Defining Recycling in the Context of Plastics


  • Valiante, U., Gies, G., Moreside, E. (2021). Defining Recycling in the Context of Plastics. A Principled and Practical Approach. Canadian Standards Association, Toronto, ON.

Executive Summary

There is no consistent definition of recycling in Canada. Many of the definitions in current usage include a long list of possible activities (e.g., collecting, transporting, handling, storing, disassembling, dismantling, sorting, separating, shredding, processing, remanufacturing) that create confusion about which step constitutes “recycling” and whether “recycling” has occurred at the completion of any step.

A clear definition of recycling is important to both public policymakers that are seeking to achieve specific environmental outcomes associated with recycling of materials and to the regulated community that must deliver them. It is also of importance to the plastics recycling sector as it will determine plastics collection, sorting, and recycling supply chain design and attendant infrastructure investments towards driving a circular economy for plastics in Canada. As such, the purpose of this research study is to propose a definition of recycling that can be used to develop a plastics recycling standard.

The research for this report was conducted by undertaking a scan of the scientific and technical literature to summarize the physical and chemical processes to make and recycle plastics, a review of existing definitions of recycling, and a jurisdictional scan of various definitions of recycling adopted by the European Union, ten American states, and all Canadian provinces and territories. In addition, a questionnaire-based survey was conducted of the production, use, and recycling value chain of plastic packaging to understand its views on the definition of recycling.

Fossil-based plastics – polyethylene, polypropylene, polystyrene, etc. – are highly ordered molecules not found in nature. They are created by using energy (primarily from fossil resources) to reform base hydrocarbons found in oil and natural gas as well as other elements into monomers (single-unit molecular building blocks) and polymers (chain-like structures made of single-unit molecular plastic building blocks).

Plastics may also be produced from biological sources (typically plant-based biomass). These can be manufactured as either biodegradable plastics (broken down by the action of bacteria or other living organisms) or as chemically identical “drop-in” substitutes for fossil-based plastics such as polyethylene terephthalate (PET). These chemically identical biomass-derived fossil plastic substitutes can be recycled in conventional recycling systems that typically recycle fossil-based plastics.

Under circular economy (CE) principles, recycling takes different forms for fossil-based and non-fossil plastics. For fossil-based plastics, the objective is to use renewable energy to reclaim fossil resources and avoid the waste (e.g., GHG, other air pollutants, effluents) associated with its production from fossil resources, while minimizing how much of the same wastes are generated in undertaking that reclamation. For non-fossil (bio-based) plastics, the objective is to return nutrients in those plastics to biological systems to support regeneration or to reclaim the hydrocarbons in those plastics to displace the use of primary or raw materials.

All plastics (fossil or bio-based) and all plastics recycling methods and technologies either in use or just emerging can be evaluated within the CE framework of recycling.

Consistent with CE principles, the following working definition of recycling is proposed:

Recycling is the reclamation of materials in such a manner that they can be used to displace the primary or raw materials they were produced from.

In the context of plastics, this definition can be stated as:

Recycling is the reclamation of plastics (as polymer, monomer, or constituent chemical building blocks) in such a manner that they displace the primary or raw materials that are used as chemical building blocks in the production of plastics and plastic products and packaging.

In the context of bio-based plastics, this definition can be stated as:

Organic recycling is the processing of bio-based plastics into biological nutrients.

Under circular economy principles, only organic recycling of bio-based plastics is recognized as recycling. The definition of recycling in the context of its production pathways is summarized in Figure E1.


A square with four quadrants is depicted. The left-hand quadrants represent organic recycling. The right-hand quadrants represent mechanical and chemical recycling. The upper quadrants represent bio-based recycling. The lower quadrants represent fossil-based recycling. Long description: Text within the quadrants are as follows: Upper left (bio-based, organic recycling) = biological nutrients. This quadrant is shaded green. Lower left (fossil-based, organic recycling) = not recycling (fossil plastics converted into a net loading of greenhouse gases to the environment). Upper right (bio-based, mechanical and chemical recycling) and lower right (fossil-based, mechanical and chemical recycling) = polymer, monomer or constituent chemical building blocks to displace primary or raw materials in the production of plastics. These quadrants are shaded blue.


Figure E1: Production and recycling of plastics

A recycling standard built upon the proposed definition will require the following elements to be developed as part of the standard:

  • Specifications for reporting the amount of plastic supplied into the market;
  • A specification establishing a measurement point where plastics are deemed recycled consistent with the definition of recycling;
  • A specification for calculating the recycling rate as the amount of recycled plastic produced at the measuring point expressed as a percentage of the total amount of plastic supplied into the market;
  • Specifications or performing mass balance calculations in chemical recycling pathways where recycled chemical carriers are produced and blended into virgin production supply chains. Such rules are not only critical for verifying the recycling of plastics but also for establishing claims of plastics recycled content made by producers of resins and plastic products; and
  • Specifications and standards for verifying the processing of non-fossil, bio-based plastics into biological nutrients.

Development of such rules will require broad industry consultation with producers of products using plastics or plastic packaging, mechanical and chemical recyclers of plastics, and plastic resin producers.