WASTEWATER TREATMENT
OPERATOR COMPREHENSIVE
TEST PAPER QUESTIONS
SOLUTIONS GRADED A+
◉ blank. Answer: sample being tested is not added
◉ buffer. Answer: A solution that minimizes changes in pH when
extraneous acids or bases are added to the solution.
◉ bulking. 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). Answer: only
the BOD required to remove carbon. based
◉ cavitation. Answer: formation and collapse of gas bubbles due to
low pressure. can cause pitting. makes noise.
◉ centrifuge. Answer: device to separate substances by spinning
them at high speed
,◉ chlorination. Answer: disinfection of water by the addition of
small amounts of chlorine or a chlorine compound
◉ comminutor. 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. Answer: mixture of several samples over 24
hrs
◉ denitrification. Answer: process by which bacteria convert
nitrates into nitrogen gas, anoxic process
◉ detritus. Answer: heavy coarse grit in wastewater
◉ Diffused-Air Aeration. 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. 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. 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. Answer: The distance from the waterline to the main
deck
◉ headworks. 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). Answer: rotten egg smell, produced
under anaerobic conditions,
◉ masking agents. Answer: chemicals used to cover unpleasant
smells
◉ mixed liquor. 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). Answer: The amount
(mg/L) of suspended solids in the mixed liquor of an aeration tank.
, ◉ ponding. Answer: condition occurring on trickling filters, voids
become plugged enough that water passage through filter is
inadequate. from excessive growth, trash, or media breakdown.
◉ primary treatment. Answer: when physically treated sewage
water is passed into a settling tank, where suspended solids settle
out as sludge; chemically treated polymers may be added to help the
suspended solids separate and settle out.
◉ recirculation. Answer: returning part of effluent from a treatment
process to the incoming flow.
◉ rising sludge. Answer: Rising sludge occurs in the secondary
clarifiers of activated sludge plants when the sludge settles to the
bottom of the clarifier, is compacted, and then starts to rise to the
surface, usually as a result of denitrification.
◉ supernatant. Answer: Clear liquid remaining after sediment
settles
◉ Total Suspended Solids (TSS). Answer: A test that measures the
total amount of solids suspended in a sample
OPERATOR COMPREHENSIVE
TEST PAPER QUESTIONS
SOLUTIONS GRADED A+
◉ blank. Answer: sample being tested is not added
◉ buffer. Answer: A solution that minimizes changes in pH when
extraneous acids or bases are added to the solution.
◉ bulking. 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). Answer: only
the BOD required to remove carbon. based
◉ cavitation. Answer: formation and collapse of gas bubbles due to
low pressure. can cause pitting. makes noise.
◉ centrifuge. Answer: device to separate substances by spinning
them at high speed
,◉ chlorination. Answer: disinfection of water by the addition of
small amounts of chlorine or a chlorine compound
◉ comminutor. 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. Answer: mixture of several samples over 24
hrs
◉ denitrification. Answer: process by which bacteria convert
nitrates into nitrogen gas, anoxic process
◉ detritus. Answer: heavy coarse grit in wastewater
◉ Diffused-Air Aeration. 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. 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. 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. Answer: The distance from the waterline to the main
deck
◉ headworks. 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). Answer: rotten egg smell, produced
under anaerobic conditions,
◉ masking agents. Answer: chemicals used to cover unpleasant
smells
◉ mixed liquor. 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). Answer: The amount
(mg/L) of suspended solids in the mixed liquor of an aeration tank.
, ◉ ponding. Answer: condition occurring on trickling filters, voids
become plugged enough that water passage through filter is
inadequate. from excessive growth, trash, or media breakdown.
◉ primary treatment. Answer: when physically treated sewage
water is passed into a settling tank, where suspended solids settle
out as sludge; chemically treated polymers may be added to help the
suspended solids separate and settle out.
◉ recirculation. Answer: returning part of effluent from a treatment
process to the incoming flow.
◉ rising sludge. Answer: Rising sludge occurs in the secondary
clarifiers of activated sludge plants when the sludge settles to the
bottom of the clarifier, is compacted, and then starts to rise to the
surface, usually as a result of denitrification.
◉ supernatant. Answer: Clear liquid remaining after sediment
settles
◉ Total Suspended Solids (TSS). Answer: A test that measures the
total amount of solids suspended in a sample
