1. Assessment of Ozone Disinfection for Bacteria Reduction (Tanks 2 &3)
Kira Christian
Lauren Hayes
Houston Johnson

2. Background Info
Ozone disinfection is a common method of treating wastewater.
Ozonation increases the dissolved oxygen (DO) concentration of the discharged wastewater.
Ozone disinfects through oxidation.
Ozone is an unstable gas that destroys bacteria & viruses
Ozone decomposes quickly, so it leaves no harmful residuals.

3. Comparison of Tanks 2 &3 Tank 2: MBR System
Helps to reduce microorganisms, however doesn’t reach optimum cleanliness
Tank 3: Ozone Generator

4. How Ozone Works
Ozone is generated by bonding 3 atoms of Oxygen to form Ozone.
Once the Ozone comes in contact with a virus or bacteria, the Ozone attacks the nucleus of the cell and destroys the bacteria or virus.
Ozone will make this kill up to 3000 times faster than Chlorine.
Once, the Ozone attacks the bacteria it reverts back to Oxygen.
Ozone is not stored, Ozone has to generated on site.

5. How Ozone Generator Works

6. Materials & Methods Sampling Procedures:
Let the system run a complete cycle
When it has finished bubbling,
Fill a bucket up with about a gallon of the water
3. Proceed to collect your samples (while keeping a close watch on the valve to avoid spillage)
4. Close valve after samples are collected .

7. Materials & Methods cont’d.
Equipment Used:
Ozone Disinfector
Disposable Gloves
Safety Goggles
Bucket
Sample Bottles
Cooler filled with Ice
Various Meters
Complete PPE in lab
Colilert test

8. Field Analysis Meters Used
While in the field, various tests were conducted.
Meters Used
-pH meter and probe
-EC meter and probe
-DO meter and probe
-Cl meter and probe
-NO3-N pocket colorimeter

9. Lab Analysis In the HEEP Lab, more thorough tests were conducted.
The water was tested for:
TKN
Coliform and E. coli counts
Turbidity
Chloride
Temperature
Water samples were also sent to Aqua-Tech Laboratories Inc.

10. Results
HEEP Lab used Colilert™ method to determine coliform and E. coli
Aqua-Tech and HEEP results were used to ensure accuracy
First day of sampling Ozone was not operational
Some data was missing which greatly affected results

11. Results (cont.)
Total coliform count decreased after being exposed to ozone
E. coli counts decreased after being exposed to ozone
Drinking water standard for total coliform count is less than 5% of sample
Less than 5 mL of sample can be positive
Drinking water standard for E. coli is <1 MPN/100mL

12. 78.3% average removal rates
94%
75%
66%
94 % removal
75%
66%
78.3% average removal rates

13. 76.5% average removal rates
50%
80.7%
98.8%
50%
80.7%
98.8%
76.5% average removal rates

14. Dissolved Oxygen Statistics
Tank #2
(mg/L)
Tank #3
6.01
7.43
6.45
8.65
6.99 _
5.93
7.42

15. Summary & Conclusions Overall, bacteria disinfection is achieved.
Meets drinking water standards (E. Coli), post treatment.
Coliform counts took dramatic improvements.
Dissolved oxygen increased from Tank 2 to 3
Ozone disinfection has shown to be reliable
Required to be secondary treatment
Ozone does not work on untreated water
Ultimately need more data points in order to be credible

16. References https://www3.epa.gov/npdes/pubs/ozon.pdf
comparison.h

17. Thank you!
Questions?