5 Water Treatment Process - Steps Remove large objects – a metal screen blocks objects from entering the pipeAdd alum (a chemical) – attracts waste solids to form clumps – these are called floc (sticky clumps formed from the reaction of alum in water, combined with sand and other waste solids)
6 StepsWater and Floc enter settling tank (water moves slowly) where floc settles to the bottomPartially cleaned water from top of tank moves through a sand and charcoal filter to remove remaining wasteChlorine added to kill organismsWater stored or delivered
7 Other Treatment Options 1. Reverse Osmosis – mechanical pressure forces water through a membrane that acts like a fine filter2. UV radiation – destroys most viruses and micro-organisms3. In nature, water absorbs minerals calcium and magnesium from surronding rock – this makes water “Hard”. This is safe to drink but when heated leaves mineral deposits.4. Boiling – boil for 3 minutes to kill micro-organisms and bacteria and drink within a few hours
9 Stormwater Management During spring; too much water for plant to handle so stormwater goes directly to lake
10 Using Water Sustainably Only a small amount of world’s water is suitable for human use.A rising population, pollution and other factors are limiting this resource.Sustainability means working and behaving in a way that protects resources to ensure that they are available to future generations.
11 Homework QuestionsList and describe the six main steps that water goes through in the water treatment processIs clear, colourless and odourless drinking water always safe to drink? Explain.Why is it important to ensure that treated water remains safe to drink when it is stored after treatment? Describe one way to make stored water safe.