Chicago, Illinois Water Quality Report
Sources Of Drinking Water in Chicago, Illinois
Where does Chicago get its water from? Lake Michigan, by volume, is the second largest Great Lake and the only one located totally within the United States. It serves as a source of drinking water, fishing, and unfortunately...industrial run off. Is Chicago's water safe to drink? Does Chicago put fluoride in the water?
Here is the process that the City of Chicago uses to filter the water for drinking. Is Chicago's tap water safe to drink?
- Water from Lake Michigan enters the intake crib at depths of 20 to 30 feet.
- Water enters the purification plant's intake basin through a tunnel beneath the lake bed.
- Water is filtered through eight traveling screens to catch debris.
- Water is pumped by low lift pumps up to 25 feet for the first chemical treatment.
- Water flows from the chemical application channels.
- Water flows through mixing basins to begin the flocculation process.
- Flocculated water passes into settling basins to sit for hours allowing floc to settle.
- Water is filtered through precisely graded sand and gravel performing a "natural polishing".
- Filtered water flows into clearwells for its final chemical application.
- From finished water reservoirs water flows to the distribution system.
The City of Chicago uses several chemicals in the purification and treatment of water:
- Chlorine: to disinfect the water.
- Aluminum Sulfate or Alum and Polymer: for coagulation to settle out impurities.
- Blended Polyphosphate: to coat pipes and prevent lead leaching.
- Activated Carbon: to remove unpleasant tastes and odors.
- Fluoride: to help fight cavities in children's teeth.
Source: City of Chicago
Contaminants Found in Chicago's Water Supply
(Detected above health guidelines)
Total trihalomethanes (TTHMs)
What are the best types of filters to remove these contaminants?
Water sources can contain contaminants that impact your long term health, the taste & smell of the water and other microbiological contaminants that can actually make people sick shortly after drinking. Fortunately, there are water filtration products that remove many of the impurities from water. These filters often use activated carbon. Activated carbon is a form of carbon processed to have small, low-volume pores that increase the surface area available for adsorption of contaminants or chemical reactions. Two dominant carbon filter choices are solid activated carbon blocks and granular activated carbon filters.
Granular activated carbon filters have loose granules of carbon that look like black grains of sand. These black grains of carbon, are dumped into a container and the water is forced to travel through the container to reach the other side, passing by all of the grains of carbon. Solid block carbon filters are blocks of compressed activated carbon that are formed with the combination of heat and pressure. These filters force the water to try to find a way through the solid wall and thousands of layers of carbon until the reach a channel which leads the water out of the filter. Both filters are made from carbon that’s ground into small particulate sizes. Solid carbon blocks are ground even further into a fine mesh 7 to 19 times smaller than the granular activated carbon filters.
Flow Channels & Less Contact Time
As water continually pass through Granular Activated Carbon filters, flow channels begin to develop that allows the water to flow around the carbon. Flow channels also develop between the granules, leading to less effective filtration as there’s less contact between the water and carbon. Solid carbon blocks are much tighter and won’t even let through microbial cysts like giardia and cryptosporidium (7 to 10 Microns in size). However, solid carbon block filters are so tight that they can often get plugged up with organic & non-organic matter, forcing owners to replace them on a more regular basis. This is why when you are using a Brita water pitcher filter (granular activated carbon), the filter will keep going and going long after it has stopped removing any water contaminants.
Carbon Block vs Granulated Activated Carbon
The granular activated carbon filters are cheap and simple to manufacture, which is why most water filtration companies choose this method for manufacturing (ex: Brita, Woder). Solid Carbon Block Filters on the other hand take longer to manufacture and are more expensive but with this expense, you get superior contaminant removal because the water must take a tortured path through thousands of layers of compressed carbon before it reaches your drinking glass.
The solid carbon block filters like the one used in the Epic Smart Shield & Epic Water Filter pitchers, remove more contaminants than the granular activated carbon filters due to the larger surface area and the tighter filters, this is why Epic Water Filters has standardized on the solid carbon block design for our water pitchers and our under the sink water filter. Unfortunately, granular activated carbon filters do not do enough to reduce contaminants, this is why they are not used when there is a chance of bacteria or cysts in the water. They are truly not "Epic" so that is why we have passed on this design and let our competitors like Woder, Brita, Pur, and Invigorated Water use these loose packed carbon filters for sub-par contaminant removal.
Solid carbon block filters, on the other hand, have millions and millions of different sized pores that cause the water to take a long slow path to get through the filter, increasing the contact time that the contaminated water has with the carbon. During this contact time is when contaminants adhere to the carbon and are removed from water. This happens during a process called adsorption, the other filtration method that carbon blocks use is called depth filtration where the thickness of the filter comes into play to help remove contaminants as they have to pass through this carbon walls.
With solid carbon block filters the contaminants are in contact with more carbon for a longer period and therefore have more time to remove stubborn contaminants like lead (Epic Pure Pitcher 99.9% removal), fluoride (Epic Pure Pitcher 97.8% removal), and PFCs (Epic Pure Pitcher 99.8% removal). Carbon blocks can remove chlorine more effectively, eliminate undesirable odors, and removal of endocrine disruptors like volatile organic compounds. Granular activated carbon filters, on the other hand, have small particles that move around under the pressure of water so they do not have as much uniformity throughout and therefore less contact time with the water and less contaminant removal.
What about Reverse Osmosis?
RO filters are good at contaminant removal. The downside of RO is that it wastes a lot of water. Each RO system wastes an average of 5 to 6 gallons for every gallon it produces of drinking water. Also RO systems remove trace minerals and other beneficial substances found in water that your body needs (calcium, manganese, iron and other important nutrients). This is why RO water is considered by many in the natural health world to be dead water and it is said that demineralized water is detrimental to general health due to vitamin and mineral depletion. The last downside of RO systems is that after your water passes through the filter process, it sits inside of steel drum that is lined with a butyl rubber bladder which is made from polyisobutylene. The filtered water sits in this butyl rubber bladder until it is used. All rubber and plastic containers leach into water at some level. Carbon block filters do not have these issues.
A hiker, blogger, clean living enthusiast, and water quality expert.
- April Jones