Transcript Slide 1

Designer Oxidizers
for
Industrial Cooling
Comparison of the Measured Residual
vs.
Dosage of ClO2 with Cl2 for a Heavily Contaminated Water.
Chlorine Dioxide - Chlorine
Table 9-8. C. parvum Inactivation Using Chlorine Dioxide Followed by Free Chlorine
Disinfectant Level of Inactivation (log-units)
pH 6.0
pH 8.0
pH 11.0
Chlorine dioxide 1
.0
1.4
1.6
Free chlorine
0
0
0
Chlorine dioxide followed by free chlorine
2.2
3.0
2.3
Inactivation attributed to synergism
1.2
1.6
0.7
Source: Finch, 1997.
Chlorine dioxide 1.3 mg/L for 120 minutes, free chlorine 2.0 mg/L for 120 minutes.
Table 9-9. G. muris Inactivation Using Chlorine Dioxide Followed by Free Chlorine
Disinfectant Level of Inactivation (log-units)
pH 6.0
pH 8.0
Chlorine dioxide
0.8
0.8
Free chlorine
0.8
0.6
Chlorine dioxide followed by free chlorine
2.2
2.0
Inactivation attributed to synergism
0.6
0.6
Source: Finch, 1997.
Chlorine dioxide: 1.0 mg/L for 10 minutes, free chlorine 2.0 mg/L for 30 minutes.
EPA Guidance Manual
Alternative Disinfectants and Oxidants
Chlorine Dioxide-Chloramine
Table 9-11. C. parvum Inactivation Using Chlorine Dioxide Followed by Chloramine
Disinfectant Level of Inactivation (log-units)
pH 6.0
pH 8.0
pH 11.0
Chlorine dioxide
1.0
1.5
1.6
Monochloramine
0
0
0
Chlorine dioxide followed by monochloramine
2.2
2.8
2.1
Inactivation attributed to synergism
1.2
1.3
0.5
Source: Finch, 1997.
Chlorine dioxide: pH 6, 8, and 11: 1.3 mg/L for 120 minutes. Monochloramine: pH 6 and 11: 2.0 mg/L for 120
minutes, pH 8: 2.8
mg/L for 180 minutes.
Table 9-12. G. muris Inactivation Using Chlorine Dioxide Followed by Chloramine
Disinfectant Level of Inactivation (log-units)
pH 8.0
pH 11.0
Chlorine dioxide
0.8
0.8
Monochloramine
0.5
0.7
Chlorine dioxide followed by monochloramine
1.7
1.5
Inactivation attributed to synergism
0.4
0
Source: Finch, 1997.
pH 8.0: Chlorine dioxide 1.0 mg/L for 5 minutes, monochloramine 2.0 mg/L for 150 minutes.
pH 11.0: Chlorine dioxide 1.0 mg/L for 5 minutes, monochloramine 2.0 mg/L for 5 minutes.
Recovery of Bacterial Activity After
Shock Dosage with ClO2 and Cl2.
L. McGuire, and T. Dishinger, "Chlorine Dioxide Solves Biofouling
Problems in a Refinery Cooling Tower Used for Phenol Destruction," CTI, Houston, 1984.
Comparison of Oxidation Potential and
Oxidation Capacity of Several Oxidants Along
with Relative Oxidation of Materials Commonly
Found in Cooling Water.
COMPARISON OF OXIDIZING BIOCIDES IN
LIGHT
OF THE CRITERIA OF AN 'IDEAL' BIOCIDE
Report Card
HOCl
HOBr
ClO2
O3
High pH
C
B
A
A
Kinetics
B
B
A
A
Selectivity
C
B
A
D
Biofilm
B
B
A
C
C
C
A
D
B
B
A
C
PERFORMANCE
System
Contamination
Bacterial Recovery
ENVIRONMENTAL
SAFETY
THM
C
C
B
A
Easy to Use
B
B
C
B
TOX
C
C
B
A
Safe to Handle
B
B
C
B
Toxicity
ECONOMICS
of primary oxidant
B
A
A
C
Clean System
A
B
B
C
of oxidation by-products
B
B
C
A
C
C
A
C
of oxidation reaction
products
Contaminated
System
B
C
A
D
residual life (short life
best)
C
B
C
A
2.6
2.8
3.3
2.7
Cumulative GPA
Cooling Tower Treatments
Choose the Treatment that is Right for You
HVAC Systems
Light Industrial
Heavy Industrial