Improving commingled recycling in Washington

We are working with local governments and recycling companies to identify ways to improve residential commingled recycling in Washington.

Using commingled recyclables

The challenge with commingled collection systems is that differing recyclables are mixed together. Recyclables must be separated to sell back to manufacturers who make then into new products and packaging. Whether commingled collection systems are here to stay is not in question. Improving the systems so that higher quality materials enter the materials recovery facility is important. This results in more materials being sent on to the intended manufacturers where the actual recycling occurs.

Benefits of a commingled system

For a collection system, there are many benefits for choosing an automated, "single bin" approach:

  • The collection trucks can compact all the materials together, rather than having to leave their route to empty the entire truckload when only one material type has reached capacity.
  • Commingled collection also reduces worker injuries and improves collection route time, which lowers costs for collection. Because there is less or no sorting required by residents, there is increased participation.
  • The increased capacity of recycling bins in commingled systems allows for higher collection volumes and the ability for programs to add new types of recyclables without having to invest in multiple bins.
  • Commingled bins have a lid and wheels, which improves public convenience and privacy, and prevents material from blowing out of the bins.
  • Bins also keep pests from getting in, keep materials drier, and makes the recyclables easier to process and worth more in the marketplace.

Limitations of a commingled system

The major limitation of a commingled recycling system is that when items are mixed together, they must then be separated. Many of the benefits on the collection side of the system can cause problems for the processor and, in turn, the end-use manufacturers.

  • Materials like glass, plastic film, and flattened containers are difficult to separate once mixed together, and can cause problems with equipment, and cross-contamination of other materials, especially paper.
  • The increase in collection volumes and participation can overwhelm the processing system, causing cross-contamination, an increase in non-program materials, and ultimately, "lost" recyclables.
  • Jurisdictions often have variations in what materials are considered recyclable. This causes confusion for residents and making it more difficult for the processors to rely on a consistent mix which aids in sorting.
  • The savings achieved from the automated collection system result in higher shifted costs to the processors and mills. It is more labor intensive to sort and produces a lower quality material.
  • The capacity, shape and privacy of the cart might lead residents to use the recycling cart for excess garbage.
  • Because automated bins offer increased capacity, many jurisdictions that switch to commingled carts will often reduce garbage service to every-other-week, exacerbating the dumping issue - an unintended consequence.
  • Residents often hold the belief that everything can go in the recycling bin, and it will get sorted and recycled.
  • Mistakes can be made due to the visual similarity of garbage and recycling bins. Either way, direct feedback to the resident is much more difficult with an automated collection system.


Since 2009, Ecology has worked with local governments to assess and address these issues with the commingled recycling system. Workgroups in Southwest Washington and Northwest Washington separately developed reports and best management practices for recycling in their regions.