Going green: Tulane scientists study recycled glass sand for coastal restoration

Posted on November 11, 2021

NEW ORLEANS (WVUE) – A small idea could one day have a big impact on Louisiana’s eroding coastline. A group of Tulane University scientists is turning to recycled glass bottles to help fight land loss.

“We were a bit fed up that we couldn’t recycle our glass, that all of the wine bottles we were drinking were going to a landfall and so we decided to do something about it,” said Franziska Trautmann, cofounder of Glass Half Full— New Orleans’s only glass recycling center, where glass bottles are turned into sand.

Trautmann, a chemical engineer, said she and a friend dreamed up the business while seniors at the university with an even bigger mission in mind.

“I always heard growing up that we lose a football field’s length of land every 100 minutes and that’s daunting,” said Trautmann. “So we thought if we could turn this glass into sand and then rebuild our coast, that would be the ultimate win-win.”

But they needed up. Trautmann said creating glass sand to rebuild the coast has to go through a lengthy process.

“We have to get approval. We have to make sure it’s safe. And that’s where our professors came in,” she said.

Julie Albert, Ph.D., Associate Professor for the Chemical and Biomolecular Engineering Department, partnered with Trautmann and a team of other scientists, using grant money to conduct a feasibility study with a goal of determining whether the glass sand could be used in coastal habitats, and where it could go to reduce land loss.

“There are two things: one is the scale, I don’t think you fully appreciate until you go out there and see how large some of these features are,” said Albert. “That was something that really came out of our building, our team, we have a couple of professors from river and coastal engineering, and Fran and I were dreaming big. We’re going to build barrier islands and then we actually did the calculation for how much sand you actually need and despite what you can see behind me in terms of their load, it’s a drop in the bucket for what you need for a project that size.”

So they’re starting small by planting marsh grass and other plants commonly found on the Louisiana coast in various sizes of recycled glass sand to see if the plants survive. The sand will also go through chemical analysis to make sure it’s clean and not introducing harmful components to the environment and marine life– like fish and crabs.

“This was another thing we learned about the project is researchers from different fields in terms of their qualitative characteristics of materials something that we think of as fine is actually considered rather course so if you compare that to dredge material, which if you think how much clay compacts in this region this won’t compact quite like that because it is a larger particle size than that dredge material,” said Albert.

“The courser sand is really good to make sure the sand stays and doesn’t get washed away,” said Trautmann. “So the heavier it is the less it will wash away.”

At Glass Half Full, glass bottles go through a glass pulverizer that crushes it up into chunk sand or gravel. From there it is sifted with a mechanical sieve into five different sizes from very fine powder to larger gravel pieces.

Trautmann said the business produces roughly 15 cubic yards of glass sand each week, but it’s not nearly enough for high-profile projects– like creating barrier islands. A project like that would require millions of cubic yards of sand.

“We’re starting very small. We’re starting with projects like building ridges and replenishing land and not necessarily rebuilding and restoring miles of coastline yet. We’re not there,” she said, but the team believes it can work… eventually.

“At the end of the day, the goal is to, number one, is to recycle glass for all of New Orleans and even the Greater New Orleans region because there’s no municipality right now in Louisiana that recycles their glass, so really being able to provide glass recycling for Louisiana to turn that glass into a reusable resource for our coast, for disaster relief, and turning that glass into something useful for those who recycled it, and then ideally being able to restore our land and not wash away.”

It’s just a matter of proving it can be done safely right here on the coast of Louisiana. The Tulane team of scientists hopes by the start of 2022, they’ll be able to begin testing the sand in small controlled areas of coastal Louisiana.

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