1|Page
Arizona Wastewater Treatment Operator Grade 1
Exam||Verified Questions and Correct Answers with
EXPLANATIONS||NEWEST EXAM!!!.pdf
When domestic wastewater enters natural waters, what
species deplete most of the oxygen? - Answer-aerobic
bacteria
Once the oxygen is depleted in a natural body of water,
which organisms take over? - Answer-anaerobic bacteria
The major gas produced by anaerobic decomposition is: -
Answer-methane
When organic wastes are discharged to receiving waters,
oxygen is depleted by: - Answer-bacteria
Coliform bacteria are: - Answer-indicators
Which indicates a good quality domestic activated sludge?
- Answer-brown color and musty odor
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Common settling times in wastewater treatment plants
range from: - Answer-2 to 4 hours
What is the most common reason for a wastewater to
contain intermittent large amounts of sand, gravel, and
grit? - Answer-storm events
Combined wastewater is defined as: - Answer-sanitary
wastewater and storm water runoff
In general , the solids content in wastewater is about: -
Answer-0.1%
In general, what is the percentage of suspended solids in
the total amount of solids? - Answer-30%
Generally, the percentage of dissolved solids in the
amount of total solids is about: - Answer-70%
Which type of organisms would most probably be
associated with poor treatment or young biomass? -
Answer-amoebas
Which gas is produced in anaerobic digesters and can be
used as a fuel? - Answer-methane
, 3|Page
The rock in most trickling filters is placed: - Answer-on a
system of tile underdrains
What is the purpose of heating and mixing a primary
anaerobic digester? - Answer-to increase the digestion
rate
Which type of organisms would most probably be
associated with very clear plant effluent, low biochemical
oxygen demand (BOD), and low amounts of suspended
solids? - Answer-stalked ciliates
Aerobic bacteria will reproduce and live in an environment
that contains only: - Answer-oxygen
Anaerobic bacteria will reproduce and live only in an
environment that completely lacks: - Answer-free or
dissolved oxygen (DO)
The biochemical oxygen demand (BOD) test usually has a
specific time of: - Answer-5 days
Arizona Wastewater Treatment Operator Grade 1
Exam||Verified Questions and Correct Answers with
EXPLANATIONS||NEWEST EXAM!!!.pdf
When domestic wastewater enters natural waters, what
species deplete most of the oxygen? - Answer-aerobic
bacteria
Once the oxygen is depleted in a natural body of water,
which organisms take over? - Answer-anaerobic bacteria
The major gas produced by anaerobic decomposition is: -
Answer-methane
When organic wastes are discharged to receiving waters,
oxygen is depleted by: - Answer-bacteria
Coliform bacteria are: - Answer-indicators
Which indicates a good quality domestic activated sludge?
- Answer-brown color and musty odor
,2|Page
Common settling times in wastewater treatment plants
range from: - Answer-2 to 4 hours
What is the most common reason for a wastewater to
contain intermittent large amounts of sand, gravel, and
grit? - Answer-storm events
Combined wastewater is defined as: - Answer-sanitary
wastewater and storm water runoff
In general , the solids content in wastewater is about: -
Answer-0.1%
In general, what is the percentage of suspended solids in
the total amount of solids? - Answer-30%
Generally, the percentage of dissolved solids in the
amount of total solids is about: - Answer-70%
Which type of organisms would most probably be
associated with poor treatment or young biomass? -
Answer-amoebas
Which gas is produced in anaerobic digesters and can be
used as a fuel? - Answer-methane
, 3|Page
The rock in most trickling filters is placed: - Answer-on a
system of tile underdrains
What is the purpose of heating and mixing a primary
anaerobic digester? - Answer-to increase the digestion
rate
Which type of organisms would most probably be
associated with very clear plant effluent, low biochemical
oxygen demand (BOD), and low amounts of suspended
solids? - Answer-stalked ciliates
Aerobic bacteria will reproduce and live in an environment
that contains only: - Answer-oxygen
Anaerobic bacteria will reproduce and live only in an
environment that completely lacks: - Answer-free or
dissolved oxygen (DO)
The biochemical oxygen demand (BOD) test usually has a
specific time of: - Answer-5 days
