As clear as mud

Middle-schoolers solve problem of stream turbidity

Posted: Wednesday, March 29, 2006


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  A pair of jars containing turbid water demonstrate the effectiveness of a flocculant. On the left, sediment is still suspended in the water while in the jar with the flocculant, the sediment is settling to the bottom just minute after both jars were shaken up. Photo by Will Morrow

Members of the Aurora Borealis Charter School's Polar Bears robotics team, from left, Colton Anderson, Crystal Coombs, Autumn Ball, Will McDermid, Lizzie McDermid, Alex Kauffman, Anton Krull and Logan Haralson pose behind a model of a stream the students created for a research project. The project tackled the topic of stream turbidity. The team presented their research at a state-wide competition in December and again at the Kachemak Bay Science Conference Friday in Homer.

Photo by Will Morrow

There’s no doubt some of our best and brightest minds are working on environmental issues affecting Alaska and, for that matter, the rest of the world.

As it turns out, some of those minds just happen to belong to middle-schoolers at Aurora Borealis Charter School in Kenai.

“The hope is that this is something they can use as a solution,” said Suzanne Phillips, a teacher at Aurora Borealis and one of the coaches of the Polar Bears robotics team, of the results of her students’ winning research project.

The Polar Bears competed in the annual Lego robotics competition in December. One component of the competition is designing a robot that will perform a set of functions; the other is for students to research a problem and come up with a solution.

The competition gave the students the broad topic of the ocean; after a brainstorming session with agencies in Homer last September, the group came up with a whiteboard full of ideas. Among them was the problem of stream turbidity, an issue affecting many streams on the Kenai Peninsula.

“Lego requires them to do something innovative; they can’t do something that’s already in use. As we looked at turbidity, there wasn’t anything out there that wasn’t invasive,” Phillips said.


A pair of jars containing turbid water demonstrate the effectiveness of a flocculant. On the left, sediment is still suspended in the water while in the jar with the flocculant, the sediment is settling to the bottom just minute after both jars were shaken up.

Photo by Will Morrow

What the students discovered is that stream turbidity — basically dirt particles suspended in stream water — is detrimental to salmon populations. Particles in water can block sunlight needed by underwater plants, resulting in less oxygen in the water, and also absorb ultraviolet light, making water temperatures warmer.

After a few weeks of frantic research — the Polar Bears actually started the competition looking at a different problem but had to switch when they discovered the solutions they had been exploring were already in use — the students discovered a substance called chitin used to make a product called Chitosan. The substance is a flocculant, and when dispersed in a turbid stream, would attract the dirt particles in the water and sink to the bottom. Because the product is biodegradable — chitin is found in the shells of crustaceans and insects — a drainage pipe could be installed in a slow-moving pool where the flocculant would settle, and the substance could be drained into the surrounding landscape without doing any damage.

“It has been used on construction sites for runoff, but it hadn’t been used in a stream before,” said Will McDermid, a member of the Polar Bears team.

According to the students’ research, some of the potential benefits of using the product to control stream turbidity include:

· Seafood processing waste could be recycled to make the product;

· The product is biodegradable. It is used in the filters of commercial aquariums that contain exotic fish, and experiments done with rainbow trout and Dolly Varden have shown the product to be safe even at concentrations greater than what is needed to be effective;

· Chitosan will remove 85 to 90 percent of sediment in stream waters. The product, a gel, is placed in a boom-like “Gel-Floc Sock,” which can be put in a stream above a slow-moving pool. The product is dispersed by the flow of the stream — no need for power — and the cost is about one dollar per 3,300 gallons of water treated. Depending on water flow, students estimated one application could last two to three weeks.

Anton Krull, another member of the team, said he learned a lot from the group’s research.

“We had no idea what was going on before this,” Krull said.

The students took on their research, meeting after school two or three times a week, in addition to their regular classwork. Several students said they put in some late evenings, staying at school until 9 p.m. or later, after they switched topics in November, just a few weeks before they were due to present their research at the competition.

The team’s presentation included a diagram of the salmon life cycle and its role in the food chain, demonstration jars of turbid water — one with flocculant and one without, and a model of a stream bed with a miniature Gel-Flock Sock, a settling pool and a drainage hose. The research was presented as a skit and even included some live guitar playing.

The Polar Bears team includes Autumn Ball, Will McDermid, Colton Anderson, Logan Haralson, Alex Kauffman, Lizzie McDermid, Crystal Coombs and Krull. The team is coached by Phillips and Elizabeth McDermid.

The students also were invited to present their research at last week’s Kachemak Bay Science Conference, where the group shared the podium with university researchers and government scientists.

Phillips said the presentation went well. Additional study would be needed to see if it would work in an actual stream, but Phillips said her team was able to field questions from the gathered scientists, and said she was told the team’s skit was a nice break from the lineup of PowerPoint presentations.

“One of the comments at the end was that everyone should have some live entertainment,” Phillips said. “They were definitely in there with some heavy-duty scientists.”

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