Can Water Be Disinfected Using Only Sunlight?

Overview

Objectives/Goals My goal was to see if I could disinfect water using the SODIS method. SODIS is a type of water disinfection process using sunlight. You put the contaminated water in a PET (water) bottle and leave in the sun to be disinfected. Methods/Materials The SODIS method to disinfect the contaminated water PET bottles Watercheck Test (Water color changing test) Coliscan Easygel Test (Growth test with petri dishes) Aluminum pan A location with sunlight for at least 9 hours Black light Distilled water Contaminated water Results My results were that it only took six hours for water to be disinfected. Water disinfection is defined as removal, deactivation, or killing of pathogenic microorganisms. Checking at three hour intervals, six and nine hours were completely disinfected of coliform and more specifically E. coli. We used E. coli as our indicator organism because it is the hardest pathogen to kill. But at three hours, the water was still contaminated. My positive and negative controls for the project turned out as expected. Conclusions/Discussion In conclusion, my hypothesis was both correct and incorrect. It was correct because I was able to disinfect the water. My hypothesis was also incorrect because it took only 6 hours for the water to be disinfected, not 9 hours that I hypothesized. I will conclude that for people who cannot boil water or afforded to buy chlorine, they can use this SODIS method, but they would only have to leave it in the sunlight for 6 hours to be fully disinfected.

Competition history

• CSEF 2015 Microbiology (Medical) (Junior Division Only) · Entry J1614

Resources

• CSEF project summary ↗

Related projects

Closest projects by meaning, across every fair and year in the corpus.

Browse more like this

• All Microbiology projects
• CSEF Microbiology projects
• Every CSEF 2015 project