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Recycling PET Clamshells

The clear plastic clamshell. Other than bottled water, I’m not sure anything instills a more divisive reaction on campus. It is the darling of many to-go food packagers and dining managers for its display properties, a chance to showcase the care that went into making a food item. For many campus diners, it allows for portability and mobility for a wide variety of dietary choices, not just the previously available paper-wrapped deli sandwich. Yet clamshells have also been the bane of many campus environmental groups, a very visual sign of the wastes associated with grab-n-go dining, and the target of many environmental initiatives. Clamshells can also be a source of frustration for cleaning crews and their managers. Wastebasket size trash cans that used to be sufficient for classroom or meeting room trash, now quickly overflow from just a few of these high-volume, low-density items as food consumption leaves traditional dining areas and moves to these other areas of campus.

“Green dining” initiatives often focus on alternatives, but many of the alternatives are at best imperfect.

There are some fantastic paper to-go containers that look like variations of the folded-paper Chinese food take-out containers. These paper containers are often both functional and compostable. And as paper products, in the compost, the offer a source of carbon to offset the nitrogen-rich food waste, which make them attractive to many composting programs. Unfortunately, these do not offer the display qualities that many dining managers and diners have come to expect.

PLA plastic offers display qualities and biodegradability, but has its own share of issues. In a landfill, that biodegradability is not necessarily a desired trait. PLA plastics compost in lab situations, but many real-world composting options have found that PLA, especially thick PLA like clamshells does not break down in a time frame that is compatible with the other food wastes and bulking agents that are going into the compost (and if your food is managed via anaerobic digestion, the digester may not generate enough heat for this PLA to degrade at all). If diners mistakenly place their PLA clamshells into the recycling, that PLA is a contaminant to other plastic recycling efforts. And the feedstocks that go into some PLA plastics are frequently-enough sourced from genetically modified crops or that too-often displace food crops. As such, with PLA, you may find that the student environmentalists that you are trying to appease and that you are counting on to support your “green dining” initiative end up being your biggest opponents.

But what if your “green dining” display package was the PET clamshell that you were already using? Demand for recycled PET plastic has led many plastics recyclers to look beyond just PET soda and water bottles to other forms of PET packaging. One of those emerging PET recycling markets is PET clamshells.

Perhaps surprisingly, one of the biggest barriers to PET clamshell recycling has traditionally been adhesives. Any of you Blues Brothers fans out there can cue up the mental image of Elwood holding the can of spray epoxy stating, “this is glue, strong stuff.” The adhesives traditionally used in the deli stickers that are typically placed on such clamshells are really strong, so much so that it impacts the recyclability of the clamshell itself. But a solution may be almost here. In November 2011, the Canadian grocers Association approved three adhesives designed to facilitate clamshell recycling. So far the results have been successful, enough so that some Canadian cities, including Toronto, Ottawa, and Calgary have added clamshells to their curbside recycling programs. Will those adhesives gain sufficient widespread acceptance in US to allow for a similar growth in clamshell recycling in the near future?

However, even if the adhesive issue is resolved, there are some other issues to be cautious of before you rush out and buy a trailerload of new PET clamshells thinking they will be recyclable. Chances are, you are not shipping directly to market. A “market-load” of material is a tractor trailer load (about 44 bales) of material. As I note in my 2-part logistics blog, there are a lot of shipping and storage issues to consider that will limit many schools ability to ship directly to market. That means that your PET clamshell recycling will involve mixing them into your other bottles & cans or single stream recycling.

That leaves you at the mercy of your local recycling program and MRF operator. If they haven’t added PET clamshells to their commingled container or single stream collection, you may be stuck until they do. Having said that, I would encourage you to reach out to your MRF operator, express your interest, and see what you can do in terms of helping them to pilot clamshell recycling.

Even if your MRF says yes, one of the biggest issues with any clamshell collection is going to be the logistics of collection. The whole point of to-go dining is that it is designed to take materials away from a central area. That to me is one of the big advantages to using recyclable PET clamshells over other compostable alternatives. Unless you are just starting out, chances are you already have recycling bins all around campus. To capture compostable clamshells, you have to develop a whole new composting collection system all across campus. That includes establishing composting in some areas in which I am not convinced that collection is viable given the putrescible nature of the other compostable materials, and the frequency with which pickup is needed to avoid pest and odor issues. To capture PET clamshells for recycling, you have to add them to an existing recycling collection infrastructure – I like those chances better for many schools. The biggest issue with the clamshells is going to be volume. They take up a lot of space which means that collection bins will overflow more often or need to be augmented or resized. And clamshells don’t fit well with existing bottle & can restrictive openings (which are typically round holes). To start, until the kinks can be worked out, it might warrant adding another recycling bin at existing collection locations for these oversized recyclable plastics.

Resin identification is likely to be another big issue with PET clamshell recycling. There are a lot of look-alike clear plastics out there that are significant contaminants to PET recycling that are difficult or impossible for most people to visually identify. That includes PVC, PP, and ironically, the proliferation of “green” PLA plastic clamshells is likely to be an issue for PET plastic clamshell recycling.

“But” you protest, “we’ve gotten our campus trained to look at the resin codes on the bottom of bottles, can’t we just tell people to only include #1 plastic clamshells?” To the degree that people look at the resin codes that will definitely help. However, this may be one of those instances in which the resin codes are too general. My understanding is that there are some subsets of PET that are used in clamshells, like PET-G, that are used in some clamshells that have slightly different properties and will impact the recyclability of your clamshells. Some of those issues will materialize on the MRF side of things. But keep in mind that the more difficult these things are for them to sort, and the less collection, processing, and other logistics costs are competitive with virgin resin production, the less likely companies will be to add PET clamshells to their acceptable materials mix and/or the greater the degree to which these things will just be sorted out and discarded as waste at the MRF.

One huge advantage that most campuses have is that they have control over their on-campus foodservice. Thus, if you can work with your MRF operator to find a type (or types) of clamshells that work for them, you can specify their use on campus. That uniformity will be a big plus. To further make this viable, I would begin a dialog with both your local MRF operator and the other major grocery store chains in your area (the other big supplier of clamshells in your region). If you and the grocers can use the same spec container and label, that should give the MRF operator a lot of the uniformity that they will need to be able to market this material (though keep in mind they still have a significant issue figuring out how to sort clamshells out of other recyclables and how to bale this material and how to finance any of the capital equipment required to do either of those things).

A pearl of many to-go dining initiatives is a container that is both compatible with green dining efforts and has the display properties that dining managers are looking for. There is potential that the pearl you are looking for is in the PET clamshell you are already using.

Written by

Roger Guzowski
Roger Guzowski

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