Centralized Wastewater Treatment
In most municipalities there is a sewerage system (sewers, manholes, pump stations, forcemains, service lines – collectively “sewerage”) that collects the sewage (the wastewater in the system, no “r”) from the homes and businesses and transports it to the wastewater treatment plant (water reclamation facility, sewage treatment plant, sh## plant – they all mean the same thing) where the wastewater is treated to make it acceptable for discharge to the environment. A very simplified and generalized flow chart of what happens at a treatment plant follows:
The most treatment is happening in Step B. Bugs are eating the poop from the wastewater thereby “cleaning” the water. I can list maybe a dozen different technologies that we use to accomplish this that involve concentrating microorganisms (bacteria and/or algae) and giving them the ideal amount of food (wastewater), the right amount of oxygen (a lot = aerobic, a little = anoxic, almost none = anaerobic; the bacteria that thrive in each different environment are specialists at ingesting specific nutrients and/or organic matter), and the right environment (temperature, pH…) to allow them to reproduce and form dense colonies that we can separate from the treatment stream in Step C.
The secret to this is that we treat the wastewater only to the point where it will cause no harm to the environment. Further dilution and treatment occurs in nature after we have done our job at the treatment plant. The old adage, “Dilution is the solution to pollution” governs all treatment plans. Any stories that you’ve heard about drinking the treated effluent from a wastewater treatment plant are really just stories about crazy people. That said, this newspaper article hangs on the side of the bookshelf behind my desk as a reminder of the importance of my profession:
June 27, 1912:
The village board are contemplating putting up a sign at the outlet of the sewer into the DuPage River, below Electric Park, so the camp dwellers can distinguish it from the spring nearby.
A few days ago some of the campers were remarking on what delicious drinking water they had found running from a tile at the river bank. Inquiry and investigation revealed the fact that it was the village sewer.
Excerpts from June, 1912 "The (Plainfield) Enterprise”
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