they serve.

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