WATER DISTRIBUTION D2
CALIFORNIA UPDATED AND VERIFIED
| WITH SOLUTIONS | GUARANTEED
SUCCESS
1. What are trihalomethanes and how are they formed? - ANSWER A
disinfection byproduct formed when natural organic substances react with
chlorine. They are known to cause cancer.
2. What are natural organic substances? - ANSWER Humic and Folic acids
from decaying vegetation, grass leaves, soil.
3. What are some benefits of Chlorine, in regards to water systems? -
ANSWER Potent disinfectant, taste/odor control, biological growth control
and chemical control.
4. Other than Chlorine, what are the other disinfectants used for the treatment
of water? - ANSWER Chloramines, Chlorine Dioxide (ClO2), Ozone (O3),
and Ultraviolet Radiation (UV).
5. What are some PROs of using Chloramines over chlorine? - ANSWER -
Long last residual, kills longer and reaches farther.
- 80% less THMs than Chlorine
6. What are some CONs of using Chloramines over chlorine? - ANSWER -
Weaker disinfectant,
,-Can cause taste/odor problems,
-Cannot be used for patients on kidney dialysis (they must be notified),
-Can lead to nitrification problems
7. When blending chlorinated waters with chloraminated waters... - ANSWER
Care must be taken. Depending on the ratio of the blend, these two
disinfectants can cancel each other out resulting in very low residuals.
8. Chlorine Dioxide (ClO2) is a compound produced on-site by... - ANSWER
using Sodium Chlorite and either Chlorine OR Hydrochloric acid. Not
generally used due to it being a hazard to work around, and killing people
via leaks.
9. What are some PROS of using Ozone (O3) over chlorine? - ANSWER a.
100x stronger than chlorine as a disinfectant
b. Great in pre-disinfection because its use has no trihalomethane formation
10.What are some CONs of using Ozone (O3) over chlorine? - ANSWER - It
is very unstable and only stays in O3 format for about 20 minutes.
- Its use creates no lasting residual for continued killing in the water
system.
11.How is the compound "Ozone" produced? - ANSWER By an electrical
discharge through air or oxygen.
12.What are some PROs of using Ultraviolet Radiation (UV) over chlorine? -
ANSWER - Kills great
- No THMs
, 13.What are some CONs of using Ultraviolet Radiation (UV) over Chlorine? -
ANSWER No residual for continued killing.
14.What is Hard Water? - ANSWER Water with GREATER than 100 mg/l
concentration of Calcium and Magnesium
15.What is Soft Water? - ANSWER Water with LESS than 60 mg/l
concentration of Calcium and Magnesium.
16.Why is Soft Water undesirable? - ANSWER Extremely corrosive due to
LOW pH.
17.Why is Hard Water undesirable? - ANSWER -Deposition of scale in boilers
-Inhibits cleansing action
-Causes formation of soap curds
-Increased use of soap
-Causes clothes to lose softness and elasticity
18.What does pH (power of hydrogen) measure? - ANSWER The intensity of
the basic of acidic qualities of water.
19.What are the two different kinds of Treatment for Hard/Soft Water? -
ANSWER -Ion exchange softening
-Lime softening
20.What is the range of a pH scale? - ANSWER 0 - 14. 0 most ACIDIC. 14
most BASIC. 7 NEUTRAL
CALIFORNIA UPDATED AND VERIFIED
| WITH SOLUTIONS | GUARANTEED
SUCCESS
1. What are trihalomethanes and how are they formed? - ANSWER A
disinfection byproduct formed when natural organic substances react with
chlorine. They are known to cause cancer.
2. What are natural organic substances? - ANSWER Humic and Folic acids
from decaying vegetation, grass leaves, soil.
3. What are some benefits of Chlorine, in regards to water systems? -
ANSWER Potent disinfectant, taste/odor control, biological growth control
and chemical control.
4. Other than Chlorine, what are the other disinfectants used for the treatment
of water? - ANSWER Chloramines, Chlorine Dioxide (ClO2), Ozone (O3),
and Ultraviolet Radiation (UV).
5. What are some PROs of using Chloramines over chlorine? - ANSWER -
Long last residual, kills longer and reaches farther.
- 80% less THMs than Chlorine
6. What are some CONs of using Chloramines over chlorine? - ANSWER -
Weaker disinfectant,
,-Can cause taste/odor problems,
-Cannot be used for patients on kidney dialysis (they must be notified),
-Can lead to nitrification problems
7. When blending chlorinated waters with chloraminated waters... - ANSWER
Care must be taken. Depending on the ratio of the blend, these two
disinfectants can cancel each other out resulting in very low residuals.
8. Chlorine Dioxide (ClO2) is a compound produced on-site by... - ANSWER
using Sodium Chlorite and either Chlorine OR Hydrochloric acid. Not
generally used due to it being a hazard to work around, and killing people
via leaks.
9. What are some PROS of using Ozone (O3) over chlorine? - ANSWER a.
100x stronger than chlorine as a disinfectant
b. Great in pre-disinfection because its use has no trihalomethane formation
10.What are some CONs of using Ozone (O3) over chlorine? - ANSWER - It
is very unstable and only stays in O3 format for about 20 minutes.
- Its use creates no lasting residual for continued killing in the water
system.
11.How is the compound "Ozone" produced? - ANSWER By an electrical
discharge through air or oxygen.
12.What are some PROs of using Ultraviolet Radiation (UV) over chlorine? -
ANSWER - Kills great
- No THMs
, 13.What are some CONs of using Ultraviolet Radiation (UV) over Chlorine? -
ANSWER No residual for continued killing.
14.What is Hard Water? - ANSWER Water with GREATER than 100 mg/l
concentration of Calcium and Magnesium
15.What is Soft Water? - ANSWER Water with LESS than 60 mg/l
concentration of Calcium and Magnesium.
16.Why is Soft Water undesirable? - ANSWER Extremely corrosive due to
LOW pH.
17.Why is Hard Water undesirable? - ANSWER -Deposition of scale in boilers
-Inhibits cleansing action
-Causes formation of soap curds
-Increased use of soap
-Causes clothes to lose softness and elasticity
18.What does pH (power of hydrogen) measure? - ANSWER The intensity of
the basic of acidic qualities of water.
19.What are the two different kinds of Treatment for Hard/Soft Water? -
ANSWER -Ion exchange softening
-Lime softening
20.What is the range of a pH scale? - ANSWER 0 - 14. 0 most ACIDIC. 14
most BASIC. 7 NEUTRAL
