Yelm’s brand new $36 million water reclamation facility up and running

Yelm Public Works Director Cody Colt had a giant smile on his face on Thursday, July 31, as he proudly showed off the newly built and recently up-and-running water reclamation facility (WRF), which cost roughly $36 million to construct.

During an exclusive tour of the historic facility, which is the city’s most expensive project in history, Colt broke down the process of how incoming wastewater is cleaned through numerous cycles and, thus, officially reclaimed. He also touted how sanitary the water is at the end of the cycle, though he did not recommend drinking it.

“Anything we don’t use goes to the canal, and when the canal shuts down, it goes to the river. It’s completely clean, purified water. You could theoretically drink that. I wouldn’t recommend it, but you could,” Colt said.

With the implementation of the plant, which Colt noted has stayed under or on budget for the entire project, the City of Yelm will be able to further accommodate for the anticipated growth locally over the next several decades. The total cost for the project is between $36 million and $40 million, which is the city’s biggest project ever, according to Colt.

Colt said the new facility can handle 2.5 million gallons of waste, while the old WRF was only able to process 600,000 gallons.

“The biggest thing is we’ve got a lot of room for growth,” Colt said, while noting the new WRF only processes about 600,000 gallons of waste currently. “We will never ever have to touch this plant in our lifetime. No matter how fast Yelm continues to grow, this plant will handle that growth for probably the next 30 to 40 years. Even if you get growth, you could add more cassettes to create more flow.”

He believes Yelm’s population could grow to 30,000 to 40,000 residents before any action is needed to expand the plant. The city began taking bids for the project in spring of 2022, and, after three years, Colt is thrilled to finally be at the finish line.

“It’s great to finally be here. With the turn on, there were obviously some hiccups, but everything is functioning well. We’re excited about having it all going,” he said. “The old system is now being turned off, and the new system is going to be more reliable, easier to access, easier for our team to train on and use. The old system was out of date.”

Perhaps the biggest upgrade in the WRF is the system’s new membrane bio reactor (MBR) system, which constantly runs to filter the waste water coming into the facility. Colt said the MBR serves as a giant sponge to soak up dirty water and output clean water.

Additionally, the reclaimed water is now UV disinfected throughout its process at the WRF. According to Colt, the water was previously disinfected with chlorine.

“UV, which is ultraviolet, and it pretty much burns it out. It’s much more powerful, but it’s like when you go suntanning. It kills everything in the water,” Colt said. “We don’t have to deal with chlorine gas anymore, which is expensive and dangerous. We still will use chlorine because we are required by law to chlorinate our reclaimed water. We will add chlorine at the very end of the system, but we use hyperchloric now. We create our own chlorine on site so we don’t have to buy gas — it’s just salt. It uses electricity to separate the particles.”

He added that the UV technology has been around for a while, but due to its recent progressions, more WRFs have begun switching to the ultraviolet technology.

Colt noted there are 44 total MBR filtration systems in the WRF, and that they’re individually called cassettes.

“The new system, with both of them online, could handle about 2.5 million gallons a day. We don’t need that much because we only bring in 600,000 gallons per day,” Colt said. “The old system is different. These tanks (in the old system) are very deep. These two big, big systems handle 600,000 gallons. The smaller (and newer) ones, because of the MBRs, handle 2.5 million gallons. You take up less space but you can do so much more.”

At the WRF, incoming sewage — directly from local sewer lines — will initially go through grit channels and headworks.

“When your toilet flushes, this is where it ends up,” Colt said. “It goes from here and goes into one of two filters so we can isolate it back and forth. That’s literally from people’s homes. If you flush it, this is where it comes.”

The facility currently doesn’t take any incoming solids due to septic tanks throughout city limits, but Colt said it will eventually add grinder pumps to handle those solid wastes. He anticipates the contents at the WRF to eventually “become chunkier.”

The transition from old equipment to a new facility has been great, but it hasn’t come without any minor hiccups, Colt said.

“One of the things we’re running into is because we can handle so much flow, there’s almost not enough flow. We need more. We’ve gone from being at capacity to being able to handle 2.5 million gallons,” he said. “The membranes like to consistently function because they create biofilms, so as long as they’re functioning, the biofilm is staying alive. When you stop and they stay stagnant, it doesn’t grow. So we’re going to have to rotate back and forth between the two to make sure they stay alive. We go from too much to not enough.”

Eventually, the WRF will no longer have to dump sludge at sites in Shelton or Centralia as it will begin to create fertilizer from dried out solid stream waste at the facility.

“The plan is to fertilize our city parks with it, and also let people in town use it. It is safe for all uses,” Colt said. “You can use it in your gardens, but a lot of people prefer to use it for growing grass. It does have that weird stigma in your mind because of where it came from.”