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Weeks 27 & 28 - Humans Depend on Water Supply and Quality

Lesson 3

Read pages 339 - 344

Lesson 3:

What is Potable Water?

Potable water is water that is safe to drink. But how do we judge if water is safe or not? We know by now that there could be dissolved chemicals and microscopic life in the a glass of water that we wouldn't be able to detect with our normal senses. In this lesson we will learn how water is tested and judged to be safe to drink.

Every major city has a water treatment facility. They treat drinking water to make it potable and treat wastewater before releasing it into reservoirs.

Edmonton's Gold Bar Wastewater Treatment Plant is an award winning facility!

 
 
 

These are some of the items that drinking water is tested for:
  • Taste and odour
  • Turbidity (cloudiness) and colour
  • Toxic substances and other pollutants
  • Bacteria
  • Hardness or mineral content
  • pH (how acidic or basic the water is)
  • Dissolved oxygen
  • Solids, including floating materials
  • Dissolved solids

 


Treating Fresh Water So Its Fit to Drink
Most communities in Alberta have water treatment plants that test and purify the water for their communities. People on farms can have their well water tested by provincial or private labs to ensure that it is safe. This is particularly important in farming country as chemicals from fertilizer like nitrites, and organisms such as bacteria from animal wastes can leach into the ground water and cause severe illness and death. This happened in a small farming community in Ontario a few years ago.
 

Methods of Treatment
Water treatment plants use filters and chemical treatment to ensure that our water is safe. At certain times of the year, when the water from lakes and rivers is dirty from runoff or has high amounts of algae, treatment plants add more chlorine to the water to ensure that the water remains safe. Many water treatment plants are changing over from chlorine to ozone to kill bacteria and other microorganisms.
Just as in the larger cities, the water treatment plants in smaller communities are constantly monitored to ensure the delivery of safe drinking water.
Doing It Yourself


To ensure safety, it is important that the hiker be knowledgeable about the use and cleaning of portable water filters. .
 Hikers and campers can't always carry enough water for their their needs so they take water from local lakes, rivers and streams. But we already know that this water is not safe to drink, so what can they do to ensure their safety?
Well... let's ask the experts!

Here are 2 great websites;

The people at Mountain Equipment Co-op have quite a bit of information about Water Treatment Options.

You can also visit the web site at Health Canada

Study the information, and then you can answer the questions.
Once these chemicals are mixed they produce a third chemical, which when mixed with suspect water, disinfects the water.

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