URI Scientist Works to Find Right Chemical Combination to Protect Rural Drinking Water
June 3, 2021
Joseph Goodwill has been studying the use of ferrate, a supercharged iron molecule, to clean drinking water since 2012. His Ph.D. dissertation at the University of Massachusetts Amherst was on the subject.
A decade later, as an assistant professor of environmental engineering at the University of Rhode Island, the New York native is still researching the subject in hopes of developing a new method to treat drinking water, especially in rural communities.
Goodwill was recently awarded a five-year, $507,240 National Science Foundation grant to work with ferrate and sulfite to develop an advanced oxidation method that can be used to treat drinking water.
Growing demand, drought, pollutants such as nitrogen and phosphorous from fertilizers, aging infrastructure and strained municipal budgets are taxing water systems, both large and small.
Goodwill noted that when it comes to ensuring a community has clean drinking water, there isn’t a one-size-fits-all solution. He said urban and rural communities have different needs, different resources and face different challenges.
“One approach to environmental engineering doesn’t work for communities of all sizes,” said Goodwill, who grew up in a small town about an hour north of Syracuse. “Rural areas, or communities with developing economies, might not be in a position to do what works in cities such as Boston or Providence.”
In fact, according to Goodwill, there is a widening gap between urban and rural communities when it comes to their ability to provide clean drinking water. He said the problems associated with smaller systems don’t receive the same attention because fewer people are impacted. He noted smaller systems struggle to keep pace with increasingly stringent regulations that are designed to deal with emerging issues such as per- and polyfluoroalkyl substances, better known as PFAS, and 1,4-dioxane.
“There is a persistent gap between the rate of drinking water violations in urban systems and rural systems,” Goodwill said. “The small, rural systems have health-based drinking water violations that occur at higher rates. That gap has gotten worse over the last 15 years. I view it as a growing problem.”
Poor regulation of agricultural waste and other pollutants, shrinking populations and antiquated infrastructure contribute to the increasing incidents of water quality violations in rural communities, according to the American Bar Association (ABA).
“There are nearly 60 thousand community water systems in the United States and 93 percent of them serve populations of fewer than 10,000 people — 67 percent serve populations of fewer than 500 people,” Madison Condon wrote in a 2019 human rights piece for the ABA. “In 2015, 9 percent of all water systems had a documented violation of water quality standards, exposing 21 million people to unhealthy drinking water. These violations were more likely to occur in rural areas, where communities often have trouble finding the funds to maintain their systems.”
The right combination
Ever since Goodwill was a doctoral student at UMass Amherst, he’s been intrigued by how chemicals could be used to convert contaminated water into drinking water.
One application would be using the technology to transform sewage into irrigation or even portable water.
“Taking wastewater, or what we would call sewage, I was trying to treat it to such a high quality that it could be reused in a beneficial way,” Goodwill said. “The reuse purposes could include irrigation, recreation or, in some instances, it could be rendered to a potable quality and be distributed back to communities.”
The doctoral student, however, didn’t get the results he had hoped.
“Evaluating ferrate in a water reuse context just wasn’t working,” Goodwill said. “We were having challenges oxidizing and treating some of the target contaminates. I was frustrated and concerned, because it was one of my first funded projects as a young professor, and it wasn’t working out so great.”
Goodwill then read about a study by researchers at Texas A&M University that described a significantly improved performance by ferrate when a tiny amount of sulfite, a form of sulfur, was added.
He and his team of URI researchers have been studying this chemical combination and have made progress.
With positive results from the ferrate-sulfite combination, the next step is to learn why the two chemicals work well together and how they can be used. That’s one of the major objectives of the grant.
“We do not really understand the fundamental chemistry of what happens when you mix ferrate and sulfite,” Goodwill said. “We know that it probably includes the formation of what we call free radicals, which we want to make because those are the strongest oxidants and are typically successful at oxidizing or transforming contaminates that are the most difficult to treat.
“But we don’’t really know how they are made and how much of them are made. Until we know exactly what’s happening, we can’t optimize, leverage and deploy this approach.”
Goodwill, however, is excited about what being able to produce the right chemical combination could mean to small water treatment operations.
“The ability to generate free radicals, very strong oxidants, could be especially valuable to rural and small systems,” he said. “However, the current methods we have for advanced oxidation, meaning oxidation using radicals, are relatively complex and require onsite generation of inputs.”
An example of an advanced oxidation method can be found at the John J. Carroll Water Treatment Plant in Marlborough, Mass. The facility has four ozone generators designed to treat 275 million gallons of water on an average day, and a peak level of 405 million gallons a day.
But, as Goodwill noted, the system requires dehumidification, power supplies and cooling systems. Advanced oxidation is also complex and potentially unsafe.
“Those types of auxiliary systems are often out of reach or not the appropriate solution for small, rural systems,” he said. “If our only choice for advanced oxidation is to do what Boston does, I don’t think that’s an adequate answer for these small systems.”
He said ferrate is a viable alternative to ozone because it doesn’t have to be made on site, and combing it with sulfite is a far simpler and safer solution.
In terms of the number of water treatment systems in the United States, as opposed to the number of people served by water treatment systems, there are many more small ones than there are large systems, according to Goodwill.
“I’m hopeful that when we figure all of this out in a few years or so, rural communities, and perhaps communities in developing countries, will have a new tool available to do advanced oxidation in an operationally simple way,” he said.