When Melinda Ward was 5 years old, she would climb a grassy hill to the digesters at the local clean-water plant, and then roll down, just for fun.

She wasn’t trespassing. In fact, she was welcome: Her father, Lynwood Sessoms, was superintendent of the plant in Tarboro, North Carolina. Over the years, Ward spent many hours at the plant, “hanging out” with her dad, going with him on rounds, helping pull samples, observing lab work and doing odd jobs. She didn’t do it for pay — instead, she was rewarded with valuable lessons.

“One thing my father always taught me was to walk through the plant on a regular basis to see what everything looks like, smell what everything is like, listen to all the different sounds, and get a feel for the plant,” says Ward. Today she tries to instill that sense of awareness in her team members as superintendent of the Mebane Bridge Wastewater Treatment Plant in Eden, North Carolina.

Since she arrived in Eden nine years ago, Ward and colleagues have dealt successfully with a sharp drop in industrial flows to the plant, rated at 13.5 mgd. Ward has also pitched right in to serve on committees of the North Carolina Water Environment Association, promoting plant safety and operator training and development. For her efforts, she received a 2016 William D. Hatfield Award from the NCWEA.

Natural attraction

Although she grew up with the clean-water industry, Ward didn’t set out right away to follow in her dad’s footsteps. After high school, she enrolled at Western Carolina University unsure about a career direction.

“Once I started exploring different fields, I realized I didn’t like anything except the environmental field,” she recalls. “My father was steering me toward private business, but once I started taking classes, the ones that interested me the most were those dealing with water and wastewater.”

She finished a degree in environmental health in 1993, along the way doing an internship at the Tarboro plant, then spending a summer in a clerical role with an engineering firm and contractor completing a plant expansion for nutrient removal at that facility. “Over the next Christmas break and the following summer, I came back as a construction worker,” she says.

Her first job after college was as a lab technician at the water plant in Rocky Mount, about 20 minutes from Tarboro. A year later, she became lab supervisor at the wastewater treatment plant, where she met her future husband, Michael Ward, who was doing an internship there. He then went to work in Clinton, North Carolina, and soon became plant superintendent. They married a couple of years later. She joined him to live in Clinton and ran a small plant in a nearby community.

Ward took several years off as a stay-at-home mom. Eventually, her husband took a job with the Henry County (Virginia) Public Service Authority, and in January 2008 she went to work for Eden, on the Virginia-North Carolina border about 30 minutes from their home.

Low-flow challenges

Eden, population 15,500, was incorporated in 1967 with the consolidation of three towns. Its clean-water plant was expanded in 1992 from 6.75 to 13.5 mgd design capacity, largely to accommodate flows from textile producers.

Wastewater passes through bar screens and a US Filter aerated grit chamber (Evoqua Water Technologies) before directly entering the secondary process. “When I started working here, a lot of the textile manufacturers had been leaving, but the flow was still about 6 mgd,” Ward says. A couple of years later, a clothing maker that had been sending up to 3.6 mgd closed down, cutting the plant flow by more than half.

Today, the flow averages just 3.5 to 4 mgd, and that creates challenges. “We have two aeration basins that each can handle about 7 mgd, as well as four clarifiers,” says Ward. “So when the flow stopped coming from the clothing plant, we saw a lot of issues real quickly with the low flow going through this plant.”

Part of the answer was to close down one aeration basin and two clarifiers. Valving work had to be done to shut off one basin and equalize the flow to the two remaining clarifiers. Then came the challenge of optimizing the process. “We had to learn the optimal levels for everything,” Ward says. “Technically, we have an extended aeration plant, but with only 3.5 mgd, the water sits in the basins so long that we can’t follow typical textbook procedures for keeping optimal treatment.

“The textbook will tell you how your plant should run, but you’ve got to check so many things. You’ve got to keep track of the bugs and the sludge levels. We have trouble maintaining the sludge blanket in the clarifiers. Most of the time it’s less than a foot in each one. We had to experiment with wasting. Our mixed liquor suspended solids is not what textbook says. We had to figure out the optimal MLSS for summer as well as winter.”

Issues upstream

Another issue was that the aerators had to run essentially around the clock to keep the basin contents mixed. That wasted electricity. The remedy was to install three Medora Corporation - SolarBee / GridBee solar-driven mixers. “That way, during the day we can turn some of the aerators off for a few hours, usually during the peak hours. We were able to reduce our electric bill by 31 percent. In terms of dollars, we saw a decrease the first year of a little over $61,000.” A fine bar screen (MN Water Treatment Solutions) installed between the grit chamber and the aeration basin traps fine fibers that at first were fouling the solar mixers.

Meanwhile, the flow reduction caused trouble in the 5 mgd pump station and 5-mile sewer line that had delivered the clothing plant’s wastewater. “It went from averaging 4 to 4.5 mgd to less than 1 mgd,” says Ward. “That flow, instead of taking a day or so to get here, now takes five days if not more. So we started seeing septic conditions in the collections system.

“Within a few months we started seeing corrosion in our headworks area. The only thing we could attribute it to was the change in the water coming to us. We had to replace a number of the electrical boxes with fiberglass or stainless steel.” Mark Bullins and the collections system team took to adding calcium nitrate at the pump station to keep the wastewater fresher so that less hydrogen sulfide is produced. They also adjusted pump runtimes and began adding water to sustain the flow and dilute the wastewater enough to keep chemical addition low.

Despite it all, the plant discharges high-quality water to the Dan River. Effluent typically contains less than 5 mg/L BOD and TSS, against permit limits of 30 mg/L for each. Effluent ammonia is usually not detectable.

Team ethic

Running the plant is a team activity. Ward relies on Joel Freeman, chief operator and pretreatment supervisor, to keep operations on a daily even keel. The operator team includes Ron Wright, Chris Powell and Michael Baxter, relief operators; and David Greer, Charlie Manley, Glenn Pulliam and Matthew Tuttle, shift operators.

Jerry Prillman is maintenance supervisor; his team includes electricians D.J. Tucker and Carl Booth, and mechanics Dan Spence and Michael Brown. They keep the equipment running and help with troubleshooting problems in the pump stations and the plant. “Chris Powell, our lab technician, is great about keeping up with the numbers,” Ward says. “If anything changes suddenly, he always lets me know and helps in determining the cause.”

As a general approach to leadership, “I try to get everybody’s input on everything,” Ward says. “For me, it’s about getting to know how the plant runs. It’s a very personal process at each plant. Once you take ownership of it, that changes your philosophy. You don’t just go out there and do a job. You really try to make it your own.

“I try to instill that in my team. Everybody here should be able to take ownership, because when they’re running the plant on their own, they’re responsible for everything that happens. I show them how to look for signs of something different going on — what to look for, what to listen for.

“We look at the mixed liquor, the color, any foam that may be appearing. We check the bugs every week to make sure we’re keeping up with the biological activity in the basins. I try to share with them what each change means so they know what kind of operational changes to look at and try. We never do anything abruptly. We try to slowly make little changes until the problem corrects itself. Everybody takes pride in how the plant runs.”

Looking ahead

They may soon have more effluent to take pride in: new development is in the offing. Just across the Virginia/North Carolina border from Eden, several hundred acres are being developed as an industrial park. Although no ground has been broken yet, Eden has extended water and sewer lines to the state border. “We’re hoping our industries will slowly build back up,” Ward says. “We’re trying to be prepared.”

Meanwhile, the plant expects in the next year or two to begin treating leachate from an electric power company coal ash landfill. Effluent nutrient limits are most likely in the future for Eden’s and other plants in the Roanoke River basin. “So we are trying to plan for alternative treatment so that we will be ready for the future,” Ward says.

The biggest item on Eden’s agenda is a U.S. EPA administrative order to improve the collections system. “A lot of the collections system is pretty old,” says Ward. “There are sections that date back to the 1920s. We’ve done a whole lot to fix the problems, but only to the extent we’ve been able to get money.” Now, with a comprehensive plan in place and a state grant and loan package in hand, the city faces a major upgrade program it must complete in five years.

Still learning

Ward looks to the future confidently. She’s well equipped for her role with a state Grade IV (highest) Biological Wastewater license, as well as certifications in pretreatment, lab analysis, land application, surface water and water distribution. She’s looking to upgrade her Grade II Collections certification to Grade III.

“I’ve had a variety of experience,” says Ward. “Whatever I have experience in, I go to one of the schools to get licensed for that area and keep a well-rounded education. That way I understand everything a little bit better.”

She gives back by serving on NCWEA committees, notably the Risk Management Committee. The Eden plant is certified under the state Safety and Health Achievement and Recognition Program (SHARP) and in 2016 received the NCWEA George W. Burke Jr. Safety Award.

Ward also chairs the state Wastewater Board of Education and Examiners, which aims to ensure that wastewater treatment class material is up to date and truly reflects what today’s operators need to know. In addition, she is vice-chair of the state Professional Wastewater Operators Committee, which hosts group tours for operators at treatment plants to expand their knowledge of processes and technologies.

Her advice to operators aspiring to grow in the profession: “Try to diversify as much as possible. Look into all areas. We encourage cross-training at our plant so that operators know not just what their job is but what others’ jobs are. You can’t have tunnel vision to just look at your little area of the world. You’ve got to see all the parts that go into it.”

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The solids side

Biosolids handling has been an issue for the Mebane Bridge treatment plant. Today, Synagro Technologies handles the biosolids (700 dry tons per year) under a design-build-operate contract. The company dewaters the material on a press to 18 to 20 percent solids and applies it to area farms. A covered pad provides storage against bad weather that could disrupt land application.

A key concern is how to accommodate rising biosolids production if new development drives plant flows upward. The one aerobic digester holds 2 million gallons, dates to the original plant built in 1967 and is in poor condition. Repairs would be costly, and room for a new digester is limited.

Therefore, Melinda Ward and the plant team plan to install the CleanB biosolids treatment solution (BCR Environmental), which chemically treats waste activated sludge and produces Class B biosolids in less than 10 minutes, bypassing the digestion process.

The one-stage process combines sulfuric acid and sodium chlorite in a generating system to produce chlorine dioxide, which in turn is injected into the solids stream to disinfect and deodorize. The compact system has control and monitoring devices to record process parameters and deliver a consistent end product.

“The system comes in a box about the size of a tractor trailer,” says Ward. “You can waste sludge directly to it. We toured sites in Florida and had a demonstration in August where they brought a system in at pretty much full scale. They ran our sludge through the system and the press just to make sure it would work. We had to make sure the state was on board too, to approve it, because it has never been done in North Carolina.”