MA Industrial Wastewater Treatment Plant
Operator Grade 2 Practice Exam 200
Questions with CORRECT DETAILED
ANSWERS (VERIFIED ANSWERS) |ALREADY
GRADED A+
oxidized by chlorine, decreasing chlorines ability to neutralize nitrite. What is a
pneumatic pump and what is it typically used to move/transport? -
ANSWER//Pneumatic pumps are positive displacement diaphragm pumps
that use pressurized air to operate a malleable diaphragm back and forth to
move fluids. It is usually used to move air and other gases, not liquids. They
must be used in dry environments. What happens first in the event of a
chlorine gas system losing its Venturi effect (vacuum)? - ANSWER//The
safety diaphragm would slam shut. This is virtually a backflow preventer.
What does an SVI of 180 mean in a settleometer? - ANSWER//Moderately
aged sludge. What does an SVI of 250 or more mean in a settleometer? -
ANSWER//Very young sludge. What does an SVI of 80 or less mean in a
settleometer? - ANSWER//Very old sludge. An anaerobic digester operating
temperature should be adjusted by how many degrees? - ANSWER//Adjusted
by as small of increments possible over as long of a time as possible. Typical
adjustments are made at a rate of 1 degree F per day. An operator does a
BOD test of 3 mL, 5 mL, and 10 mL. The higher BOD samples are getting a
higher oxygen uptake reading. If the operator did all the quality control
requirements correctly, what is the problem with the higher OUR readings? -
ANSWER//There is a toxic substance in the samples. What are the vector
attraction reduction requirements for lime stabilization to accomplish class B
stabilization standards? - ANSWER//Sludge pH up to 12 for for the first 2
hours, and then 11.5 for the next 22 hours. How much BOD in lbs does every
person contribute to collected wastewater per day? - ANSWER//0.17
lbs/person/day What type of filament is associated with very old sludge that
denitrifies, bulks up, and has lots of red worms, water bears, and rotifers? -
ANSWER//Thiothrix. If solids are rising in the secondary clarifier, that means
that the sludge is undergoing what process? - ANSWER//Denitrification. The
pressure on a mechanical blower is high and the blowers keep kicking on and
off. What is the cause and what is happening? - ANSWER//There is a valve
closure downpipe at the aeration basin. The blowers have nowhere to blow air
to and pressure gets high, so the VFD is turning the blower off. Which is
stronger, hypochlorous acid or hydrochloric acid? - ANSWER//Hydrochloric
acid is stronger. Ammonia levels are all of a sudden unusually high in the
aeration basin. What should be done to account for this? - ANSWER//DO
levels should be increased, as extra DO will be needed to neutralize ammonia.
A wastewater treatment plant has 2 large bubble compressors. For some
reason the compressors keep switching over to the other over and over again.
What is a likely problem? - ANSWER//The compressors are overheating,
likely because the air filters are dirty. The air filters should be replaced. What
orientation should 150-pound chorine containers be stored and moved at? -
ANSWER//Vertically. An operator connects a chlorine line to the bottom valve
, of a 1 ton container expecting to remove liquid chlorine. Instead, chlorine gas
comes out through the lower valve. They switch the line to the upper valve,
but still pull gas instead of liquid. What is the most likely reason for both
valves to produce gas? - ANSWER//The eductor tube has broken off within
the container. What is an eductor tube? - ANSWER//A tube inside a cylinder
or container attached to the cylinder valve which allows liquid product
withdrawal from the cylinder. Which of the following chemical species will not
be measured in the total chlorine residual? Hypochlorite ion, monochloramine,
hypochlorous acid, chloride ion. - ANSWER//Chloride ion. Chlorine and
hypochlorite break down in water to form what? - ANSWER//Hypochlorous
acid and hypochlorite ion. How many fusible plugs does a one-ton chlorine
container have? - ANSWER//Six (three on each side). It is best practice to
open chorine tanks by ___ turns so you don't have to panic close the valve in
the case of emergency. - ANSWER//1/4 turns. Fusible plugs melt at what
temperature range? - ANSWER//70-74 degrees C or 158 to 165 degrees F.
By law, chlorine cylinders and containers are filled to a maximum of... -
ANSWER//80%. A river typically has a fecal coliform number of 15 MPN
upstream of a WWTP and 25 MPN downstream of a WWTP. One day, lab
data shows an MPN of 275 upstream and 319 downstream. What is the likely
cause? - ANSWER//An overflow of inflow and infiltration from a collection
system went into the river upstream of the plant. A BOD bottle can be
removed from the incubator at 5 days plus or minus... - ANSWER//3 hours.
Filamentous bulking of activated sludge may be controlled temporarily by... -
ANSWER//The addition of chlorine to the mixed liquor. Using the breakpoint
chlorination method of ammonia removal, how many parts of chlorine are
needed to remove one part of ammonia? - ANSWER//8-10 parts of chlorine to
convert 1 part of ammonia. What issue can cause liquid chlorine to flow
backwards back into the tank? - ANSWER//Broken injection check valve. A
BOD test can be preserved for __ hours if it is cooled to __ degrees Celsius. -
ANSWER//48 hours; 4 degrees C. What is the only acceptable piece of
equipment that should be stored in a chlorine cylinder gas feed room? -
ANSWER//Empty chlorine tanks. Where is the pressure relief valve located in
a chlorine or sulfur dioxide evaporator? - ANSWER//Downstream of the gas
outlet. The preservative used for transport of the fecal coliform sample is... -
ANSWER//Trick question. The only thing to preserve it is being stored at 4
degrees C in a cooler with ice. What does the Winkler method test for? -
ANSWER//DO. A loud banging can be heard from the plant water pumps.
Upon inspection you notice that they are severely shaking and are running
very hot. They are running at 100%. What could be the issue? -
ANSWER//They are only pumping air. The volatile acid to alkalinity ratio of a
properly operating anaerobic digester is... - ANSWER//0.1 Which wavelength
of UV light is needed for proper disinfection of bacteria? - ANSWER//254 nm.
How much alkalinity is put back into the MLSS for each pound of nitrate used
as a source of oxygen during the denitrification process? - ANSWER//3.6 lbs.
When are monthly reports due to the MA DEP? - ANSWER//The 15th day of
every month. What two chemicals are used for DE-CHLORINATION? -
ANSWER//Sulfur dioxide and sulfite salts (including sodium sulfite, sodium
bisulfite, and sodium metabisulfite). How long are you required to keep
MAINTENANCE records? - ANSWER//Three years. How long is an NPDES
Operator Grade 2 Practice Exam 200
Questions with CORRECT DETAILED
ANSWERS (VERIFIED ANSWERS) |ALREADY
GRADED A+
oxidized by chlorine, decreasing chlorines ability to neutralize nitrite. What is a
pneumatic pump and what is it typically used to move/transport? -
ANSWER//Pneumatic pumps are positive displacement diaphragm pumps
that use pressurized air to operate a malleable diaphragm back and forth to
move fluids. It is usually used to move air and other gases, not liquids. They
must be used in dry environments. What happens first in the event of a
chlorine gas system losing its Venturi effect (vacuum)? - ANSWER//The
safety diaphragm would slam shut. This is virtually a backflow preventer.
What does an SVI of 180 mean in a settleometer? - ANSWER//Moderately
aged sludge. What does an SVI of 250 or more mean in a settleometer? -
ANSWER//Very young sludge. What does an SVI of 80 or less mean in a
settleometer? - ANSWER//Very old sludge. An anaerobic digester operating
temperature should be adjusted by how many degrees? - ANSWER//Adjusted
by as small of increments possible over as long of a time as possible. Typical
adjustments are made at a rate of 1 degree F per day. An operator does a
BOD test of 3 mL, 5 mL, and 10 mL. The higher BOD samples are getting a
higher oxygen uptake reading. If the operator did all the quality control
requirements correctly, what is the problem with the higher OUR readings? -
ANSWER//There is a toxic substance in the samples. What are the vector
attraction reduction requirements for lime stabilization to accomplish class B
stabilization standards? - ANSWER//Sludge pH up to 12 for for the first 2
hours, and then 11.5 for the next 22 hours. How much BOD in lbs does every
person contribute to collected wastewater per day? - ANSWER//0.17
lbs/person/day What type of filament is associated with very old sludge that
denitrifies, bulks up, and has lots of red worms, water bears, and rotifers? -
ANSWER//Thiothrix. If solids are rising in the secondary clarifier, that means
that the sludge is undergoing what process? - ANSWER//Denitrification. The
pressure on a mechanical blower is high and the blowers keep kicking on and
off. What is the cause and what is happening? - ANSWER//There is a valve
closure downpipe at the aeration basin. The blowers have nowhere to blow air
to and pressure gets high, so the VFD is turning the blower off. Which is
stronger, hypochlorous acid or hydrochloric acid? - ANSWER//Hydrochloric
acid is stronger. Ammonia levels are all of a sudden unusually high in the
aeration basin. What should be done to account for this? - ANSWER//DO
levels should be increased, as extra DO will be needed to neutralize ammonia.
A wastewater treatment plant has 2 large bubble compressors. For some
reason the compressors keep switching over to the other over and over again.
What is a likely problem? - ANSWER//The compressors are overheating,
likely because the air filters are dirty. The air filters should be replaced. What
orientation should 150-pound chorine containers be stored and moved at? -
ANSWER//Vertically. An operator connects a chlorine line to the bottom valve
, of a 1 ton container expecting to remove liquid chlorine. Instead, chlorine gas
comes out through the lower valve. They switch the line to the upper valve,
but still pull gas instead of liquid. What is the most likely reason for both
valves to produce gas? - ANSWER//The eductor tube has broken off within
the container. What is an eductor tube? - ANSWER//A tube inside a cylinder
or container attached to the cylinder valve which allows liquid product
withdrawal from the cylinder. Which of the following chemical species will not
be measured in the total chlorine residual? Hypochlorite ion, monochloramine,
hypochlorous acid, chloride ion. - ANSWER//Chloride ion. Chlorine and
hypochlorite break down in water to form what? - ANSWER//Hypochlorous
acid and hypochlorite ion. How many fusible plugs does a one-ton chlorine
container have? - ANSWER//Six (three on each side). It is best practice to
open chorine tanks by ___ turns so you don't have to panic close the valve in
the case of emergency. - ANSWER//1/4 turns. Fusible plugs melt at what
temperature range? - ANSWER//70-74 degrees C or 158 to 165 degrees F.
By law, chlorine cylinders and containers are filled to a maximum of... -
ANSWER//80%. A river typically has a fecal coliform number of 15 MPN
upstream of a WWTP and 25 MPN downstream of a WWTP. One day, lab
data shows an MPN of 275 upstream and 319 downstream. What is the likely
cause? - ANSWER//An overflow of inflow and infiltration from a collection
system went into the river upstream of the plant. A BOD bottle can be
removed from the incubator at 5 days plus or minus... - ANSWER//3 hours.
Filamentous bulking of activated sludge may be controlled temporarily by... -
ANSWER//The addition of chlorine to the mixed liquor. Using the breakpoint
chlorination method of ammonia removal, how many parts of chlorine are
needed to remove one part of ammonia? - ANSWER//8-10 parts of chlorine to
convert 1 part of ammonia. What issue can cause liquid chlorine to flow
backwards back into the tank? - ANSWER//Broken injection check valve. A
BOD test can be preserved for __ hours if it is cooled to __ degrees Celsius. -
ANSWER//48 hours; 4 degrees C. What is the only acceptable piece of
equipment that should be stored in a chlorine cylinder gas feed room? -
ANSWER//Empty chlorine tanks. Where is the pressure relief valve located in
a chlorine or sulfur dioxide evaporator? - ANSWER//Downstream of the gas
outlet. The preservative used for transport of the fecal coliform sample is... -
ANSWER//Trick question. The only thing to preserve it is being stored at 4
degrees C in a cooler with ice. What does the Winkler method test for? -
ANSWER//DO. A loud banging can be heard from the plant water pumps.
Upon inspection you notice that they are severely shaking and are running
very hot. They are running at 100%. What could be the issue? -
ANSWER//They are only pumping air. The volatile acid to alkalinity ratio of a
properly operating anaerobic digester is... - ANSWER//0.1 Which wavelength
of UV light is needed for proper disinfection of bacteria? - ANSWER//254 nm.
How much alkalinity is put back into the MLSS for each pound of nitrate used
as a source of oxygen during the denitrification process? - ANSWER//3.6 lbs.
When are monthly reports due to the MA DEP? - ANSWER//The 15th day of
every month. What two chemicals are used for DE-CHLORINATION? -
ANSWER//Sulfur dioxide and sulfite salts (including sodium sulfite, sodium
bisulfite, and sodium metabisulfite). How long are you required to keep
MAINTENANCE records? - ANSWER//Three years. How long is an NPDES
