Water, water, everywhere
We had a good amount of rain yesterday. So did Chicago, and Milwaukee. Uh, oh… where does all the stormwater go? And what about wastewater? Certainly no sewage flows into our beautiful Lake Michigan? Here is the simplified scoop on the water impact from Lake Michigan’s two largest cities.
History
Back in the late 1800’s, sewers dumped combined rainwater and sewage thru the same pipes. Newer cities separated the two streams, but for Chicago and its’ older suburbs sewage and rainwater flow thru the same pipes. Cities across the world dumped their dirty water in the nearest body of water… streams, rivers, lakes, or the ocean.
Chicago ultimately dumped their dirty water directly, or indirectly into Lake Michigan. During large storms, the plumes of tainted water stretched all the way out to the water intakes. The pipes where Chicago pulled in “fresh” water.
Solutions
How to save citizens from massive sickness and death? Their solution was engineering the reversal of the Chicago river so that it no longer flowed into Lake Michigan. Instead, the dirty water flowed away from the lake, ultimately down the Mississippi river. Problem solved! But not for St Louis and other communities downstream. Milwaukee did not have that choice. Finally, after several dubious solutions, and a huge typhoid scare of 1909, they built a wastewater treatment plant. And additional ones as Milwaukee grew. As did Chicago.
Wastewater treatment plants became more and more effective. Now, dirty water is cleaned so well that the water could be directly piped into a city’s water intake, treated and used for drinking water. Parched California cities have proposed doing exactly that. Yet citizens resist the notion of drinking “sewer water” vehemently. So instead, the reclaimed water is pumped into the ground in one spot and pumped back out of the same aquifer as fresh water.
All is solved? The Mississippi river gets cleaned water from Chicago? Milwaukee pours perfectly fine cleaned water back into Lake Michigan?
Just one problem
Rain.
Chicago has yet to get their act completely together. Rain can still quickly overwhelm their mixed stream system. They routinely overflow sewage into the Chicago river… about once every six days recently. Billions of gallons a year. And very heavy rain means partially treated and untreated sewage flows into Lake Michigan. The Chicago river re-reversed.
Even Milwaukee can be overwhelmed by rain. A separate sanitary sewer system is impacted by rain. Water entering thru manhole covers, illegal tie-ins, leaks, etc… all contribute to separate sanitary systems being overwhelmed when it rains. Partially treated, or untreated, tainted water enters Lake Michigan.
The good news
It is important to understand that a water treatment plant works like a river. Just much faster. Water is filtered. Solids settle to the bottom. Bacteria eats and eats. Water is eventually clean again. The riverbed restored. Small, occasional overflows are probably unavoidable. Chicago can eventually make the Chicago River a pleasant place to be.
Lake Michigan fights off the occasional heavy rain insults like a river… and remains…. Lake Michigan.
