Eyes on the Prize

Process automation and observation help the team at Caryville-Jacksboro produce excellent effluent and keep treatment costs down for the community.
Eyes on the Prize
Staff members at the Caryville-Jacksboro Utilities Commission include, from left, Steve Russell, Frank Wallace, Jamie Wright, Rodney Wilson, Tim Sieber, Wayne Clotfelter, Greg Smith, Bob Smith, Earl Wilson, Michael Green, Jim Dial, Steve Russell, Lynn Gwin and Jordan Allen.

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Frank Wallace must feel like he has a staff of 62 people operating his Caryville-Jacksboro Utilities Commission wastewater collection and treatment systems.

That’s because the utility employs a network of technologies that track and control all 49 pump stations and provide live camera views at 13 points within the wastewater treatment plant — some 62 contact points in all.

The technology consists of a cellular-to-web SCADA system provided by Mission Communications and remote cameras from Computer Concepts of Jacksboro. Together, the systems have enabled Caryville-Jacksboro to reduce flow to its treatment works by 36 million gallons a year and cut power, labor, and maintenance costs and capital expenses some $185,000 annually.

For its efforts, the utility received the 2012 Outstanding Leadership and Successful Achievement Award from the U.S. EPA, and an Energy Efficiency Award from the Tennessee Department of Environment and Conservation. Besides saving money, the improvements enable the Caryville-Jacksboro system to practice environmental stewardship.

The treatment plant’s discharge goes to a tributary of Norris Lake, a pristine body of water in Cove Lake State Park, and the collection system surrounds the lake. “What we do is important,” says Wallace, general manager and executive secretary. “We live in a fishbowl. We can’t afford any bypasses or overflows or discharge violations.”

Heavily modernized

The wastewater treatment plant handles flows from a population of about 18,000 in the towns of Caryville and Jacksboro and surroundings, about 30 miles northeast of Knoxville. Wastewater has been treated at the current site since 1966, when a package treatment plant was installed. In 1987, the plant was modernized, and since then it has been upgraded to extended aeration treatment. A pretreatment program has been in place since the 1990s, and more recently the utility added the automated process control and camera systems.

The plant’s design flow is 2.1 mgd, and the average flow is 0.86 mgd. The utility is working toward an economic development grant to expand design capacity to 3.1 mgd. Influent from a 12-inch force main enters the plant through a headworks with a comminutor (Franklin-Miller) and flex rakes (Duperon) before passing to the extended aeration biological treatment process. The two 40- by 80-foot, 766,000-gallon aeration basins are divided down the center, with three mechanical surface aerators on each side.

After aeration, the flow splits between two 46-foot-diameter clarifiers (143,000 gallons each). Envirex (Siemens Water Technologies) supplied the aeration-clarification process. Clarifier overflow passes to a chlorine contact chamber, followed by dechlorination with sulfur dioxide. Final effluent cascades down an aerated spillway to Cove Creek, a tributary of Norris Lake.

Return activated sludge cycles back to the head of the system, while waste activated sludge is digested aerobically, thickened with polymer, and dewatered on a belt press (Frontier Technology) to 16 to 18 percent solids. Farmers spread the cake on grasslands, with excellent growing results. “It’s a Class B biosolids,” says Wallace. “We have farmers getting grass growing fence-post high after they’ve applied our material.”

Being neighborly

The plant team takes extra precautions against odors. An organic chemical fed into the wastewater at outlying pump stations prevents grease buildup, and a 50 percent solution of hydrogen peroxide is injected at the two main pump stations to reduce odors. At the plant itself, a carbon filter (Calgon Carbon) downstream of the comminutor scrubs odorous gases released by the treatment process.

The plant is staffed 16 hours a day, and one operator visits periodically on weekends. All processes can be viewed on laptops each operator carries. “We have great operators — real teamwork,” says Wallace. “When we go home at night we’re thinking about what we need to do tomorrow to make the plant better. Our operators protect their part of the process.” Team members are:

  • Steve Elkins, plant operator
  • Earl Wilson, pretreatment coordinator and dewatering operator
  • Greg Smith, lab technician
  • Bob Smith and Lynn Gwin, collections
  • Jamie Wright, CMOM
  • Wayne Clotfelter, coordinator, I&I
  • Steve Russell, backup operator, I&I
  • Michael Green, camera operator, I&I
  • Jordan Allen, rodding machine operator, I&I
  • Rodney Wilson, operator, right-of-way I&I

Eyes and ears

The plant staff gets a big boost from the remote views of various plant processes provided by the 13 cameras installed by Computer Concepts. Outdoor cameras are located at the clarifiers, aeration basin, chlorine contact chamber, outfall, and the sludge digesters. Inside, cameras are located at the main control board and also monitor the Dulcometer chlorine controller (ProMinent), chlorine and sulfur dioxide feed rate points, and rate of return flow. They provide live remote views of these parameters, and the operators can access the views on their iPads, cell phones or laptops.

“The cameras, along with the computerized daily plant control program, let our operators know where they are each day and what needs to be done during the day,” Wallace says. “We know the amount of sludge to be wasted, how much is in the digesters, and other values. Before, we just had to sort of get a feel for where we were, and if something was wrong, we might not see it for 25 to 30 days because we had to wait for lab results.”

Computer Concepts IT specialist Jim Dial says the utility special-ordered the cameras. “They’re not security cameras, although we’ve done security cameras for the utility,” he says. “They don’t provide a recorded history but simply give the plant staff an extra set of eyes to look at various operations from remote locations. It’s especially helpful during storms, power outages and rain events. We’re talking with the utility about putting this type of camera into the underground pump stations, so operators don’t have to climb down 20 feet to inspect the pumps.”

Saving dollars

Improvements in the collection system provide the lion’s share of the cost-savings at Caryville-Jacksboro. Since 2007, the organization has spent more than $5 million replacing old concrete collector lines with PVC pipe; re-routing culverts, streams, and bridges; and equipping pump stations with the SCADA system. These measures have reduced I&I and cut pumping costs.

“We have a high water table here,” Wallace notes. “Our old lines were 8 to 10 inches in diameter and dated to former WPA days.” Besides tightening the sewers, the agency has redirected surface flows so that they don’t infiltrate the collection system. All that has significantly reduced flows to the treatment plant, reducing costs and helping sustain permit compliance.

The SCADA system has cut pumping station power and maintenance costs even further. “This is a hilly area with a lot of cul-de-sacs,” Wallace observes. “We have 49 pump stations and a total of 139 pumps.” Before installing the SCADA system, the utility used a crew of six workers to inspect each pump station, requiring a total of 48 man-hours per day.

“The SCADA system has been a lifesaver,” Wallace says. “Within 10 to 15 seconds of a problem, we get an alert, whether it’s a high wet well, or a pump that didn’t come on. Now, we need just one person to check the reports every morning. We’ve assigned the other personnel to other responsibilities.”

Wallace says the SCADA system is saving the utility over $185,000 in operation and maintenance costs for pumps every year. “Before, we might not know about a problem until Monday or Tuesday,” he says. “Now, we know immediately, and we can go out and take care of the problem.”

Cutting power usage

The system helps the utility avoid expensive pump repairs or replacements.  “We have total control over our pumping stations,” says Wallace. “We can see the problem and tell the pump what to do until we get there.”

It is also saving energy. Before, pumps kicked on and off on their own as water levels rose and fell — as many as 250 starts and stops a day. “That increased energy costs. Our power bill was going up.” Now, the starts and stops are sequenced, and no two pumps kick on at the same time. “On our own, we’ve reduced starts and stops to around 8 to 30 a day,” Wallace says. “They come on only when it’s absolutely necessary.”

The same approach inside the treatment facility adds to the energy savings. Automation technology allows the plant to smooth out power consumption in its aeration blowers. “Our aerators are rated for 15 hp each,” he says. “If they all come on at once, it spikes our power use to 90 hp, and we pay for electricity at a higher rate.”

With the automation system in place, the aerators cycle, coming on one at a time and keeping the plant’s power usage in a lower range. “Again, we’re only using the power we need at any one time,” says Wallace. “The power company (TVA) had to do a power audit here twice because they couldn’t believe how much we’ve reduced our electricity bill. Without our Mission Communications system, our community could not afford the cost of wastewater treatment.”

Still improving

The improvements haven’t stopped at power consumption. The installation of two 4-inch flowmeters (Badger Meter) at the discharge point improved flow measurement accuracy. “At a point just above our outfall, we recycle water for non-potable use within the plant — clarifier spraying and other things,” says Wallace. “It amounts to 175,000 gallons a day. We had been counting that water twice.”

Now, the plant has an accurate calculation of water in and water out and can verify that it is staying below its organic loading maximum, which is based on a flow of 0.86 mgd.

It’s the tale of two eras at Caryville-Jacksboro. In the old days, Wallace says, the utility might get a commissioner’s order announcing that it had been sued by the state and EPA for discharge violations and would have to go to the state capital in Nashville for a show-cause hearing.

Now, the utility goes to Nashville as a poster child for energy savings and treatment efficiency.

“Caryville-Jacksboro was one of 10 utilities chosen to receive awards from the EPA and the state for participation in the energy efficiency program,” Wallace says. “Some of the participants were big systems, up to 20 mgd. But when it came time to make the presentation about the program, they chose Caryville-Jacksboro to come and give it.”



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