BUSINESS

Willow Lake Wastewater Treatment plant reduces waste

Beth Casper
Special to the Statesman Journal
An aerial view of the Willow Lake Wastewater Treatment Facility where over 30 million gallons of water is treated every day.

Willow Lake Wastewater Treatment plant handles more than 30 million gallons a day of the stuff most people want to flush away and forget.

But it’s the staff’s focus on that wastewater — how it is treated, recycled, and used to produce energy — that has a significant impact on the environment, particularly places that people love, such as the Willamette River.

“Wastewater treatment itself is the greatest environmental improvement since the 60s and 70s when the environmental movement picked up steam,” said Steve Hall, a lab analyst at Willow Lake and the treatment facility’s green team leader. “Wastewater treatment has had the greatest impact on the environment. Everything comes here from people’s houses and industries and the health of the Willamette River and the greater community is dependent on what goes on here.”

Willow Lake Wastewater Treatment plant services more than 60 square miles and includes the cities of Salem, Keizer and Turner.

The facility has been EarthWISE certified since 2010. The EarthWISE program is a free business environmental assistance program of Marion County. EarthWISE staff helps businesses recycle, save energy, reduce waste and much more. To earn certification, a business meets criteria in six areas. Willow Lake is one of more than 150 EarthWISE agencies, nonprofits and businesses in Marion County.

Kaley Adams runs laboratory tests to ensure that treatment is meeting water quality standards.

Since Willow Lake deals with so much water each day, it makes sense that reusing it is one of the facility’s top priorities. After treatment, at least a million gallons per day is used to either irrigate the 40 acres that comprise the facility or for other internal processes such as cooling pumps or being processed in the natural treatment wetlands.

“Recycled water is fully treated but not potable,” said Stephanie Eisner, wastewater treatment operations manager. “Instead of returning it to the river, we use it here.”

The solids in the wastewater are also put to good use at Willow Lake. Once the solids are separated from the liquid, they are put in a digester where they decompose and produce methane. Willow Lake captures that methane, burns it and makes energy —enough to cover one-third of the energy needed to run the facility.

A new cogeneration engine is being designed right now that will produce 50 percent of the energy needed to run Willow Lake. It should be running in two to three years.

Other energy-saving projects — made possible with incentives from the Energy Trust of Oregon — add up to hundreds of thousands of dollars saved each year. By replacing the diffusers in the aeration basin, the facility saves about $91,000 a year. The replacement of a primary effluent pump for a smaller, more efficient one has saved about $18,000 a year on the electric bill. And by installing an efficient turbo blower for the aeration basin, the annual utility bill has dropped another $18,000 a year.

This cogeneration engine produces energy from methane gas captured from decomposing wastewater solids. A higher efficiency model is being designed that will produce 50% more energy.

“We have an energy team and we do a lot of things internally to reduce energy,” Eisner said. “That’s one of our largest expenses for our plant. We’ve been working with the Energy Trust of Oregon to continually look for ways to reduce our energy usage. We’ve found air leaks, new ways to process the material and times when we can turn off pumps.”

Even though they produce smaller savings, lighting updates have helped the facility be more energy efficient. Motion sensors, outdoor lighting on timers and T8 and LED bulbs are helping to keep the electricity costs at the plant to a minimum.

In keeping with conserving resources, the 53 employees at Willow Lake generally don’t use gas vehicles to drive around the campus. There are 14 electric carts and approximately 20 bicycles (with baskets) for employees to quickly move from one area of the treatment facility to another.

A recycling area ensures that paper, cardboard, plastic and aluminum cans from employees are all property recycled. The cogeneration facility uses motor oil, and Willow Lake recycles about 1,000 gallons of it a year.

“We get good ideas from employees related to coming up with energy-saving or other green ideas,” Eisner said. “I think that our employees work at being good stewards and keeping the Willamette clean. We all think of ourselves as environmentalists.”

For more information on other projects that are planned for the Willow Lake Treatment Facility, go to www.cityofsalem.net/Pages/willow-lake-wastewater-treatment.aspx. To learn about the EarthWISE program, visit www.mcEarthWISE.net.

A natural wetland adjacent to the Willow Lake Wastewater Treatment Facility treats wastewater by removing pollutants while cooling water before reuse.