Hatfield Award winner Scott Thompson thrives on the challenges that go with plant upgrades, new processes and advancing technology.
Scott Thompson admits that daily life in a clean-water plant can be routine. But over many years, constant change makes for a thrilling career.
In more than 30 years at the Bend (Oregon) Water Reclamation Facility, Thompson has seen design capacity expand from 1 mgd to 6 mgd while regulations have tightened. He has helped direct a major change to the secondary treatment process and the addition of a water reuse system. And he has spurred his team to implement new technologies that improve treatment efficiency and performance.
“I love this field,” says Thompson, winner of a 2016 William D. Hatfield Award from the Pacific Northwest Clean Water Association (PNCWA). “The wastewater field is always changing. I’ve always endorsed change, and I’ve encouraged my operators to do the same. I tell them to be proud of putting out clean water to the environment 24 hours a day, every day.”
He’s especially proud of advances in the plant’s biosolids program, which includes land application of dewatered Class A material on farmland, a pilot project in mine land reclamation with the U.S. Forest Service, and plan to mix compost with biosolids to create a nutrient-rich garden mix.
Like many clean-water professionals, Thompson came to the profession by chance. After high school in The Dalles, Oregon, he studied to become a welder and joined the Iron Workers Union, building bridges and high-rises, the same career path his father chose.
“Then the economy crashed in 1980 and I found myself out of work, going fishing quite a bit,” he says. A friend told him the city of Bend had an opening for a sewer line cleaner. “I thought, well, my unemployment is about to run out. My mom’s probably getting tired of me hanging around the house. So I took an interview with the plant manager. He hired me right on the spot.”
He earned $6.10 an hour to start after making $17 in construction, but when he moved to the treatment plant after a year, he found a calling: “What it took to treat wastewater fascinated me. Taking samples, taking them to the lab, running BODs, chlorine residuals, coliforms and turbidities. It was amazing, the transformation from what the water looked like coming in and what it looked like going out of the plant. It just grabbed me.”
No stream discharge
The Bend plant sits on 1,600 acres of range land. Effluent discharges to evaporation/percolation ponds on the property. BOD and TSS permit limits are 20 mg/L, stricter than for typical stream discharge. Both parameters in effluent average less than 10 mg/L.
“Our groundwater is about 600 feet deep in the high desert here,” says Thompson. “We have monitoring wells up-gradient and down-gradient of the ponds. We monitor those wells quarterly to make sure we’re not having any adverse effect on the groundwater.”
For the first 15 years of Thompson’s tenure, the plant ran a conventional activated sludge process. The community grew rapidly, and by the mid-1990s was treating nearly 4 mgd. “We knew a nitrogen permit limit was coming from the Department of Environmental Quality, so we pilot-tested the modified Ludzack-Edinger (MLE) process, which includes nitrification and denitrification.
“We had good results, so we retrofitted our two aeration basins and added a third one. When we switched to MLE, our process control was greatly simplified. Before that, we would go through episodes of filamentous bulking with Nocardia and struggle to make permit. Nitrification really smoothed out the process. It’s much easier to control.”
In 2005, the team added a water reuse facility using AquaDisc filters (Aqua-Aerobic Systems) to achieve less than 2 NTU turbidity. The city supplies reclaimed water from spring into fall to a resort and golf course for irrigation.
In 2008, the plant went through its first major equipment replacement project. The existing headworks was replaced by a screening system (JWC Environmental) with 3 mm and 6 mm punch plates and a Muffin Monster screening washer/compactor (also JWC). “It costs about $20 a day in electricity to run that system,” says Thompson “That’s because we tapped into the hot-water loop of the anaerobic digester boiler system to heat the building and provide hot water to clean the screens automatically through the SCADA system at 100-hour intervals.”
The fine screening helped elevate the biosolids to Class A by efficiently removing debris that otherwise passed through the process. Grit removal at the headworks isn’t necessary because with only about 10 inches of annual rainfall and deep groundwater, I&I is extremely low and very little grit is washed into the collections system. Grit settles in the primary clarifiers.
Primary and waste activated sludges are anaerobically digested, yielding about 1,300 dry tons per year. For 18 years of Thompson’s career, liquid biosolids were land-applied. Now the material is dewatered on a belt filter press (BDP Industries) and solar-dried to 90 percent solids on asphalt drying beds before land application.
At present, Thompson is working with DeSchutes Recycling to blend Class A biosolids and some recycled yard trimmings to make a compost available to the local gardening community.
Leading the team
Now functioning as a program manager, Thompson worked his way up the ranks at the Bend plant, becoming senior operator in 2000 and operations supervisor in 2006. His team includes:
- Tim Truax, his successor as operations supervisor
- George McConnell, water reclamation operations lead, and Roy Bradley, Sam Borgognoni, Aaron Utley, Ethan Parent, Erynne Fore and Elmer Roshone, operators
- Joe Burghardt, water reclamation plant mechanic lead, and Lance Finney and Marc Mickey, mechanics
Thompson leads a staff of whom seven have five years’ or less experience in the field and two more are set to retire in the next couple of years. That makes mentoring and training essential. He created an apprenticeship program in Bend to help groom a new generation. Its first enrollee was to begin the program this past summer.
“In my career I’ve hired and trained a number of people, and after a few years they move back over to the west side of the Oregon Cascades,” Thompson says. “It’s been a little difficult to retain staff here. Some of the people were trained at small plants and private utilities, to the south of us. Our last two hires attended two-year wastewater programs at community colleges. We send our new people to short schools and work side by side with them, going through the facility standard operating procedures. It takes almost a year before they feel comfortable.”
Thompson benefited from a nine-month supervisory leadership program in 2000-01 at Oregon State University. As part of a class with 15 members from public entities and private industry, he practiced public speaking, teamwork, leadership, conflict resolution and other skills.
He helps motivate and train staff members by encouraging them to work as teams to solve problems: “When we have a process control challenge, we all sit down together and try to work out a solution. Should we waste more sludge? Turn the chlorine dosage up or down?” The energy-saving heat recovery process in the headworks building grew out of a team discussion.
Staff members meet weekly to make microscopic observations. The resulting information is beneficial in making process control decisions.
Advising young people new to the career, Thompson stresses the importance of automation and online control: “They need to embrace new technology. When I started we didn’t have online DO control. Now we do. I see in the future being able to get BOD results from an online instrument. We currently experiment with nitrate and ammonia control in our aeration basins.
“It’s also important for operators to understand what goes on in the laboratory, because that directly reflects what goes on out in the field. For example, online instruments need to be calibrated. You have to be able to take samples from the field to the lab and validate that the instruments are in calibration, and it has to be done in a timely manner.”
The challenges for Thompson are mainly in the rearview mirror — he retired last summer but will be around as needed to help Truax through another major change in the treatment system: a conversion to the integrated fixed-film activated sludge (IFAS) process (Kruger). The process uses plastic-media discs in the aeration basins that grow a film of microorganisms; it enables more treatment capacity in the same tankage.
“It makes expansion in the future much easier. You don’t have to build more tanks. In this expansion we’re going to increase capacity to 8.5 mgd. From that point on, the city will only have to buy more plastic media to take aeration capacity all the way up to 11.9 mgd.”
In retirement, Thompson expects to work part time as a wastewater consultant, drawing on his experience with more than three decades of operations and multiple plant upgrades and construction projects. He won’t mind at all having more time to himself and with his family.
He’ll also do some fishing for salmon in spring and fall on the Columbia River. Last spring he took his 9-year-old granddaughter on her first river drift boat fishing trip for smallmouth bass.
In an important way that brings his life full circle — getting to enjoy the kind of resources he spent his career protecting.
New life for old mines
Scott Thompson sees biosolids management as the most challenging side of wastewater treatment. In his years with the city of Bend, he has worked to make the process easier, less costly, and more beneficial.
Thompson is proud of a four-year pilot project aimed at testing Bend’s Class A biosolids as a soil amendment to help reclaim land depleted by mining. The city has partnered on that project with the U.S. Forest Service and the Oregon Department of Environmental Quality.
The mine reclamation site lies along Clear Creek in northeast Oregon’s Granite Creek Watershed, which includes mostly land in the Wallowa-Whitman and Umatilla national forests. The watershed is designated high risk/high value, partly because it sends water to the lower John Day River, which supports critical salmon and steelhead habitat.
For the reclamation project, started in 2014, researchers created seven test plots that received treatment with different soil amendments and combinations: biosolids, biochar (a charcoal product made in the absence of oxygen), wood chips, biosolids and biochar mixture, biosolids and wood chips mixture, biochar and wood chips mixture, and biosolids with biochar and wood chips. An eighth (control) plot received no treatment. The plots were then planted or seeded with grasses and vegetation.
Preliminary results showed that the plot with biochar and biosolids supported much more growth of grasses and vegetation than the others. Preliminary conclusions stated that treating mined land with biosolids, biochar and wood chips create opportunities for soil restoration in the western U.S. The pilot project is continuing through 2018; the researchers recommended further research with larger test plots.