Plastic Packaging and Recycling
The use of plastics in packaging continues to grow, fueled by replacement of materials such as glass and steel with much lighter weight plastic containers. Additionally, replacement of rigid plastic systems with flexible packaging, either all-plastic or containing plastics in at least one layer, is common. While this typically brings savings in cost and provides weight reduction, it also may reduce the likelihood that the packages will be recycled at their end of life.
Figure 1 shows the increase in plastic packaging material use over time.
Figure 1. Packaging material changes over time in the U.S. (U.S. EPA, 2016)
This increase in plastics packaging use, along with problems associated with improper disposal, has resulted in increasing criticism of plastic packaging, and even calls to ban plastics packaging altogether. The purpose of this paper is to provide information on the current state of plastics packaging recycling in the U.S., and some comparison to recycling of other materials.
If we examine use of all types of packaging materials, plastics is currently second by weight, although paper and paperboard still account for more than half of all packaging, as shown in Figure 2.
Figure 2. U.S. packaging materials use in 2014 (U.S. EPA, 2016)
One of the things that makes recycling of plastic packaging materials complex is the variety of types of plastic that are used, as shown in Figure 3. For most end uses, the plastics must be separated by resin type, as the various resins are not compatible with each other.
Figure 3. Types of plastics used in packaging, 2014 (U.S. EPA, 2016)
Most recycling efforts target plastic bottles. Other forms of plastics packaging are collected and recycled at lower rates. The U.S. EPA categorizes packaging into 3 groups: containers (38.8% in 2014), bags, sacks and wraps (28.3% in 2014), and “other” which includes “coatings, closures, lids, PET cups, caps, clamshells, egg cartons, produce baskets, trays, shapes, loose fill, etc.” (U.S. EPA, 2016). The distribution of resin types varies dramatically by category. Containers are dominated by PET and HDPE, while bags, sacks and wraps are dominated by low density polyethylene, as shown in Figure 4. In the “other” category resin use is much more varied.
Figure 4. Resin use by packaging type, 2014 (U.S. EPA, 2016)
Effective recycling of plastic packaging requires that there be systems to collect the material, processing capacity to transform it into usable form, and end-use markets for the reprocessed material. Containers are easier to collect and to process than are flexible packages or the variety of forms in the “other” category, both because their weight:volume ratio is higher and because of the dominance of HDPE and PET, which simplifies the sortation process. Most major communities provide curbside recycling opportunities that include plastic containers.
While low and linear low density polyethylene dominate the “bags, sacks and wraps” category, these materials tend to be difficult to process in recycling facilities, and are most often collected through drop-off programs (merchandise bags) and from businesses (stretch wrap).
In the “other plastics packaging” category, recycling opportunities vary. Some curbside programs will accept a wide variety of plastic packaging (although they do not usually accept bags, films, or foams) while others are more limited. Most programs to accept items such as plastic caps (closures). Recycling of foams is generally limited to expanded polystyrene, and carried out through drop-off sites. Drop-off locations for collection of foams are more limited than for merchandise bags.
Figure 5 shows the overall 2014 U.S. plastics recycling rates as well as the breakdown by resin type and by category.
Figure 5. U.S. plastic packaging recycling rates, 2014 (U.S. EPA, 2016)
It should be noted that in 10 U.S. states many beverage containers are covered by deposit laws which provide a monetary incentive for consumers to return the empty containers to a collection site. Recycling rates for covered containers in such states are much higher than the overall U.S. average. For example, in California, the 2015 redemption rate for PET bottles was 77%. In Michigan, the overall redemption rate for covered containers was 94.2% (Bottle Bill Resource Guide, accessed 9/28/17).
While it is obvious that the ability to fulfilling the needed functions to protect the product and get it to the consumer is critical in design and selection of packaging systems, and the need to consider costs and availability is also obvious, increasingly those responsible for making packaging decisions are being called on to consider the environmental impacts of the decisions that they make. The fate of packages at the end of life – and as part of this, the likelihood that they will be recycled – is one of the aspects of environmental impact that should be considered in making such decisions.
References
1. Bottle Bill Resource Guide. (accessed 9/28/17). http://www.bottlebill.org/legislation/usa.htm.
2. U.S. EPA. (2016). Advancing Sustainable Materials Management: 2014 Tables and Figures.
Susan Selke, Ph.D. is a Professor and Director for the School of Packaging at MSU. You may reach her at sselke@msu.edu or visit her contributor page.
