Water Filtration System (Randy Daniels & Erango Kelbisow)

Author(s)

Erango Kelbisow, Science Teacher, Middle College High School, LAUSD

Randy Daniels, Science Teacher, Hillside Middle School, Simi Valley, CA

NGSS Engineering Standards

HS-ETS1-1. Analyze a major global challenge to specify qualitative and quantitative criteria and constraints for solutions that account for societal needs and wants.

MS-ETS1-4. Develop a model to generate data for iterative testing and modification of a proposed object, tool, or process such that an optimal design can be achieved.

MS-ETS1-2. Evaluate competing design solutions using a systematic process to determine how well they meet the criteria and constraints of the problem.

MS-ESS2-4. Develop a model to describe the cycling of water through Earth's systems driven by energy from the sun and the force of gravity. [Clarification Statement: Emphasis is on the ways water changes its state as it moves through the multiple pathways of the hydrologic cycle. Examples of models can be conceptual or physical.] [Assessment Boundary: A quantitative understanding of the latent heats of vaporization and fusion is not assessed.]

Materials needed

• Plastic Water Bottle

• Scissors

• Rubber Band

• Cotton balls and coffee filters

• Paper or plastic cups

• Simulated waste water

• TDS Meter

• pH test strips

• sand, or gravel

• paper towels

Procedure

1. Remove all labels. Set one of the bottle tops aside. Keep one cap screwed on the other bottle (For this bottle, it is best to use a flip-top cap with a spout like the one I use in the video below).

2. Cut the bottle halves of each of the bottles off.

3. Take the top half of bottle #1 (the one with the cap on), and fill it with about three or four alternating layers of cotton balls, gravel, coffee filters, and more gravel.

4. Take the top half of bottle #2. Screw this bottle cap on tightly.

5. Insert bottle #1 face down, into the open end of bottle number #2. Make certain that the spout on bottle #1 is open.

6. Measure the pH and conductivity of the simulated waste water. Be sure to document your measurement.

7. Pour waste water into the open end of bottle #1 slowly and through the filtration medium.

8. Once the water filters through and deposits into bottle #2, measure and document the pH and conductivity of the filtered water.

9. Compare the before and after pH and conductivity measurement.

Questions

1. If the types of filtering media used (cotton balls, gravel, and coffee filters) had been used independently of the one another, which filter do you think would have worked the best and why?

• I believe the coffee filters would have worked the best because the cotton balls would only be effective until it reached its maximum saturation level. The gravel, though effective, contains tiny spaces through which some of the water would pass unfiltered. The coffee filter, however, has a much densely packed construction, and therefore, would limit how much of the actual dirt would pass through with the water.

2. What other types of filter media could be used in this water filter?

• Cheesecloth could be used as a filter media as well.

3. What else could be done to this water filter to optimize it?

• First of all, although the plastic water is very inexpensive, I believe a bottle with thicker plastic would make the overall filter sturdier, which could increase the amount of water that the filter could hold at one time. Also, larger sized bottle would allow for more better water filtration because more of the filtration medium could be used inside.

Photos

Movies

World Population & Meeting Clean Water Challenge

The World Water Crisis

New Nanotechnology Water Filtration System