 Our Drinking Water Where is it coming from??

Where Chicago Gets its Water  Lake Michigan supplies our water  The city takes up to 2.1 billion gallons of water a day!!  A variety of steps and chemicals are used to make sure our water is safe to drink

The Process Take notes on your handout as the video progresses.

Some of the Details

The Process 1. Water from Lake Michigan enters the intake crib at depths of 20 to 30 feet. 2. Water enters the purification plant's intake basin through a tunnel beneath the lake bed. 3. Water is filtered through eight traveling screens to catch debris. 4. Water is pumped by low lift pumps up to 25 feet for the first chemical treatment. 5. Water flows from the chemical application channels..

The Process 6. Water flows through mixing basins to begin the flocculation process. 7. Flocculated water passes into settling basins to sit for hours allowing floc to settle. 8. Water is filtered through precisely graded sand and gravel performing a "natural polishing". 9. Filtered water flows into clearwells for its final chemical application. 10. From finished water reservoirs water flows to the distribution system

The Chemicals in the Process  Very Very Very small amounts are used  For every 100 gallons only a teaspoon full of chemicals is used  There are 5 main chemicals that are used at various times in this process.

Chemicals in the Process  Chlorine - Used to disinfect the water  Alum OR Aluminum Sulfate – To help with coagulation and to settle impurities  Blended Polyphosphate – Coats the pipes to prevent lead contamination  Activated Carbon – Removes unpleasant odors and tastes  Fluoride - Cavity protection for children’s teeth

Sometimes the process doesn’t work  It is rare that there are issues here in the U.S.  To be effective testing and re-evaluation of the system has to happen often.  We will talk about a few times that the system failed  Many of these issues could be prevented by better management of our water at its source

1993- Milwaukee, WI Criptosporidium contamination  What is criptosporidium?  It is a protozoan (single celled organism)  It causes severe diarrhea in people who consume them

1993- Milwaukee, WI Criptosporidium contamination  Where does it come from?  It’s a water borne pathogen  Typically carried in the feces of both wild and domestic animals  Cannot be killed through chlorination  It must be FILTERED out of the water

1993- Milwaukee, WI Criptosporidium contamination  This was the largest and most devastating waterborne disease outbreak in U.S. history  400,000 people were affected (25% of the population of Milwaukee)  As many as 100 individuals died from this exposure

1993- Milwaukee, WI Criptosporidium contamination  Led to improvements and understanding of watershed management  Wisconsin does not have an over-abundance of wildlife  But it does have a large number of farms and domestic livestock  Run-off from farms into Lake MI and it’s watersheds most likely caused the increase in cryptosporidium oocysts  Improvements in water filtration and purification processes

2014 – Lake Erie Algal Bloom  Some species of algae can give off a harmful neurotoxin  Symptoms  Nerve damage  Liver damage  Can cause death if untreated – especially in younger children or pets  Cannot be treated by traditional water treatment processes

2014 – Lake Erie Algal Bloom  What causes Algal blooms?  Run-off from homes and farms  Increased levels of Phosphorus and Nitrogen which are used in fertilizers. erie-suffering-from-harmf/

What is the theme?  What similarity did the two situations have to each other?  Why do we need to be aware of what we put into our water?  Raise you hand if you have ever dumped something down the sewer in the city OR dropped trash on the street without thinking about it.