“The most expensive water treatment system in the country and it still dumps millions of pounds of solid waste into the lake when it rains.”
When there are extremely heavy rains, yes the system can overflow and backup into the lake. That’s not a standard occurrence, though. The normal procedure is for the waste to get dumped in the Mississippi :)
--after a few stages of treatment. What I remember was that after a flood the Chicago River would stink and with a really heavy flood the muni water would need boiling. My civil engineering past tells me Chicago area is one of the cleaner areas, and per person much cleaner than rural areas. They don't have outhouses in Chicago.