#### Title

The effect of ultrasound on *E.coli* decontamination

#### School Name

Spring Valley High School

#### Grade Level

10th Grade

#### Presentation Topic

Physiology and Health

#### Presentation Type

Non-Mentored

#### Oral Presentation Award

3rd Place

#### Written Paper Award

1st Place

#### Abstract

Water pollution is an enormous problem in many third world countries and even in some first world countries. With many people living without fresh and clean water due to dangerous bacteria, there are new ideas emerging trying to decontaminate infected water. One of these ways is the use of ultrasonic waves, which are sound waves above 20,000 hertz. The purpose of this experiment was to test whether higher frequencies of ultrasound could more effectively kill E.coli. To test this, 15 beakers of water were inoculated with K-12 strain E.coli. Then each of the beakers was assigned a group, either 1, 2, or 3. Each group was exposed to a different frequency of ultrasound: group 1 was the control, group 2 was 1 megahertz, and group 3 was 3.3 megahertz. After exposure, 2 petri dishes were inoculated from each beaker, and the bacteria were allowed one day to grow. Bacteria were then counted in quadrant four and the data were recorded. The results showed that there was statistical significance when it came to group 3 by the use of an ANOVA (F(2,27)= 5.05, p=0.014) and a Tukey test. The p-value was shown to be 0.014, which is less than the alpha value of 0.05. This suggests significance; therefore, the null hypothesis was rejected. In conclusion, the results suggest that the higher frequencies of ultrasound destroy bacteria more effectively than lower frequencies of ultrasound.

#### Recommended Citation

Hook, Noah, "The effect of ultrasound on *E.coli* decontamination" (2017). *South Carolina Junior Academy of Science*. 218.

https://scholarexchange.furman.edu/scjas/2017/all/218

#### Location

Wall 321

#### Start Date

3-25-2017 11:00 AM

#### Presentation Format

Oral and Written

#### Group Project

No

The effect of ultrasound on *E.coli* decontamination

Wall 321

Water pollution is an enormous problem in many third world countries and even in some first world countries. With many people living without fresh and clean water due to dangerous bacteria, there are new ideas emerging trying to decontaminate infected water. One of these ways is the use of ultrasonic waves, which are sound waves above 20,000 hertz. The purpose of this experiment was to test whether higher frequencies of ultrasound could more effectively kill E.coli. To test this, 15 beakers of water were inoculated with K-12 strain E.coli. Then each of the beakers was assigned a group, either 1, 2, or 3. Each group was exposed to a different frequency of ultrasound: group 1 was the control, group 2 was 1 megahertz, and group 3 was 3.3 megahertz. After exposure, 2 petri dishes were inoculated from each beaker, and the bacteria were allowed one day to grow. Bacteria were then counted in quadrant four and the data were recorded. The results showed that there was statistical significance when it came to group 3 by the use of an ANOVA (F(2,27)= 5.05, p=0.014) and a Tukey test. The p-value was shown to be 0.014, which is less than the alpha value of 0.05. This suggests significance; therefore, the null hypothesis was rejected. In conclusion, the results suggest that the higher frequencies of ultrasound destroy bacteria more effectively than lower frequencies of ultrasound.