By Elizabeth Zollner (member of the West Middle School Future City team in Lawrence, Kansas being mentored by CH2M HILL wastewater project manager Stacey Lamer)
When you think of field trips, you don’t really think of going to a waste water treatment plant. At least I don’t. And yet there I was, riding along in a white van, going to see what happens after you flush a toilet. This was supposed to help us with our Future City competition, but I wasn’t so sure. As the van stopped in front of a normal looking building, I hoped that this was worth my time.
On our tour we first saw (through these amazing protective goggles) the place where they began to filter all of the large objects. Our guide then showed us how they sifted out all of the smaller objects, such as sand and gravel. Outside there were huge basins filled with water where objects left in the water would either float to the top or settle to the bottom. After blades skim the surface and the bottom of the basins, the water is 85 to 90 percent clean. But that was just the primary treatment.
In 1976, the waste water treatment plant was granted a new expansion for secondary treatment. The secondary treatment begins when water is pumped into aeration basins where the water is then cleaned by microbes. At this point in the water cleaning process the water is over 99 percent clean! After the water is chemically disinfected, it flows back into the river.
I can honestly say that I learned a lot on this crazy-sounding field trip. I learned that there are different types of microbes such as water bears, oligochaetes, rotifers, nematodes, suctorians, and ciliates. I also learned that, unlike some cities, Lawrence does not have a combined sewer system. So if someone offers to take you to a waste water treatment plant, say yes. You get used to the smell.