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2025 - 2026 WATER TREATMENT OIT TEST|ACTUAL EXAM
QUESTIONS AND ANSWERS|A+GRADE
b) Kilopascals What units are used to measure water pressure? a) Kilowatts b) Kilopascals c) Horsepower d) Head units a) Exhaust fan Which of the following is NOT an example of PPE (Personal Protective Equipment)? a) Exhaust fan b) SCBA c) Face shield d) Traffic vest d) Be the operator with overall operational responsibility of the system Which of the following are operators-in-training NOT allowed to do? a) There are no restrictions on the duties of an operator-in-training b) Any operational duties if not in the presence of another operator c) Anything which could effect the quality of the water/wastewater d) Be the operator with overall operational responsibility of the system
c) The height or energy of water above a specified point Define the term "head" as used in hydraulic systems. a) The block of an internal combustions engine b) The ability of a piston pump to overcome the force of gravity c) The height or energy of water above a specified point d) The distance between the liquid level and the cover of a well b) Is a greenish/yellow gas with a penetrating odour; is heavier than air Which of the following statements accurately describes some of the properties of chlorine? a) I a colourless gas which is toxic to plants and animals; is flammable and explosive b) Is a greenish/yellow gas with a penetrating odour; is heavier than air c) Is a yellowish gas with an irritating odour; insoluble in water d) Is lighter than air; soluble in water and forms a salt which is lethal to microorganisms a) chemical compound is formed What happens when two or more different elements combine? a) chemical compound is formed b) atom is created c) molecule is formed d) concentration is created
d) 450 The volume of chlorine increases ______ times when it is depressurized into gas a) 100 b) 200 c) 350 d) 450 c) dissolved mineral salts What causes hardness in water? a) high pH b) low turbidity c) dissolved mineral salts d) alkalinity d) sewage works operators O. Reg. 129/04 addresses the licensing of: a) drinking water operators b) water quality analysts c) medical officers of health d) sewage works operators b) check
Which of the following is NOT an isolation valve? a) ball b) check c) butterfly d) globe d) Do not enter the confined space until there is no hydrogen sulphide detected, and then only when all safety equipment is in place An operator smells hydrogen sulphide at the entrance of a deep confined space. that actions should the operator take? a) hydrogen sulphide is only detected in low concentrations and will only cause headaches at this concentration. Proceed if the task is short b) Vent the confined space while working c) Hydrogen sulphide gas in all concentrations is only an irritant, so proceed with the task d) Do not enter the confined space until there is no hydrogen sulphide detected, and then only when all safety equipment is in place b) Protect human health What is the main purpose of the Safe Drinking Water Act? a) Certify operators b) Protect human health c) Supervise drinking water systems d) Sample and test drinking water
d) suspend floc c) organic materials Trihalomethanes are produced when chlorine reacts with: a) inorganic materials b) chlorine dioxide c) organic materials d) ultra violet light d) amount of chlorine that remains in water after disinfection What is the chlorine residual in water? a) the amount of chlorine applied to the water daily b) low concentrations of chlorine gas c) chlorine salt which is left after water evaporates d) amount of chlorine that remains in water after disinfection b) 0.3 mg/L
The chlorine dosage of a town's water source is 4.0 mg/L. The chlorine demand for the water is 3.7 mg/L. What is the chlorine residual? a) 0 mg/L b) 0.3 mg/L c) 3.7 mg/L d) 4.3 mg/L a) screens, coagulation, flocculation, filters, chlorination Which of the following is the correct order of processes within a cognitional surface water treatment plant? a) screens, coagulation, flocculation, filters, chlorination b) screens, flocculation, coagulation, chlorination, filters c) chlorination, screens, filtration, coagulation, flocculation d) screens, filters, flocculation, coagulation, chlorination b) it is the amount of time allowed for chlorine to react in water to provide disinfection What does the term 'contact time' mean? a) it is the amount of time a person is exposed to chlorine
c) peak demand (L/hour) Which of the following best describes the largest volume of water a distribution system would normally supply during a day? a) minimum demand (L/hour) b) average demand (L/hour) c) peak demand (L/hour) d) average demand per person (L/hour/person) d) remove deposits from the pipeline Distribution lines are flushed periodically to: a) increase water pressure in the system b) reduce the risk of water hammer c) ensure that chlorine does not accumulate in pipes d) remove deposits from the pipeline d) to store a large volume of water for long periods of time What is NOT one of the main purposes of distribution storage?
a) to help satisfy peak demand b) to allow for a uniform water treatment and pumping rate c) to provide water for firefighting needs d) to store a large volume of water for long periods of time c) curb stop What is the name of the valve which connects the customer's service line to the municipal water line? a) bypass valve b) control flume c) curb stop d) check valve b) aeration tank In an activated sludge process, some of the sludge collected in the secondary sedimentation tank is returned to the _______ to maintain the mass of the mixed liquor. a) grit channel b) aeration tank c) primary sedimentation tank
Which of the following devices is used to measure the flow of wastewater in an open channel? a) comminutor b) compactor c) parshall flume d) sluice gate c) grit channel, primary sedimentation, aeration tank, secondary sedimentation Which of the following is a correct order of processes within a conventional activated sludge treatment facility? a) grit channel, aeration tank, primary sedimentation, secondary sedimentation b) primary sedimentation, grit channel, aeration tank, secondary sedimentation c) grit channel, primary sedimentation, aeration tank, secondary sedimentation d) grit channel, primary sedimentation, secondary sedimentation, aeration tank d) 80-99% Secondary treatment typically removes ______ of the BOD and suspended solids. a) 20-39%
b) 40-59% c) 60-79% d) 80-99% c) large objects Water entering a wastewater treatment plant will pass through a bar screen. The bar screen is designed to remove which of the following items? a) dissolved solids b) grit and sand c) large objects d) nutrients c) the liquid located above a sediment or precipitate Define the term 'supernatant' a) a solution which is supersaturated b) a substance used to reduce odour in polluted waters c) the liquid located above a sediment or precipitate d) an operator who is extremely proficient in fulfilling their duties
a) hepatitis b) giardiasis c) cryptosporidiosis d) all of the above b) stormwater and sewage are collected in the same sewers What is meant by the term "combined sewers"? a) industrial sewage and domestic sewage are collected in the same sewers b) stormwater and sewage are collected in the same sewers c) the main sewer line which takes all of a city's sewage to the treatment plant d) a sewer which contains both gravity sewers and force mains d) leads to corrosion of certain types of sewers Why is hydrogen sulphide gas a problem in sewers? a) results in an increase in rodent populations b) the gas can block the flow of sewage c) since it is odourless, workers will not know when they are exposed d) leads to corrosion of certain types of sewers
d) it will prevent the build up of solids in the sewer Why is a minimum wastewater velocity of 0.6 m (2.0 feet) per second necessary in a gravity sewer? a) it will ensure that sewage has enough velocity to go up minor increases in sewer elevation b) it will prevent the growth of roots in sewers c) it will prevent the erosion of the bottom of the sewer d) it will prevent the build up of solids in the sewer a) infiltration from a high water table Which of the following is a source of excessively clear water in a collection system? a) infiltration from a high water table b) exfiltration from a high water table c) excessive recirculation d) inverted siphon a) you Who is primary responsible for your safety?
