Restoring Louisiana’s Shoreline, One Glass Bottle at a Time

A 2022 glass sand demonstration in the Big Branch Marsh National Wildlife Refuge.

Louisiana's shoreline is rapidly eroding due to sea level rise and extreme weather fueled by climate change. But a scrappy New Orleans glass recycling initiative, Glass Half Full, is rounding up as many of the city's glass bottles as possible to create sand for coastal restoration.

The team, a winner of the 2023 Gizmodo Science Fair, got started in 2020, right before covid-19 disrupted life across the globe. Their goal was to make use of Louisiana's discarded glass, which is largely not recycled. At first, cofounders Franziska Trautmann and Max Steitz could only pulverize one glass bottle at a time from their backyard operation. After a successful GoFundMe campaign raised about $150,000, Glass Half Full was able to invest in larger machinery and a proper facility, and they now turn over 150,000 pounds of glass into sand per month.

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According to Trautmann, using recycled glass for shoreline restoration was an early goal. But they needed help, so in 2021 they reached out to their former professors at Tulane University. Glass Half Full, Tulane University professors and students, and researchers from other universities formed ReCoast to work together on testing if recycled glass could eventually be placed onto the coast for shoreline restoration.

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This connection led them to apply for and win a National Science Foundation grant to study how land loss is affecting the Gulf state. According to the U.S. Geological Survey, Louisiana lost an estimated 2,000 square miles of land between 1932 and 2016, an area larger than the state of Rhode Island. With that grant money, researchers and students at Tulane University placed native plants in the recycled sand and sediments similar to what they’d be exposed to in the Mississippi River. They observed the plant growth and saw that native plants did survive in the recycled glass sand and sediment mixture.

When I first spoke with Glass Half Full in 2022, the team had just completed their first installation using recycled glass in Louisiana's coast. Members of the team and volunteers added 12,000 pounds of recycled glass sand to the coast, in a collaboration with the local Pointe-au-Chien tribe.

The group also conducted a similar glass demonstration a few weeks later in the Big Branch Marsh National Wildlife Refuge north of New Orleans. Glass Half Full deposited about 20,000 pounds of recycled glass sand, along with burlap sacks and 5,000 native plants, into the refuge to repair damage from Hurricane Ida.

These early demonstrations were part of Glass Half Full's first phase of testing to learn if their sand is safe for plants and animals. Months later, Trautmann returned to the refuge to see whether the plants had taken to the recycled glass sand in nature, like they had in the lab. Sediments had built up on the sand, and the plants placed in the mix were still growing. "Both projects are doing amazing," she said.

Through ReCoast, Glass Half Full has ramped up its operations and testing—boosted by another grant from the National Science Foundation this past September. Tulane University received an additional $5 million to expand lab testing and conduct more demonstrations along the coast. "Phase two will be more implementation projects in Louisiana, and then expanding the research beyond Louisiana," Trautmann explained. "We’re looking at Alabama, Florida, potentially Hawaii—different environments that also have coastal erosion issues and then also do not have glass recycling."

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One concern is how local marine animals will react to the sand. Henry L. Bart, an ecology professor at Tulane University, led testing in which he and students exposed crabs and local fish, like the Atlantic croaker, to the pulverized glass sand. The marine animals burrowed and moved around in the sand; after months of exposure, the researchers studied how the sand affected the animals’ bodies. "The croakers had ingested quite a bit of sand," he said. "We checked to see if there was any injury to their stomach or their abdomen from that, and there wasn't, didn't cause any sores or wounds."

Steitz and Trautmann said they are often in disbelief over how supportive the local community has been and how much glass they’ve been able to repurpose for different needs. Glass recycled by Glass Half Full is also used to create beads for jewelry. Glass Half Full has also continued to sell different textures of recycled glass for construction and disaster relief sandbags.

What started as a rogue operation, in which both the cofounders had to pester friends to bring them their glass bottles, has become a larger company with growing local impact. "I hope our story inspires folks to look for solutions within seemingly overwhelming problems," Steitz said.

Read more: Pulverized Glass Is Becoming Much-Needed Sand Along Louisiana's Coasts

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Restoring Louisiana’s Shoreline, One Glass Bottle at a Time