For most of us, we turn on the water faucet and clean water comes out. But we may not realize the water pipes that deliver the water to our homes have a micro slime inside them.
WVU professor and researcher Emily Garner has a grant from the National Science Foundation to look into micro-organisms in water systems. She spoke with News Director Eric Douglas to explain what she is finding.
This interview has been lightly edited for clarity.
Douglas: First off, introduce yourself and explain who you are.
Garner: My name is Emily Garner. I’m an assistant professor in Civil and Environmental Engineering at West Virginia University. I’ve been in that position for four years and I study the role of microorganisms and engineered systems for the treatment and transport of drinking water and wastewater.
Douglas: Let’s talk for just a second about what it takes to deliver water from the treatment plant to your house.
Garner: When drinking water leaves the treatment plant, it still has a really long journey to travel before it arrives at your home or the businesses in your community. It can take days or even weeks for the water to make that journey. It’s one of the biggest jobs that our water utilities have – is making sure that that water stays high quality and safe for people to drink from the time it leaves the treatment plant to the time when it arrives at people’s homes. Even a relatively small community might have hundreds of miles of pipe that are buried underground.
Douglas: That’s, that’s actually kind of stunning. I would never have thought it would be in the system that long. Is it going to a holding tank somewhere?
Garner: Certainly tanks are really prevalent throughout distribution systems, especially in West Virginia, where we’ve got a lot of hills. They can help us overcome some of the elevation differences that might exist throughout a community. Those things are also really important for holding water so the treatment plant can treat the same amount of water throughout the day and night and not need to kind of adjust to the fact that everyone wakes up at 6am and takes a shower. But water doesn’t usually sit in those tanks for days or weeks at a time. It’s just that when water has to travel through hundreds of miles of pipe, it can take a really long time. That time just starts to add up.
Douglas: Explain to me what biofilms are within the water distribution system.
Garner: It’s very normal in any aquatic environment. If you’ve gone down to the river or the stream, you might see kind of a film that forms on the surface of rocks. That’s exactly what we’re talking about in drinking water. But of course, the water is much cleaner. When that water leaves the treatment plant, the utility has dosed some sort of chlorine disinfectant to kill harmful microorganisms. But there’s lots of research out there that shows that there still might be some microorganisms present in that water. Most of those are going to be harmless, they’re not going to make people sick but as that water flows over the surface of pipes continuously, it can lead to formation of those biofilms.
We care about those for a number of different reasons. When they accumulate in great enough quantities, they can affect water quality in different ways like compounds that affect taste and odor. They could slough off into the water and lead to discoloration events. Really importantly, they can also create environments where harmful bacteria do get into the system. While these biofilms are totally normal, in small quantities, it is really important to have strategies to control them and to make sure they don’t get out of hand and start to accumulate in ways that can affect water quality.
Douglas: You’re not talking like big green slimy build up inside of a water pipe. This is a microscopic level, typically.
Garner: We’re talking about these really, really thin biofilms. But when they accumulate on the inside of many, many miles of pipe, it can still be something that can affect water quality.
Douglas: In West Virginia, especially in the rural areas, some of the smaller communities, there’s some aging infrastructure, there’s aging water systems. So what do we do about some of that? Is that a growing problem?
Garner: Certainly our infrastructure is aging across the country, but certainly in a lot of parts of West Virginia. I think it’s important to be really concerned about the state of that buried infrastructure that we can’t see that was maybe put in the ground 50, 60 plus years ago. And so that’s absolutely an important thing to be concerned with, and making sure that we can minimize some of these impacts to water quality.
Douglas: Is chlorine what we’re using and it just works best beyond anything?
Garner: It’s a balancing act. Chlorine is really, really important. You know, it wasn’t much more than 100 years ago that we had diseases like cholera that were affecting huge swaths of the population because we weren’t able to disinfect our water before we drank it. So chlorine is absolutely essential, making sure we can disinfect that water is absolutely essential.
But today, we do know that it can react with other compounds in water, like organic matter, to create compounds known as disinfection byproducts. A lot of these disinfection byproducts are possible carcinogens. And so we certainly want to minimize how prevalent those are in our water. It’s a really big balancing act for water utilities to deal with: how do they make sure there’s enough chlorine present in our water to kill microorganisms, while making sure that they don’t contribute to the propagation of these disinfection byproducts? And that’s one of the reasons we really care about control of biofilms. Because organic matter can accumulate in those biofilms — microorganisms are organic, they create organic compounds, to help them kind of stick to the walls of the pipe. And so controlling biofilms are also important to help make that balancing act a little bit easier.
Douglas: One of the big issues facing the water community is people who can work in these systems, who have a lot of these water facilities, are aging out or they’re retiring. Talk to me a little bit about what you’re doing to help get people who can work in the water systems?
Garner: This grant from the National Science Foundation that is supporting a lot of my work, it has two major goals. One is research, and the other is education. That education includes things like, I plan to work with a lot of undergraduate and graduate students so they will come out of this better trained to engineer good systems, designing good systems that can address some of these challenges that we’re talking about.
But the other part of my education component associated with this grant is through K through 12 outreach. My goal is to help K through 12 students better understand what opportunities they might have for careers in the water sector. I want them to, you know, decide whether or not they want to pursue careers in that field, how important water workers in our state are for the health of our communities.
Douglas: What haven’t we talked about?
Garner: I did want to mention that for this National Science Foundation project, one of our main goals for this research is to better integrate our understanding of the microbiology of drinking water systems with modeling of flow patterns present in drinking water distribution systems. With lots of other aquatic environments, we know that the forces that are exerted by flowing water can impact how biofilms grow, but we don’t really have a thorough understanding of how flow impacts what happens to microorganisms in drinking water distribution systems. And part of why this is so important, and interesting to my research team, is that one of our key hypotheses driving this research is that we think these conditions will be very different in rural areas where it can take many, many miles of pipe to reach even a relatively few number of homes in a small community compared to much more densely populated urban areas where we’ve got a lot more data on this subject.
That’s what one of our goals is, to better understand what some of the challenges that might exist to integrating flow modeling of distribution systems with understanding microbiology especially in rural communities.
