When I drove up the hill to the Chambers Creek Wastewater Treatment Center for my tour on a very rainy May 18, I expected the clouds to part overhead and the bright sun to bathe the poo tanks in the holiest of lights.
That didn’t happen.
But, I did get to see some cool shit.
The Chambers Creek facility is the largest of all the poo plants I’ve toured. It processes 17 million gallons of poo every day. But, the size of the facility meant that a lot of the coolest features, including the huge grinder that is the first stop on the Great Poo Journey, happened out of view.
There were several giant grinders but all were housed underground and our tour guide wouldn’t lift any of the screens to show us anything horrifying. In my previous two tours, the grinders were the highlights. I was able to see toothbrushes, rubbers, dental floss, tampons, and more getting ground up and smashed into a dry pulp that went to the landfills. It was fantastic.
Of course, I didn’t let the lack of visible grinders sour me on the entire tour. First of all, the tour guide was named Rob Lowe. Really. Rob Lowe. He looked nothing like he does on TV. But, he did say “poop” a lot, which made me laugh every time. There’s something about a man in his 60s saying the word “poop;” it’s always hilarious. Second, I was easily the most excited person on the tour. Of the 10 of us, I was the only one who didn’t work in military or municipal public works. Their passion for sewage had clearly extinguished years earlier, but I was still fresh and excited. I hope my enthusiasm buoyed their spirits. Third, there were three Army Rangers on the tour. In uniform. Attractive men and municipal wastewater…I was in heaven.
At Chambers Creek, they transform the poop you and I flush every day (ideally) into two things: water that is cleaned and pumped back into Puget Sound and dry fertilizer pellets. Here’s a brief and non-scientific rundown of how it all happens.
All the non-poop is pulled out in the screening and grit tanks. Rob Lowe mentioned finding concrete chunks, wood, and assorted other decidedly non-flushable items, as well as more expected items like corn and peanuts (this made me laugh so hard, by the way). Those things are ground up and taken to the landfill. What’s left behind goes through two clarifiers, a primary and secondary clarifier, that further separate unusable solids (sand, dirt, etc.) from liquids (we’ll get back to the solids in a minute).
The poop-water left behind is then aerated in a series of giant concrete tanks. Oxygen is pumped up through the sewage, forcing lighter materials to the top. Several tanks on the tour were covered with a thick cake of crusty brown foam, scattered with bits of lettuce, peas, and grease, which is skimmed off the top. Very gross…and awesome to see. As it moves through the progression of tanks, there’s less and less to skim off.
The poop-water, now free of all solid yuck, goes through an ultraviolet light that destroys any dangerous nasties that may have survived the process. Rob Lowe informed us that bacteria is not killed by the ultraviolet light, but it is genetically modified so it’s unable to reproduce. Weird, eh?
While all of this is happening to the liquids, the solids are going through an entirely different process. After they are separated out, the solids go to digesters, where anaerobic bacteria work their magic, reducing the volume of the solids and producing hot, smelly gas. This gas is captured and used to run the boilers that power the huge centrifuges, the next stop for the solids, where the bulk of the water is pulled out.
The almost-dry solids are then sent to drying drums (similar to dryers for laundry, but huge and methane-powered), where they are turned into hard pellets. The pellets are then sorted, cooled, and put into storage before they are ultimately sold as fertilizer. The whole process takes about 20 days.
Since coming back from the tour, most people have asked me about the smell. In truth, it didn’t smell all that bad. The worst part was actually before the tour started, when Rob Lowe led us through a maze of tunnels below the processing tanks to get to the screening area, our official starting point. Below ground, in a confined area, the smell got really, really bad. I kept wanting to ask the Army Ranger to my right, “Whew, dude, is that you?” but I didn’t want to seem immature. I said it in my head about 100 times, though.
Another high point was in the testing lab, where water samples are tested for bacteria. In the office was a bathroom and, while we were all crammed in there learning about the computer system, one of the workers came in and went to the bathroom. We could hear everything. It was really awkward and funny. There’s no way in hell I’d go to the bathroom with a tour group standing five feet away. But, maybe if I was surrounded by poop 40 hours a week, I’d get over it.
Shockingly, a couple of the really cool things I saw were not sewage related. In the control room for the drying area, there was a combination microwave-coffee pot on the table. I never before knew such a machine existed. It was really cool. A microwave and a coffee pot all in one! Brilliant! And, I really, really liked Rob Lowe’s fancy wastewater treatment plant jacket. If I had one of those, I’d never take it off. (As a sidenote, Rob Lowe also told us that he wanted to be a marine biologist when he was in college, but he didn’t like all the travel so he went into wastewater. I wanted to make a comment about brown trout, but I kept it to myself and giggled instead.)
So, that was it. Forty-five minutes that will last a lifetime. I can’t wait for the next one!