Kentucky wastewater treatment
operator certification 2026/2027
version with correct answers
activated sludge - correct answer>>>produced in raw or settled wastewater by the
growth of bacteria, in the presence of dissolved oxygen.
activated sludge process - correct answer>>>A biological wastewater treatment process
which speeds up the decomposition of wastes in the wastewater being treated.
Activated Sludge is added to wastewater and the mixture (mixed liquor) is aerated and
agitated. After some time in the aeration tank, the activated sludge is allowed to settle
out by sedimentation and is disposed of (wasted) or reused (returned to the aeration
tank) as needed, the remaining wastewater then undergoes more treatment.
adsorption - correct answer>>>The process of binding or sticking to a surface.
advanced waste treatment - correct answer>>>Any process of water renovation that
upgrades treated wastewater to meet specific reuse requirements.
aeration - correct answer>>>the process by which air is circulated through, mixed with
or dissolved in a liquid or substance.
aerobes - correct answer>>>Bacteria that require oxygen to grow
aerobic bacteria - correct answer>>>bacteria that use oxygen for cellular respiration
air lift - correct answer>>>type of pump, air injected at the bottom to lift water to the top,
like percolator coffee pot
algae - correct answer>>>microscopic plants. live in or on water or on structures near
water, make o2 during day, use o2 at night, affect PH and DO
aliquot - correct answer>>>A portion of a well-mixed sample removed for testing
alkalinity - correct answer>>>ability of water to buffer acids
anaerobic - correct answer>>>Process that does not require oxygen
anaerobic bacteria - correct answer>>>bacteria that do not require oxygen to survive
anaerobic digestion - correct answer>>>is the decomposition of waste under anaerobic
conditions to produce biogas and a compost-like residue
,anoxic - correct answer>>>oxygen deficient less than .5 ppm
bacteria - correct answer>>>(microbiology) single-celled or noncellular spherical or
spiral or rod-shaped organisms lacking chlorophyll that reproduce by fission
absorption - correct answer>>>taking in substance into body of another
acid - correct answer>>>A substance that increases the hydrogen ion concentration of a
solution.
lowers PH
corrosive
baffle - correct answer>>>board used to direct flow, uniform velocities, absorb energy,
divert, guide, agitate liquids
base - correct answer>>>a compound that produces hydroxide ions in solution. raises
PH
biomass - correct answer>>>the total mass of organisms in a given area or volume.
biosolids - correct answer>>>A primarily organic solid product produced by wastewater
treatment processes that can be beneficially recycled. The word biosolids is replacing
the word sludge when referring to treated waste.
Biochemical Oxygen Demand (BOD) - correct answer>>>A measure of the amount of
dissolved oxygen required to break down the organic material in a given volume of
water through aerobic biological activity
blank - correct answer>>>sample being tested is not added
buffer - correct answer>>>A solution that minimizes changes in pH when extraneous
acids or bases are added to the solution.
bulking - correct answer>>>a condition arising when sludge floats rather than settles in
secondary sewage treatment. can be caused by filamentous bacteria
Carbonaceous Biochemical Oxygen Demand (CBOD) - correct answer>>>only the BOD
required to remove carbon. based
cavitation - correct answer>>>formation and collapse of gas bubbles due to low
pressure. can cause pitting. makes noise.
centrifuge - correct answer>>>device to separate substances by spinning them at high
speed
, chlorination - correct answer>>>disinfection of water by the addition of small amounts of
chlorine or a chlorine compound
comminutor - correct answer>>>(A Preliminary Treatment) A circular grinder designed
to grind the solids coming through the screen into pieces about 0.3 cm or smaller.
composite sample - correct answer>>>mixture of several samples over 24 hrs
denitrification - correct answer>>>process by which bacteria convert nitrates into
nitrogen gas, anoxic process
detritus - correct answer>>>heavy coarse grit in wastewater
Diffused-Air Aeration - correct answer>>>A diffused-air activated sludge plant takes air,
compresses it, and then discharges the air below the water surface of the aerator
through some type of air diffusion device.
Equalizing Basin - correct answer>>>A holding basin in which variations in flow and
composition of a liquid are averaged. Such basins are used to provide a flow of
reasonably uniform volume and composition to a treatment unit.
Eutrophication - correct answer>>>A process by which nutrients, particularly
phosphorus and nitrogen, become highly concentrated in a body of water, leading to
increased growth of organisms such as algae or cyanobacteria.
freeboard - correct answer>>>The distance from the waterline to the main deck
headworks - correct answer>>>The facilities where wastewater enters a wastewater
treatment plant. The headworks may consist of bar racks or bar screens, comminutors,
a wet well, and pumps.
Hydrogen Sulfide (H2S) - correct answer>>>rotten egg smell, produced under
anaerobic conditions,
masking agents - correct answer>>>chemicals used to cover unpleasant smells
mixed liquor - correct answer>>>When the activated sludge in an aeration tank is mixed
with primary effluent or the raw wastewater and return sludge, this mixture is then
referred to as mixed liquor as long as it is in the aeration tank.
Mixed Liquor Suspended Solids (MLSS) - correct answer>>>The amount (mg/L) of
suspended solids in the mixed liquor of an aeration tank.
ponding - correct answer>>>condition occurring on trickling filters, voids become
plugged enough that water passage through filter is inadequate. from excessive growth,
trash, or media breakdown.
operator certification 2026/2027
version with correct answers
activated sludge - correct answer>>>produced in raw or settled wastewater by the
growth of bacteria, in the presence of dissolved oxygen.
activated sludge process - correct answer>>>A biological wastewater treatment process
which speeds up the decomposition of wastes in the wastewater being treated.
Activated Sludge is added to wastewater and the mixture (mixed liquor) is aerated and
agitated. After some time in the aeration tank, the activated sludge is allowed to settle
out by sedimentation and is disposed of (wasted) or reused (returned to the aeration
tank) as needed, the remaining wastewater then undergoes more treatment.
adsorption - correct answer>>>The process of binding or sticking to a surface.
advanced waste treatment - correct answer>>>Any process of water renovation that
upgrades treated wastewater to meet specific reuse requirements.
aeration - correct answer>>>the process by which air is circulated through, mixed with
or dissolved in a liquid or substance.
aerobes - correct answer>>>Bacteria that require oxygen to grow
aerobic bacteria - correct answer>>>bacteria that use oxygen for cellular respiration
air lift - correct answer>>>type of pump, air injected at the bottom to lift water to the top,
like percolator coffee pot
algae - correct answer>>>microscopic plants. live in or on water or on structures near
water, make o2 during day, use o2 at night, affect PH and DO
aliquot - correct answer>>>A portion of a well-mixed sample removed for testing
alkalinity - correct answer>>>ability of water to buffer acids
anaerobic - correct answer>>>Process that does not require oxygen
anaerobic bacteria - correct answer>>>bacteria that do not require oxygen to survive
anaerobic digestion - correct answer>>>is the decomposition of waste under anaerobic
conditions to produce biogas and a compost-like residue
,anoxic - correct answer>>>oxygen deficient less than .5 ppm
bacteria - correct answer>>>(microbiology) single-celled or noncellular spherical or
spiral or rod-shaped organisms lacking chlorophyll that reproduce by fission
absorption - correct answer>>>taking in substance into body of another
acid - correct answer>>>A substance that increases the hydrogen ion concentration of a
solution.
lowers PH
corrosive
baffle - correct answer>>>board used to direct flow, uniform velocities, absorb energy,
divert, guide, agitate liquids
base - correct answer>>>a compound that produces hydroxide ions in solution. raises
PH
biomass - correct answer>>>the total mass of organisms in a given area or volume.
biosolids - correct answer>>>A primarily organic solid product produced by wastewater
treatment processes that can be beneficially recycled. The word biosolids is replacing
the word sludge when referring to treated waste.
Biochemical Oxygen Demand (BOD) - correct answer>>>A measure of the amount of
dissolved oxygen required to break down the organic material in a given volume of
water through aerobic biological activity
blank - correct answer>>>sample being tested is not added
buffer - correct answer>>>A solution that minimizes changes in pH when extraneous
acids or bases are added to the solution.
bulking - correct answer>>>a condition arising when sludge floats rather than settles in
secondary sewage treatment. can be caused by filamentous bacteria
Carbonaceous Biochemical Oxygen Demand (CBOD) - correct answer>>>only the BOD
required to remove carbon. based
cavitation - correct answer>>>formation and collapse of gas bubbles due to low
pressure. can cause pitting. makes noise.
centrifuge - correct answer>>>device to separate substances by spinning them at high
speed
, chlorination - correct answer>>>disinfection of water by the addition of small amounts of
chlorine or a chlorine compound
comminutor - correct answer>>>(A Preliminary Treatment) A circular grinder designed
to grind the solids coming through the screen into pieces about 0.3 cm or smaller.
composite sample - correct answer>>>mixture of several samples over 24 hrs
denitrification - correct answer>>>process by which bacteria convert nitrates into
nitrogen gas, anoxic process
detritus - correct answer>>>heavy coarse grit in wastewater
Diffused-Air Aeration - correct answer>>>A diffused-air activated sludge plant takes air,
compresses it, and then discharges the air below the water surface of the aerator
through some type of air diffusion device.
Equalizing Basin - correct answer>>>A holding basin in which variations in flow and
composition of a liquid are averaged. Such basins are used to provide a flow of
reasonably uniform volume and composition to a treatment unit.
Eutrophication - correct answer>>>A process by which nutrients, particularly
phosphorus and nitrogen, become highly concentrated in a body of water, leading to
increased growth of organisms such as algae or cyanobacteria.
freeboard - correct answer>>>The distance from the waterline to the main deck
headworks - correct answer>>>The facilities where wastewater enters a wastewater
treatment plant. The headworks may consist of bar racks or bar screens, comminutors,
a wet well, and pumps.
Hydrogen Sulfide (H2S) - correct answer>>>rotten egg smell, produced under
anaerobic conditions,
masking agents - correct answer>>>chemicals used to cover unpleasant smells
mixed liquor - correct answer>>>When the activated sludge in an aeration tank is mixed
with primary effluent or the raw wastewater and return sludge, this mixture is then
referred to as mixed liquor as long as it is in the aeration tank.
Mixed Liquor Suspended Solids (MLSS) - correct answer>>>The amount (mg/L) of
suspended solids in the mixed liquor of an aeration tank.
ponding - correct answer>>>condition occurring on trickling filters, voids become
plugged enough that water passage through filter is inadequate. from excessive growth,
trash, or media breakdown.
