SODIS Method

Solar disinfection for water purification

Amanda M. Icazatti Burtell

Fernando Pacheco Ocasio

RISE Program

University of Puerto Rico - Cayey

What is the SODIS Method?• Solar Disinfection for Water Purification (SODIS)

• Why use the SODIS Method?• Simple procedure• Affordable • Kills pathogens

• What kind of pathogens?

S.C. Rivera, T.C. Hazen, G.A. Toranzos. 1988. Isolation of Fecal coliforms from pristine sites in a tropical rain forest.

Why is important to have purified water?

Avoid diseases!•1.1 million people do not have access to safe water

•Diarrhea is the second main cause of death among children under 5 years old.

How does the SODIS Method work?

• Water sample• PET bottles • UV rays from sunlight• 6 hours full exposition

• Finally, Drink purified water!

Important details

• How recontamination is prevented?

• What are some problems that the SODIS Method may confront?

• Turbidity• Cloudy days• Rainy days

How is contamination tested in water?• Indicator

• Bacteriophages • Coliphages ( E. coli)

• Why use coliphages as an indicator of contamination in the water sample?

• What would a positive coliphages result for E. coli indicate?

Problem• Will the SODIS Method be proved to reduce the

presence of pathogens (coliphages) in water samples and make water safe to drink?

Hypothesis

• The SODIS Method will be proven with empirical evidence to reduce the presence of pathogens (coliphages) in water samples making water safe to drink.

Materials

PET Bottles Host bacteria: E. coli Medium Broth

Petri dishes Multimeter UV Rays Machine

Methodology

Choose a place Measure water for pH, temperature,

Atmospheric pressure & oxygen

level

Collect 800 mL of water

Aseptic techniqueSterilize PET Bottles

Transfer water sample to PET Bottles50 mL per PET Bottle

Prepare bacteria, medium & water (3X)

15 minutes for agar solidification

Incubate at 37˚C for 24 hours

Results• 4 hours after incubation at 37˚C• What does the presence of bubbles indicate?

pH Temperature Atmospheric pressure

8.34 24.8˚C 730.7 mmHG

• 19 ½ hours after incubation

Control: 0 minutes Control: 10 minutes

Experimental: 0 minutes Experimental: 10 minutes

24 hours of incubation

Control: 10 minutes Experimental: 10 minutes

Control

Experimental

Conclusions• Water samples from Rio La Plata, Cayey were collected

and tested for coliphages.• The SODIS Method was not performed effectively using a

UV light machine.• Samples were incubated at 37˚C for a period of 24 hours.• Samples were analyzed after 4 hours, 19 ½ hours after,

and 24 hours of incubation.

Future Work• Repeat SODIS Method using UV Rays from sunlight

exposition.

• Perform SODIS Method for Enterococcus to investigate if there is any human fecal pollution in Rio La Plata, Cayey.

Acknowledgments • We want to thanks the RISE Program for this learning

experience.

• Prof. Javier Arce for letting us participate in water sampling testing experiments.

• Jennifer Paredes for the all the help, time dedicated, and patience.

• Giovanni Cruz for letting us use the laboratory and the UV rays machine.

Thanks for your attention!

Solar disinfection for water purification

Amanda M. Icazatti Burtell

Fernando Pacheco Ocasio

RISE Program

University of Puerto Rico - Cayey