Treating water is more than a profession for Nate Tillis. You could easily say it's a calling. His deep appreciation for water comes from his studies of kung fu and Eastern religions, and from teachers who include actor and martial arts expert Bruce Lee and Taoism founder Lao Tzu.

"What really got me interested were the philosophical properties of water and the way people relate water to life," says Tillis, at age 32 the supervisor of operations and maintenance at the Beloit (Wis.) Water Pollution Control Treatment Facility. "It's said about water that when it's still, it takes on the visage of whatever is in it. But when it's moving, it's aggressive — it can deteriorate even the hardest of rocks."

It was perhaps the mystical attraction to water that led him to change focus during his technical college studies from health inspection to wastewater treatment. He earned an associate degree in Environmental and Pollution Control Technology from Milwaukee Area Technical College (MATC) and later a Grade 4 (highest) Wisconsin wastewater operator license.

After 10 years in operations and maintenance at the treatment facility in Waukesha, Wis., he moved to the Beloit plant, where he's just finishing his first year.

Changing course

Tillis has come a long way from working in a Milwaukee pizza restaurant just after high school. "I didn't have any direction on what exactly I wanted to do," he recalls. "I had a new wife and a kid on the way, and I knew I had to do something." He struck up a friendship with the county health inspector who visited the pizza place, found that job prospect interesting, and enrolled at MATC to pursue a similar career.

The course work covered topics like food inspection, sanitation, bacteriology and epidemiology, but also air, soil and water pollution. "After my first semester, I gravitated toward water," says Tillis. "I enjoyed learning about the equipment and the processes, but I was also intrigued by water, not just as a resource but as a model for life.

"I had studied kung fu for several years, and I had studied Eastern philosophy. They both reference water as a model for how to live. There are so many amazing properties water has. Physically, it doesn't act the way we think it should. It has hydrogen bonds, and that changes everything: its boiling point, the fact that when it freezes it expands rather than contracts. It's a universal solvent. It has a neutral pH and a specific heat index of one. It's basically our ground zero for everything we measure."

Up the ladder

While in his first year of schooling, Tillis took a four-week internship in the wastewater department of a galvanizing company. That helped lead to his first full-time position, as a wastewater operator for a metal plating business.

He didn't wait long to start giving back to MATC: For the past eight years he has sat on the Advisory Committee for what is now the school's Environmental and Water Quality program. "Twice a year, they consult with graduates and people in the industry to keep the program current," says Tillis.

"I'm deeply interested in operator development," he adds. "In wastewater, there are a lot of qualified professionals, but on average they're near the end of their careers. There aren't enough young people coming along, so I'm trying to make a difference in that area."

He is now enrolled at the University of Wisconsin-Parkside in a four-year Sustainable Management degree program.

Taking a big step

After a year on the industrial side, Tillis was hired on at Waukesha. He made the move to Beloit — a role carrying much more responsibility — with confidence but a little trepidation as well.

"It was kind of daunting because I didn't know exactly what to expect," he recalls. "Two members of the team had been operators for longer than I'd been alive. I had considerable experience, but not to the level they did. I came in new, and I'm young, and I'm 5-foot-3, and I just didn't know how all that would go over."

It has gone over fine. From the start, Tillis worked hard to build rapport with his team members, who include:

Environmental technician III Joe ValeriusCertified wastewater operators Tim Cunningham, John Siam and Gary ZimmermanMaintenance technicians Pat Garvey, Gary Hallmann, Dave Hebb, Allen Hocking, Jeff Jones and Wayne SteurerInstrumentation and control technicians Scott Varney and Jerry MeKeelCustodian Suzanne Parr

He's grateful to director of water resources Harry Mathos for acting as a mentor: "He's helped me learn how to deal with people. I had to coach a couple of employees soon after I got here, and he sat in on those meetings. We typically talk in the mornings about things that are going on in the plant. Above all, he taught me to keep a positive attitude. As a leader, you need to show some positivity for people to feed off of."

Quickly impressed

Arriving at the Beloit plant, Tillis found much to be positive about. "You come to our plant and it's stunning," he says. "I was surprised to see how clean and new everything looked — even though it's a relatively old plant. It was put online on Nov. 14, 1991, so now we're reaching the point where a lot of things have to be replaced."

The facility lies near Interstate 43, about two miles from the downtown riverfront site of the former treatment plant. That site still hosts the larger of two main pump stations that deliver influent to the new 11 mgd design (3.5 mgd average) plant. It's a gravity-flow conventional activated sludge process with sodium hypochlorite for disinfection before discharge through a two-mile pipeline to the Rock River.

While the mechanical systems may be old, the plant's operation is sophisticated, thanks to the SCADA system built by instrumentation and control technician Varney, using iFix software (GE). "It's basically designed to fit our plant," says Tillis. "It's very intuitive. It's visually representative of the plant, and it has all the pertinent information that we want. When we need an upgrade, Scott can add it right on. When we want to look at specific data, he can give us access.

"Some plants use SCADA mostly for monitoring. We actually use ours for control. We can change the strength of our polymer. We can change our hypochlorite dosing. The vast majority of our pumps are run on variable-speed drives to save energy, save wear on the pumps, and enhance process control."

Meeting challenges

That's not to say life is without challenges. One immediate issue is the impending construction of a casino near the plant. While the casino will not be a big wastewater generator, its presence will require the plant to clamp down on odor.

To that end, the primary clarifier weirs have been boxed in, and control valves have been installed to reduce splashing and misting. In addition, a biofilter (Bohn Biofilter Corp.) scrubs the discharge air from the plant's preliminary treatment building. The odorous air is forced underground and percolates up through several layers of gravel and rock media — the process uses no chemicals.

Also challenging are phosphorus limits being imposed by the state Department of Natural Resources. Tillis expects an interim limit of 0.4 mg/L to be in effect beginning in 2016 and a final limit of 0.1 mg/L to take effect by 2018.

Rather than add mechanical or chemical treatment, the plant is contemplating using the state's adaptive management program for phosphorus. That means creating green spaces between farms and the Rock River to capture runoff and its nutrients. "Once we know what our interim phosphorus levels will be, we'll determine the scope of our project — how many parcels we'll have to develop and how many people we'll have to contact," Tillis says.

Improvements are also in the works for the biosolids program. Historically, the plant has gravity-thickened aerobically digested biosolids for land application as liquid. A new 3-meter belt filter press (Ashbrook Simon-Hartley) arrived in 2010, and the team is fine-tuning it with the aim of producing biosolids cake at 20 percent solids. Reaching that goal means increasing volatile solids destruction in the digesters. At present, the digesters operate in parallel; Tillis wants to operate them in series, instead.

"Our volatiles coming off the digesters have been in the 70 percent range," he says. "Based on what the experts tell me, there is a world of difference between 70 percent and 65 percent. We plan to feed into one digester and draw off the other. We'll have a gravity equalization line to keep both digesters at equal levels — we won't have to pump from one to the other."

Other challenges

Surprisingly, another challenge comes from the city engineering department's aggressive inflow and infiltration control program, which reduced average flows from 8 mgd to 3.5 mgd. "Our BOD loadings haven't changed, but we have more concentrated wastewater," says Tillis. "We're dealing with the challenge of being right on the precipice, of having limited leeway with our treatment because we no longer have the dilution we once did. It makes our process more susceptible to shock."

The most significant project in the offing is replacing the aging pumps at the two influent lift stations. The main station at the old treatment plant site contains five 250 hp Fairbanks Nijhuis centrifugal pumps that have been fitted with variable-frequency drives (ABB). The staff members have worked to optimize the pumps, but the ultimate solution is new pumps. They're developing a Request for Proposals in an effort to determine the best course of action. The other lift station uses old driveshaft-style pumps that will be replaced with dry-pit submersible pumps.

Greatest resource

As he leads the team through these changes, Tillis treasures each member's contributions. "I have a personality where I seem to get along with everyone," he says. "First of all, you have to recognize that everyone has specific talents. No matter what their position is, they have value to contribute to the plant. How can you cultivate that? How can you get them to perform at their best?

"It's important to have a good rapport with each member of your team so that you can talk to them as if they're not just co-workers but friends, too. I try to take a certain portion of my day and talk to the employees.

"Something I learned from my mom is: 'If there is no reason to say no, your default answer should be yes.' When someone asks you a question, your answer should be, 'Let me check on it — yes, we can see about it.' Then if the result is not what they wanted, they'll at least know you tried — at least they'll know you heard them out.

"The team members are the greatest resource at this plant. They know it. They've been here forever. They do the work. I'm support staff. I coordinate what they do, and the best way for me to do that is to listen to what they have to say."

When times get tough, Tillis can draw on a resource close to home: "I have two amazing kids (Gavin, 12 and Ethan, 8). They love coming down here to the plant. They both want to be wastewater operators. They're my inspiration for everything I do."