In the enhanced-biological-nutrient-control activated sludge system for the process control
of phosphorus removal, what are the primary controlling variables for the desired microbial
population?
a. volatile fatty acids b. soluble BOD5 and phosphate c. pH and alkalinity d. oxidized nitrogen
and DO - ANSWER d. oxidized nitrogen and DO
In the four-stage Bardenpho process, ammonia from the influent is converted to nitrate in
which area?
a. anoxic zone b. aeration basin c. anaerobic zone d. aerobic zone - ANSWER b. aeration
basin
. What is the theoretical amount of oxygen in milligrams required to convert 1 mg of ammo-
nia nitrogen to nitrate nitrogen?
a. 2.5 mg b. 3.3 mg c. 4.6 mg d. 7.1 mg - ANSWER c. 4.6 mg
What is the operating guideline in the four-stage Bardenpho process for the mean cell resi-
dence time?
a. 15 to 20 days b. 20 to 25 days c. 20 to 30 days d. 20 to 40 days - ANSWER c. 20 to 30
days
The optimum pH range in the enhanced chemical nutrient control reactions for phosphorus
removed by Fe3+ addition is
1
,a. 4.0 to 6.0 b. 4.5 to 6.0 c. 4.5 to 6.5 d. 5.0 to 6.5 - ANSWER a. 4.0 to 6.0
What is the desired DO level for an anaerobic selector?
a. 0.05 mg/L b. 0.10 mg/L c. 0.15 mg/L d. 0.20 mg/L - ANSWER b. 0.10 mg/L
Which one of the following types of foam is the most persistent and most difficult to con-
trol?
a. solids from the dewatering process b. filamentous or Nocardia organisms c. polymer over-
dosing d. nutrient deficiencies - ANSWER b. filamentous or Nocardia organisms
In the reaction of hydrogen sulfide with chlorine to form sulfuric acid, it takes one part hy-
drogen sulfide for every _______ parts of chlorine.
a. 2.5 b. 4.5 c. 6.5 d. 8.5 - ANSWER d. 8.5
. Dichloramine will be present in wastewaters at pH values below what?
a. 5.5 b. 5.0 c. 4.7 d. 4.3 - ANSWER a. 5.5
What is the recommended withdrawal of chlorine from a 100- or 150-lb cylinder for each de-
gree Fahrenheit ambient temperature such that freezing does not occur?
a. 1 lb b. 2 lb c. 3 lb d. 4 lb - ANSWER a. 1 lb
What chlorine emergency repair kit is used to stop leaks only at the valves of tank cars?
2
, a. emergency repair kit A b. emergency repair kit B c. emergency repair kit C d. emergency
repair kit T - ANSWER c. emergency repair kit C
If a liquid sulfonator was misting, what would most likely be the cause?
a. loss of water pressure b. wrong size injector valve c. dirty injector valve d. defective evap-
orator - ANSWER d. defective evaporator
To prevent reliquefaction of sulfur dioxide gas in a conducting pipe, what should the temper-
ature range of the room be?
a. 60 to 80°F b. 70 to 85°F c. 80 to 90°F d. 90 to 100°F - ANSWER c. 80 to 90°F
If the floc is too small in the solids removal physical-chemical treatment process, what is the
most probable cause?
a. paddle speed of flocculators too slow b. not enough dilution water c. improper or misa-
ligned baffling d. change in pH - ANSWER d. change in pH
If the floc is too small in the solids removal physical-chemical treatment process, what is the
most plausible solution?
a. increase paddle speed of first flocculator b. add a coagulant aid c. check dosage with jar
test d. increase detention time by pumping out sludge - ANSWER c. check dosage with jar
test
If the floc is too large and thus settles too soon in the solids removal physical-chemical treat-
ment process, what is the most probable cause?
3
of phosphorus removal, what are the primary controlling variables for the desired microbial
population?
a. volatile fatty acids b. soluble BOD5 and phosphate c. pH and alkalinity d. oxidized nitrogen
and DO - ANSWER d. oxidized nitrogen and DO
In the four-stage Bardenpho process, ammonia from the influent is converted to nitrate in
which area?
a. anoxic zone b. aeration basin c. anaerobic zone d. aerobic zone - ANSWER b. aeration
basin
. What is the theoretical amount of oxygen in milligrams required to convert 1 mg of ammo-
nia nitrogen to nitrate nitrogen?
a. 2.5 mg b. 3.3 mg c. 4.6 mg d. 7.1 mg - ANSWER c. 4.6 mg
What is the operating guideline in the four-stage Bardenpho process for the mean cell resi-
dence time?
a. 15 to 20 days b. 20 to 25 days c. 20 to 30 days d. 20 to 40 days - ANSWER c. 20 to 30
days
The optimum pH range in the enhanced chemical nutrient control reactions for phosphorus
removed by Fe3+ addition is
1
,a. 4.0 to 6.0 b. 4.5 to 6.0 c. 4.5 to 6.5 d. 5.0 to 6.5 - ANSWER a. 4.0 to 6.0
What is the desired DO level for an anaerobic selector?
a. 0.05 mg/L b. 0.10 mg/L c. 0.15 mg/L d. 0.20 mg/L - ANSWER b. 0.10 mg/L
Which one of the following types of foam is the most persistent and most difficult to con-
trol?
a. solids from the dewatering process b. filamentous or Nocardia organisms c. polymer over-
dosing d. nutrient deficiencies - ANSWER b. filamentous or Nocardia organisms
In the reaction of hydrogen sulfide with chlorine to form sulfuric acid, it takes one part hy-
drogen sulfide for every _______ parts of chlorine.
a. 2.5 b. 4.5 c. 6.5 d. 8.5 - ANSWER d. 8.5
. Dichloramine will be present in wastewaters at pH values below what?
a. 5.5 b. 5.0 c. 4.7 d. 4.3 - ANSWER a. 5.5
What is the recommended withdrawal of chlorine from a 100- or 150-lb cylinder for each de-
gree Fahrenheit ambient temperature such that freezing does not occur?
a. 1 lb b. 2 lb c. 3 lb d. 4 lb - ANSWER a. 1 lb
What chlorine emergency repair kit is used to stop leaks only at the valves of tank cars?
2
, a. emergency repair kit A b. emergency repair kit B c. emergency repair kit C d. emergency
repair kit T - ANSWER c. emergency repair kit C
If a liquid sulfonator was misting, what would most likely be the cause?
a. loss of water pressure b. wrong size injector valve c. dirty injector valve d. defective evap-
orator - ANSWER d. defective evaporator
To prevent reliquefaction of sulfur dioxide gas in a conducting pipe, what should the temper-
ature range of the room be?
a. 60 to 80°F b. 70 to 85°F c. 80 to 90°F d. 90 to 100°F - ANSWER c. 80 to 90°F
If the floc is too small in the solids removal physical-chemical treatment process, what is the
most probable cause?
a. paddle speed of flocculators too slow b. not enough dilution water c. improper or misa-
ligned baffling d. change in pH - ANSWER d. change in pH
If the floc is too small in the solids removal physical-chemical treatment process, what is the
most plausible solution?
a. increase paddle speed of first flocculator b. add a coagulant aid c. check dosage with jar
test d. increase detention time by pumping out sludge - ANSWER c. check dosage with jar
test
If the floc is too large and thus settles too soon in the solids removal physical-chemical treat-
ment process, what is the most probable cause?
3
