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Tidal Vision Says Its Crab Shell-Derived Solution Is A Cleaner Way To Treat Wastewater

  • 23 March 2022
  • ckearns

Treatment plants in the United States process about 34 billion gallons of wastewater every day, according to the Environmental Protection Agency. But conventional treatment products that contain metals like aluminum and iron can cause their own problems with the “cleaned” water that’s discharged, says a Washington state company called Tidal Vision.

The company’s vision for a cleaner solution is called Tidal Clear.

Tidal Vision upcycles crab shells, a commonly discarded byproduct of the seafood industry, into a biopolymer called chitosan. They turn that chitosan into a ready-to-use liquid for treating stormwater and wastewater.

Chitosan has a net-positive charge that binds to suspended solids, heavy metals and minerals, hydrocarbons and other pollutants. In the end, only clarified water remains.

“Generally, the most consumed products (by volume) in wastewater treatment facilities are the coagulants and flocculants,” says Craig Kasberg, CEO and founder of Tidal Vision. 

“The traditional coagulants are non-biodegradable, metal-based chemicals ... all non-biodegradable aluminum metals that end up in the wastewater sludge generated at the treatment sites. They are used because they are cationic, or positively charged, so they bind to the anionic or negatively charged contaminants in the water.”

Chitosan, on the other hand, is the only naturally occurring biopolymer in the world with a positive charge. And Tidal Clear can beat the price of metal coagulants, Kasberg says.

“Essentially, chitosan works like a magnet on a microscopic level—with chitosan's positive charge binding to the small negatively charged pollutants and coagulating them so they can easily be filtered out,” he says.

Tidal Vision gets its crustacean shells from “sustainably managed fisheries in hopes of giving them an economic advantage over those not operating on sustainable yield principals,” Kasberg says.

The fisheries are located in Oregon, Washington and St. Paul Island in the Alaska Bering Sea. Most of the crabs are opilio or snow crabs, but Tidal Vision is working to expand its infrastructure to use invasive species like green crabs.

“What's amazing is how much water can be cleaned with such a small amount of processed shells,” the CEO says. “There is roughly 24% chitosan in those shells, which means for every 1,000 pounds of shells we get 240 pounds of chitosan.

“240 lbs of chitosan is enough to, on average, treat about 29 million gallons of contained stormwater or wastewater.”

He adds that chitosan as a material doesn't get you all the way to a water treatment coagulant or flocculant.

Chitosan is the active ingredient in Tidal Clear. However, Tidal Clear is a product line of chitosan-based formulas and there are several formulation technologies included that lead to the performance mentioned by Kasberg.

More than 25 wastewater treatment companies across the U.S. are using Tidal Clear, Kasberg says. “As of this month, we've received an NSF 60 certification that will now enable us to sell Tidal Clear to drinking water treatment facilities as well, where aluminum-based coagulants that are nonbiodegradable are still commonly used.”

There has been extensive testing by EPA, the Washington Department of Ecology and independent organizations like NSF.

Tidal Vision is reportedly the only company commercially producing chitosan in the United States. The company was founded seven years by Kasberg and Zach Wilkinson in Juneau, Alaska. They worked with a team of advisers to invent Tidal Vision's process, Kasberg says.

“We have a proprietary zero-waste extraction process, where the byproduct is sold as a nitrogen fertilizer,” he says.

“The chemistry, methods for recycling the non-hazardous solvents we use and the ability to turn the ‘byproduct’ or rest of the shell biomass into fertilizer is what makes our process unique.

“This green chemistry also allows us to produce a wider range of chitosan molecular weights, which has led to a 200%-plus improvement in efficacy in water treatment. This process is also less than half the cost of the traditional process, which has enabled us to make chitosan lower cost than the nonbiodegradable metal coagulants for the first time.”

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