Plastic is ubiquitous in daily life, appearing in countless products and packaging. While recycling plays an important role in environmental efforts, it is often misunderstood as a universal solution for all plastic waste. Not all plastics are accepted in standard recycling programs, which can lead to confusion for consumers attempting to dispose of items responsibly. This article aims to clarify which plastics are not recyclable and the underlying reasons for these limitations.
How Plastics Are Identified
Plastics are identified by Resin Identification Codes (RICs), symbols featuring a chasing arrows triangle with a number inside. This system, standardized by ASTM International (ASTM D7611), indicates the type of plastic resin used. The presence of an RIC symbol does not automatically signify an item is recyclable; it identifies the plastic’s composition.
The codes range from 1 to 7, each corresponding to a specific polymer type. For instance, #1 is polyethylene terephthalate (PET), found in beverage bottles, and #2 is high-density polyethylene (HDPE), used for milk jugs. Local recycling facilities have varying capabilities, so plastics accepted in one area might not be in another. Understanding these codes helps identify the material, but local guidelines determine actual recyclability.
Types of Plastic Generally Not Recycled
Several plastic types and forms are not accepted in curbside recycling programs. Polyvinyl chloride (PVC), marked with the number 3, is used in pipes, blister packaging, and some flexible items. This plastic is difficult to recycle due to its chlorine content and potential to damage recycling equipment. Polystyrene (PS), identified by the number 6, includes rigid plastics and foamed materials like Styrofoam used for disposable cups and takeout containers. It presents challenges because it is lightweight, bulky, and easily breaks into small, contaminating pieces.
The “Other” category, number 7, encompasses various plastics, including polycarbonates, multi-layer packaging, and mixed plastics. The diverse and often unknown compositions within this category make sorting and processing difficult for standard recycling facilities.
Beyond these specific codes, certain forms of plastic are also largely non-recyclable in curbside bins. Plastic films and bags, even if made from otherwise recyclable resins like #2 or #4, tangle in sorting machinery. Small plastic items, such as bottle caps, straws, and cutlery, often fall through sorting equipment, preventing them from being processed. Multi-material packaging, such as pouches or coffee pods, are also challenging to recycle because their components cannot be easily separated.
Why Some Plastics Are Not Recycled
The reasons behind a plastic’s non-recyclability are multifaceted, stemming from material composition, processing challenges, and economic factors. The chemical structure of some plastics, like PVC, includes chlorine, which can release harmful substances and degrade the quality of other plastics if mixed. Different plastic types melt at varying temperatures, making it difficult to process mixed plastics without compromising material quality. Optical sorters, which identify plastics, can also struggle with certain materials, such as dark-colored plastics, reducing sorting efficiency.
Contamination from food waste, labels, or other non-plastic elements significantly reduces the purity and value of recycled plastic, often rendering entire batches unusable. Small or flimsy items, such as plastic film or tiny bottle caps, frequently clog or bypass mechanical sorting equipment, leading to operational inefficiencies and potential machinery damage.
The economic viability of recycling also plays a significant role. The low market value for certain recycled plastics, especially those that are bulky or require extensive cleaning, often makes their processing more expensive than producing new plastic from virgin materials. In many regions, the infrastructure for collecting and processing less common or more complex plastic types is limited, further hindering their recycling.
Disposing of Non-Recyclable Plastics
For plastics that cannot be recycled through conventional means, the most effective approach is to reduce their consumption. Opting for reusable alternatives helps minimize the amount of non-recyclable plastic entering the waste stream.
For certain materials, specialized collection programs offer alternatives to landfill disposal. Grocery stores and retailers provide drop-off points for plastic bags and films made from #2 and #4 plastics, which can be recycled into products like composite lumber. Companies like TerraCycle offer mail-back programs for hard-to-recycle items, including snack wrappers, coffee pods, and toothbrushes, through partnerships with brands or for a fee. For very specific or potentially hazardous plastic waste, such as containers that held chemicals, local hazardous waste collection events may be available. Ultimately, for many non-recyclable plastics, the general waste bin leading to a landfill remains the primary disposal method, emphasizing the importance of responsible consumption and waste prevention.