Until the upgrade for the Warren (Ohio) Water Pollution Control facility becomes reality, Mike Welke and his crews nurse and coerce every piece of aging equipment.

The plant was upgraded in 1988, and the biosolids facility went online in 1998. “Our greatest challenge is age,” says Welke, biosolids manager and maintenance supervisor. “Each day I walk in wondering what’s next. I’ve sweated out how to do things more often than I care to admit.”

Ingenuity and an associate degree in electrical engineering technology from Youngstown State University have been strong assets for Welke, enabling him to work with the resources at hand. His ability to keep equipment running and the plant compliant is one reason he won the 2014 F. D. Dean Stewart Award from the Ohio Water Environment Association (OWEA) recognizing exemplary efforts in plant operations, maintenance and recordkeeping.

Treatment trains

Built in 1962, the 16.5 mgd (design) activated sludge plant averages 12 mgd from more than 15,800 customers in Warren, Champion and Lordstown. Wastewater flows past a raw influent sampler (Hach), over two catenary bar screens and a manual bar screen (E & I Corp., a Division of McNish Corp.), and into four Detritor tanks (Ovivo USA).

Leaving the tanks, liquid passes through five primary settling tanks. Secondary treatment occurs in four aeration tanks and a mixed liquor channel. After four final clarifiers, a chlorine contact tank and two post-aeration tanks, the effluent discharges to the Mahoning River.

Sludge passes through a gravity thickener into a holding tank. The biosolids facility is designed to process 240 wet tons per day, yielding Class A exceptional quality biosolids. It has two 2-meter Klampress belt presses (Alfa Laval Ashbrook Simon-Hartley), dual conveyors (Serpentix Conveyor Corp.) and an EnVessel Pasteurization system (RDP Technologies) that uses electric heat and hydrated lime. The facility won first place in the U.S. EPA 1999 National Biosolids Exemplary Awards.

Welke was a maintenance mechanic 3 when the biosolids plant went online. Then Director Tom Angelo moved him to the Biosolids Division and shared his goal of aggressively marketing the product using the brand name Nature’s Blend. “His ideas intrigued me, and I became very interested in the beneficial reuse of biosolids,” says Welke.

As a biosolids technician, he worked with engineers as they finished the build. The experience solidified his understanding of how components operated, and that helped him through the startup phase. Welke worked with the electrical engineer to verify that the circuits met plant specifications. Later, he explained situations over the phone to engineers, then implemented their suggestions.

“It was hands-on work — just what I went to school for,” says Welke, who has 27 years with the city. “I initially envisioned myself as the person who built and tested prototypes based on engineers’ designs of amplifiers or circuits, then suggested modifications if they didn’t work,” he says. “This is one of those weird life situations that worked out well. My training transitioned seamlessly into the wastewater industry, and I wouldn’t change a thing.”

Duty calls

Welke joined the city in 1988 and worked his way up to his present position. He manages the biosolids facility and 14 people who maintain the collections systems, seven lift stations, and treatment plant equipment. His degree allows him to maintain the facilities’ electrical systems.

Because of time constraints, Welke relies on versatile Paul Geist, lead maintenance mechanic 3, and Jim Valentine, maintenance mechanic 3, to manage daily treatment plant operations. Tom Yauger, lead wastewater operator, monitors the treatment process and alerts Welke to major changes that would require his presence. Welke depends heavily on Ryan Hathhorn, lead biosolids technician, to oversee production and two other technicians. When situations turn difficult, though, Welke gets down and dirty with his crews.

One example was Christmas Eve 2010, a Friday. A pipe clamp had loosened in an inground pump station, allowing sewage to flood the dry well and short out the two 40 hp pumps. Welke responded with his crew. He called John Silbaugh of the Sewer Division, who brought the city’s Vactor combination truck and its crew. After they lowered the level in the dry well, they shut off the power and closed the inlet valve.

“We started portable heaters and used dielectric sprays to dry out panels, contactors and circuits,” says Welke. “If I couldn’t dry one of the motors enough to start the pump, there wasn’t a spare at the shop and no stores would open until Monday.”

Jim Wilden, plant superintendent, was also present. While components baked, workers tightened the pipe clamp and cleaned. Around midnight, Welke restored power and switched on the redundant pump. It ran. “John and his men stayed with me the whole time,” says Welke. “I was proud of my crew, because many were newer and hadn’t seen this before.”

Quality product

Welke devotes most of his attention to the biosolids plant. The dual train can process 240 wet tons per day, but the treatment plant averages 36 to 40 wet tons.

The extra capacity was designed for redundancy and to accommodate material from other municipal plants that contracted with Nature’s Blend processing facility.

“We can make anything into Class A exceptional quality material, but it must have a marketable appearance,” says Welke. “Therefore, we conducted trials with material from local facilities and New York City.” The latter produced a sloppy product with high ammonia, both unacceptable to farmers. Because correcting the situation would mean extra processing and increased costs, city officials stopped receiving material from New York.

While the price partners paid covered production costs and was less than the landfill tipping fees, most facilities had no way to ship sludge. “Once we added transportation costs to production costs, communities chose to landfill,” says Welke. “The bottom line blinded them to the benefit of reuse.”

That left Warren to market its own product. Most went to farmers for $1 per dry ton, but some was mixed into Nature’s Blend potting soil. Between 2000 and 2007, 450 Giant Eagle grocery stores sold 6-pound bags of the product in four states.

The program ended when the U.S. EPA held Warren accountable for a misstatement in its biosolids management plan that said all products would meet 503 regulations for all parameters including pH. “Officials wanted the potting soil to have a 10.5 pH, which would have burned every plant it touched,” says Welke. “Potting soil needs a neutral pH of 7.”

Today, farmers apply the plant’s annual production of 2,500 to 3,000 dry tons. “We start with 4.5 to 5.5 percent feed solids that dewater to 24 percent cake,” says Welke. “After pasteurization, the granules are 36 to 40 percent solids.

“Besides the EPA, our greatest obstacle was and remains the municipal mentality of how quickly and cheaply can I get rid of this,” he continues. “We never convinced partners and potential partners that if they put a value on their product, others would eventually believe it.”

Positive reinforcement

Setbacks in the program haven’t stopped Welke from talking about biosolids to grade school students during Earth Day. One of his favorite demonstrations involved Nature’s Blend potting soil. He gave classes little growing pots and some sunflower and marigold seeds, then asked the kids to plant them in the organic fertilizer. “One class sent a picture of marigolds growing so well that the kids gave them as presents for Mother’s Day,” he says.

Welke needed figures, not flowers, to convince some council and community members to stay the course. “We average 8,000 to 10,000 wet tons of biosolids per year, and in 2014, it cost $34 to $59 per wet ton to process,” he says. “Selling the product to farmers generated $11,865, which didn’t offset production costs.

However, even Milorganite, the most successful biosolids program in the nation, doesn’t generate enough income to cover production.”

A recent decrease in landfill tipping fees reopened the conversation. “While fees of $40 to $50 per ton sound enticing, I still have to turn the material into cake before landfills will accept it,” says Welke. “Last year’s figures show it is at least $200,000 cheaper to hold our course. We’re much further ahead and we believe beneficial reuse is the responsible choice.”