Water intake from Lake Michigan: How and where is water taken in from Lake Michigan for
City of Chicago drinking water? How does it get to the treatment plants, and where in the city
are they located? Plot these on a map using Google Earth. How much drinking water does
Chicago treat on a daily basis? Find the most recent analysis of “Raw Lake” water. Are any of
the inorganic parameters reported close to exceeding the Primary or Secondary Drinking Water
Standards? If so, which ones?
Drinking Water Treatment: What does the City of Chicago do to treat our drinking water to
make it potable? Read the most recent City of Chicago Water Quality Report. In the most recent
report, how many samples were reported to be above the MCLs for drinking water? Describe
the first steps for drinking water treatment, focusing on filtration, flocculation, and settling (not
chlorination or fluoridation). What are those processes? What do they do to “clean” the water?
Where in Chicago are these processes performed? What happens to the waste products from
these processes?
Chlorination and Fluoridation: What is chlorination, why is it done, how effective is it? How
much chlorine is added, and how? What (if any) limits are set on the amount of chlorine that
can be added? Is there a drinking water standard (primary or secondary) for chlorine? In the
most recent City of Chicago Water Quality Report, what is the range of chlorine concentrations
measured? Do any of these exceed MCLs? What is fluoridation, why is it done, how effective is
it? How much fluoride is added, and how? What (if any) limits are set on the amount of fluoride
that can be added? Is there a drinking water standard (primary or secondary) for fluoride? In
the most recent City of Chicago Water Quality Report, what is the range of fluoride
concentrations measured? Do any of these exceed the standards?
Emerging Contaminants: What is an “emerging contaminant”? What emerging contaminants
persist in our drinking water? Are they known to cause health problems? What can be done
about it? List and describe the categories of chemicals and give some of the common
contaminants and their sources.
Distribution to Users: How is water distributed to users? How much is distributed? What
proportion goes to residences/businesses, and what proportion to industrial uses? What
facilities/infrastructure are needed to distribute tap water? Does anything happen to the water
quality during the process of distributing it?
Lead in Drinking Water: What are the potential sources of lead in drinking water? What are the
possible negative effects of lead in drinking water? How bad is the problem in Chicago? What
are the Drinking Water Standards for lead, and
Waste Water
Wastewater and Water Quality in Local Waterways: What is the MWRD, and what do they do?
What geographic area to they serve? Find the Waterway Ambient Water Quality for the most
recent year on the MWRD website, and examine the data. Consider TDS as an overall indicator
of water quality. Each month, what are the highest recorded values of TDS. What month has
the highest TDS values? At what sampling locations were the highest values found? Looking at
the “Waterways Locations” worksheet, find where these points are located, and plot them on a
map using Google Earth and the latitude and longitude. Add to your map the locations of the
wastewater reclamation plants. Is there a correlation?
Sanitary Sewage: What is sanitary sewage, and how does it leave our homes? What are catch
basins? Looking at the sewage pipes leading away from a typical home in Chicago, where do the
sewer pipes go? What do they lead to next? Where does the sewage end up?
Storm Water and the Deep Tunnel: What happens to the water that drains into the gutter of
the streets in Chicago? Where does it go next? Where does it end up? Is it considered
“sewage”? It is mainly rainwater, so does it need to be treated the same way sewage does?
Does it get treated, and why or why not? (This was a conscious decision on the part of the
people who built Chicago; see if you can figure out why they made the decision.) What is the
Tunnel and Reservoir Plan (TARP)? Why was it constructed? Where is it located? How does it
work? Is it 100% effective, and why or why not? What happens when storm runoff is too
extreme for the Deep Tunnel to handle it?
Water Reclamation Plants and Wastewater Treatment: What is involved in primary treatment
of waste water? How is it performed? Where in the Chicago area is this treatment performed?
What is involved in secondary treatment of waste water? How is it performed? Where in the
Chicago area is this treatment performed? What is involved in disinfection of waste water?
What are the options for how disinfection might be performed? How is it performed in
Chicago?
Releasing Treated Wastewater: Where does our treated wastewater go after it is treated by
one of our water reclamation plants? It hasn’t always gone there; where did it used to go? Why
and how was the change made? Is there any evidence that it causes a problem downstream?
What is the role of the canal system in Chicago? In particular, what is the purpose of the North
Shore Channel, Calumet-Sag Channel, and Sanitary and Ship Canal?