Faced with population growth, limited infrastructure, decreasing water supplies and environmentally sensitive coastal waters, Onslow County, N.C., is taking a centralized approach to wastewater management in the Stump Sound service area.

 

The Onslow Water & Sewer Authority (ONWASA) is acquiring existing localized facilities and acreage, developing a regional reclaimed water facility, and enhancing current facilities.

The approach will ultimately make life easier for ONWASA operators by eliminating the need for new on-site package treatment plants to serve individual developments. It will also improve effluent quality from existing plants.

 

A water reclamation system scheduled for start-up this year will treat wastewater from the Holly Ridge community and future developments. More improvements will be made in the next few years, with the ultimate goal of creating a regional wastewater treatment solution.

 

“A regional wastewater approach will improve water quality by allowing ONWASA to manage wastewater and reclaimed water resources,” says Frank Sanders, engineering director. “Even more important, it will stop the proliferation of individual on-site wastewater treatment plants, owned and maintained by homeowner associations, contract operators or private utilities, at every new coastal development.”

While Sanders and the operations staff look forward to the program’s completion, their biggest hurdle is finding ways to fund the various projects. “We’re waiting to hear whether we will get federal stimulus package funding for one project,” he says. “Another project was cancelled because the Clean Water Management Trust Fund money was frozen. So, it’s a challenge.”

 

Fragmented systems

The Stump Sound service area includes three small communities: North Topsail Beach, Holly Ridge and Sneads Ferry. The service area is divided further into four management zones.

Sneads Ferry is served mainly by septic systems. Because there is no centralized sewer service, new waterfront developments rely on on-site treatment plants.

 

The Central Management Zone, between Marine Corps Base Camp Lejeune and the Intracoastal Waterway, has little wastewater infrastructure and is served by septic systems. A projected increase in troops at Camp Lejeune has led to proposals for new housing developments with privately owned sewer systems.

 

The Western Management Zone includes the Town of Holly Ridge, whose treatment facility consists of an aerated lagoon and disinfected secondary effluent, land-applied to an ONWASA-owned spray field. This zone also includes a large subdivision with a new sewage collection system built by developers. Five more large developments are planned, each possibly with its own treatment plant.

 

North Topsail Beach is served mainly by a private utility, but ONWASA serves about 10 percent of the community.

 

Short-term answer

While it would be ideal to construct a regional wastewater system that serves the entire county, that would take too long and frustrate developers who need to proceed with planning, design and permitting for their projects.

 

The short-term solution is a reclaimed water system that provides highly treated effluent for beneficial reuse. In February 2009, ONWASA purchased the 0.4-mgd Summerhouse Water Reclamation Facility (WRF). Built in August 2008 by the developer of a new 1,040-lot subdivision, the Summerhouse plant consists of a centralized sewage collection system, membrane bioreactor (MBR) treatment facility, and dual rapid-infiltration basins. Equipment includes:

• An equalization basin with fine screenings conveyor, Discfuser (a division of Siemens Water Technologies) coarse-bubble aeration, WILO-USA submersible mixers, Fontaine sluice gates, Gardner Denver Sutorbilt blowers, and electric flow valves.

• A Siemens package MBR system with Memcor (a division of Siemens Water Technologies) hollow fiber membranes, Envirex (a division of Siemens Water Technologies) coarse-bubble aeration system and Dontech drum screen.

• An Aquionics UV disinfection system.

• A digester with Discfuser coarse-bubble aeration, WILO-USA mixers, Gardner Denver Sutorbilt blowers, Penn Valley Pump sludge transfer pumps, and Vapex odor control.

• LMI Milton Roy chemical feeders.

 

When the new developments’ homes are connected to the Summerhouse facility, the MBR-treated water will go to infiltration basins, and the high-quality reclaimed water will be used for irrigation and other non-potable uses. The reclamation facility will replace an aerated lagoon and eliminate pumping of that water three miles for spraying on an 88-acre field.

 

“We’re waiting for stimulus money for a new lift station and a raw sewage force main to convey wastewater from Holly Ridge to the new Summerhouse facility,” says Sanders. “A reclaimed water line will convey highly treated wastewater to future developments that can use the water for irrigating lawns and golf courses.

 

“We will decommission the aerated lagoon and remove, dewater and land-apply the residual biosolids. Developers can tie into the new plant rather than build individual treatment plants. It’s a win-win situation.”

 

The Summerhouse WRF will bring greatly needed wastewater treatment capacity to the area and help reduce demand on the potable water supply. It is just phase one of nine project phases to be implemented over the next few years as part of ONWASA’s wastewater management master plan. If all goes well, the plan will culminate in the new regional 0.5-mgd Northwest Water Reclama-tion Facility that will serve the northwest area of Onslow County.

 

In 2008, ONWASA purchased 1,000 acres for this plant, which will include a dual-train, dual-barrier design concept, a five-day lined upset basin, influent equalization, chemically assisted biological nutrient removal, membrane filtration for reliable liquid-solid injection, UV disinfection and sodium hypochlorite injection, odor control and SCADA. Plant construction is scheduled to begin in January 2011, depending on funding. When completed, it will operate in parallel with the Summerhouse WRF to provide the ONWASA service area with 1.0 mgd of treatment capacity.

 

Impact on operators

“The impact will be huge, when you consider that the small on-site treatment plants do not always meet discharge specifications,” says Sanders. “The 28 package plants that are already operating will stay, and we are gradually taking them over and operating them. But, there will be no new ones once the developments can tie into our wastewater reclamation plants.”

 

The current economic climate and tight credit market has slowed down some of the developers’ projects, giving ONWASA time to implement the water management project before new on-site plants are built. “On-site plants don’t have to go through public hearings, whereas larger, publicly-owned plants have to go through a greater permitting process,” says Sanders. “So, it takes us longer to get our plants up and running than it does for developers.”

 

Finding enough operators to cover the plants ONWASA is taking over is a challenge, as is keeping operators up to speed on technology upgrades.

 

“There never seem to be enough operators,” says Sanders. “With limited budgets, trying to get operators up on the new technologies is always a problem. We can accomplish this by including operators in on the project design and including sufficient training in the project budget so training can occur before the plant starts, not after.”

 

Operators have been struggling to meet discharge specifications from private on-site treatment plants. “Some of the plants are old, and the upkeep has not been that good,” says Jimmy Powell, ONWASA field operations director. “We have to spend quite a bit of money to get them to meet effluent quality. Sometimes the data collected by previous operators is way off compared to the data we collect.”

 

Sanders agrees: “Some of these plants were put together piece-meal, and it’s a real challenge for our operators to meet the require-ments. Their collection systems are old, and if the infiltration and inflow gets too high, the sand filters have to be replaced.”

 

Sanders and Powell believe that working closely with the State’s Division of Water Quality is key to dealing with those issues. “We talk to the state and ask them to tour the plant so they can see the condition it’s in,” says Sanders. “The state tends to visit municipal plants more than private systems. The walk-through is useful so that if problems occur later, everyone is on the same page.”

 

In spite of the challenges, Sanders says ONWASA’s 10 treatment plant operators are optimistic about the future. “Our operators at Holly Ridge are overseeing an aerated lagoon, but once the membrane plant is running, they will go from an antiquated system to a very good system that will produce much better quality water,” he says.

 

Surprisingly, operator turnover at ONWASA has been non-existent. “The operators care about what they’re doing and about the environment,” says Powell. “I am really proud of them, and I couldn’t ask for better operators and the knowledge they have, regardless of the treatment process.”

 

Challenge of growth

In June 2009, Powell was promoted from deputy operations director to his current position, where he is in charge of water treatment plant operations, wastewater collection crews, SCADA, maintenance and laboratory. He supervises 70 employees and expects to hire more lab personnel. “We now do 50 to 60 percent of our water and wastewater sampling and testing, but we will be hiring more chemists so we can do the majority of the testing,” he says.

 

The treatment plant superintendent’s position is in the capable hands of Karen Wallace. With 13 years in the municipal water treatment business in Onslow County, she is no stranger to water management challenges.

 

“I started as an operator and worked my way up,” she says. “I had been working at a recycling facility that had its own spray field, so I took it over and became certified. I liked the hands-on aspect of the job where operators did pretty much everything. It wasn’t as specialized as it is now.”

 

Her day typically starts at 7 a.m., when she gets caught up on paperwork, completing reports, signing requisitions for new equipment, repairs and parts, and dealing with warranty issues. She oversees seven supervisors who in turn are in charge of one to six operators.

 

Wallace’s biggest challenge is learning about the wastewater side of the business, what equipment is in the system, and what condition it is in. Despite the learning curve, she looks forward to helping implement the new wastewater management program, which she says will be “better for the environment and our citizens.”