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- Gathering
We gathered together in the building before heading outside.
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- Outside
On a typical day, the plant processes 3 million gallons of water. Of course, this fluctuates. During heavy rainfall, 5 times as much can come through the system, which is not good because we can't handle it and have to discharge.
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- Big basins
I can't remember exactly what they're called, but after the water is brought into the plant, it flows through some filters to filter out bigger particulate matter and ends up in one of these three large basins.
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- Drained basin
The basins (like this one) are drained regularly, one at a time, for cleaning. Here you can see the arm at the bottom, which sweeps across the bottom and pulls the settling sludge to the center, where it is pumped out.
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- Full basin
The water sits here and the sludge eventually settles to the bottom, where it is gathered by the arms into the center. The cleaner water (now with less sludge) flows over the outside of the basin as you see here, on to its next destination.
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- Water comes in
Gravity brings all the sewage to the plant, and there are lift stations all around town to make sure that happens. Once it's here, this large Archimedes screw pulls the water up and into the plant. From here it travels through a series of filters to remove the larger material.
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- Listening
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- Next stage - bio activity
Here is where the water comes after the basins. It flows through these large rotating things where biological material eats away at the junk in the water. It collects on these large drums (that's why they are black) along with millions of little snails, which live off the crud.
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- Almost done
The water then flows out to these last two basins, where the sludge settles for yet another time. The idea is that, once it leaves these basins, it is more or less clean. Not drinkable, but clean enough to release back into the environment to the lake.
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- Overflow basin
When there is overflow - such as in heavy rainfall - the overflow is pumped here, where it sits until it is either pulled back into the plant or - if there's too much of it - discharged without treatment back into the stream. We get big fines from DNR for doing that, and they won't actually even allow us to discharge anymore. Which is, of course, a big problem.
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- Leaving the plant
As the water leaves the plant, it passes through this, which has sensors to measure the flow of the water.
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- Back out to the stream
Here is the stream where the water leaves the plant and flows out to Bear Creek Lake.
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- Oxygenated water
That froth isn't soap - it's air bubbles, due to the high oxygen content of the water. The fish love it. John said there's a healthy-sized school of bluegill living just downstream.
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- Sludge truck
The sludge from the process is collected in large outdoor tanks (not shown) and undergoes another biological process. Methane gas is produced, which helps run the plant, and the leftover sludge is put into these trucks and hauled out for spreading. It makes great fertilizer for area farmers, or it gets spread across a nearby lagoon on city property.
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- Sludge pipe
Here's the pipe that drops the sludge into the truck. Yummy.
