WILMINGTON — The city of Dunn has a supply problem where wastewater is concerned.
All too often, Mother Nature is supplying the Black River Wastewater Treatment plant with too much water, causing the facility to exceed daily capacity limits. On average, more than half of the water flowing to the plant is a result of leaky pipes, and the amount is drawing the city closer to mandated state capacity guidelines that could result in a freeze on adding new customers.
“We are diligently looking for sources of inflow and infiltration in our collection systems and trying to keep that water from getting to the plant to take up that capacity,” Heather Adams, director of public utilities, said at this weekend’s Dunn City Council retreat in Wilmington. “It’s going to be a challenge and obviously it will cost money, too.”
With a capacity of 3.75 million gallons a day, the Black River plant easily could handle the amount of water distributed to residents by the city, which averages around 1.5 million gallons a day. In 2020, however, the average daily flow going into the facility surpassed 3.3 million gallons a day and drew the city in range of a rule to prevent such capacity discrepancies. Wastewater treatment plants operate under a 80/90 rule that requires municipalities to evaluate their systems when surpassing certain thresholds. When a treatment plant surpasses 80% of its capacity, which at Black River is 3 million gallons a day, the rule requires cities to complete an evaluation of the facility’s disposal needs and future utilization. Should the plant exceed 90% or 3.38 million gallons a day in Black River’s case, the city must submit permits needed for an expansion, and final plans for construction if needed. The city reported a daily flow rate of 3.34 million gallons last year.
“We should be treating a lot less ratio,” said City Manager Steve Neuschafer. “That shows the magnitude of the issue and all of those leaks. We’re getting 1.5 million gallons of stormwater which is doubling our treatment. It’s really all about the inflow and infiltration in the sewer lines with the ground water. That’s the main thing.”
Dunn is not alone in its need for infrastructure improvements, as many cities across the country face similar issues with aging and leaky pipes. A recent smoke test conducted last year helped the city identify numerous problem areas across Dunn that now are prioritized in terms of repairs. Neuschafer said city crews stay busy locating and replacing cracked pipes that often are more than half century old in places.
“We don’t need to be treating fresh water,” Neuschafer said. “We just need to be spending our money treating the water that needs to be treated. You talk to any community, they are always chasing that down because ground water is the part that really becomes expensive. Every community deals with it, from Raleigh on down. Every community has aging infrastructure across the United States. It’s not anything unique to us, but we need to make sure we have it on a priority to where we don’t get too far behind.”
Figuring out where the larger leaks are will help alleviate some of the problem, but Adams said aging pipes won’t get any younger, especially as the area continues to expand.
“We did an assessment last year and approximately 75% of our sewer collection system is 50 years or older and around 20% is 75 years or older,” said Adams. “The growth that we expect from all these building projects we’ve got going on and the I-95 expansion, is just going to add to that. The council has always been supportive of growth and I think they realize that they’ve got to have viable infrastructure to bring that growth here.”
Funding such infrastructure projects also is a dilemma a lot of cities face, and Neuschafer said the city currently is seeking ways to pay for it all by turning over every stone available. In the past year, Dunn secured grant funding for several major projects that helped replace numerous water and sewer lines on thoroughfares such as Crescent Drive, North Magnolia Avenue, West Broad Street and North Watagua Avenue. The city, Neuschafer said, should be constantly focused on addressing these issues whenever money becomes available.
“It always takes money, resources and manpower to get it done and is just something we want to keep on the front page so that we’re always dealing with it,” Neuschafer said. “We’ve got a couple of large grants out there and if we’re able to be successful in those requests that’s $6 million of work on the pipes itself, on the collection system, and that’s going to help us make a dent. Everything that comes in from water and sewer bills goes towards the maintenance and upkeep of these resources, whether it’s the plants or the collection system of the pipes in the ground. It’s not about expanding the system for us right now as far as the pipes in the ground. It’s really maintaining what we have in the ground right now and keeping ahead of the curve on the maintenance.”
As the numbers at Black River showed, the time for planning has arrived.
“When we’re over the 3-million-gallon point, which we are, that’s when the state says ‘you need to start planning,’” said Neuschafer. “When it gets to 90% is when you need to be in construction. We’re at the point where they want us to begin planning and so that’s what we’re going to do. We look at the amount of inflow and infiltration we’re having. Those are always high priority. We’ve identified where the weakest links are in the system and now we can prioritize from that. Each study that we do helps us prioritize.”
If Dunn can keep the rain water out of its treatment plant, its unwanted supply problem will take care of itself.
Eliot Duke can be reached at email@example.com or 910-230-2038.