Margaret Gainer: Conditions leading to recycling contamination

To improve efficiency of collecting more recyclables at the curb, in the early 2000s, many communities changed from source separation of all the materials before set-out on the street, to dual stream. 

With dual stream collection, paper and cardboard are sorted from the plastic, metal and glass beverage containers – with further separation after collection at materials recovery facilities (MRF). Arcata Community Recycling Center designed and built the MRF in Samoa for this purpose.

By 2009-2013, local governments across the United States and here in Humboldt County were wrestling with the difficult decision of whether or not to switch from recycling collection that required materials be separated by the consumer, to mixed recycling collection. Local government had important pros and cons to weigh. These considerations and unknown factors at the time have led to the current high contamination rate of recycling.


• When garbage haulers design recycling collection, they prefer single-stream recycling collection because it resembles garbage collection and requires less time and effort.

• Recycling advocates hoped that residents would perceive single-stream as increasing convenience and attract more people to participate, thereby increasing the amount of material recycled, and diverted from landfill. This was probably the biggest selling point.

• The MRF in Samoa was already built and could be adapted for the sorting required of mixed recycling loads after collection on the streets.

• It was anticipated that the simplicity of putting all recyclable materials in one container would reduce the numbers of phone calls from the public about proper sorting. This was especially desired by understaffed small towns.

• Standardized automated collection trucks and carts would improve efficiencies and reduce costs, including Workers Compensation claims for collectors who had previously lifted containers.


• While single-stream recyclables are less expensive to collect, they are more expensive to process than dual-stream recyclables. Mixed, single stream sorting facilities require more square footage, more extensive and expensive machinery, and more staff.

• Thirty years of public education and forming habits aimed at recycling quality control would be ditched. For avid recyclers, the very act of sorting was part of the definition of “recycling.”

Subscribe to the Mad River Union and enjoy online access to the full print edition for just $40/year!

• Mixing glass, plastics, paper grades, cardboard and metal would make it more difficult to develop local end-use markets for the materials. Local companies need clean materials to be able to integrate recycled feedstock into their manufacturing processes. This is the desired “Circular Economy” for our region.

• Recycling truckdrivers working on their collection routes would not likely have the time to provide the feedback needed to correct mistakes of contamination in recycling containers. 

Unknown Factors and Lessons Learned

• It was not certain that the MRF would be able to adequately sort the increased tonnage of materials collected to the specifications of the markets. Once mixed, materials cannot be completely “unmixed.” Broken glass in paper bales has made paper sourced from single-stream programs unpopular with paper mill operators.

• Several West Coast mills and manufacturers closed because their equipment damage and downtime caused by contaminated loads became more than they could afford to continue operating.

• By February 2013, China implemented “Operation Green Fence” inspections to enforce already existing regulations and reduce environmental pollution from the imported loads from the U.S. and other countries under the name of “recyclables.” Under China’s National Sword rule, it no longer permits imports of recyclables.

• The cost of virgin oil and natural gas became (and continues to be) cheaper for manufacturing plastics than for the plastic industry to manufacture with recyclable plastic.

• The content of food and beverage packaging entering the waste stream is continually changing; especially with single use plastics, new types of containers that are not recyclable, but look just like recyclables, are introduced regularly into the marketplace. This confuses both consumers and MRF sorters.

• The plastic packaging and food and beverage industries stepped up their greenwashing efforts to mislead the public about what is and isn’t recyclable. This includes passage of state laws that mandate use of the number plastic resin triangles (e.g. #1 PETE).

• It was not understood at the time how strong the urge for “wishcycling” would be – consumers putting nonrecyclable materials in the recycling container to feel good, in the hopes that it will be recycled.

I recently reached out to Mark Bowers, to learn about his 30 years of experience in the design, startup, and management of the Sunnyvale Materials Recovery and Transfer Station. When asked about contamination, Bowers explained that a “well-managed dual stream system will send 5-12 percent of collected material to landfill. The best single-stream systems landfill at least 15 percent residue, and 30 to 35 percent is typical. Some single-stream systems landfill more than 50 percent of the material collected.”

 Almost 10 years ago, Humboldt cities and the County made the decision to establish contracts with Recology and Humboldt Sanitation for Mixed/Single Stream Recycling Collection. Today, Humboldt County’s average recycling collection contamination rate is 25 percent. That means that a fourth of everything you think is being recycled is not. Environmentally and economically, this is not sustainable.

Margaret Gainer is the president of Zero Waste Humboldt.

Second in a series. Next week: What needs to be done, including what you can do to reduce our high recycling contamination rate.


Related posts