The Trash Blog

Is Recycling Green Glass Good?

Dr. Michael Munger, Professor of Political Science and Economics at Duke University, 2008 Libertarian gubernatorial candidate for North Carolina, and author of the blog Kids Prefer Cheese, has some things to say about recycling glass.

Michael MungerProfessor Munger told us about municipalities that were required by law to collect green glass at great expense, and yet had no buyers for their collections and were thus forced to landfill at additional cost. He cited several instances–Eugene, OR; North Mankota, SK; and Columbus, SC–where glass or green glass was landfilled after being collected for recycling. Professor Munger also pointed out that since glass is inert and does not pose a risk when landfilled, perhaps there is a cheaper way to deal with it.

Glass is often held up as a recycling poster child, being “endlessly recyclable.” Munger’s observations are a somewhat dismaying revelation, considering how fully our society has embraced recycling. In an effort to learn a little more about the market for green glass, I called several glass recyclers around the US.

One of these recyclers was Strategic Materials Inc., the largest glass recycler in North America. Richard Abramowitz, their Vice President for Governmental Affairs, spoke to me about their experience with green glass.

SMIIn bottles, there are three types of glass: clear, brown, and green. Clear glass cullet usually commands the highest prices, while brown’s prices are significantly lower. Green glass cullet has trouble commanding any price at all. Due to contamination, mixes of these different types of glass are usually worth significantly less than pure products.

If you are making clear glass bottles, your feedstock needs to be mostly clear, if not entirely clear. If you are making brown glass bottles, your feedstock needs to be mostly brown, although it tolerates a larger range of mix. Green glass requires mostly green feedstock, but tolerates an even wider range of mix.

Abramowitz said that the story of green glass comes down to supply and demand. Glass cullet is heavy and plentiful. Sand, the raw material from which we make glass, is also plentiful and easy to access. Glass does not command the same relatively high values as scrap metals and is much heavier than recycled plastics. Shipping something as heavy and inexpensive as glass cullet leads to shipping costs that quickly devour your profit margins.

The case with green glass cullet, Abramowitz pointed out, exemplifies this: there are about 100 glass furnaces in the US. Only a small portion of these produce green glass products. Recylers who are distant from green glass manufacturers haven’t a hope in hell of selling their green glass. So the US appetite for green glass cullet is small, but due to the large amount of imported green glass (e.g. wine bottles and Heineken) there is no shortage of supply. And due to glass cullet’s weight, it is not competitive to ship it back to Europe where there is a demand that can be satisfied by closer virgin and cullet sources.

As far as the issue of contamination goes, Abramowitz said SMI doesn’t have too much trouble. They use optical sorting technology that can sort a very mixed load of cullet into its separate colors. Separating the mixed loads does cost money, and Abramowitz noted that sometimes it is not cost effective to go to the expense of sorting loads. They have other uses for mixed cullet: abrasives, fiberglass, reflectors (ever wonder what your headlights are glinting off as you drive down the road?)—and in many cases these products do not require a pure feedstock of glass cullet.

Professor Munger believes that the US has embraced recycling so fervently, we are blind to cases where recycling isn’t doing any good. Our mindset is that recycling is always good. Such single-mindedness can be a dangerous thing.

Featured image from Texture Images.

This entry was written by Philip and published on March 10, 2014 at 12:27 pm. It’s filed under Glass, Recycling and tagged , , , , , , . Bookmark the permalink. Follow any comments here with the RSS feed for this post.

5 thoughts on “Is Recycling Green Glass Good?

  1. Uncle Chris on said:

    It is always good to use common sense. . . . . Great post!

  2. Fascinating! Thank you.

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  5. So interesting! Thanks to this article, I’ve started avoiding buying products in green glass. And I now generally try to buy beer in cans instead of bottles. It does seem like a long-term solution is to implement more container deposit laws which increase the quality of glass collected, thereby making it more economically viable for recyclers. The glass recycling industry is a big supporter of container deposit laws. Thanks for your research!

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