Lesson Plan: How Do We Clean Polluted Water?

Transcription

1 Lesson Plan: How Do We Clean Polluted Water? Oil Spill Cleanup / Phosphate Cleanup / Groundwater Contamination / Water Treatment Simulation Estimated Time: 2-4 days State Standards taught and addressed Grade 8: Standards Taught (and evaluated at end of lesson) Science Strand 3: Concept 1 PO 1. Analyze the risk factors associated with natural, human induced, and/or biological hazards, including: waste disposal of industrial chemicals Science Strand 5: Concept 1: Properties and Changes of Properties in Matter Standards addressed (could provide more detail if desired) Science Strand 1: Inquiry Process Science Strand 2: C1 PO 4. Evaluate career opportunities related to life and physical sciences. Science Strand 2: Concept 2 Nature of Scientific Knowledge Vocabulary: Oil Spill Cleanup Phosphate Cleanup Groundwater Contamination Pollutant Contaminant Petroleum Natural Resource Dispersant Skimmer Absorb Phosphate Ion precipitate Wastewater Eutrophication treatment Aquifers porous Water Treatment Simultion Aeration Coagulation Sedimentation Filtration Chlorination Floc Suspended dissolved Objectives: Students will understand key vocabulary associated with lab experiences and will use the vocabulary during partner and class discussions. Students will evaluate the affects of various contaminants during water experiments. Students will generalize results from in-class lab experiences to real world problems and issues affecting our community.

2 Lesson Supply List: Water Aluminum pie pans Vermiculite (alternate material: shredded bubble gum prepared by freezing Super Bubble or other chunk style bubble gum overnight and grating wit a food grater) Motor oil Toothpicks Paper distilled water (available at most grocery stores alum (or some other source of aluminum) clear plastic cups measuring spoons measuring cup plant food containing phosphate *Note: most fertilizers or plant foods have three numbers listed on the label. The second number represents the amount of phosphate. Choose one with a value of 20 or higher. Miracle-Gro works well and has a phosphate number of 30. marking pens clear plastic cups 4 x 4 gauze squares (nylon net also works) Eyedroppers Pencils (unsharpened pencils also work) Aquarium gravel Food coloring Water 4 clear plastic cups water alum potting soil clean sand o note: playground sand should be washed thoroughly prior to use clean aquarium gravel measuring spoons paint filters cone shaped coffee filters disinfectant (very dilute bleach water approximately 4 drops of bleach in one quart of water) distilled water (available at most grocery stores alum (or some other source of aluminum) clear plastic cups measuring spoons

3 measuring cup plant food containing phosphate *Note: most fertilizers or plant foods have three numbers listed on the label. The second number represents the amount of phosphate. Choose one with a value of 20 or higher. Miracle-Gro works well and has a phosphate number of 30. marking pens

4 Water Pollution: Background information: Through natural processes such as erosion and decay, all water contains dissolved or suspended substances. Some natural substances found in water include gases such as air, salts, organic material from plants and animals, microorganisms such as bacteria, and solids such as sand and clay. Water quality is a measure of the types and amounts of these substances in the water. Water quality is also affected by people. In addition to the natural contaminants found in water, many pollutants are being added to our water supplies by human activities. Major sources of water pollution are sewage, industrial wastes, and the runoff of agricultural fertilizers and pesticides. Other sources of water pollution include oil spills, seepage from landfills, septic tanks, mines, and underground fuel storage tanks. Water pollution can also be caused by storm-water runoff from streets, parking lots, and buildings and even the dumping of household chemicals down the drain. Water pollution lowers water quality and presents a potential health problem. In addition, water pollution destroys the natural beauty and health of lakes, rivers, and oceans. Water Purification: Earth is referred to as the water planet because two-thirds of the earth s surface is covered in water. However, most of the water on earth is seawater and is unfit for drinking, irrigation, and industrial uses because it contains large amounts of dissolved salts. Only about 3 percent of the earth s water is fresh water and only a small portion of that water can be used for drinking and other human needs. Nearly all the water to be used for drinking and other human requirements must be treated to make it safe. Treatment plants purify water by removing suspended particles, bacteria and other harmful substances. Two activities are presented to demonstrate water purification. These activities are Water Treatment Simulation and Removing Organic Chemicals from Water. Oil Spill Cleanup: Oil, or petroleum, is an extremely valuable natural resource because it is a major source of energy. Petroleum is used mostly as fuel for industry, heating and transportation. It

5 is also an important source of raw material for the manufacturing of plastics, synthetic fibers, insecticides, detergents, paints and some medicines. Oil spills can be harmful to the environment. Oil spilled on the ground can contaminate groundwater, streams, rivers, and lakes that may be used as sources of drinking water. Oil spills on water can be harmful to aquatic plants, fish and other animals. Some of the largest oil spills have occurred in the oceans, seas, and most recently in the Gulf of Mexico. Several techniques can be used to clean up oil spills on water such as surrounding the spill with a floating barrier and suing pumps or skimmers to remove the oil or spreading dispersants over the oil which cause the oil to break up into very tiny drops that mix with the water. Phosphate Cleanup: Phosphates are important plant nutrients and are used in most fertilizers. In some areas of the country phosphates are also used in detergents to increase the cleaning power of the detergent. Runoff of fertilizers from farmland when it rains and the release of wastewater containing phosphates can cause phosphates to end up in ponds and lakes. This causes algae and other aquatic plants to grow so rapidly that the water becomes choked with plants. This process is called eutrophication. Because phosphates can lead to eutrophication, many areas of the country have banned or restricted the use of detergents with high phosphate content. Wastewater treatment plants use techniques to remove the phosphate from wastewater before the treated water is released into rivers or lakes. The activity can be used to demonstrate how phosphate can be removed from water using aluminum ions in a process very similar to that used in water treatment facilities. Groundwater Contamination: Ground water is stored in aquifers, zones of porous rock, gravel, or sand located under the earth s surface. This water is often pumped out of the ground and used for many purposes, including drinking. Approximately 53 percent of the U.S. population gets its water from underground aquifers. Once polluted, ground water is very difficult to clean up. Water Treatment A water company must go through several steps to insure safe and pure drinking water for the community.

6 The water that is processed comes from the natural water cycle and has usually been transferred and stored in a reservoir before processing. The following steps are followed in a typical water treatment plant: Aeratioin Coagulation Sedimentation Filtration Chlorination

7 Procedures: Oil Spill Cleanup Materials: Water Aluminum pie pans Vermiculite (alternate material: shredded bubble gum prepared by freezing Super Bubble or other chunk style bubble gum overnight and grating wit a food grater) Motor oil Toothpicks Paper Premise: Many different types of absorbent materials are used to clean up oil and other chemical spills. Activity demonstrates oil-absorbing materials as method of cleanup. Steps: 1. Discuss Water Pollution & Water Purification prior to conducting activities (use the background information section). This will serve as base-level knowledge for the information presented and other activities in this lesson. 2. Fill the pie pan half full with water. 3. Carefully drip ten drops of the motor oil on the surface of the water. Try to form one large drop of floating oil on the surface of the water. 4. Use the toothpicks to gather small drops of oil into one large drop if necessary. 5. Carefully sprinkle the vermiculite over the entire oil drop. It may be useful to use the paper to assist in this task. 6. Use the toothpicks to move the vermiculite-covered oil around. Experiment with methods of removing the oil coated vermiculite from the water. Observe the mixture after it has remained undisturbed in the water for thirty minutes. 7. Record observations. Discussion / background information: Hold a class discussion about the results of the investigation. Allow students to record observations and conclusions in their lab notebook. Discuss what techniques they used to clean up the oil spill and why they thing oil is harmful to the environment. Use the following discussing points to guide their learning. Oil, or petroleum, is an extremely valuable natural resource because it is a major source of energy. Petroleum is used mostly as fuel for industry, heating and transportation. It is also an important source of raw material for the manufacturing of plastics, synthetic fibers, insecticides, detergents, paints and some medicines. Oil spills can be harmful to the environment. Oil spilled on the ground can contaminate groundwater, streams, rivers, and lakes that may be used as sources

8 of drinking water. Oil spills on water can be harmful to aquatic plants, fish and other animals. Some of the largest oil spills have occurred in the oceans, seas, and most recently in the Gulf of Mexico. Several techniques can be used to clean up oil spills on water such as surrounding the spill with a floating barrier and suing pumps or skimmers to remove the oil or spreading dispersants over the oil which cause the oil to break up into very tiny drops that mix with the water. Making the Connection: Questions: Summarize what we learned about water pollution specifically oil pollution. What were the ways BP tried to clean the oil spill in the gulf coast in 2010? What are the complications of an oil spill besides obvious harm to the environment? What else happens as a result? Who else is affected? Review new vocabulary: Pollutant Contaminant Petroleum Natural Resource Dispersant Skimmer Absorb Activity Closure: Allow students to share their new learning with a partner, or summarize three things they learned in their science notebook or lab journal.

9 Procedures: Phosphate Cleanup Materials: distilled water (available at most grocery stores alum (or some other source of aluminum) clear plastic cups measuring spoons measuring cup plant food containing phosphate *Note: most fertilizers or plant foods have three numbers listed on the label. The second number represents the amount of phosphate. Choose one with a value of 20 or higher. Miracle-Gro works well and has a phosphate number of 30. marking pens Premise: A cloudy solid should form when the alum water is added to the polluted water. The aluminum ions in the alum water combine with the phosphate ions in the polluted water to form a substance called aluminum phosphate. Aluminum phosphate is not soluble in water which is why the cloudy solid appears. This is called a precipitate. The precipitate will slowly settle to the bottom of the glass. This precipitate can then be removed from the wastewater. Steps: 1. Prepare alum water by dissolving one teaspoon of alum in one-quarter cup of water. Label the cup as alum water a. Note: some of the alum may not dissolve. Allow the alum water to sit for one minute before using. 2. Prepare phosphate contaminate water by dissolving one tablespoon of plant food into one-half cup of water. Stir to dissolve the fertilizer in the water. 3. Clean up the phosphate contaminated water by adding one-half teaspoon of the alum water to it. After mixing, allow to set for several minutes to several hours before recording observations. 4. Record observations. Discussion / background information: Hold a class discussion about the results of the investigation. Allow students to record observations and conclusions in their lab notebook. Use the following discussing points to guide their learning. Phosphates are important plant nutrients and are used in most fertilizers. In some areas of the country phosphates are also used in detergents to increase the cleaning power of the detergent.

10 Runoff of fertilizers from farmland when it rains and the release of wastewater containing phosphates can cause phosphates to end up in ponds and lakes. This causes algae and other aquatic plants to grow so rapidly that the water becomes choked with plants. This process is called eutrophication. Because phosphates can lead to eutrophication, many areas of the country have banned or restricted the use of detergents with high phosphate content. Wastewater treatment plants use techniques to remove the phosphate from wastewater before the treated water is released into rivers or lakes. The activity can be used to demonstrate how phosphate can be removed from water using aluminum ions in a process very similar to that used in water treatment facilities. Making the Connection: Questions: Summarize what we learned about water pollution specifically phosphates. Where do phosphates come from? Who is ultimately in charge of cleaning phosphates out of wastewater? Why is in important to do this? Why should we be concerned about cleaning or treating wastewater? What is wastewater used for? Why? Review new vocabulary: Phosphate Ion precipitate Wastewater Eutrophication treatment Activity Closure: Allow students to share their new learning with a partner, or summarize three things they learned in their science notebook or lab journal.

11 Procedures: Groundwater Contamination Materials: clear plastic cups 4 x 4 gauze squares (nylon net also works) Eyedroppers Pencils (unsharpened pencils also work) Aquarium gravel Food coloring Water Premise: Demonstrate how water may be stored underground and how it may become contaminated. Students will create a miniature well so they can observe the effects of groundwater contamination. Steps: 1. Wrap the straw with the gauze. 2. Hold the wrapped straw in the center of the cup and carefully place the gravel around the millimeters of the top of the gauze. 3. Carefully slip the straw out of the gauze allowing the cloth to remain in the hole. 4. Pour clean water into the cup. 5. After a few minutes the water should appear in the opening of the well. 6. Use the eyedroppers to remove the clean water from the well. Return the clean water to the well. 7. Add a drop of food coloring (simulates contamination) to the gravel surrounding the well. 8. After a few minutes remove the water again from the well. The water will now contain contamination from the food coloring. Discussion / background information: Hold a class discussion about the results of the investigation. Allow students to record observations and conclusions in their lab notebook. Use the following discussing points to guide their learning. Ground water is stored in aquifers, zones of porous rock, gravel, or sand located under the earth s surface. This water is often pumped out of the ground and used for many purposes, including drinking. Approximately 53 percent of the U.S. population gets its water from underground aquifers. Groundwater can be polluted by many sources. Once polluted, ground water is very difficult to clean up.

12 Making the Connection: Questions: Summarize what we learned about groundwater and groundwater contaminants. Do you think groundwater is more or less pure after it is pumped from the ground? Why? Why is groundwater harder to clean? Knowing what we know now about groundwater contaminants and cleanup, how do you suggest we protect groundwater from becoming polluted in the first place? Review new vocabulary: Aquifers porous Activity Closure: Allow students to share their new learning with a partner, or summarize three things they learned in their science notebook or lab journal.

13 Procedures: Water Treatment Simulation Materials: 4 clear plastic cups water alum potting soil clean sand o note: playground sand should be washed thoroughly prior to use clean aquarium gravel measuring spoons paint filters cone shaped coffee filters disinfectant (very dilute bleach water approximately 4 drops of bleach in one quart of water) Premise: Demonstrates the process utilized to produce finished drinking water. Steps: 1. Prepare water to be purified by mixing one cup water with approximately ½ tsp potting soil. 2. Aeration: simulate aeration by pouring the dirty water back and forth between two cups. 3. Water is sprayed into the air to release any trapped gases and to absorb additional oxygen. 4. Coagulation: add one teaspoon of the alum to the dirty water. Mix well. 5. To remove dirt suspended in the water, powdered alum is dissolved in the water and it forms tiny, sticky particles called floc which attached t the dirt particles. The combined weight of the dirt and the floc becomes heavy enough to sink to the bottom during sedimentation. 6. Sedimentation: allow the sample to remain undisturbed for several minutes. While the sample is settling, prepare the filter materials described in step 7. The larger floc particles settle to the bottom. 7. Filtration: prepare the filter by lining the paint filter with two cone-shaped coffee filters and adding a layer of gravel to the bottom of the filter assembly followed by the layer of sand on top of the gravel. 8. Place the filter over a clean, empty cup. Pour the sample that has been allowed to settle into the filter. 9. The floc particles are trapped in the layers of sand and gravel.

14 10. Disinfection: add a small amount of very dilute bleach solution to disinfect the sample. At this point, you can us a pool kit capable of measuring chlorine to measure how much disinfectant is present in the finished sample. 11. A small amount of disinfectant is added to kill the remaining bacteria. a. Note: DO NOT allow students to drink this water! 12. *Optional: Review the water treatment process using visuals provided at the training session. Give to student groups in random order and have them put them in the order they followed. Discussion / background information: Hold a class discussion about the results of the investigation. Allow students to record observations and conclusions in their lab notebook. Use the following discussing points to guide their learning. 1. A water company must go through several steps to insure safe and pure drinking water for the community. 2. The water that is processed comes from the natural water cycle and has usually been transferred and stored in a reservoir before processing. 3. The following steps are followed in a typical water treatment plant: a. Aeration b. Coagulation c. Sedimentation d. Filtration e. Chlorination Making the Connection: Questions: Summarize what we learned about the water treatment process. Why are there so many steps? Why is each step important? Why is water treatment important for human health? Do we need to treat water for other uses other than drinking? Review new vocabulary: Aeration Coagulation Sedimentation Filtration Chlorination Floc Suspended dissolved

15 Activity Closure: Allow students to share their new learning with a partner, or summarize three things they learned in their science notebook or lab journal.