Ozone is only one reason the Valdosta water Treatment Plant ranks as exceptional in Georgia. It won the 2013 Plant of the Year Award from the Georgia Association of Water Professionals (GAWP) for excellence across the board, including well field operations, chemical processes and documentation, scoring 90 percent or better in all areas.

“We were the first plant in the state to use ozone to oxidize organics in drinking-water treatment,” says Craig Dozier, plant superintendent. “Visitors from plants from the Atlanta area and others came to see ours in operation before considering ozone in their processes.”

During the visits, they might have noticed Valdosta’s other strengths: safety and training procedures, operations manuals, energy conservation and more. On all counts, Valdosta ranked at or near the top among Georgia groundwater systems pumping more than 10 mgd.

“The competition is tight,” says Pamela Burnett, GAWP executive director. “For groundwater treatment facilities, the checklist includes assessment of 43 items on documentation and paperwork, 23 on system monitoring, 22 on the laboratory and 85 for each well.  No permitting violations are allowed.”

The honor brought praise from city officials. “Every day thousands of customers in our city turn on their faucets with little thought to the water that streams out and how it moves from its source through the treatment process and ultimately to their taps,” says Henry Hicks, Valdosta director of utilities. He commends Dozier, along with Jason Barnes, assistant superintendent, and the “other skilled men and women responsible for bringing Valdosta water customers quality drinking water every day.”

The winning system

Expanded and upgraded in 2007, the Valdosta water plant pumps about 10 mgd on average and has a capacity of 22.5 mgd. The water comes from a well field near the treatment plant. Seven wells (two more are planned) each draw about 1,500 gpd from the porous limestone that forms the Upper Floridian Aquifer 200 to 400 feet below the surface.

Besides Dozier and Barnes, the staff includes Randy Jones, maintenance supervisor; Charlie Marsh, maintenance helper; Victor Durden, Russell McBride, Kenneth Hadley, Kathy Chavez, Brian Sunbom and Steve Patelski, operators; and Phillip Walker and Kenneth Hughes, lab analysts.

At the treatment plant, air strippers (Indusco Environmental) remove hydrogen sulfide, and then the water is treated with ozone produced on site. The ozone generators (WEDECO) combine oxygen and water to produce the gas. “There’s lots of sulfur in the water and the smell is objectionable to people, so we strip it out,” says Dozier. “That also reduces the ozone needed to eliminate the hydrogen sulfide. Without the strippers we’d use a lot more ozone.”

Phosphate is added for corrosion control and chemicals are introduced to maintain the desired pH. Fluoride is also added. The finished water is disinfected with sodium hypochlorite, which replaced chlorine gas for safety reasons. Valdosta generates the hypochlorite on site but is evaluating a switch to purchasing the chemical.

The treatment plant site includes three 1.5-million-gallon inground reservoirs, and the city maintains three elevated storage tanks, one brand-new, that total 4 million gallons in capacity.

The distribution system consists of 300 miles of piping, including a 6-mile transmission line completed in 2012. An 11-member staff operates the system around the clock. All processes, including the distribution system and the water levels in all elevated tanks, are monitored and controlled by a SCADA system.

Meeting challenges

Running the system means facing daily challenges that include dealing with surface water intrusion and naturally occurring groundwater impurities. The Withlacoochee River flows south through the Valdosta area into Florida, and in some sections it “disappears” beneath the ground. In addition, the limestone aquifer has cracks, solution channels and caverns that can allow surface water to enter and affect the water supply.

The water in the aquifer moves slowly through the limestone: Travel time from the point where the river goes underground to the well field has been measured at up to 75 years. Nonetheless, the Valdosta team needs to guard against surface water influence in the wells. The groundwater itself contains sulfides, organics, iron and manganese.

“The water treatment plant was moved from downtown to the current site northeast of the city in 1992 to get away from surface water influence,” says Dozier. In 2007 the plant was upgraded to sodium hypochlorite disinfection and two ozone generators were added, joining three older generators. The new setup includes a pair of contactors, one of which is normally in service. In summer when volume picks up, the flow is split and both contactors are used, producing a more effective ozone contact time.

For preventive maintenance, the Valdosta staff inspects each side of the ozone contact basin every six months, closely following confined-space safety practices. “We notify the fire department every time we go down,” says Barnes.

The sodium hypochlorite is produced in a ClorTec system (Severn Trent Services). Brine is delivered by truck. Finished product is stored in three tanks at the plant. The staff uses muriatic acid to clean the electrodes in the hypochlorite generators. Water leaving the plant has a chlorine concentration of 1.8 parts per million. “We’re evaluating the on-site process to see if it’s still cost-effective to make our own sodium hypochlorite versus buying it,” Barnes says.

Limiting water loss

Valdosta protects its investment in clean water by monitoring the distribution system for leaks, breaks and excess usage. A regular water loss audit helps spot problems. “We monitor how much we’re pumping versus how much we’re selling,” says Barnes. “We pump 3 billion gallons a year, and there’s some water loss — up to 30 percent. We’re working to get a handle on it.”

Maintenance and monitoring are important. The team closely watches water used by the parks and fire departments as well as in the flushing of mains. “We train the fire department in how much water they’re using during training exercises,” says Barnes. “We put a monitor on it and measure how much is going down the storm drain.”

Valdosta uses a computerized maintenance management system (Hyperweb). “We’ve had it for roughly four years,” say Randy Jones, maintenance supervisor. “We generate all our work orders and preventive maintenance tasks with it, and it provides us with a historical data bank on all our equipment.” The city still uses manual-read and touch-read water meters but is considering an automated system.

Pursuing quality

The overriding goal is to provide the best quality water as cost-effectively as possible to Valdosta’s 57,000 residents. The improvements and recent capital investment help: The city’s water rates are lower than those of at least 100 other utilities of all sizes in the state.

The Valdosta plant deserves its award-winning status, GAWP’s Burnett affirms. “The fact that the plant had no permit violations in 2013 and that it received a score of at least 90 percent on the inspection review made it exceptional,” she says.  “The award recognizes the exceptional quality water that is delivered to customers of the Valdosta system and also recognizes the water professionals at work in the city every day.”