Out of sight, out of mind – that's the way many of us feel about flushing the toilet. But the City’s wastewater system doesn’t happen by magic. It takes the work and sweat and dedication of hundreds of Bureau of Environmental Services workers like Christa Overby. She oversees maintenance for the pumps and treatment plants that are the heart of a system that handles as much as 450 million gallons of flow a day. We caught up with her at the Columbia Boulevard treatment plant, which is the biggest in the state.
What does your workday look like? I manage the maintenance for our treatment plants and pump stations. That’s about 78 people. We do maintenance, troubleshooting, and repair work at our two treatment plants and for the 98 pump stations located across the city. We’ve got pumps and shafts and gates and clarifiers and all kinds of assets. Altogether there’s about 20,000 items in our system. Mechanical, electrical, instrumentation, automation, you name it. We have a lot of infrastructure. Our goal is to keep it operating and maintained properly to maximize its lifespan and meet our permit requirements.
Wait, we have pumps for our poop? Yes. Sewage is 99% water. Our system is based on gravity flow. When you flush the toilet, gravity pulls the flow through the pipes to a low point. But then we need to get it to the plant for treatment. So we use pumps to push it through pipes to the plant. Some of those pumps are pretty big. The Swan Island CSO Pump Station is so big the Portland Building could fit inside it.
What happens to the wastewater when it gets to the plant? First it goes through our headworks where we screen out debris and other junk – you know, people still flush down wipes, even though we ask them not to. Then we use a biological treatment process known as activated sludge. Microorganisms break down the organic waste. It goes on to further treatment including chemical disinfection and is sent out into the Columbia River. The biosolids settle out and are treated in our digesters and eventually hauled away to Eastern Oregon, where they are applied in pastures and grain fields to improve the soil.
How did you get into this line of work? I grew up in Portland and went to Oregon State University and got into civil engineering. When I was in engineering school, I did an internship with the City and learned about how you design pipes and pumps for wastewater. Most people, my son included, would be like “Oh, that’s gross,” but I find it fascinating. I worked on the Big Pipe project before I came over to maintenance.
What happens when something goes wrong? First of all, we have amazing people here who all take a lot of great pride in their work. Everybody steps up to help out. We have people at the plant 24 hours a day. We have maintenance staff who are on call after hours. It's amazing to see, no matter what time of the night, if one person needs help, folks step in to help out. Like last night we had a big storm and we had multiple pumps down, and people responding to issues at all hours of the night. We know what response time we have at each pump station, so we work together to solve problems.
Are storms a big deal for you? Yes! We’re constantly looking at the weather, making sure we're prepared. We meet every morning to look at the forecast and assess any issues. Because it matters for us.
What do you like to do when you're not on the job? I love to spend time with family and friends. My son plays basketball, which is really fun. We like playing card games like canasta and cribbage. And I like watching the Blazers. Rough times now, but they’re on the rebound.