Presentation on theme: "Take out C42 Write up HW: None. C42 Water Purification Today’s Target: I will be able to describe how filtration and coagulation work to remove contaminants."— Presentation transcript:
C42 Water Purification Today’s Target: I will be able to describe how filtration and coagulation work to remove contaminants from water. Introduce activity Gather data Analysis (complete for HW)
C42 Water Purification What is the purest form of water? Distilled water When in the water cycle is liquid water likely to be the purest? When it falls as precipitation
NOTE: Boiling water will kill biological contaminants, but concentrate chemical contamination. Why?
C42 Water Purification What were the contaminants found in each of the three water sources in Willow Grove? Fenton River (Recreation) Acidic Well Water (Some residents rely on for drinking) Nitrates Willow Lake (main source of drinking water) Turbid – Fine particles of sand or dirt in it
C42 Water Purification How does our sample compare to the water in Willow Lake? Much worse – higher turbidity Distillation would work to remove most hazardous materials from water, but it is very expensive. We will look at two other methods that are currently in use today – Coagulation and Filtration. Procedure
C42 Water Purification What kind of contaminants were removed by coagulation in part A as compared to filtration in part B? Coagulation (clumping) removed the very fine materials that were floating or suspended in the water. Filtration removed the materials that were dissolved in the water as well as the larger materials not removed by coagulation.
C42 Water Purification 1. What was the purpose of the water in Vial A? The water in Vial A served as a control that lets us compare how fast the contaminants settled with and without the addition of alum. 2. How well did the coagulation steps in Part A work to remove contaminants from the water? Be sure to explain how your observations support your answer. It worked somewhat, because it made the cloudy material settle much faster and left a cleaner layer of water on top. However, it didn’t work completely, because the dark color and some floating solids were left in the water.
C42 Water Purification 3. What was the purpose of filtering some clean water in Part B? It was a control so we could see if any dirt came out of the filter. Some sand does come out, but not much.
C42 Water Purification 4. How well did coagulation followed by filtration work to remove contaminants from the water? Be sure to explain how your observations support your answer. The two processes together appeared to work pretty well. The second step removed additional contaminants, including the dissolved material that made the water orange and large pieces of material that looked like soil or plant matter.
C42 Water Purification 5. What more would you want to know about your coagulated and filtered water sample before you would be willing to drink it?
C42 Water Purification 1. Coagulate: When chemicals are used to attract contaminants in water into large clumps. These clumps then settle to the bottom of the water tank. 2. Filtration: The process of removing suspended particles of solid from a liquid, usually by passing the liquid through a material that allows the liquid to move through, but traps the solid particles.
C43 Municipal Water Treatment Read activity C43 and answer the Stopping to Think Questions. Answer analysis questions 1 through 5.