The improvements just keep coming at the Glasgow (Kentucky) Wastewater Treatment Plant.

Built in 1962 as a trickling filter plant with upflow sand filters and anaerobic digesters, the plant was upgraded four times, most recently in 2014. Today, it operates as a 4.0 mgd SCADA-controlled extended aeration facility with new headworks, circular clarifiers, biosolids press and peracetic acid instead of chlorine for disinfection.

The improvements haven’t gone unnoticed. For outstanding performance, Glasgow won the 2017 Kentucky Water & Wastewater Operators Association Plant of the Year award. Last year, the Glasgow Water Co. received the Kentucky Excellence in Energy Leadership Award sponsored by the Kentucky Energy and Environment Cabinet.

“The plant is in a lot better shape than when I got here,” observes Jacob Billingsley, superintendent, who joined the staff in 2010.

Service provider

The Glasgow plant serves its community of 15,000 people in south-central Kentucky, not far from the Tennessee border. It also provides treatment for nearby Barren River State Park and two elementary schools roughly 8 and 15 miles outside the city limits. There are just over 1,000 commercial clients and 67 industrial users.

Wastewater enters the plant through an influent pumping station with new submersible pumps (Flygt - a Xylem Brand) that Billingsley calls “rock solids.” They were added during the 2014 improvement project. The headworks, also upgraded in 2014, includes a pair of perforated plate screens (Parkson Corp.) and a PISTA Grit system (Smith & Loveless).

Following primary treatment, the flow enters a series of seven aeration tanks with Hoffman swing air diffusers (Hoffman & Lamson, by Gardner Denver) that use detachable socks at the pipe ends to disperse air, a system that dates to 1977. Centrifugal blowers (also Hoffman & Lamson, by Gardner Denver) driven by GE Industrial Motors and Baldor Electric motors provide the air.  

Secondary effluent settles in two 100-foot-diameter, 16-foot-deep clarifiers with turntables (WesTech Engineering) and brush systems (Weir-Wolf from Ford Hall Co.). New Gorman-Rupp and Vogelsang pumps handle return and waste activated sludge.

Ready for the rains

“The circular clarifiers were added in 2014 and replaced our old rectangular basins,” Billingsley says. “They give us much better settling capability and have added solids capture capacity. We get solids at the bottom of the clarifier thick enough to press without polymer.”

Disinfected effluent flows to Huggins Branch, a small creek that feeds into South Fork Creek and eventually the Barren River.

To handle wet-weather overflows, which can push the plant from 1 to 17 mgd, there’s a new 7-million-gallon equalization basin, built in 2015 and designed to fill by gravity. An existing pump station was repurposed to deliver water from the EQ basin to aeration tanks. 

“It really helps,” Billingsley says. “If we get a 2- or 3-inch rain, we can handle up to 9 mgd, but anything over that gravity flows into the EQ tank to be fed back into the plant. We went to over 17 mgd during storms in September 2017. In the old days, we’d have to shut our blowers off and let solids settle in the aeration tanks.”

Highly automated

Biosolids are digested and then, in cold weather, dosed with polymer and dewatered using a rotary fan press (Fournier Industries) installed in 2011. “It has worked great for us,” Billingsley says. “We run it about 3 1/2 days a week. Up to this year, we’ve spent less than $400 for parts, and we only use a gallon and a half of polymer an hour. That’s our biggest savings.”

In summer, solids are spread on drying beds to save on power costs. In all seasons, dewatered cake is trucked to the city landfill.

A SCADA system (HTI Instrumentation) provides monitoring and control of the entire system, including remote access. Billingsley appreciates the ability to dial up plant operations, receive alarms and make process adjustments using his cellphone. “We had some SCADA on our lift stations and at some points around the plant before, but the 2014 upgrade put SCADA on everything except our effluent outflow.” That will be added during the next phase of upgrades.

“Having the SCADA system decreases the chances of a failure and loss of solids,” Billingsley says. Staff can see rising flows and make adjustments to containing the flow among the aeration basins and clarifiers.

A quality staff

The in-plant laboratory has also undergone a face-lift. It is state-certified for all weekly and monthly NPDES samples, plus surcharge samples for local industries. All full-time treatment plant staff members are trained in lab procedures. Billingsley is proud of that group, which includes a young tandem of operators: Tyler Bragg, also lab supervisor, and Adam Headrick, also lab technician. Two retirees come back to work part time. “We’re solid,” Billingsley says. “We’re all Kentucky Class IV operators and are cross-trained in all plant operations. Everybody understands all the SOPs (standard operating procedures). Plus, the retired guys really help out. They’re familiar with all our operations. Without them, we’d have to hire another full-time person.”

In addition to the lab work, the Glasgow team handles most plant maintenance: “We pull pumps, replace coolant and inspect impellers at least twice a year. Unless it’s something really large, we fix it in-house.”

Still improving

While the city has invested more than $12 million since 2011 to keep its processes up to date, Billingsley sees even more improvements and adjustments ahead. A bulk tank for peracetic acid will replace the tote system the plant uses now. “We made the move away from chlorine for safety reasons, generally. The acid is also more environmentally friendly. It’s totally biodegradable, and we’re getting really good results with it.

“Don’t get me wrong, chlorine worked great. But we were using 1-ton cylinders, and with the community close to us, there was always the risk of a leak and possible evacuation of the neighborhood. We’re spending a little more, but we’re looking out for the safety of our operators and our residents.” Peracetic acid also avoids the risk from disinfection byproducts.

Another improvement, long overdue, will be the replacement of the aging swing air diffusers: “We’ll be tackling them soon. They’re 40 years old. We’re seeing some deterioration and pitting. We’re also getting some fouling when trying on/off aeration.”

With new aerators, Billingsley expects to be able to shut off the blowers for short periods each day to operate with a lighter mixed liquor, saving on energy while storing solids. The team also expects to make more modifications to the aeration basins to enable biological nutrient removal. 

The Glasgow crew already benefits from another modification; this one homegrown. “We figured out that we could take the filtrate off the rotary fan press and run it directly to our drying beds,” Billingsley says. “We had enough drop to do it without having to pump it.” The staff installed the necessary piping. In the first few months, the filtrate reconfiguration removed 8,000 pounds of solids that otherwise would have gone back to the head of the plant.

Energy efficient

Of all the improvements, Billingsley and his staff may be most proud of reducing energy usage saving significant dollars. Glasgow took part in an energy optimization pilot study with the state Division of Compliance Assistance, University of Kentucky (Don Colliver), University of Memphis (Larry Moore) and U.S. EPA Region 4.

Through treatment process changes, variable-frequency drives on the blower motors, dissolved oxygen meters, SCADA, and the addition of LED lighting and occupancy sensors, Glasgow cut overall power consumption by 25 percent. The $250,000 invested in energy improvements, added in February 2017, could see payback in just four years.

Glasgow also takes advantage of a unique opportunity available because the landfill is nearby. “The landfill produces methane gas,” Billingsley says. “We can tap into the methane gas generator if we have a power outage. We have Siemens switchgear on our blowers, RAS and WAS pump stations and the main building. It’s our backup to our normal power source, the Glasgow Electric Plant Board.

“During an ice storm, we would be able to keep power and save money. I don’t know of any other plants that have a similar opportunity, but it’s pretty clever. By taking our biosolids to the landfill, I know we’re helping the cause.”

And, there’s still more. Billingsley and his staff have identified several air leaks in equipment and yard piping that could be wasting up to $4,000 worth of air per month. They plan to fix those in the last phase of plant improvements.

These and energy saving plans for the future made Glasgow a winner in the Kentucky Excellence in Energy Leadership Award competition. Rick Bender, executive director of the Kentucky Office of Energy Policy, commended the Glasgow Water Co. for optimizing wastewater operations through energy efficiency.

“Not only have they realized significant savings,” he says. “They have demonstrated leadership for the citizens of Glasgow. They can serve as a model for other wastewater operations in the commonwealth.”

Brendan Held, environmental engineer with the U.S. EPA Energy Optimization Program in Atlanta, adds, “Under Jacob’s leadership, the staff showed great enthusiasm and adaptability while taking steps to reduce excess aeration energy usage. They really pushed the envelope to maximize savings.”

Bench strength

The Glasgow (Kentucky) Wastewater Treatment Plant runs with three full-time Class IV operators, but it has a little extra in reserve. Superintendent Jacob Billingsley has contracted with two retired operators to help out on a part-time basis as needed.

They’re both Class IV operators, and Billingsley says they’d rather come in and do a little part-time work than just sit at home. That’s the way Ronnie Poynter looks at it. Poynter loves working at the plant where he was superintendent before his retirement two years ago: “I was there 37 years, and now I just go in and run the dewatering press. I know how to do it, and I enjoy doing it. There’s no stress.”

David Huffman retired on Jan. 1, 2016, after 29 years with at the plant. Now he spends just about every weeknight refereeing high school football and Little League baseball. Two days a week, he’s back at the plant: “It’s an all-new plant now, and there are different things to learn. I enjoyed it back then, and I still do.”