Helping Missouri communities with water safety choices
There are a lot of public water operators who would like to blow some steam right now.
Their frustrations flow from tightened federal regulations on certain “disinfection byproducts,” suspected cancer-causing chemicals created in the water treatment process. Public water suppliers aren’t steamed with the Environmental Protection Agency for regulating a health risk; they are frustrated because they don’t know what to do to purge the threat.
“The problem is we can’t turn around and start adding our disinfectant byproduct remover — there isn’t one,” said Everett Baker, an environmental engineer with the Missouri Department of Natural Resources who works with communities to ensure they are in compliance. “We’re equally frustrated at the Department [of Natural Resources] because we understand communities are willing to comply but don’t know what to do. It’s a lot easier to get into compliance when you know what to do to get into compliance.”
That is where Mizzou engineers can relieve some of the pressure. Faculty and students at the Missouri Water Resources Research Center are collaborating with communities to understand how the byproducts are formed and to optimize their removal.
“We’re helping communities to evaluate appropriate strategies,” said Enos Inniss, a civil and environmental engineering assistant professor who is leading a project involving three northeastern Missouri communities. “There’s a list of things you could do, so we’re working with these communities to evaluate which ones are most appropriate for their water systems.”
Nationwide, small communities are having the most trouble meeting the new standards. Big cities with a big customer base have the resources either to hire private firms to research solutions or to bring in expensive technologies, such as reverse osmosis systems.
Realizing small communities don’t have those kinds of resources, the federal government created a national network of eight Environmental Protection Agency Technology Assistance Centers. These centers provide low-cost assistance and expertise to small communities struggling to meet the new standards. One of these centers, the Missouri Technology Assistance Center (MOTAC), is housed in the College of Engineering-affiliated Missouri Water Resources Research Center, and it is through MOTAC grants that Inniss is helping three northeast Missouri communities, Monroe City, Trenton and Marceline, discover exactly where and how the unwanted disinfection byproducts are entering their water systems.
The basics are already understood: Disinfection byproducts result when chlorine and other disinfectants combine with naturally occurring organic materials in the water, such as decaying leaves. As doing without the disinfectants is not an option — the public frowns on cholera, typhoid and other such outbreaks — Mizzou engineers are focusing on managing the organic “precursors” that react with chlorine to form the unwanted, regulated byproducts.
“A lot of the methods we’re looking at are to prevent or at least lower the formation of the disinfection byproducts [as opposed to removing them after formation],” says Inniss, who earned his PhD in civil engineering at the University of Notre Dame and spent six years at the University of Texas at San Antonio before coming to MU in 2007. “If we can lower the amount of precursors that are present, then we don’t have to make adjustments to the chlorine dosage.”
For the three northeastern Missouri communities taking part in MOTAC’s “Small Systems Assistance Field Program,” the plan to lower disinfection byproduct levels has two phases. In the first, Inniss and his team of graduate students took water samples throughout the water systems, starting with points of raw water acquisition and going through the treatment process, water towers and distribution pipes. Then the team used specialized equipment back in Inniss’ lab at MU, equipment purchased with EPA grant monies, to determine the levels of organic precursors at each sampled point, as well as the levels of trihalomethanes and haloacetic acids, the two types of disinfectant byproducts regulated by the EPA.
That gave Inniss and his team detailed profiles that showed the potential for byproduct formation, as well as the actual byproduct levels, at each stage of the water system, which in turn allowed the researchers to locate optimal points for treatment. Those findings brought them to the second project stage, which is still ongoing and focuses on evaluating different treatment strategies. Because every system begins with different raw water quality, uses different treatments and distributes water in different ways, what works really well for one water system might not work at all for another.
As Inniss and his team go through the list of potential treatments for each community, no one is expecting to find a silver bullet; instead, Inniss expects most communities will have to do a combination of treatments, and some might have to make adjustments throughout the year to accommodate seasonal water changes. However, a general technique he is exploring now is “enhanced coagulation.” Treatment facilities already use coagulation, a chemical/physical process in which either iron or aluminum salts are added to the water to cause particles to become more attracted to each other. The water is then slowly churned, allowing clumps to form and unwanted solids — some visible, some not — to settle out, transforming turbid water into clear water.
That process also helps remove some of the precursors, but to optimize the effect, operators will need to add more iron or aluminum salts before churning, thus the name “enhanced coagulation.”
Another tactic Inniss is researching is using activated carbons to absorb the precursors; because there are several activated carbons on the market, he is running experiments to see which kinds work best for the different waters.
All of the methods Inniss and his team are exploring have been proven effective somewhere; innovation for them is limited to potentially new combinations of treatments. However, other researchers with the center are exploring new methods. Dr. Tom Clevenger, a civil and environmental engineering professor and director of the Missouri Water Resources Research Center, mentions he’s excited about a nanocarbon material impregnated with iron that a Mizzou Engineering grad student developed to remove arsenic.
“It’s really a super-material,” Clevenger said. “It was so-so effective for the intended purpose, but I think it might have potential for removing these precursors. If we got really lucky and it worked, then that would be a breakthrough, in my opinion.”
Helping communities sort through their options is a service that separates the University from a certified lab, which can also provide communities with profiles of their systems.
“The lab will send back: ‘Here are the results. You interpret what you want to do from here,’ ” Inniss explained. “When I go and meet with the community, I say, ‘This is what we did, this is what we found, these are some of the things we learned, and these are some of the things we think you can do.’ That’s where the communities that have chosen to use the university are getting an extra benefit from the relationship.”
It’s a benefit Donnie Parsons, superintendent of utilities at the Monroe City Water Treatment Facility, appreciates.
“I get to be involved,” he said of the process. “We help collect samples, we know where they are collecting, and we are able to run comparison tests at the same time. It just helps our operators out to be involved in the study and to see results, what the water was doing that day, at that temperature.”
Echoing this sentiment is Roger Sullivan, chief operator of the Marceline Water Treatment Plant. He said, “I’m able to make suggestions, ‘Let’s try this or try that or not use this, if possible,’ so it’s a real partnership between us, the University of Missouri and the Department of Natural Resources.”
Sullivan also points out the financial advantage of teaming up with Mizzou Engineering, an advantage that can add up to tens of thousands of dollars.
“We’re a town of 2,500,” he said, after mentioning the cost benefit. “It doesn’t take long to figure out who you’re going to go with.”
Inniss anticipates the project communities won’t be the only ones to benefit from the research. He’s hoping to unravel mysteries concerning which precursors react to create which byproducts, along with how and in what conditions.
“There are still a lot of questions that need to be answered, and the minutia of the details that we’re looking at from that perspective are not what the communities need,” he said. “They need to know, ‘ If I do this with my water, will I see a reduction in disinfection byproducts?’
“We’re able to give them that information, but then we also start asking why: ‘Why does this strategy work for Community X but a different strategy works for Community Y?’ As we start getting a better feel for how the different strategies tie to water quality and other variables, then we put ourselves in a position to help more communities.”
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