2024 GRADE 4 WASTEWATER
CERTIFICATION (PART 1) PRACTICE
TEST EXAM WITH CORRECT
ANSWERS
What is the odor detection limit of chlorine gas?
a. 0.1 ppm b. 0.3 ppm c. 0.5 ppm d. 1.0 ppm - CORRECT-ANSWERSb. 0.3
ppm
What is a cathode?
a. negative pole of an electrolyte b. positive pole of an electrolyte c.
negative pole of an electrolytic cell or system d. positive pole of an
electrolytic cell or system - CORRECT-ANSWERSnegative pole of an
electrolytic cell or system
What is the beneficial concentration range of magnesium in an anaerobic
digester?
a. 50 to 100 mg/L b. 75 to 150 mg/L c. 100 to 200 mg/L d. 150 to 250 mg/L -
CORRECT-ANSWERSc. 100 to 200 mg/L
If the supernatant from an anaerobic digester that is returning to the plant
process is of poor quality and is causing plant upsets, what is the most
probable cause?
a. organic overload has occurred b. a toxic load has entered the digester c.
there is excessive mixing and settling time is insufficient d. sludge
recirculation line is partially or completely plugged - CORRECT-ANSWERSc.
there is excessive mixing and settling time is insufficient
If the odor of the supernatant is sour from either the primary or secondary
anaerobic digester, what is the most probable cause?
a. digester being overheated b. recirculation of gas is excessive c. digester
pH is too low d. volatile-acid-to-alkalinity ratio has increased to 0.8 -
CORRECT-ANSWERSc. digester pH is too low
What is the most probable cause of foam in the supernatant from either the
single stage or the primary tank?
, a. digester too stagnant as mixing is inadequate b. filamentous organisms
are dying off by the billions c. excessive gas recirculation d. digester being
overheated - CORRECT-ANSWERSc. excessive gas recirculation
At what pH will sodium hydroxide control sulfide generation for periods of
about a month or more?
a. 9.5 b. 10.5 c. 11.5 d. 12.5 - CORRECT-ANSWERSd. 12.5
What is the recommended organic loading rate in lb BOD/d/yd3 of media for
an odor removal tower?
a. 0.2 b. 0.5 c. 1.0 d. 1.4 - CORRECT-ANSWERSb. 0.5
The best temperatures reported for combusting odorous gases from a
wastewater plant begin at temperatures greater than
a. 1,000°F b. 1,200°F c. 1,500°F d. 1,800°F - CORRECT-ANSWERSc. 1,500°F
How many times can activated carbon be regenerated before it is usually
replaced?
a. 3 times b. 6 times c. 9 times d. 11 times - CORRECT-ANSWERSa. 3 times
A modified version of the activated sludge process for removing phosphorus
and nitrogen would have the following sequence of tank environments:
a. anaerobic, anoxic, and aerobic b. aerobic, nitrification, and anaerobic c.
anaerobic, anoxic, and denitrification d. anaerobic, nitrification, aerobic, and
denitrification - CORRECT-ANSWERSa. anaerobic, anoxic, and aerobic
To what should the pH be raised for converting NH4 + to gaseous ammonia
(NH3)?
a. 9.4 to 9.8 b. 9.5 to 10.5 c. 10.5 to 11.5 d. 11.0 to 11.3 - CORRECT-
ANSWERSc. 10.5 to 11.5
The clinoptilolite used in ion exchange for nitrogen removal is regenerated
with
a. HCl b. NaOH c. KMnO4 d. NaCl - CORRECT-ANSWERSd. NaCl
The least reactive metals are called a. anodic metals b. galvanic metals c.
cathodic metals d. tempered metals - CORRECT-ANSWERSc. cathodic metals
CERTIFICATION (PART 1) PRACTICE
TEST EXAM WITH CORRECT
ANSWERS
What is the odor detection limit of chlorine gas?
a. 0.1 ppm b. 0.3 ppm c. 0.5 ppm d. 1.0 ppm - CORRECT-ANSWERSb. 0.3
ppm
What is a cathode?
a. negative pole of an electrolyte b. positive pole of an electrolyte c.
negative pole of an electrolytic cell or system d. positive pole of an
electrolytic cell or system - CORRECT-ANSWERSnegative pole of an
electrolytic cell or system
What is the beneficial concentration range of magnesium in an anaerobic
digester?
a. 50 to 100 mg/L b. 75 to 150 mg/L c. 100 to 200 mg/L d. 150 to 250 mg/L -
CORRECT-ANSWERSc. 100 to 200 mg/L
If the supernatant from an anaerobic digester that is returning to the plant
process is of poor quality and is causing plant upsets, what is the most
probable cause?
a. organic overload has occurred b. a toxic load has entered the digester c.
there is excessive mixing and settling time is insufficient d. sludge
recirculation line is partially or completely plugged - CORRECT-ANSWERSc.
there is excessive mixing and settling time is insufficient
If the odor of the supernatant is sour from either the primary or secondary
anaerobic digester, what is the most probable cause?
a. digester being overheated b. recirculation of gas is excessive c. digester
pH is too low d. volatile-acid-to-alkalinity ratio has increased to 0.8 -
CORRECT-ANSWERSc. digester pH is too low
What is the most probable cause of foam in the supernatant from either the
single stage or the primary tank?
, a. digester too stagnant as mixing is inadequate b. filamentous organisms
are dying off by the billions c. excessive gas recirculation d. digester being
overheated - CORRECT-ANSWERSc. excessive gas recirculation
At what pH will sodium hydroxide control sulfide generation for periods of
about a month or more?
a. 9.5 b. 10.5 c. 11.5 d. 12.5 - CORRECT-ANSWERSd. 12.5
What is the recommended organic loading rate in lb BOD/d/yd3 of media for
an odor removal tower?
a. 0.2 b. 0.5 c. 1.0 d. 1.4 - CORRECT-ANSWERSb. 0.5
The best temperatures reported for combusting odorous gases from a
wastewater plant begin at temperatures greater than
a. 1,000°F b. 1,200°F c. 1,500°F d. 1,800°F - CORRECT-ANSWERSc. 1,500°F
How many times can activated carbon be regenerated before it is usually
replaced?
a. 3 times b. 6 times c. 9 times d. 11 times - CORRECT-ANSWERSa. 3 times
A modified version of the activated sludge process for removing phosphorus
and nitrogen would have the following sequence of tank environments:
a. anaerobic, anoxic, and aerobic b. aerobic, nitrification, and anaerobic c.
anaerobic, anoxic, and denitrification d. anaerobic, nitrification, aerobic, and
denitrification - CORRECT-ANSWERSa. anaerobic, anoxic, and aerobic
To what should the pH be raised for converting NH4 + to gaseous ammonia
(NH3)?
a. 9.4 to 9.8 b. 9.5 to 10.5 c. 10.5 to 11.5 d. 11.0 to 11.3 - CORRECT-
ANSWERSc. 10.5 to 11.5
The clinoptilolite used in ion exchange for nitrogen removal is regenerated
with
a. HCl b. NaOH c. KMnO4 d. NaCl - CORRECT-ANSWERSd. NaCl
The least reactive metals are called a. anodic metals b. galvanic metals c.
cathodic metals d. tempered metals - CORRECT-ANSWERSc. cathodic metals
