I worked in 4 different plants, or "units", as they were also called: Water Treatment (Water Treat), Chlorine (Chlor-Alkali), Ethylene Oxide (EO), and Styrofoam (Styro). In terms of safety, the most "unsafe" was Chlorine. The easiest to work in was a tie between Water Treat and EO, and the most physically demanding was Styro.
At Water Treatment, we produced treated water from raw water from the North Saskatchewan River. We had no river water pumps, so we bought the water from nearby Sherritt-Gordon Mines who sent it by pipeline to our raw water pond. Inside the plant was a vertically-mounted 100 horsepower pump that was in a "deep well", connected by pipe to the pond. The water was pumped to clarifiers outside the plant where settling of dirt and other suspended matter would settle out. Powdered alum (aluminum sulfate) was added by automatic feeders located inside the plant. The alum created "floc" that hung onto the dirt, making it heavy enough to drop to the bottom.
One day when I went to blow down the clarifiers, I saw a big hairy animal at the bottom of the ladder. It wasn't moving and I was sure it was dead, but I had to know for sure. I threw things at it and it didn't move, but I figured it was just playing dead, waiting for me to go down there, then it would attack. With a piece of pipe in my hand I stepped down the ladder, pausing on the second last rung, in case this thing jumped up at me suddenly. Feeling really brave, I stepped down to the last rung, and then kicked this animal with my steel-toed boot. Whew! It was dead. I grabbed it by the tail, and brought it to the plant floor for inspection. Then I dumped it around the building, putting a comment in the shift log book about it. I also indicated the dangers of working at this plant. My supervisor looked at the animal the next day an said it was a muskrat. We suspected that the rat was in the clarifier and came out through the 8" blow-down lines when I opened them up on a previous occasion. How it got into the clarifiers was a mystery because it would have had to pass through the deep-well pump.
The water from the clarifiers entered the Clear Well. This water was treated with sulfuric acid, to control the pH level and flowed into the cooling tower basin. This thing was an underground concrete reservoir that the cooling towers and huge cooling tower pumps sat on top of. Cooling water was a very important product that we produced because it was necessary in all other processes: if this failed, the other plants would have to shut down. Eight large pressurized sand filters filtered the cooling water on a continuous basis, taking the water from the pressurized headers and returning it to the cooling water sump.
The cooling tower pumps, 5 in all, were vertical, multi-stage high pressure, high volume pumps, operating on 2300 volts. Together they pumped out 40,000 gallons per minute into a 36" pipe, at about 85 pounds per square inch (psig). A natural gas-driven "fire engine" also pumped out of the reservoir into the same header, pressurizing the header to about 100 psig when the other pumps were on. It was used in case of power failure, when it would automatically start.
We also produced boiler feedwater. Boilers are more finicky than humans when it comes to treated water so their demands are greater. We had to soften the water using Zeolite softeners, filter it, making sure it passed all laboratory tests before we sent it to the steam plant. The softeners had to be monitored closely, and when boiler feed water was being used, we had to regenerate them quite often on a shift. This was done by backwashing the softener, then slowly adding a concentrated brine solution, allowing it to permeate the Zeolite so its hardness removal capabilities would become restored. A regeneration took about 1-1/2 hours.
Drinking water was also produced at our plant. The water from the clear well entered a sand and charcoal filter and chlorine gas was added for purification. Many times the chlorinators stopped working, or the tanks went empty, so frequently people were drinking unchlorinated water. (You know, the sewage from the City of Edmonton immediately upstream!). Sorry guys.
The chlorine came in huge 2 ton cylinders that we put on a scale so we could monitor when the chlorine started to run out. It was kind of strange and ironic, that with all the chlorine the Chlorine Plant produced, these 2 ton cylinders full of the liquid (it became a gas at atmospheric pressure), came from another source who bought the chlorine from us!