Do more with less.

That’s the philosophy of Pedro Grondin, supervisor of the Newport (Vermont) Wastewater Treatment Plant.

Faced with the shortage of qualified operators that affects the whole profession, Grondin is working hard to improve and automate his plant so it can operate with the minimum staff.

“There are only two of us here,” he says. “There was a third, but he left to take another job. Looking for a replacement has not been easy.”

To date, the improvements at Newport include a new biosolids press, revamped sludge pumps, new state-of-the-art aeration blowers, a SCADA system and cameras that enable staff to view all plant operations from the control room. “These upgrades have made it easier to operate the plant with fewer people,” Grondin says.

Close to Canada

The Newport plant serves a population of 4,400. The community is so close to the northern border that Grondin can see Canada from his office. Built in 1963 and upgraded in 1982 and 2006, in addition to the current improvements, the plant (1.3 mgd design) treats an average of 0.5 to 0.6 mgd.

Influent first travels through a lower headworks consisting of a bar rack, Muffin Monster grinder (JWC Environmental) and cyclonic grit removal (Lakeside Equipment) before being pumped into a wet well. From the well, the flow goes to an upper headworks where it passes through a mechanical fine screen.

Then the flow moves through two primary tanks to two trains of aeration basins. Air is provided by two new Atlas Copco rotary screen blowers. Treated water settles in a pair of secondary clarifiers, then is disinfected with sodium hypochlorite and dechlorinated with sodium bisulfite before discharge to the Clyde River.

Biosolids are digested in two tanks, one for primary solids, the other for secondary. After thickening, they are dewatered on a new Prime Solution fan press to 20-25% solids cake, which is hauled to landfill.

Biogas acts as fuel to heat the digesters. Other energy-saving programs include LED lighting and the recent conversion to hot water heat for buildings from more costly electric heat. The plant accepts septage, and although Grondin says some of that material can be “pungent,” there is no odor problem. He would like to send more septage to the digesters: “I think it might make the plant run more smoothly.”

A Mission 123 SCADA system gives the two-person operating staff automated monitoring and control of all processes and includes cellphone access when staff is offsite. “It’s been a big help in enabling us to stay ahead of problems,” Grondin says. “We can look at the screen every day and see what’s going on.”

Labor savings

Many of the manpower-saving measures at Newport have been aided by grants from Efficiency Vermont, a statewide utility program that provides energy audits, consulting and financial assistance to municipalities, businesses and residents. Much of the work has been accomplished by staff and the new biosolids press is a good example. 

“Previously, we were storing liquid material and hauling it and spreading it on a field near the airport,” says Grondin. Daily volume was several thousand gallons, totaling 5-6 wet tons and requiring a city truck plus trucks from a local vendor: “We were making 30-40 trips a day.”

About two years ago, the community purchased the new fan press, which has performed well: “We’re very happy.” Solid content is up and landfill trips are down. The staff did most of the installation work, including converting an old equipment garage to house new press and modifying two Penn Valley pumps for biosolids. Grondin estimates that saved about $30,000.

“We have a camera on the new press,” he says. “But we don’t have to babysit it. It pretty much runs by itself. It’s been a good investment and has already paid for itself. Plus, I think the plant runs three times better.”

Better aeration

The Atlas Copco rotary screen blowers have likewise saved on labor and have proven cost-effective and energy efficient; Efficiency Vermont again helped defray the cost. The new blowers replaced a pair of stacked-disc units. The blowers ramp up or down automatically, and the plant usually needs only one blower operating at a time. That enables the blowers to alternate every three months.

The energy efficiency is dramatic. “Previously, our aeration costs were 47% of our overall electricity usage, costing us between $8,000 and $13,000 a month,” says Grondin. “The old aerators ran 24 hours a day at 75 hp.” Now the aeration power usage is down about 25% of the plant’s overall draw.

“Sixty percent of the day, these new blowers are running at just 20-40% of the maximum motor speed,” says Grondin. He appreciates that the blowers can alert him on his cellphone if there’s a problem and connect him with the manufacturer. The plant also installed a dissolved oxygen meter to ensure that the levels in the aeration basins remain above the lower limit of 3.5 mg/L.

Next upgrades

Grondin and his team aren’t finished improving the treatment plant. Grondin wants to improve the screens in the lower and upper headworks with automatic, self-cleaning units. “Rags are a pain,” he says. “We have to use a Vactor truck to clean out those wet wells periodically.

“We also want to add brushes and skimmers on our secondary clarifiers to reduce cleaning time, and reduce green algae accumulation.”

He also wants to improve the looks of the facility: “We’re in a park setting, and I’d like to see us make the plant more appealing to the public.” His ideas include bringing in high school students to come up with creative designs and paint the tanks and buildings. “Maybe we could make the old brown tanks look like fish bowls.”