Experimental device to take aim at plastics in the Delaware
Smart Trash Boom, which is specially designed to work in the heavily trafficked river, is expected to be tested in 2023
| September 20, 2022
A new weapon is set to be tested next year in the battle against plastics pollution that can accommodate the heavily trafficked Delaware River, an experimental device known as Smart Trash Boom, spearheaded by a Utah-based company.
Company officials say the device is well suited to waterways like the Delaware that are frequented by container ships, tankers and other large commercial vessels.
What makes the device unique is that it can close like a pair of scissors to get out of the way of ships plying the river and then reopen to resume doing its job, said Riverine Technologies, the maker of the device.
The company said static trash booms have been successfully deployed to capture plastics, such as Mr. Trashwheel in Baltimore Harbor, sponsored by Waterfront Partnership, and The Interceptor, sponsored by The Ocean Cleanup, but booms cannot be effectively deployed in high-traffic waterways like the Delaware.
Focus on macroplastics
Though there have been reports assessing the presence of microplastics in the Delaware, the Riverine project focuses on its bigger brother, macroplastics, such as water bottles.
The Water Power Technology Office of the U.S. Department of Energy estimates that approximately 8 million tons of plastic waste enter the ocean from U.S. rivers every year. There is one ton of plastic in the sea for every three tons of fish, it said, and by 2050, that estimate is projected to be one for one.
Attention is increasingly turning to rivers, which serve as conveyor belts of plastic pollution that ultimately makes its way to oceans, researchers have found. Strategies are being recalibrated to intercept trash in rivers while the debris is still relatively intact and concentrated and before it enters oceans.
In fact, a 2021 peer-reviewed study identified the top 1,000 rivers in the world that are arteries for 80 percent of the plastic pollution in oceans. The remaining 20 percent of plastic emissions are spread over 30,000 other rivers.
The study named the Delaware River as the No. 1 source of macroplastics pollution leading to oceans in all of North America.
Once waterborne, macroplastics harm ecosystems as they break down into smaller pieces that are ingested by marine organisms. These microplastics, which are about as big as a sesame seed, fill the digestive systems of aquatic life and introduce toxins into the food chain. This also allows microplastics to enter fish consumed by humans.
How Smart Trash Boom works
Even though the Riverine device features “boom” in its name, it’s actually made up of latticework-like trusses that deflect trash into receptacles at their ends, said Wyatt Felt, a principal investigator with Riverine.
As the river flows toward the ocean, it directs the trash into the bins, where it will remain captured. As for what becomes of the material collected, Felt said the company was looking for partners “who can help us sustainably repurpose the debris collected.”
Smart Trash Boom is designed so that it can close and leave the navigable waterway unimpeded in both flow directions, he said, adding that fish should be able to easily avoid the device as they would other objects in the river, such as boats, pylons and rocks.
Booms submerged two feet deep in the water are held in place by a moored platform and buoys. The wings for the prototype will extend a total of 100 feet and will be manually collapsed by actuating cables when a vessel approaches. The device is expected to rely on the river’s kinetic energy for power it but it could also rely on solar energy, Felt said.
A second, more sophisticated design calls for a sensor that will cause the wings to automatically close with the pending arrival of a ship. That model will rely on radar and an Automatic Identification System that tracks vessel traffic by pinging a ship’s location and heading.
Felt said the company is using a RayMarine Quantum 2 doppler radar with automatic target tracking, which can detect and track small objects and smaller vessels.
Riverine’s pilot project will be based at a site near Pigeon Point, Del., that is managed by the U.S. Army Corps of Engineers, which is processing and storing material as part of a dredging operation.
That section of the river records an average of six major cargo vessels per day, though seasonally, that figure can climb, Felt said. In 2020, nearly 2,200 ships arrived at Delaware River port facilities, according to a report from the Maritime Exchange for the Delaware River and Bay. That traffic was down 6.6 percent from 2019, a decrease attributed in part to the pandemic.
Larger industrialized rivers – such as the Mississippi, the Delaware and the Yangtze River in China – tend to be the most polluted but also “economically vibrant,” he said. The question then becomes how to balance the need for commerce with the desire to clean the rivers.
“How can we help mitigate the trash problem without impeding the important commercial and recreational traffic on the river?” Felt asked.
Phase I of the project was a $200,000 pilot underwritten by the U.S. Department of Energy to test the device in Utah Lake in Utah. The department is expected to underwrite Phase II, which is a $1.1 million, two-year commitment to test the device in the spring or summer of 2023 in the Delaware.
The definition of success for Riverine’s experiment would be to develop a device that is scalable and deployable around the world, Felt said.
He said the company was actively seeking additional federal funding and development partners, including logistics partners for the Delaware River testing. He said the company did not see its project as necessarily being in competition with other initiatives.
For instance, he called Seabins — a garbage collection device being tested on the Delaware and Schuylkill Rivers that is part pool skimmer, part pump and part trash can — a “fantastic product for what it does” and said companies like Riverine and others “all have a shared mission for cleaning the rivers.”
Project is ‘ill-advised’
Judith Enck, president of Beyond Plastics, which is based at Bennington College in Bennington, Vt., and seeks to end plastic pollution through policy and advocacy, was skeptical of the Riverine project or any others like it that attempt to remove plastics from waterways.
“Once the plastic is in the ocean or the river, it’s practically impossible to get it back” because so much of it falls to the ocean floor or river bottom, she said.
“There is no technology so effective in getting it out of the water,” she said. “If they want to do something in the water, they should just put out booms and put them at storm drains.”
As for Riverine’s pilot project, she said, “I would say this is ill-advised and should be reconsidered,” adding, “We are way past the pilot projects.”
In response, Felt said the company was developing camera technology to help identify areas where interventions can be most effective. “The sad truth, however, is that storm drain covers are not enough to solve the problem of mismanaged waste,” he said.
Trash that sinks to the bottom is certainly a concern, he added, but one that Riverine’s system does not address.
‘Last line of defense’
Felt described the Smart Trash Boom as “a last line of defense for highly floatable litter” that gets picked up by rain and swept into the river system.
“There’s a lot of people all over the world thinking about this,” he said.
Gerald Joseph McAdams Kauffman Jr., director of the University of Delaware Water Resources Center, said if the four states in the Delaware River basin were united in a plastic bag ban, it would be a step in the right direction to alleviating the problem of plastics pollution.
He likened efforts to ban plastic bags to past successful efforts to eradicate lead in gasoline or phosphorus in detergents.
He said other technologies, such as skimmers, which have been used for decades in places like Baltimore’s harbor, have been effective but those same approaches won’t work in big flowing rivers like the Delaware.
“The technology is there to come up with sustainable alternatives,” he said.