William DeSisto, University of Maine professor of chemical and biomedical engineering, was working at the beginning of the pandemic to address hand sanitizer issues. Credit: Linda Coan O'Kresik / BDN

A rush on disinfecting products at the start of the pandemic led to stores everywhere being sold out of hand sanitizer and sanitizing wipes. Now, chemical engineers at the University of Maine are working to make sure that doesn’t happen again.

The chemical engineers have been working on a way to create an effective disinfectant on-site at a low cost. The project grew from a UMaine team that worked to address critical shortages during the pandemic.

William DeSisto, a professor of chemical and biomedical engineering, was a chemical engineer with no particular experience in disinfecting or sanitation when he was tapped to join the team.

“There was a concern early on that there was going to be a shortage of a lot of different critical items and hand sanitizer was one of those,” DeSisto said. “

DeSisto worked with distillers around the state to get ethanol to make the sanitizer that was in demand at that moment. He was disturbed, however, to see how difficult it was to get sanitizing products to Maine when the supply chains broke down, like they did at the beginning of the pandemic.

“We made the quantities needed until the shortage had passed [but it was] striking how quickly that came about. It exposed a vulnerability in our supply chain,” DeSisto said.

A friend of his who is a dentist turned him on to a different kind of disinfectant: hypochlorous acid. The disinfectant, which has been identified by the U.S. Environmental Protection Agency as an effective disinfectant against SARS-CoV-2, is simple to make. All you need is salt water and electricity.

Hypochlorous acid is made by using electricity to break down a salt water solution into its essential elements, including the chlorine ions that kill pathogens and bacteria by breaking down their chemical bonds.

But the process of making hypochlorous acid can be inefficient — for example, it generally requires very clean water to be effective.

DeSisto’s work aims to change that.

“Even though the process is simple on paper, that chemical reaction is very complex and takes place in a number of different steps,” DeSisto said. “We’ll be looking at that to make it more efficient, using less ingredients to make your final product in a chemical process.”

Hypochlorous acid is presently more expensive to produce and less well-known than bleach, despite being 70 to 80 times more effective and less toxic for people using disinfectants to work with. That’s something that a new process could change.

DeSisto is working with Maine manufacturers like Craig Cunningham, owner of Maine Manufacturing LLC in Sanford, to create machines that will cheaply and efficiently produce hypochlorous acid on-site for places like wastewater treatment plants, which use enormous amounts of disinfectant in order to clean bacteria out of wastewater.

After testing their machines at such a scale, Cunningham hopes eventually that the units can scale to help both large scale needs and smaller ones.

“Hopefully what you’ll have too is a quick and easy to use generator that generates it right in your home or greenhouse or something like that,” Cunningham said. “You can certainly buy it on the market but you can generate some and you don’t really care about how long it’s going to last you’re going to generate enough to use and do it again when you need it.”

Hypochlorous acid has a short shelf life, but DeSisto sees the potential for local production as a boon for Maine, either for local businesses looking to get into the disinfectant market or even for existing institutions to start making their own disinfectant on-site without having to rely on importing products.

As an added benefit, DeSisto hopes that by improving the production process, eventually it will be economical to use seawater to make hypochlorous acid — something that Maine has an abundance of.

“That would be a big goal,” DeSisto said. “The problem with seawater is that it’s not very pure salt water, it has lots of other stuff in it. That’s something you have to deal with as an engineer, you have to figure that out.”

DeSisto’s new hypochlorous production method was tested in Saco in May of this year.

Howard Carter, director of the Water Resource Recovery Department at the city of Saco, said initial tests of DeSisto’s new process were promising.

“It certainly kills the bacteria, there is no question about it,” Carter said. “A few months from now or a few years from now, it could be a viable product. It’s very exciting, we’re on the cutting edge of it. The analysis that they’re showing is that it could be a cost saver which is always a win win. How neat would that be if you could make your own disinfectant from your own wastewater?”

Typically, Saco tuses sodium hypochlorite and sodium bisulfate, which is “like a stronger bleach,” to kill bacteria in the final step of the wastewater process.

“That’s a good product [and] it’s safer than the chlorine bleach used years ago, but the one problem with that is that it’s made offsite,” Carter said. “I think the biggest issue is the sustainability part of it. Say they make it in New Jersey and it’s coming up to a tank or a depot in Portland in Bangor and then they truck it to me.”

But Carter said that if that truck is taken off the road for some reason due to an environmental event — or, perhaps, a pandemic — the wastewater treatment plant and its surrounding would be left in a lurch. The on-site production of hypochlorous acid changes that.

“If we run out of disinfectant, the thing about wastewater is that it never stops,” Carter said. “A loss of disinfectant could affect all the fisheries on the Saco River.”

Still, despite the benefits, hypochlorous acid may not be a more environmentally friendly alternative to conventional disinfectants.

“Hypochlorous acid will dissipate over time, but it may leave toxic byproducts in its wake,” said Michael Belliveau, executive director of Defend Our Health, a nonprofit advocacy group working on issues of clean and safe food and drinking water in Portland. “There may be technical or business advantages [like] you can produce it locally onsite, but those are not environmental health improvements per se.”

Belliveau said that disinfecting ultraviolet radiation or other chemical treatments such as peracetic acid which is similar to the active ingredient in vinegar.

On a large scale, however, Carter said that those options are not yet cost effective.

Though it seems too early to worry about the potential for another pandemic, that is something in the back of researchers’ minds as well. DeSisto was recently awarded $374,752 by the U.S. Economic Development Administration utilizing CARES Act funding for economic development assistance programs to help communities prevent, prepare for, and respond to coronavirus.

“We don’t want what happened last year to happen again,” DeSisto said. “I also think that having a supply chain of critical items that is not compromised or cannot be compromised will help in the future so there won’t be shortages of what we need.”

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