What's the Deal With Recycling Pizza Boxes?

This is one post in a series, describing what I've learned while attempting to understand my ecological footprint.

Most pizza boxes are made out of corrugated cardboard and corrugated cardboard is an ideal candidate for recycling. So why won't most municipal recycling programs accept pizza boxes for recycling? Are they made of some magic cardboard that can't be recycled?

Two weeks ago I got some answers when I met the director of recycling programs at E.L. Harvey & Sons Waste & Recycling Managers. When I asked him "What's the deal with not being able to recycling pizza boxes?" he chuckled. Apparently he gets this question a lot... Anyway here's what I learned:

You can absolutely recycle pizza boxes! What you can't do is recycle the parts that have grease or pizza stuck to them.

Recycling Tip: The top of the pizza box is almost always clean, so I rip that off and recycle it as a bare minimum step in recycling any pizza box. If you are up for a bit of extra work cut out any grease or cheese covered spots and recycle all the clean parts of the box.

So why do people say you can't recycle pizza boxes? - There is nothing special about pizza boxes. They are typically made out of cardboard that is ideal for recycling. The problem is with pizza boxes that have grease or cheese on them which causes two specific issues.
  1. Smell and Disease - Recycling transfer stations work with huge amounts of material. There is a lot of opportunity for things to grow, smell really horrible and create a health hazard which needs to be addressed. When I visited E.L. Harvey I was stunned first by the volume of material they go through in a few minutes and second by how good it smelled. It wasn't like a spring breeze mind you, but it didn't smell bad either. They do an amazing job of keeping things clean when working with very dirty things. So it's understandable that people running recycling programs might frown on left over pizza in their recycling containers.

  2. Slurry Oil - When cardboard is recycled its mixed with water and turned into a slurry. If someone puts greasy pizza boxes into the mix then a layer of oil forms at the top of the slurry. It's just like if you pour vegetable oil into a cup of water. Once there is oil in the slurry, the recycling process needs to be stopped and the machines need to be cleaned. You end up waisting all that recycled material and slowing up the next batch while you wait for the cleaning. So you not only can't recycle greasy pizza boxes, but if you do, you ruin it for everyone else that recycled something non-greasy.

It seems to me that the reasoning behind the original "You can't recycle pizza boxes" directive is similar to that of dealing with a mass health issue. In this case, they (I mean the proverbial "they" not E.L. Harvey) knew that greasy & cheesy pizza boxes were bad for recycling and didn't think they could get people to only provide clean ones. So they elected to put a ban on all pizza boxes.

Now that recycling and eco-consciousness are more in vogue, perhaps it is time to revisit the ban on pizza box recycling. I for one am following the Recycling Tips I mentioned above.