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1. What must the effluent NTU for a slow sand filter be Less than 1.0 NTU
kept at during operation?
2. When water is added too fast to this treatment chem- Sulfuric acid
ical, it will generate heat and splattering of the chem-
ical.
3. In the lime-softening process, besides CaCO3 being Magnesium hydroxide
precipitated, what other carbonate hardness chemical
is precipitated?
4. Dry alum has a formula of Al2(SO4)3 · 14H2O
5. What is the most common chemical used for pH and Lime
alkalinity adjustment?
6. After breakpoint chlorination, what may remain be- Chloroorganics
sides the free chlorine?
7. Although algae do not typically pose a health concern, neurotoxins and hepatox-
some do produce __________ that can be a concern. ins, tastes and odors and
Other problems they frequently cause in regard to filter-clogging
treatment are __________.
8. The oxidation process using chlorine will also con- alkalinity
sume
9. Dry chemicals should be in solution before mixing Softened water
them with the water to be treated. What water is rec-
ommended to mix the dry chemical in some cases to
avoid precipitates?
10. How are manganese greensand beds regenerated? Backwashed with per-
manganate solution
, Water Treatment AWWA Questions Grades 1 and 2: Treatment Process
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11. Once breakpoint chlorination has been reached, what 0%
percentage of the original reducing agents are typi-
cally still present in a particular water sample?
12. The most preferable method of removing manganese potassium perman-
is by using ganate.
13. When iron alone is treated using manganese green- 1.0 to 1.2 times the iron
sand filters, the chlorine feed rate should be about concentration.
14. What problem can be solved in a sedimentation basin Slow floc formation
by recycling some previously settled sludge?
15. To eliminate hydrogen sulfide (H2S), the pH of the wa- 6.0
ter should be lowered to ____ or less before beginning
aeration.
16. What factor will make chlorination successful? Higher concentration
17. How can an operator compensate for low tempera- Increase alum dosage
ture water and thus slower floc formation when using
alum?
18. What is (are) the combined chlorine residual(s) at pH Monochloramine and
values ranging from 6.5 to 8.5? dichloramine
19. What is an advantage for installing a pressure filter for Air binding will not occur
a small water system?
20. How is magnesium noncarbonate hardness removed? With lime, then soda ash
21. 6 to 10
, Water Treatment AWWA Questions Grades 1 and 2: Treatment Process
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When adding chlorine and sodium hydroxide to water
containing manganese, the oxidation works best in a
pH range of
22. Why can rapid sand filters handle higher filtration Coarser sand
rates compared to slow sand filters?
23. UV is used as a disinfectant because it is effective in Cryptosporidium, does
the inactivation of _________ and because it __________. not produce DBPs
24. Industrial bleaches used in water treatment disinfec- 9% to 15%
tion range in percentage strength of available chlorine
from
25. Monomedium filter media is __________ than a conven- deeper, coarser
tional filter because the media is __________.
26. Membranes made of Teflon (polytetrafluoroethylene) high
have __________ oxidant resistance.
27. What chemical does not cause hardness but must carbon dioxide
be considered when the lime dosage is being deter-
mined?
28. Manganese greensand filtration is used to remove Manganese, iron, and hy-
drogen sulfide
29. What does the optimal pH establish when applied to detention time
iron and manganese oxidation?
30. Carbon dioxide is a __________, __________ gas that is colorless, odorless, heav-
__________. ier than air
31. Wheeler Bottom