When a water utility has won as many awards as Spartanburg Water, for sustainable management and consecutive years of 100% permit compliance and more, it must be doing a few things right.

Spartanburg Water received the 2019 Sustainable Water Utility Management Award from the Association of Metropolitan Water Agencies. It also won a Platinum 7 Award from the National Association of Clean Water Agencies for seven years of 100% compliance at its Fingerville Wastewater Treatment Facility, Platinum 6 awards at the Clifton-Converse and Page Creek wastewater treatment facilities, and a Platinum Award at the Cowpens Wastewater Treatment Facility.

In the previous two years, the utility, in northwestern South Carolina, received recognition from various organizations for permit compliance, operational excellence and customer service. It also won a Utility of the Future award in 2018 from the National Association of Clean Water Agencies.

“For years and years, Spartanburg Water has really been on top of its game as far as compliance,” says Rick Jolley, wastewater treatment manager. “That’s what we’ve tried to drill into all of our operators. They own it. They own compliance. It all comes back to them. They’re the ones who have to make adjustments.”

Extra basin capacity

Spartanburg Water has resiliency designed into its treatment systems. That helps the utility get through heavy rainfalls or extended rainy periods without exceeding permits.

“In fall 2018, we had torrential rainfalls, but we have a lot of redundancy in our plants,” Jolley says. “We have enough basin space that the operators know what they can do. They know we can only send so much through the plant.

“It really comes down to being a shell game in a sense. You’ve got to sort out where you’re going to put water and when you are going to put it there. Then you’ve got to constantly be thinking about bleeding it off and getting it through the system.”

Spartanburg Water has eight wastewater treatment facilities with a combined 32 mgd capacity (about 14-15 mgd average flow). The largest is the A. Manning Lynch Wastewater Treatment Facility with 25 mgd design capacity and 11-12 mgd average flow.

The plant has a 10 million-gallon basin that can be used for temporary storage in a high-water surge. It is also connected to a large pump station that used to be a wastewater treatment plant and has additional basin capacity.

“We always manage to be able to move water around,” Jolley says. “Our other plants have enough basin capacity, too. It’s all about sustained capacity and handling peak loads. It takes work and a lot of focus, but it enables them to stay in compliance.”

Disinfection alternative

Spartanburg Water continuously looks for efficiencies and ways to reduce risk. The team is exploring the use of peracetic acid instead of UV light or chlorine for disinfection. Peracetic acid doesn’t leave residual sodium in the effluent the way chlorine disinfection does, and it requires less electricity than UV.

“In a couple of our plants, we’re looking at peracetic acid.” Jolley says. “It’s very environmentally friendly and takes little electricity to run. It’ll be a proving ground. It will show our ability to handle a different disinfection system.” Peracetic acid is being tested at a plant that has a UV system due for replacement. It is also being considered at a plant that uses chlorine disinfection.

“We tend to want to get away from using chlorine gas,” Jolley says. “We run chlorine gas at our main plant. We have large, 1-ton cylinders there. We want to take that risk out. In other plants, we use the liquid version, sodium hypochlorite. Then you have to dechlorinate with sodium bisulfide. There are more chemicals involved. It tends to be costly, too.”

Although peracetic acid has been embraced by the U.S. EPA as a wastewater disinfectant for only a few years and has been considered expensive, the cost has been dropping as the process is used in more places. “What kept people from using it in wastewater treatment was the expense,” Jolley says.

Conversion of a chlorine plant is not difficult because disinfection with peracetic acid requires less contact time: “If chlorine is taking 30 minutes, peracetic acid is taking close to 10,” Jolley says. On the other hand, if a UV plant is converted to peracetic acid, it’s likely more contact time will have to be built into the disinfection process. That’s a potential problem, but solving it might be worthwhile to achieve the savings from peracetic acid as the costs come down.

“It’s two to three times cheaper using peracetic acid compared to UV, and you don’t have the capital and operation and maintenance costs,” Jolley says.

Team effort

Whatever the disinfection method, the goal is to discharge water that is cleaner than the receiving stream. “I would wager we could go upstream from any of our outfalls and we could compare that sample to what’s coming out of our wastewater treatment plants, and our plants would far and above exceed the quality of water that’s in the river.”

That has even been true through some big rain events, when stormwater infiltration stresses the plant capacities and dilutes the influent, causing other problems. “You dilute what’s coming in, you have less food for the microorganisms,” Jolley says. “You have certain limits for TSS and BOD going out, and we have a percentage reduction we have to achieve.

“We have to keep our eyes on the ball, especially at some of the smaller plants. We have to make sure we’re doing the right things. It’s a team effort between all of the people. They pay perfect attention to what’s going on, and they are ready to react.”