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The grease and cheese study that proved pizza box recyclability

Sponsored: A new study debunked the long-held myth that corrugated pizza boxes are unrecyclable. Now, they’re aiming for a slice of the recycling pie.


WestRock’s grease and cheese study found that pizza boxes can be recyclable. Image courtesy of WestRock

This article is sponsored by WestRock

In the United States, an estimated 3 billion pizzas delivered in corrugated pizza boxes are consumed each year. Taking into account the average weight and size of a standard box, that’s about 600,000 tons of corrugated cardboard going into circulation annually that ideally, we’d want to recover.

And although these boxes should be recyclable, only about 21 percent of recycling programs in the U.S. have clear and explicit acceptance guidelines for them. In addition, most consumers believe corrugated pizza boxes are not recyclable. Ask your average pizza eater and they’ll likely tell you the boxes need to be trashed due to the residue left behind from grease and cheese. The result is far too many pizza boxes in landfills and not enough in recycling facilities.

However, the fibers in high-quality corrugated board, the kind used to construct pizza boxes, can be recycled at least five to seven times. If we can change perceptions around the recyclability of these boxes, we can have a major impact on building a circular economy by putting valuable materials back into the fiber recovery stream. Doing so will require two efforts in tandem: increasing the number of municipalities that have clear acceptance guidelines for corrugated pizza boxes and educating consumers.

The reality about grease and cheese

In 2019, we challenged ourselves to consider how to take the world’s love of pizza and turn it into an opportunity to advance the circular economy and reduce waste.

We conducted a grease and cheese study to determine to what degree these two elements affected the quality of the fibers in the paper. What we found was that grease and cheese had minimal impact on fiber and therefore did not hinder its ability to be recycled.

Here’s the issue with grease: It’s hydrophobic (meaning it doesn’t mix well with water), so when it comprises about 20 percent of the weight concentration on corrugated pizza boxes, the paper experiences significant strength loss. That said, anything under 10 percent does minimal impact to the strength of the fibers, meaning they could be repulped to create new corrugated cardboard packaging.

Our study found that corrugated pizza boxes in the recycling stream have an average grease content of 1 to 2 percent by weight level. The fiber structures are barely affected by the residue left by the pizza.

"The results of the study support the conclusion that there is no significant reason to prohibit post-consumer pizza boxes from the recycling stream," concluded the American Forest & Paper Association (AF&PA), the national trade association of the paper and wood products industry, which peer reviewed and endorsed the study and ultimately awarded it an industry sustainability award for fiber recovery.

To get the word out about these findings, we worked with Domino’s to launch the website to share the facts about pizza box recycling. Our goal is to create a common understanding that empty, corrugated pizza boxes are recyclable, and to facilitate their acceptance in residential recycling programs. As a packaging provider, we are innovating towards a circular economy at every step of the way, but we need the partnership of both municipalities and consumers to help realize this goal.

Getting municipalities on board

This program is already sparking change. Just two months after launch, the news reached Suzanna Caldwell, a recycling coordinator for the Municipality of Anchorage Department of Solid Waste Services in Anchorage, Alaska. Inspired, Caldwell worked with her local recycling processor and waste hauler to accept pizza boxes for recycling starting in August 2020.

"Once this report was released," a Portland-based recycling company said of the grease and cheese study, "we confirmed that as long as there is no actual food inside the boxes, we could accept them in our facility to be recycled at the mills."

Still, misconceptions about the impact of grease and cheese have permeated deep into the recycling community, and municipalities are understandably cautious about the materials they accept to protect the functionality of their material recovery facilities (MRFs). Only 21 percent of U.S. geographies are served by programs that explicitly state acceptance of corrugated pizza boxes. Yet, 49 percent of geographies have guidelines that implicitly accept corrugated pizza boxes, meaning guidelines are not clear to consumers. With the results of this study, we hope that we can encourage more municipalities to explicitly accept pizza boxes in their guidelines.

To help encourage updates to municipal guidelines, The Recycling Partnership created the Pizza Box Recycling Toolkit in partnership with Pratt Industries. The toolkit includes messages and tools to educate municipalities and local communities about the fiber industry acceptance of and demand for recycled pizza box material. Municipalities, MRFs, haulers and other stakeholders in the recycling community are encouraged to use the toolkit to help facilitate change.

Changing consumer behavior

Explicit acceptance aside, consumer education remains a hurdle for increasing pizza box recycling.

As the actual recyclers or trashers of pizza boxes, consumers are a critical piece of the solution. Changing municipality acceptance guidelines is an important first step, but it must be followed up with consumer education efforts.

Our partnership with Domino’s is just one example of how multiple stakeholders with a vested interest in pizza box recyclability can come together to increase consumer awareness around this issue. Domino’s is a first-rate example around how a popular, well-loved brand can help influence meaningful change. We’d encourage more of our partners to consider supporting consumer education campaigns or helping push policy reform by contacting your local municipality.

Packaging materials can also be used to educate consumers — such as a printed recycling sign on boxes with a recommendation to check local guidelines. Performance Food Group, for example, uses WestRock’s Scan.Learn.Recycle. QR code on its packaging to make it easy for consumers to find and learn more about their local recycling program.

As a consumer, there are a few things you can do to keep fiber-based materials from ending up in the landfill. The first is, of course: Recycle. Spread the word about pizza box recyclability to friends and neighbors so that the next pizza party can be a little greener. Here’s where to find out if your local recycling program accepts pizza boxes. If they don’t, consider contacting them and requesting that they change their guidelines to explicitly accept pizza boxes.

It takes partnership

For consumers, recycling guidelines and laws can seem daunting. Corporations, municipalities and local recycling facilities can make it easier for them.

As a sustainable fiber-based packaging solutions provider, we are always thinking about how to help close the loop on waste. The high volume of pizza boxes generated in the U.S. every year means that if we can clear up misconceptions of their recyclability, we can make a huge impact on the circular economy by keeping resources in the system.

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