DOC PREVIEW
Water Filtration

This preview shows page 1 out of 2 pages.

Save
View full document
View full document
Premium Document
Do you want full access? Go Premium and unlock all 2 pages.
Access to all documents
Download any document
Ad free experience
Premium Document
Do you want full access? Go Premium and unlock all 2 pages.
Access to all documents
Download any document
Ad free experience

Unformatted text preview:

EPA ENVIRONMENTAL EDUCATIONWATER FILTRATIONBACKGROUND: Water in lakes, rivers, and swamps often contains impurities that make it look andsmell bad. The water may also contain bacteria and other microbiological organisms that can causedisease. Consequently, water from surface water sources must be “cleaned” before it can beconsumed by people. Water treatment plants typically clean water by taking it through the followingprocesses: (1) aeration; (2) coagulation; (3) sedimentation; (4) filtration; and (5) disinfection. Demonstration projects for the first four processes are included below.OBJECTIVE: To demonstrate the procedures that municipal water plants use to purify water fordrinking.MATERIALS NEEDED:5 liters of “swamp water” (or add 2 ½ cups of dirt or mud to 5 liters of water)1 two-liter plastic soft drink bottle with its cap (or cork that fits tightly into the neck)2 two-liter plastic soft drink bottles—1 with the top removed, 1 with the bottom removed1 one-and-one-half-liter (or larger) beaker (or another soft drink bottle bottom)20 grams of alum (potassium aluminum sulfate—approximately 2 tablespoons) (Hint: should be available in pharmacy or spice aisle in grocery store)Fine sand (about 800 ml in volume)Course sand (about 800 ml in volume)Small pebbles (about 400 ml in volume) (Hint: washed natural color aquarium rocks will work)1 large (500 ml or larger) beaker or jar1 coffee filter1 rubber band1 tablespoon1 clock with a second hand (or a stopwatch)PROCEDURE:1. Pour about 1.5 liters of the swamp water into a 2-liter bottle. Have students describe theappearance and smell of the water.2. Aeration is the addition of air to water. It allows gases trapped in the water to escape and addsoxygen to the water. Place the cap on the bottle and shake the water vigorously for 30 seconds. Continue the aeration process by pouring the water into either one of the cut-off bottles, and thenpour the water back and forth between the cut-off bottles 10 times. Ask students to describe anychanges they observe. Pour the aerated water into a bottle with its top cut off.3. Coagulation is the process by which dirt and other suspended solid particles are chemically“stuck together” into floc so that they can be removed from water. With the tablespoon, add 20grams of alum crystals to the swamp water. Slowly stir the mixture for 5 minutes.BEAKERFINE SANDCOARSE SANDPEBBLESCOFFEE FILTER4. Sedimentation is the process that occurs when gravity pulls the particles of floc (clumps of alumand sediment) to the bottom of the cylinder. Allow the water to stand undisturbed in the cylinder. Ask students to observe the water at 5 minute intervals for a total of 20 minutes and write theirobservations with respect to changes in the water’s appearance.5. Construct a filter from the bottle with its bottom cut off as follows:a. Attach the coffee filter to the outside neck of the bottle with a rubber band. Turn thebottle upside down and pour a layer of pebbles into the bottle—the filter will preventthe pebbles from falling out of the neck.b. Pour the coarse sand on top of the pebbles.c. Pour the fine sand on top of the coarse sand.d. Clean the filter by slowly and carefully pouring through 5 liters (or more) of clean tapwater. Try not to disturb the top layer of sand as you pour the water.6. Filtration through a sand and pebble filter removes most of the impurities remaining in water aftercoagulation and sedimentation have taken place. After a large amount of sediment has settled onthe bottom of the bottle of swamp water, carefully—without disturbing the sediment—pour the toptwo-thirds of the swamp water through the filter. Collect the filtered water in the beaker. Pour theremaining (one-third bottle) swamp water back into the collection container. Compare the treatedand untreated water. Ask students whether treatment has changed the appearance and smell of thewater.Advise students that the final step at the treatment plant is to add disinfectants to the water topurify it and kill any organisms that may be harmful. Because the disinfectants are causticand must be handled carefully, it is not presented in this experiment. The water that was justfiltered is therefore unfit to drink and can cause adverse effects. It’s not safe to


Water Filtration

Download Water Filtration
Our administrator received your request to download this document. We will send you the file to your email shortly.
Loading Unlocking...
Login

Join to view Water Filtration and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view Water Filtration 2 2 and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?