BIDDEFORD, Maine — It’s impossible to tell from the outside, but within a tiny, wood-shingled wastewater treatment plant nestled next to a private golf course at ritzy Biddeford Pool, a small revolution is taking place.
Inside, a new invention, thought up by a Mainer, is using wastewater, salt and electricity to produce a nontoxic disinfectant to replace the nasty chlorine bleach the plant normally uses to make toilet-flushed water safe before piping it out into the ocean. What’s more, the innovative, new process also makes hydrogen gas, which someday could heat the building or generate electricity.
The technology, called DiriGoH20, is still in its early stages, but if successful, it could eliminate the need for chlorine bleach wastewater plants, saving municipalities thousands of dollars while also going easier on the environment at the same time.
Caribou native Craig Cunningham, managing director of Maine Manufacturing Partners, thought up the technology and then approached the city of Biddeford about trying it out, free of charge, on a small scale, at its Biddeford Pool facility. Now, after three months of testing, Cunningham is calling the small-scale test a success.
Alex Buechner, Biddeford’s wastewater superintendent, agrees. He hasn’t used any chlorine bleach, known as sodium hypochlorite, since Cunningham’s system has been online.
But his sights are set firmly on the future.
“For what it is today, it’s not really about saving money,” Beuchner said. “It’s more about what it could do in the future to make this a safer operation.”
At the height of summer, the Biddeford Pool plant treats 20,000 gallons of effluent a day. In the off season, it’s closer to 5,000 gallons. That translates into about 140 gallons of bleach a year, which costs the city around $260.
However, Biddeford’s primary wastewater treatment plant uses 30,400 gallons of bleach annually, at a cost of $56,700.
Cunningham’s DiriGoH20 system works by drawing off a small portion of wastewater, after the solids have been removed, then adding a small amount of sodium. The liquid then gets pumped through six, baseball-sized reactors. Inside each one, electricity is fired through five titanium-coated rods.
“The electricity routed into these reactors is pulsing at about 10,000 times per second,” Cunningham said.
The voltage reacts with the salted water, producing hydrogen gas and hypochlorous acid.
The acid is an effective antiseptic which can kill most bacteria and pathogens within 12 seconds. It is then used to disinfect the outgoing water.
Normally, most wastewater treatment facilities must dose their water with bleach at the end of the process, then use sodium bisulfite to dissipate the bleach before releasing the water back into the environment. With hypochlorous acid, the final step is not needed as the acid dissipates on its own.
Beuchner is happy to not have his workers transporting dangerous barrels of bleach to and from the Biddeford Pool facility.
“The hypochlorous acid seems to be just as — if not more — effective than sodium hypochlorite,” he said. “And It doesn’t burn your skin, it doesn’t burn your eyes.”
Then there’s the hydrogen gas.
“Right now the hydrogen is just being vented out of the building, but in the future we’re hoping to capture that and try to utilize it to generate heat or electricity,” Beuchner said. “There’s a lot of untapped energy in that.”
The new process isn’t the only way to treat wastewater without chlorine bleach, Cunningham points out. Other established systems also use ultraviolet light or ozone to disinfect water. But his DiriGoH20 solution is the only one that uses on-site wastewater in the process.
Word of Cunningham’s invention is starting to get out, and he’s already demonstrated it at the Biddeford Pool station for both of Maine’s U.S. senators, as well as several college professors.
The next step for Cunningham’s new technology is to try and scale it up for a larger facility. One that’ll need to disinfect about 100,000 gallons a day ought to do it, he reckons.
Beuchner is excited at the prospect.
“I’m thinking of the environment, my kids, my grandkids,” he said. “If clean water ever goes away, we’re in big trouble.”
