(Part 1) Grade 4 wastewater certification practice test
Study online at https://quizlet.com/_cyjaqa
1. What is the odor detection limit of chlorine gas? b. 0.3 ppm
a. 0.1 ppm b. 0.3 ppm c. 0.5 ppm d. 1.0 ppm
2. What is a cathode? negative pole of an elec-
a. negative pole of an electrolyte b. positive pole of trolytic cell or system
an electrolyte c. negative pole of an electrolytic cell or
system d. positive pole of an electrolytic cell or system
3. The least reactive metals are called a. anodic metals b. c. cathodic metals
galvanic metals c. cathodic metals d. tempered metals
4. Unless water cooled, the operating temperature of a d. 160°F (71°C)
mechanical seal in a pump should never exceed a.
95°F (35°C) b. 120°F (49°C) c. 140°F (60°C) d. 160°F
(71°C)
5. What term describes the condition that exists when b. suction lift
the source of the water supply is below the centerline
of the pump? a. total discharge head b. suction lift c.
velocity head d. pressure head
6. All occupied trenches 4 or more ft deep must provide c. 25-ft intervals
exits at a. 15-ft intervals b. 20-ft intervals c. 25-ft inter-
vals d. 30-ft intervals
7. What is the difference between a weak acid and d. amount of hydrogen
a strong acid? a. amount of buffering released b. ions released
amount of hydroxyl ions released c. amount of car-
bonate ions released d. amount of hydrogen ions re-
leased
8. b. pressure-relief
, (Part 1) Grade 4 wastewater certification practice test
Study online at https://quizlet.com/_cyjaqa
Which one of the following is the best type of valve to
use to dampen a water hammer? a. needle b. pres-
sure-relief c. pressure-reducing d. pinch
9. A shock load of toxic wastes coming into a plant can d. coagulants or chlorine
be treated or controlled with
a. coagulants only b. coagulants and lime c. coagu-
lants and coagulant aid d. coagulants or chlorine
10. Toxic solids should be disposed of in b. an approved sanitary
landfill
a. a digester to destabilize and break down the toxins
b. an approved sanitary landfill c. an incinerator d. a
sludge pond for further aerobic breakdown
11. Which one of the following best defines the term b. decomposition of a ma-
stray-current corrosion? terial caused by an outside
electric current
a. decomposition of a metal by its reaction with an
acidic water b. decomposition of a material caused by
an outside electric current c. reaction between a metal
and water d. reaction between two different metals
with water acting as an electrolyte
12. On startup of a small package wastewater treatment b. 7.0
plant, lime should be added to the digestion unit when
the pH goes below
a. 6.8 b. 7.0 c. 7.2 d. 7.5
13. If the effluent to a small package wastewater treat- b. pumping rate for the
ment plant using the activated sludge process ap- return of activated sludge
pears turbid, what is most probably the cause? is out of balance
, (Part 1) Grade 4 wastewater certification practice test
Study online at https://quizlet.com/_cyjaqa
a. low concentration of dissolved oxygen (DO) in the
aeration tank b. pumping rate for the return of activat-
ed sludge is out of balance c. excessive aeration rates
in the aeration tank d. alkalinity is too high
14. If a small package treatment plant utilizing the activat- c. reduce the aeration
ed sludge process has a lightcolored floating sludge rates
on the surface of the clarifier, which one of the follow-
ing would most likely eliminate the floating sludge?
a. increase the sludge wasting rate b. add a pH stabi-
lizer, as pH is too low c. reduce the aeration rates d.
increase the return sludge rate
15. What usually causes frothing in the activated sludge d. too long a detention
process? time
a. too low a solids level b. too high a solids leaving c.
too short a retention time d. too long a detention time
16. Which one of the following suggestions would most b. water sprays
likely control foaming?
a. increase the detention time b. water sprays c. in-
crease the dissolved oxygen d. increase solids wasting
17. What is the ideal level of solids in a jar test sample d. ½ of the jar depth
collected from an aeration tank if it is allowed to settle
for 30 min?
a. ¼ of the jar depth b. ⅓ of the jar depth c. ⅖ of the
jar depth d. ½ of the jar depth
18. a. 2 hr
Study online at https://quizlet.com/_cyjaqa
1. What is the odor detection limit of chlorine gas? b. 0.3 ppm
a. 0.1 ppm b. 0.3 ppm c. 0.5 ppm d. 1.0 ppm
2. What is a cathode? negative pole of an elec-
a. negative pole of an electrolyte b. positive pole of trolytic cell or system
an electrolyte c. negative pole of an electrolytic cell or
system d. positive pole of an electrolytic cell or system
3. The least reactive metals are called a. anodic metals b. c. cathodic metals
galvanic metals c. cathodic metals d. tempered metals
4. Unless water cooled, the operating temperature of a d. 160°F (71°C)
mechanical seal in a pump should never exceed a.
95°F (35°C) b. 120°F (49°C) c. 140°F (60°C) d. 160°F
(71°C)
5. What term describes the condition that exists when b. suction lift
the source of the water supply is below the centerline
of the pump? a. total discharge head b. suction lift c.
velocity head d. pressure head
6. All occupied trenches 4 or more ft deep must provide c. 25-ft intervals
exits at a. 15-ft intervals b. 20-ft intervals c. 25-ft inter-
vals d. 30-ft intervals
7. What is the difference between a weak acid and d. amount of hydrogen
a strong acid? a. amount of buffering released b. ions released
amount of hydroxyl ions released c. amount of car-
bonate ions released d. amount of hydrogen ions re-
leased
8. b. pressure-relief
, (Part 1) Grade 4 wastewater certification practice test
Study online at https://quizlet.com/_cyjaqa
Which one of the following is the best type of valve to
use to dampen a water hammer? a. needle b. pres-
sure-relief c. pressure-reducing d. pinch
9. A shock load of toxic wastes coming into a plant can d. coagulants or chlorine
be treated or controlled with
a. coagulants only b. coagulants and lime c. coagu-
lants and coagulant aid d. coagulants or chlorine
10. Toxic solids should be disposed of in b. an approved sanitary
landfill
a. a digester to destabilize and break down the toxins
b. an approved sanitary landfill c. an incinerator d. a
sludge pond for further aerobic breakdown
11. Which one of the following best defines the term b. decomposition of a ma-
stray-current corrosion? terial caused by an outside
electric current
a. decomposition of a metal by its reaction with an
acidic water b. decomposition of a material caused by
an outside electric current c. reaction between a metal
and water d. reaction between two different metals
with water acting as an electrolyte
12. On startup of a small package wastewater treatment b. 7.0
plant, lime should be added to the digestion unit when
the pH goes below
a. 6.8 b. 7.0 c. 7.2 d. 7.5
13. If the effluent to a small package wastewater treat- b. pumping rate for the
ment plant using the activated sludge process ap- return of activated sludge
pears turbid, what is most probably the cause? is out of balance
, (Part 1) Grade 4 wastewater certification practice test
Study online at https://quizlet.com/_cyjaqa
a. low concentration of dissolved oxygen (DO) in the
aeration tank b. pumping rate for the return of activat-
ed sludge is out of balance c. excessive aeration rates
in the aeration tank d. alkalinity is too high
14. If a small package treatment plant utilizing the activat- c. reduce the aeration
ed sludge process has a lightcolored floating sludge rates
on the surface of the clarifier, which one of the follow-
ing would most likely eliminate the floating sludge?
a. increase the sludge wasting rate b. add a pH stabi-
lizer, as pH is too low c. reduce the aeration rates d.
increase the return sludge rate
15. What usually causes frothing in the activated sludge d. too long a detention
process? time
a. too low a solids level b. too high a solids leaving c.
too short a retention time d. too long a detention time
16. Which one of the following suggestions would most b. water sprays
likely control foaming?
a. increase the detention time b. water sprays c. in-
crease the dissolved oxygen d. increase solids wasting
17. What is the ideal level of solids in a jar test sample d. ½ of the jar depth
collected from an aeration tank if it is allowed to settle
for 30 min?
a. ¼ of the jar depth b. ⅓ of the jar depth c. ⅖ of the
jar depth d. ½ of the jar depth
18. a. 2 hr
