A Look at the Bugs Tells This Operator How the Planet Is Running

Whether doing wastewater microscopy or operating a membrane-based reuse system, Andrew Shepherd ensures quality plant performance.

A Look at the Bugs Tells This Operator How the Planet Is Running

The team at the Newberg Wastewater Treatment Plant includes, from left, Mike Fischer, plant mechanic; Jennifer Valdez, administrative support coordinator; Jon Hodgkins, operator; Andrew Shepherd, operator III/regulatory specialist; Ed Thomas, senior plant mechanic; and Connor Pomeroy, operator. 

When Andrew Shepherd looks into the microscope, he sees more than wastewater organisms.

He gets a picture of the entire plant operation and can tell how the process is performing out there among the pipes and valves and pumps and basins. “It crystallizes the whole process for me,” says Shepherd, operator and regulatory specialist at the Newberg (Oregon) Wastewater Treatment Plant. “I can see how the microbiology works. It’s a macro versus micro view. It’s pretty phenomenal.”

What he didn’t see coming was the 2020 Operator of the Year award from the Pacific Northwest Clean Water Association. “It shocked me and humbled me,” he says. “There are so many good operators up here in the Northwest. It was extremely special just to be nominated for the Lower Columbia Section award.”

It was no surprise to colleague April Catan, regulatory compliance specialist: “He’s been great. He has worked all over the plant. He’s curious and tries new things. He’s conscientious, works hard, and is always learning. He deserves the award and I’m happy he was the winner.”

Variable flow

The treatment plant Shepherd monitors is a Level 4, activated sludge operation with a pair of 2 million-gallon elongated racetrack oxidation ditches. Dry-weather design flow is 4 mgd, and average daily flow ranges from 2 to 15 mgd, depending on the season. Wet weather accounts for the differences in seasonal flows.

There are no primary clarifiers. Wastewater enters the ditches, each with four brush aerators (paddles from Evoqua Water Technologies). Four secondary clarifiers follow, and the overflow is disinfected with 0.8% sodium hypochlorite generated onsite. The dichlorination step uses sodium bisulfite (38%).

Effluent is discharged to the Willamette River about a quarter mile away. A Wonderware SCADA system (AVEVA) controls and monitors the treatment process. Waste activated sludge is pumped to a pair of 80,000-gallon storage tanks, then dewatered on a pair of screw presses (HUBER Technology) to cake at 16-20% solids.

Class A compost

The cake is composted with dried sawdust and recycled compost. Shepherd is familiar with the operation because that’s where he started full time back in 2010, after working at the plant as a seasonal laborer for a year and a half.

“We operate an in-vessel composting system consisting of two 66-foot-long reactor tunnels,” he says. In mid-tunnel, long probes monitor temperature and pressure; blowers provide aeration to ensure Class A material, and a hydraulic push door forces composted solids out the end of the tunnel on a batch basis. If temperature conditions aren’t met, the batch is recomposted. 

A front-end loader takes the compost to a staging area. Branded as Newgrow, it is sold bulk at $10 per cubic yard or in 1½-cubic-foot bags that local gardeners and landscapers can purchase for $4.50. “They absolutely love it,” Shepherd reports. The dried sawdust may be a unique wrinkle. It comes from a local wood products plant and is dewatered from 50-60% solids to 90-95% solids using a reconditioned alfalfa dryer.

Residents get even more benefit from their clean-water plant in the form of recycled water. During the spring and summer dry seasons, a portion of the effluent passed through Pall AP6 membrane filters. The high-quality water is then pumped to the Chehalem Glenn Golf Course and used for irrigation. Volume varies from 200,000 to 600,000 gpd.

Meeting permit

Shepherd starts his typical day around 7 a.m., calibrating the pH meter, collecting samples around the plant and then starting a rigorous testing program. “I log the samples and run several tests throughout the day, some for regulatory purposes, some for process control or both,” he says. “Total chlorine residual, pH, TSS, SVI, ammonia, SOUR, alkalinity, CBOD5, et cetera.”

Newberg is required to report CBOD and TSS twice a week and to monitor twice weekly for nutrients — total phosphorus, TKN, ammonia and nitrate-nitrite — depending on the time of year. The composted solids are monitored for moisture content and tested quarterly for metals and nutrients. An outside lab tests for Salmonella quarterly.

Newberg’s permit varies with the seasons. During the dry months of May through October, the monthly average limits are 10 mg/L CBOD and TSS; they are 25 mg/L and 30 mg/L for November through April. The plant meets those limits with relative ease.

“Usually our effluent TSS is less than 3 mg/L and our CBOD is under 2 mg/L,” says Shepherd.

The lab has full suite of Hach equipment, including a DR 3900 spectrophotometer, a TitraLab AT 1000, a TU 5200 turbidity meter and a DRB 200 digestion block.

Shepherd becomes lead operator when plant manager Craig Pack is away, taking on responsibilities for plant operations and supervising a staff of eight. The team includes April Catan, regulatory compliance specialist; Jon Hodgkins and Travis Hyder, treatment operator II; Nick Moore and Connor Pomeroy, treatment operator I; Ed Thomas, senior plant mechanic; and Mike Fischer, plant mechanic. Pack also helps operate the recycled water process during the dry season, looking after the membrane filters and making sure that reuse water standards are being met consistently.

Shepherd handles the various tasks capably. “He’s someone I never have to worry about,” says Wastewater Treatment Superintendent Craig Pack. “He’s in charge of all our lab testing, planning and scheduling, and he can step in and direct the day-to-day operation at the plant in his lead operator’s role. He’s thoroughly reliable.”

Shepherd says on-the-job experience is the key: “Really, nobody here went to school for formal wastewater course work. We’ve learned on the job and through certification training.”

Lab rehab

 As with clean water professionals, the COVID-19 pandemic presented unique challenges to the Newberg plant and staff, including the lab operation.

“Since September 2020, along with about 40 municipalities, we have been providing Oregon State University with weekly influent samples to test for the presence of SARS-CoV-2 virus in the wastewater,” says Shepherd. “It’s part of the Oregon Health Authority’s wastewater surveillance program for detecting COVID-19 in participating communities.”

But the most difficult issue he’s had to face recently is the renovation of the treatment plant laboratory. The lab equipment was moved to a new building while the old building was being remodeled. It was difficult work in new surroundings for an extended time, sharing space with other plant operations. But it needed to be done.

“We’re 34 years old,” he notes. “Some of the apparatus was beyond its useful life, and the old layout was not efficient. We didn’t change the footprint all that much, but we made it better so the flow through the lab is improved.”

A new drop-off area, more counter space, a microscope station and more open areas will improve efficiency. Dedicated hand-washing sinks will increase sanitation and personnel safety.

The lab was opened last fall, but that was several months beyond the planned completion date.

Shepherd notes that sourcing issues and the “worldwide shortage of everything” caused delays.

He enjoyed being the point person working with contractor: “It was a real opportunity to get involved. The improvements will position Newberg for new permit requirements in the future.”

When those come along, it’s a good bet that Shepherd and the Newberg staff take them on with professional pride and enthusiasm: “We’re really proud of what we do here. We help keep our waterways clean. We like being part of the solution and not part of the problem.”   


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