Old Glass Mountain Coming Down

Part 5 in a series – The Value of Glass

Here it is! “Recycle Glass Day!” Can you feel the excitement?

My adventures in glass recycling started in Atlanta and I’m returning to that visit to forecast the future.

The Mount McKinley of all glass piles that lay in the back lot when I visited Strategic Materials (SMI) had a more seedy appearance than the cullet piles, not quite so sparkly. According to Hazel Mobley, glass specialist and our tour guide, this pile of old bottles of every color has been accumulating for years in anticipation of the day when technology would arrive to sort the muddled array of colored glass where all colors of glass end up in the same curbside recycle bin.

Until now the barrier to co-mingling all color bottles has been the labor of separating glass by color to be recycled back into new products of the same color. The future is upon us and particularly at SMI as they prepare to implement a new single-stream operation where all colors of glass coming from one humongous heap will be sorted by machine.

Now you wonder, how does a machine sort a mountain of dirty old glass of all different colors?

By dropping it.

First the glass, primarily from bottles, is broken, washed and placed on a conveyor where it’s vibrated into a single layer moving along. At the end, it drops off the conveyor into free fall. As glass pieces are falling, they pass in front of scanners capturing the images at a rate of 10,000 pieces per second. The scan is identifying a selected color (e.g. looking for green, looking for clear, looking for amber, etc.).

At the same time color is being scanned, a metal detector identifies metal pieces and separates them out. The glass of the determined color is selected and separated by a blast of compressed air. Other color pieces continue on to be scanned and singled out by color in another drop.

My description is quite simplified, but what I’m trying to tell is that technology has arrived to make possible rapid glass recycling from a single stream of multi color glass.

We have an ancient commodity that is endlessly recyclable, trustworthy for health safety, and beautiful enough to wear as jewels, and we’re throwing it away. How silly we are.

The Glass Packaging Institute announces the winner of the student YouTube Competition. University students enrolled in packaging science fields participated. The submissions are terrific! The winner is almost a tear jerker. You can watch it at http://www.gpi.org/recycleglassday/youtube/.

For a more in-depth explanation of the Morgensen glass sorting technology