The North Cary (North Carolina) Water Reclamation Facility has been in service since 1974, but to the casual observer, it doesn’t look its age.

Equipment is rigorously maintained. Aging equipment gets replaced under a capital improvement plan. Housekeeping is impeccable. Buildings and equipment are kept freshly painted. Most of all, the plant consistently releases effluent that complies with strict nutrient limits for the Lower Neuse River Basin.

Paul Ray, plant manager, gives a simple reason for the facility’s success: “A great staff and a very good employer.” In reality, Ray significantly shares in the credit, according to Jamie Revels, director of the Town of Cary Utilities Department.

“Paul has always believed in the power of a great maintenance program to support plant operations,” Revels said in nominating Ray, successfully, for a 2017 William D. Hatfield Award. “He has established an innovative and efficient approach to operations and maintenance, producing an exceptionally high-quality effluent that protects the natural environment.” 

Upgrade and expansion

The North Cary facility (12 mgd design, 7.2 mgd average) is one of three water reclamation facilities in the town. The others are South Cary (12.8/5.3 mgd) and Western Wake Regional (18/4.5 mgd). Together, the three serve about 215,000 residents.

Ray joined the North Cary team in 1988 after serving in the Army. He signed on as a maintenance worker and went to night school at Wake Technical Community College. Along the way, he earned promotions to mechanic and chief of maintenance. After finishing his associate degree in electronics engineering technology, he became chief of operations and maintenance, and in 2012 he assumed his current position.

While Ray progressed in his career, the North Cary plant expanded. “When I started, we were a 4 mgd extended aeration facility with tertiary filtration and chlorine disinfection,” he recalls. “Because we discharged into the small Neuse River tributary that is Crabtree Creek, we knew we would be required to meet more stringent limits, primarily for nutrients.”

In 1997 the town commissioned a new biological nutrient removal facility running two oxidation ditch trains using the Bio-denitro process (Veolia Water Technologies). To meet growing demand, a third train was added in 2002. DynaSand filters (Parkson Corp.) provide tertiary treatment, followed by two TrojanUV4000 disinfection units. A reclaimed water distribution system delivers 0.5 to 1 mgd to customers for irrigation.

The upgraded facility was designed to meet limits of 6 mg/L total nitrogen and 2 mg/L total phosphorus. Later the town joined the Lower Neuse Basin Association, and the total nitrogen limit was converted to a total poundage requirement while retaining the total phosphorus limit of 2 mg/L. In 2013, the North Cary plant earned Exceptional Quality Effluent status from the state Department of Water Resources for consistently low effluent nutrients and years of compliance. The plant maintains a state-certified laboratory led by Jason Parker, senior analyst, and Alyssa Benson, analyst.

Biosolids from all three of the town’s facilities are dried and processed into Class A Exceptional Quality pellets at South Cary (rotary drum dryer from Andritz Separation) and Western Wake Regional (two belt dryers from Veolia Water Technologies). Finished material is sold in bulk to a contractor for sale to farmers.

Attention to detail

In maintaining the plant, Ray applies the watchword: “original fit and finish.” He observes, “If something was intended to be there, it still should be, unless we have a reason for it not to be. There’s a tendency over time to say, ‘Well, we just don’t need that anymore,’ and it goes away. Somebody had a reason for putting it there, for designing it. We need a reason for it to go away — otherwise we need to maintain it.”

The same concept applies to keeping a sharp appearance: “The facility had a nice paint job at the time it was constructed. We maintain that nice paint job. We routinely paint equipment, and we paint the new equipment that we replace older equipment with.”

A computerized maintenance management system helps keep routine tasks on track. That is augmented by extensive predictive maintenance using vibration analysis and infrared thermography, along with routine sight, sound, touch, and smell inspections of equipment.

“We have a facility condition assessment team that meets routinely so that all the divisions within the utility can compare notes and talk about issues,” Ray says. “At North Cary, we do an overall equipment condition assessment. We look at wear points and assess potential failures. Much of the equipment is tied to a SCADA system. For items that have variable-frequency drives, we have data connections through digital links. We can read a lot of what’s going on with those drives and can see what the end source is doing.

“We have a capital program so we can fund the upgrades we need, when we need them. Are there things we have to do right now? Are we going to need maintenance in one year? Five years? Ten years? Then we put some dollars with that and get the repairs scheduled.” 

Trained and dedicated

It’s an extensively cross-trained and highly certified team that takes care of the maintenance and keeps the plant producing high-quality water. Jonathan Bulla is team leader for operations and the lab supervisor, and Brian Cartwright is team leader for the maintenance side. Team members are:

• Senior mechanic/operators Jim Bridges, Mike Dismuke, Leonard Hill and Rick Sellars.
• Mechanic/operators Brian Pittman, Ryan Smith, Jon Stimach, Kenny Morris, John McDonald and Bernard Royal.
• Tammy Coppedge, administrative assistant.

A formal career ladder program encourages team members to advance in their careers. “We promote our employees to better themselves, and they provide better job performance for the town,” Ray says. “The career ladder covers the laboratory, operations, and maintenance. It’s a voluntary program, but virtually everybody participates.”

Meanwhile, the town provides funding for the training that team members need to attain higher-level licenses. “As a result, we get much more competent and skilled individuals,” Ray says. “As they progress through Grade II, III and IV and other certifications, we end up with better-qualified, more well-rounded employees.”

As head of the team, Ray believes in leading by example: “If it’s a miserable, dirty job, I’m probably going to be the first person out there because I want people to understand that I know what they’re going through.

“Whatever we do, we plan it out as much in advance as we can. We try to foresee as much as humanly possible. The people I surround myself with jump in when they need to. Nobody is afraid of getting dirty. We all work with the same goal to accomplish the same task, making sure that water quality is maintained and everybody is safe.”

Tackling challenges

Among Ray’s proudest accomplishment is continuous improvement in total nitrogen removal, and here he credits the staff for initiating a significant change in the re-aeration zone of the secondary treatment process, the last stage before the secondary clarifiers.

“In an effort to reduce the effluent total nitrogen, the staff evaluated the BNR process,” Ray says. “A re-aeration zone after each set of second anoxic tanks follows the BNR reactor basins. We hypothesized that too much air was being added in these zones before discharge to the secondary clarifiers. Thus, the surplus air was causing residual ammonia bound deep within the biomass to nitrify further, causing higher nitrate levels in the secondary clarifiers.”

The re-aeration zones consisted of positive displacement blowers driven by pulleys using 1,800 rpm single-speed motors. The first test was to change the pulleys and belts in one BNR basin to reduce the speed. The result was a noticeable reduction in nitrate leaving the re-aeration zone.

“We repeated that experiment with a second BNR basin with similar results,” Ray says. “The staff then devised a longer-term solution, pairing variable-frequency drives with the original belt-and-pulley combinations to cover a broad range of dissolved oxygen requirements. We installed DO meters and tied them back to a plantwide SCADA system.

“After considerable testing, we found that a DO setpoint of 1 mg/L was optimal for the desired nitrate levels leaving the zone. We added controls to the SCADA system to allow the operations group to adjust that number as necessary. The overall result was an effluent total nitrogen reduction of 1 to 2 mg/L. This relatively simple modification led to improved effluent quality while using less energy.”

Aside from process improvements, Ray has been challenged with a variety of construction projects as the plant has evolved and takes pride in bringing them in on time and on budget. “On most of the ones I’m responsible for, the budgets are in the range of $500,000 or less,” he says. “It’s about getting engaged and involved from the time we decide we’re going to do something until the contractor is no longer on site and we’re running it.

“You have to remain engaged all the time. You should be continuously providing feedback to the engineers and whatever team is working on the project. I’ve spent countless hours going through blueprints and working out details ahead of time, with the idea that by doing so we can eliminate most change orders associated with jobs.

“The more people who look at it, the more years of experience are brought to bear, the less likely we are to have a lot of significant changes while we’re doing construction. It’s all public money. We need to make sure we spend it as wisely as we possibly can.”

Source of pride

Looking back over his career, Ray is proud of the North Cary plant and his team: “The town of Cary has grown enormously. It’s a beautiful community. I’ve seen the facility grow and the people grow. I’ve been privileged to see people come in relatively green and develop into highly capable operators. It’s the same with the facility. It started out pretty small and has become much more expansive. I know I’ve had a significant part in making it successful.”

His plan for the future? “Continue to do what we are doing. We always treat to the highest level we can. We by far exceed the minimum standards on our permit. If the permit limit is 10, we still try to get as close to zero as possible. We’ve always done that, and I want to continue to do that. I think it pays back in many ways.”

No odor. No noise.

Paul Ray and his team at North Cary aim for zero impact from their facility beyond the property boundary. “We basically have a zero tolerance for noise and odor offsite,” Ray says.

“We are the in-town facility. We’re located right next to some Fortune 500 companies and residential areas. We’re right off a parkway. Apartment complexes have been built directly across the road from us. We’re also near a large trailhead that is the center point for three park systems. We’ve done quite a bit over the past decade to ensure that people for the most part don’t know we’re here.”

Plant staff members stay in touch with businesses nearby to make sure there are no issues. They’ve introduced themselves to the apartment complex managers so they know whom to contact. “We’re extremely proactive in ensuring that there are no impacts outside the fence line to any of the citizens or businesses within the town of Cary,” Ray says.

A BIOREM Technologies biofilter is installed at the influent pumping station, and a Monashell odor scrubber (Bord na Mona) is at the distribution box that feeds the biological treatment process. The headworks is equipped with a carbon odor scrubber. The influent pumping station structures, the flume, and the influent distribution box at the headworks are covered, and the interior concrete is epoxy-coated.

Noise hasn’t been an issue. The plant doesn’t use large blowers for aeration; the brush rotors that serve that purpose are relatively quiet. “We’ve also concentrated on keeping our light profile down,” Ray says. “In recent years, we’ve switched most of the facility to LEDs, and this coming year, we’ll switch the remainder. Most of our exterior fixtures project light downward instead of outward. We are cutting down the light that travels offsite.”