Everyone knows you can’t recycle pizza boxes. Soaked in grease and flecked with bits of leftover cheese, a used cardboard pizza box can contaminate the recycling process and spoil an entire batch of material. Greasy pizza boxes belong in the garbage pile, right?
Wrong, some industry experts argue; used pizza boxes aren’t necessarily destined for the landfill.
William Moore, president of Moore & Associates, a paper recycling consulting firm, said most of the companies he works with are able to process pizza boxes without a problem.
“Food contamination is a standard thing that mills are able to deal with, and have been able to for a long time,” Moore said.
A moderate amount of food contamination can be washed out during the stock preparation cleaning process at a paper mill, Moore said. Entire slices of pizza or a pile of crusts left in a box could gum up the process, but a few greasy boxes won’t harm the final product. Disposing of oils and food residue can incur additional costs, however, he said.
Odor is the biggest problem with food contamination, Moore said. When wet or dirty cardboard sits in storage, it can begin to smell, grow bacteria and sometimes attract pests. But typically, there aren’t enough pizza boxes in a load of recyclable material to cause a big problem, he said.
Matt Naimi, owner of Recycle Here!, Detroit’s recycling drop-off center, said he’s never had a problem recycling used pizza boxes.
“Let’s say if an entire load of cardboard going to a paper mill ... contained nothing but pizza boxes that were soaked through with grease — that particularly might be a problem,” Naimi said. “That’s not going to happen.”
Recycle Here! processes four tons of paper each Saturday, Naimi said. Of that amount, “maybe 100 pounds are pizza boxes, maybe 40 pounds have a grease stain — not going to contaminate the load, not even going to show up in the mix,” he said.
An estimated 29 million tons of corrugated cardboard was discarded in 2010, according to information from the U.S. EPA. About 85% was recovered.
Detroit’s recently launched pilot curbside recycling program accepts pizza boxes, Naimi said. But some other municipalities prohibit them.
Seattle, for example, prohibits soiled pizza boxes in its curbside recycling containers, according to its public utilities website. Instead, the city collects greasy cardboard with food and yard waste, which is then processed into compost. And some municipalities encourage residents to cut out and discard greasy sections of pizza boxes and recycle the rest.
“I know that historically, it’s been that we’ve tried to keep contamination out of the OCC [old corrugated containers] stream,” said Bill Gardner of International Paper.
Gardner said he’s not aware of any scientific study evaluating how much contamination can be reasonably handled, and how to control that amount. So when pizza boxes are excluded from recycling, it may be an effort to keep the contamination from becoming overwhelming, he said.
Moore called the idea that pizza boxes can’t be recycled “misguided.”
“I think to say you shouldn’t recycle pizza boxes because there may be some food residue in there, I think that’s a mistake,” he said. “We need the fiber, and we should recycle those things.”
Contact Waste & Recycling News reporter Kerri Jansen at firstname.lastname@example.org or 313-446-6098.