Wastewater Operator Class D Exam Questions and
Answers.
The natural exchange of water between the earth and the air - Correct Answer
hydrologic cycle
______________ causes surface water to enter the atmosphere and begin the
Hydrologic Cycle - Correct Answer Evaporation
Rain or snow falling from the clouds - Correct Answer Precipitation
what causes water vapor to form clouds - Correct Answer Condensation
generally better protected from contamination than surface water sources - Correct
Answer Groundwater sources
to properly collect, transport, and treat both domestic and industrial wastewater prior to
discharge into the environment - Correct Answer Goal of wastewater systems and
wastewater operators
Wastewater entering surface water at a specific point from a specific source - Correct
Answer Point-Source
Contaminated water that enters surface water intermittently - Correct Answer Non-
Point-Source
A key determining factor whether or not the plant can meet its discharge permit
requirements - Correct Answer The wastewater treatment plant operator's knowledge of
the treatment process
The major piece of national legislation that governs wastewater treatment - Correct
Answer Clean Water Act of 1972
Controls the wastewater regulations in Texas - Correct Answer The Texas Commission
on Environmental Quality (TCEQ)
,Have the authority to inspect water quality within their jurisdictional boundaries and
ensure wastewater treatment facilities are meeting their permit requirements - Correct
Answer Local governments
Groundwater entering the collection system through leaking joints, cracks, or holes in
system pipes - Correct Answer Infiltration
The result of surface runoff entering through leaking manhole covers, or illegal rood,
gutter and sump pump connections to the collection system - Correct Answer Inflow
In addition to increased hydraulic loading, infiltration and inflow can deliver _________
__________ water to the treatment plant that can upset the biological treatment process
- Correct Answer Nutrient Deficient
Warmer water temperatures will result in _________biological activity in a collection
system - Correct Answer Increased
Increased biological activity increases the production rate of _________ __________
which is a dangerous byproduct of organic material decomposition - Correct Answer
hydrogen sulfide
Normal raw wastewater COD ranges between ________ and ______mg/L - Correct
Answer 200 and 600
_________ is typically higher than _____ with the typical relationship between BOD and
COD 0.5:1 (BOD:COD) for raw wastewater - Correct Answer COD is typically higher
than BOD
There is an ________ relationship between water temperature and its ability to maintain
dissolved oxygen in solution - Correct Answer inverse
As water gets _________, it is capable of holding more dissolved oxygen - Correct
Answer colder
As water gets ________, its ability to hold dissolved oxygen in solution goes down -
Correct Answer warmer
,When performing the CBOD test on biological process effluent water, a ____________
__________ must be added to that only carbonaceous BOD is measured - Correct
Answer nitrification inhibitor
Since ___________ require a host cell to reproduce, they do not increase in number
while in the wastewater - Correct Answer viruses
a term used to describe all of the solids that are contained within wastewater - Correct
Answer Total Solids
Increasing ammonia levels in the primary clarifier is an indication of a __________
_________ in the primary sludge - Correct Answer septic condition
are commonly the cause of large amounts of sand, gravel, and grit entering the
treatment plant - Correct Answer storm events
A _____________ wastewater collection system carries both sanitary wastewater and
storm water runoff - Correct Answer combined
The total solids concentration in most wastewater is approximately _____% - Correct
Answer 0.1 %
approximately ________ of the total solids in wastewater is characterized as suspended
solids - Correct Answer 30%
Approximately _______ of the total solids in wastewater are characterized as dissolved
solids - Correct Answer 70%
__________ conditions in wastewater are caused by a lack of dissolved oxygen and the
presence of _________ bacteria - Correct Answer septic anaerobic
Floatable scum is usually removed from wastewater in the __________ clarifier -
Correct Answer primary
_____________ _____________ will deplete the dissolved oxygen in a river or lake if
domestic wastewater is discharged without proper treatment - Correct Answer aerobic
bacteria
, ________ bacteria will dominate a natural body of water that lacks dissolved oxygen -
Correct Answer anaerobic
Secondary treatment is defined as consistently producing an effluent that contains no
more than ______ BOD and ________ Suspended solids based on a 30-day average -
Correct Answer 30 mg/L / 30mg/L
The clean water act requires WWTPS to achieve greater than or equal to ________%
removal of TSS and BOD - Correct Answer 85%
Wastewater is sampled for ________ control and __________compliance purposes -
Correct Answer process / regulatory
failing to collect, analyze and perform required compliance samples can result in
____________ and ____________penalties - Correct Answer criminal / civil
The appropriate type of sample for PH, dissolved oxygen and chlorine residual is a
_________________sample - Correct Answer composite
There are two types of composite samples which are __________ and
______________ - Correct Answer time based and flow-proportional
Continuous samples are used by online instrumentation to monitor parameters that
would typically be collected by a _____________ - Correct Answer grab sample
______________sample points are determined by the primacy agency while ________
control sample points are determined by treatment plant staff - Correct Answer
Compliance / Process
Preserving samples with acid results in a sample pH less than ____pH units - Correct
Answer 2
When cooling is used for sample preservation, the sample should be stored at ______
plus or minus 2 degrees - Correct Answer 4 degrees Celsius
Answers.
The natural exchange of water between the earth and the air - Correct Answer
hydrologic cycle
______________ causes surface water to enter the atmosphere and begin the
Hydrologic Cycle - Correct Answer Evaporation
Rain or snow falling from the clouds - Correct Answer Precipitation
what causes water vapor to form clouds - Correct Answer Condensation
generally better protected from contamination than surface water sources - Correct
Answer Groundwater sources
to properly collect, transport, and treat both domestic and industrial wastewater prior to
discharge into the environment - Correct Answer Goal of wastewater systems and
wastewater operators
Wastewater entering surface water at a specific point from a specific source - Correct
Answer Point-Source
Contaminated water that enters surface water intermittently - Correct Answer Non-
Point-Source
A key determining factor whether or not the plant can meet its discharge permit
requirements - Correct Answer The wastewater treatment plant operator's knowledge of
the treatment process
The major piece of national legislation that governs wastewater treatment - Correct
Answer Clean Water Act of 1972
Controls the wastewater regulations in Texas - Correct Answer The Texas Commission
on Environmental Quality (TCEQ)
,Have the authority to inspect water quality within their jurisdictional boundaries and
ensure wastewater treatment facilities are meeting their permit requirements - Correct
Answer Local governments
Groundwater entering the collection system through leaking joints, cracks, or holes in
system pipes - Correct Answer Infiltration
The result of surface runoff entering through leaking manhole covers, or illegal rood,
gutter and sump pump connections to the collection system - Correct Answer Inflow
In addition to increased hydraulic loading, infiltration and inflow can deliver _________
__________ water to the treatment plant that can upset the biological treatment process
- Correct Answer Nutrient Deficient
Warmer water temperatures will result in _________biological activity in a collection
system - Correct Answer Increased
Increased biological activity increases the production rate of _________ __________
which is a dangerous byproduct of organic material decomposition - Correct Answer
hydrogen sulfide
Normal raw wastewater COD ranges between ________ and ______mg/L - Correct
Answer 200 and 600
_________ is typically higher than _____ with the typical relationship between BOD and
COD 0.5:1 (BOD:COD) for raw wastewater - Correct Answer COD is typically higher
than BOD
There is an ________ relationship between water temperature and its ability to maintain
dissolved oxygen in solution - Correct Answer inverse
As water gets _________, it is capable of holding more dissolved oxygen - Correct
Answer colder
As water gets ________, its ability to hold dissolved oxygen in solution goes down -
Correct Answer warmer
,When performing the CBOD test on biological process effluent water, a ____________
__________ must be added to that only carbonaceous BOD is measured - Correct
Answer nitrification inhibitor
Since ___________ require a host cell to reproduce, they do not increase in number
while in the wastewater - Correct Answer viruses
a term used to describe all of the solids that are contained within wastewater - Correct
Answer Total Solids
Increasing ammonia levels in the primary clarifier is an indication of a __________
_________ in the primary sludge - Correct Answer septic condition
are commonly the cause of large amounts of sand, gravel, and grit entering the
treatment plant - Correct Answer storm events
A _____________ wastewater collection system carries both sanitary wastewater and
storm water runoff - Correct Answer combined
The total solids concentration in most wastewater is approximately _____% - Correct
Answer 0.1 %
approximately ________ of the total solids in wastewater is characterized as suspended
solids - Correct Answer 30%
Approximately _______ of the total solids in wastewater are characterized as dissolved
solids - Correct Answer 70%
__________ conditions in wastewater are caused by a lack of dissolved oxygen and the
presence of _________ bacteria - Correct Answer septic anaerobic
Floatable scum is usually removed from wastewater in the __________ clarifier -
Correct Answer primary
_____________ _____________ will deplete the dissolved oxygen in a river or lake if
domestic wastewater is discharged without proper treatment - Correct Answer aerobic
bacteria
, ________ bacteria will dominate a natural body of water that lacks dissolved oxygen -
Correct Answer anaerobic
Secondary treatment is defined as consistently producing an effluent that contains no
more than ______ BOD and ________ Suspended solids based on a 30-day average -
Correct Answer 30 mg/L / 30mg/L
The clean water act requires WWTPS to achieve greater than or equal to ________%
removal of TSS and BOD - Correct Answer 85%
Wastewater is sampled for ________ control and __________compliance purposes -
Correct Answer process / regulatory
failing to collect, analyze and perform required compliance samples can result in
____________ and ____________penalties - Correct Answer criminal / civil
The appropriate type of sample for PH, dissolved oxygen and chlorine residual is a
_________________sample - Correct Answer composite
There are two types of composite samples which are __________ and
______________ - Correct Answer time based and flow-proportional
Continuous samples are used by online instrumentation to monitor parameters that
would typically be collected by a _____________ - Correct Answer grab sample
______________sample points are determined by the primacy agency while ________
control sample points are determined by treatment plant staff - Correct Answer
Compliance / Process
Preserving samples with acid results in a sample pH less than ____pH units - Correct
Answer 2
When cooling is used for sample preservation, the sample should be stored at ______
plus or minus 2 degrees - Correct Answer 4 degrees Celsius
