Treating water with low turbidity with marginal seasonal fluctuations in iron and manganese keeps operators busy at the Lawton (Okla.) Water Treatment Plant. Their routines were complicated by drought and the repair of a leaking clearwell.

Superintendent Carl Gray, a Class A (highest) water and wastewater operator and laboratory technician, worked alongside six operators until his promotion last October. He witnessed their ingenuity and dedication to water quality. “They always put the interest of the plant before personal interests, ignore any friction between them and concentrate on what needs to be done,” he says. “Their coterie of fellowship forms the health and backbone of the plant.”

The highly motivated operators impressed Gray, president of the Oklahoma Water & Pollution Control Association and former award committee member. In 2013, he nominated Class C operators and laboratory technicians Scott Golden and George Spicer and Class B laboratory technician Lyn Kisner for awards.

Golden won Outstanding Water Operator of the Year (the Stapley Award) and Kisner was named Laboratory Technician of the Year. Both had worked at the plant for two years. With only 18 months under his belt, Spicer received the Newcomer of the Year Award. Other plant personnel include Mike Sass, line supervisor; Courtney Breshears, chief chemist; Guy Neely, Wade Lewis and Bret Kelly, maintenance technicians; and Dustin Childers, John Elwell, Nick Joslyn, Nicki Watts, Robert Sandford and Michael Simpson, operators.

Dual treatment trains

The 40 mgd (design) plant, built by the City of Lawton, was upgraded in 2005 to enhanced coagulation with high-rate clarification and dual-media filters. Finished water is distributed through 525 miles of mains to nearly 100,000 customers.

Water from Lake Lawtonka flows by gravity 750 feet through a 42-inch pipe to the plant, where sulfuric acid and liquid alum are added to begin enhanced coagulation. After the water passes through a bar screen, it enters the east and west treatment trains. Each train has a vacuum assist Superpulsator clarifier (Infilco Degremont) that mixes cationic polymer with the water before it flows to a three-baffle vault. Injectors in the vault introduce ozone — produced on site from liquid oxygen and an ozone generator — as a pre-disinfectant.

From the ozone vault, water enters the FilterWorx (Leopold – a Xylem Brand) filters with 6 inches of sand and a 34-inch cap of granulated activated carbon to help control taste and seasonal odors. “We also feed powdered activated carbon to the SuperPs if odors persist,” says Gray. “For iron and manganese problems, we feed 35 percent peroxide, liquid alum or a cationic polymer on the filters.”

A 30-inch prestressed ductile iron pipe transports water to the 2-million-gallon above-ground concrete finished water storage tank at the plant. Just before distribution through four lines, injectors add liquid ammonium sulfate. A 42- and a 30-inch gravity line feed three 5,000 gpm PACO (Grundfos) pumps in Station No. 4. A 24-inch line supplies the Fort Sill Army base, while another 24-inch line feeds rural districts.

Blowdown valves in the Superpulsators remove sludge, which flows to an equalization basin, then to a sludge clarifier where it mixes with a nonionic polymer and aluminum chlorohydrate and settles out. Effluent discharges to Medicine Creek. Sludge is sent to a pump station, then to a three-cell lagoon discharging to an outfall.

The in-house laboratory uses ozone analyzers from WEDECO – a Xylem Brand, Hach 1720C online turbidimeters, a desktop analyzer, a PLC analyzer (Evoqua Water Technologies) and spectrometers.

Nature’s surprises

The process is not without its challenges. Operators expect iron in the raw water, but they find outbreaks of colloidal manganese harder to treat. By July and August, the condition can turn raw water the color of tea and produce an odor.

“This isn’t elemental manganese,” says Gray. “It’s bound up with organics and must be burned out. Ozone helps, but manganese comes back into solution in the next treatment phase. Our challenge is to keep it out of the water, and we’re researching ways to do it.”

Another challenge is getting chemicals to the plant. Freight is often the overriding factor when Gray accepts bids, because caustic soda arrives in the Port of Catoosa on barges, then must be trucked 200 miles to the plant. To keep from running out of chemicals in summer, Gray awarded primary and secondary trucking contracts. “We need chemical deliveries within three days of the orders,” he says. “If one company can’t deliver on time, I call the second trucker.”

The facility also has two tasks seldom seen elsewhere. Every week, operators check piezoelectric sensors that measure compressive loading (strain) along the Lake Lawtonka dam. The sensors detect shifts in the structure or changing water levels. Staff engineers inspect the dam annually. During seven- to eight-year drought cycles, operators routinely unhook the clutches and run the motors that drive the dam’s sluice gates. However, years can pass before lake levels and downstream conditions are right to exercise the gates for flood control.

Tapping resources

In 2012, operators faced their biggest upheaval when the clearwell went offline for two years of repairs. During its absence, they buffered water in the finish water tank. “We were walking a tightrope,” says Gray. “At 17.2 feet, the finish tank overfills into the clearwell, but contractors were building the new one inside it. If the level in the finish tank fell below 10 feet, some pumps lost prime. We had to regulate flow manually throughout the day.”

The need for constant adjustments alerted Gray to a problem. On some days he had too many people in the control room and had to look for things they could do. On other days, he struggled to find someone to cover a shift. For help in drafting a staffing plan, Gray turned to Golden, who had worked eight years in the city’s revenue services division and at the wastewater treatment plant. He used that experience to schedule two operators per shift.

“I implemented his idea,” says Gray. “It guarantees that someone is always at the plant if the other person doesn’t come in. Double coverage is a safety initiative should something happen to an operator. Scott’s plan made our 24/7 operation more consistent.”

Gray was also impressed with Golden’s ability to apply general knowledge to troubleshooting. “He pays attention,” Gray says. “For example, when he checked the computer monitor and noticed the water level rising in the sludge equalization basin, he went to the basin to verify what he saw instead of recording the water level on a form and walking away.”

Golden’s investigation revealed a blowdown valve stuck open, and yet the water hadn’t risen in the basin during the last two shifts. Gray suspected the valve had been air-locked and that the air bled off over 16 hours. “Scott caught the discrepancy before it became a problem, which impressed the awards committee when they interviewed him,” Gray says.

Meanwhile, in the laboratory, Kisner and his team perform almost 80,000 analyses annually, including tests for rural water districts and Fort Sill, and 90 coliform tests monthly. Besides the daily cleaning and calibration of instruments, Kisner ran verification samples to check online instrumentation. Other tasks included special testing such as high-low chlorine demand in the system and algae identification. Kisner has an associate degree in microbiology.

“Lyn has moved on since the award, but he left a proud legacy,” says Gray. “Probably his greatest contribution was bridging the communication gap between our operators and dedicated maintenance staff. He explained the different analyses to them, what they mean, and how they work in the plant’s design. Now, instead of just fixing gears and motors, they understand the process.” Golden was promoted to Kisner’s position.

Seizing the initiative

Spicer may be a newcomer, but his thoroughness and demeanor reflect his years as a U.S. Army paratrooper and trainer. He impressed Gray by looking for trouble on his rounds before it happened. For example, if a valve malfunctions at a sample point, chemical drains into a sump, triggering a float that closes the valve. If the sump isn’t running, the area floods instead of liquid being pumped to the outside containment area. Therefore, Spicer carries a flashlight and inspects each pump and valve to make sure they are working. “George is very conscientious about wearing his personal protection equipment, and reminds other workers to do the same,” says Gray. “Now he’s our safety officer.”

Gray is also proud of the innovation shown by Sass. In 2008, valves were operated by two unreliable water-cooled air compressors that caused frequent plant shutdowns. “Mike found a kit to convert the compressors to air cooled,” says Gray. “He saved us more than $45,000 in engineering expenses and helped stabilize the system.”

In another instance, sludge was accumulating in the Superpulsator units. Slits in the bottom of the collection pipes weren’t drawing in enough material as it slid down the V-trough. “Mike suggested cutting additional slits in the top of the pipe, enabling sludge to flow straight into them,” says Gray. “Overnight, our quality improved by a factor of 10.”

While staff attends to daily operations, Gray tries to anticipate future unfunded mandates and plan how to deal with them. “We can’t function on rumors about regulations,” he says. “For an accurate evaluation of what is on the horizon, we stay active in our state association and in the local branch of the state Department of Environmental Quality. Whatever is coming, my operators will meet it with ingenuity and integrity.”  

More Information

Evoqua Water Technologies, LLC - www.evoqua.com

Grundfos Pumps - 800/921-7867 - http://us.grundfos.com

Hach Company - 800/227-4224 - www.hach.com

INFILCO DEGREMONT - 804/756-7600 - www.degremont-technologies.com

Leopold - a Xylem Brand - 855/995-4261 - www.fbleopold.com

WEDECO - a Xylem Brand - 855/995-4261 - www.wedeco.com/us