WASTEWATER D LICENSE EXAM UPDATED QUESTIONS AND ANSWERS
How many PPB equals one PPM? - CORRECT ANSWER✅✅One thousand parts per billion equals one
part per million
If the bubbler system air supply line at the wet well is clogged, what will this cause the pump to do? -
CORRECT ANSWER✅✅Pressure build up in the supply line would signal more water column then there
really was, causing the pump to run longer than necessary, possibly not kick off and run continually
If the bubbler system air supply line at the wet well has a hole in it above the water level, what will this
cause the pump to do? - CORRECT ANSWER✅✅It would cause a low pressure reading showing a lower
water level then there really is, or possible not even kicking on the pump
What is the best way to keep within the operating budget? - CORRECT ANSWER✅✅keep list of
purchases and expenses to date during fiscal year
comparisons should be made with budget allocations to avoid excess purchases
review purchases monthly and compare to budget
If a diaphragm pump has 2 check valves open, what will the pump do? - CORRECT ANSWER✅✅It would
not pump properly because 1 check valve should be shut while the other is open
A suction lift pump on the inlet side normally reads 2in of mercury on the psi vacuum gauge but not
reads 3in of mercury. What is the problem with the pump? - CORRECT ANSWER✅✅A higher vacuum
than normal may indicate a partially plugged or restricted suction line.
A lower vacuum may indicate a higher wet well level or a worn pump impeller or wearing rings.
One mg per L equals how many pounds per 1 MG? - CORRECT ANSWER✅✅8.34
What is the proper way to put packing in a pump? - CORRECT ANSWER✅✅cut the packing rope about
45 degree angle, place around shaft, be sure to offset/stagger the next joint from the previous
,How many drips of water should you have coming out of a packing seal? - CORRECT ANSWER✅✅no
drip on a mechanical seal
How many drips of water should you have coming out of a packing seal? 2 - CORRECT ANSWER✅✅what
the operation and maintenance manual recommends
A one horsepower motor that runs on 110 volts using 10 amps has what efficiency? - CORRECT
ANSWER✅✅most motors run from 80-95% efficiency
A motor that has 440 volt supply is usually what phase of power? - CORRECT ANSWER✅✅3 phase
NPDES - CORRECT ANSWER✅✅National Pollutant Discharge Elimination System
the regulatory agency document issued by either a federal or state agency which is designed to control
all discharges of pollutants from point sources into US waterways - CORRECT ANSWER✅✅NPDES
permit
What is the name of our operating permit? - CORRECT ANSWER✅✅NPDES
What is the best way to promote safety in the workplace? - CORRECT ANSWER✅✅the supervisor needs
to be safe and promote safety in such a manner to get the employees involved
What is normally used to raise the pH in sludge? - CORRECT ANSWER✅✅lime
What is the common device used to measure the effluent of a lagoon? - CORRECT ANSWER✅✅v notch
weir
What concentration of H2S is unsafe to humans? - CORRECT ANSWER✅✅death in a few minutes at
0.2%. Paralyzes respiratory center
, What is the minimum O2 concentration that is safe for workers to enter a manhole? - CORRECT
ANSWER✅✅If O2 is less than 19.5%, do not enter space without respiratory protection. Normal air
contains 20.93% of O2.
Normal air contains ______% of O2 - CORRECT ANSWER✅✅19.5%
What knob is turned to control the usage of chlorine applied? - CORRECT ANSWER✅✅rotameter
Can you store BOD at 4C for 48 hours? - CORRECT ANSWER✅✅yes
What is the minimum velocity of the water flow for a grit chamber and the maximum flow? - CORRECT
ANSWER✅✅1.0 feet per second minimum
1.5 feet per second optimum
2.0 feet per second maximum
How many mg/L equals one grain per gallon? - CORRECT ANSWER✅✅17.1 mg/L
Dissolved oxygen increases when the temperature __________ - CORRECT ANSWER✅✅decreases
You can tell if a clarifier scraper arm is working by what means? - CORRECT ANSWER✅✅the simplest is
to visual check to see if the scum scraper arm is moving properly
check into foam
If the sludge is thick or thin, then what does this tell you about the sludge scraper? - CORRECT
ANSWER✅✅possible answer is the flights are damaged or the speed of the scrapers(flights) need to be
increased if sludge is too thick
or slowed down if the sludge is too thin
How many PPB equals one PPM? - CORRECT ANSWER✅✅One thousand parts per billion equals one
part per million
If the bubbler system air supply line at the wet well is clogged, what will this cause the pump to do? -
CORRECT ANSWER✅✅Pressure build up in the supply line would signal more water column then there
really was, causing the pump to run longer than necessary, possibly not kick off and run continually
If the bubbler system air supply line at the wet well has a hole in it above the water level, what will this
cause the pump to do? - CORRECT ANSWER✅✅It would cause a low pressure reading showing a lower
water level then there really is, or possible not even kicking on the pump
What is the best way to keep within the operating budget? - CORRECT ANSWER✅✅keep list of
purchases and expenses to date during fiscal year
comparisons should be made with budget allocations to avoid excess purchases
review purchases monthly and compare to budget
If a diaphragm pump has 2 check valves open, what will the pump do? - CORRECT ANSWER✅✅It would
not pump properly because 1 check valve should be shut while the other is open
A suction lift pump on the inlet side normally reads 2in of mercury on the psi vacuum gauge but not
reads 3in of mercury. What is the problem with the pump? - CORRECT ANSWER✅✅A higher vacuum
than normal may indicate a partially plugged or restricted suction line.
A lower vacuum may indicate a higher wet well level or a worn pump impeller or wearing rings.
One mg per L equals how many pounds per 1 MG? - CORRECT ANSWER✅✅8.34
What is the proper way to put packing in a pump? - CORRECT ANSWER✅✅cut the packing rope about
45 degree angle, place around shaft, be sure to offset/stagger the next joint from the previous
,How many drips of water should you have coming out of a packing seal? - CORRECT ANSWER✅✅no
drip on a mechanical seal
How many drips of water should you have coming out of a packing seal? 2 - CORRECT ANSWER✅✅what
the operation and maintenance manual recommends
A one horsepower motor that runs on 110 volts using 10 amps has what efficiency? - CORRECT
ANSWER✅✅most motors run from 80-95% efficiency
A motor that has 440 volt supply is usually what phase of power? - CORRECT ANSWER✅✅3 phase
NPDES - CORRECT ANSWER✅✅National Pollutant Discharge Elimination System
the regulatory agency document issued by either a federal or state agency which is designed to control
all discharges of pollutants from point sources into US waterways - CORRECT ANSWER✅✅NPDES
permit
What is the name of our operating permit? - CORRECT ANSWER✅✅NPDES
What is the best way to promote safety in the workplace? - CORRECT ANSWER✅✅the supervisor needs
to be safe and promote safety in such a manner to get the employees involved
What is normally used to raise the pH in sludge? - CORRECT ANSWER✅✅lime
What is the common device used to measure the effluent of a lagoon? - CORRECT ANSWER✅✅v notch
weir
What concentration of H2S is unsafe to humans? - CORRECT ANSWER✅✅death in a few minutes at
0.2%. Paralyzes respiratory center
, What is the minimum O2 concentration that is safe for workers to enter a manhole? - CORRECT
ANSWER✅✅If O2 is less than 19.5%, do not enter space without respiratory protection. Normal air
contains 20.93% of O2.
Normal air contains ______% of O2 - CORRECT ANSWER✅✅19.5%
What knob is turned to control the usage of chlorine applied? - CORRECT ANSWER✅✅rotameter
Can you store BOD at 4C for 48 hours? - CORRECT ANSWER✅✅yes
What is the minimum velocity of the water flow for a grit chamber and the maximum flow? - CORRECT
ANSWER✅✅1.0 feet per second minimum
1.5 feet per second optimum
2.0 feet per second maximum
How many mg/L equals one grain per gallon? - CORRECT ANSWER✅✅17.1 mg/L
Dissolved oxygen increases when the temperature __________ - CORRECT ANSWER✅✅decreases
You can tell if a clarifier scraper arm is working by what means? - CORRECT ANSWER✅✅the simplest is
to visual check to see if the scum scraper arm is moving properly
check into foam
If the sludge is thick or thin, then what does this tell you about the sludge scraper? - CORRECT
ANSWER✅✅possible answer is the flights are damaged or the speed of the scrapers(flights) need to be
increased if sludge is too thick
or slowed down if the sludge is too thin
