Class I Wastewater Collection System Operator Exam

Free Sample Exam

Questions: 50

Passing standard: 70.0%

Select an answer to get immediate feedback and an explanation. When you finish, submit the exam to see your diagnostic score and the categories that may need additional study.

Question 1 of 50

During a manhole inspection, groundwater is visibly entering through a crack in the wall. What condition is being observed?

Normal air exchange through a properly ventilated collection-system structure

Stormwater inflow entering directly through a surface opening during rainfall

Groundwater infiltration entering the collection system through a defect

Wastewater exfiltration leaking outward from the sewer into surrounding soil

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Question 2 of 50

Which outcome is a primary objective of domestic wastewater treatment before discharge or reuse?

Settle only the heaviest solids and discharge the remaining wastewater unchanged

Dilute untreated wastewater with clean water until pollutant concentrations are lower

Remove large debris while leaving dissolved and biological contaminants untreated

Reduce pollutants and pathogens to protect public health and the environment

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Question 3 of 50

Before joining gasketed sewer pipe, what is a sound construction practice?

Reuse a gasket with a cut if it still fits securely in the gasket groove

Clean the joint surfaces and gasket and inspect them for damage before assembly

Use petroleum grease instead of the manufacturer-approved joint lubricant whenever assembly is difficult

Force a misaligned joint together until the insertion reference mark is reached

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Question 4 of 50

In a typical centrifugal wastewater pump, what does the rotating impeller do?

Transfer mechanical energy to the wastewater so the pump can move the liquid

Isolate the pump from the discharge line so maintenance can be performed

Prevent reverse flow through the discharge pipe after the pump stops

Sense the wastewater level and signal when the pump should start or stop

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Question 5 of 50

What is a primary function of a sanitary sewer manhole?

Raise wastewater to a higher elevation when gravity flow is not practical

Connect an individual building sewer directly to the public collection main

Provide access to the sewer for inspection, cleaning, and maintenance

Store wastewater for long periods before it enters the collection main

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Question 6 of 50

What is the main purpose of 30 TAC Chapter 217 for a Class I collection operator to recognize?

It sets minimum design and construction standards for domestic wastewater systems

It establishes drinking-water treatment requirements for public water systems

It contains wastewater operator licensing requirements for the license classes

It sets temporary traffic-control standards for utility work zones

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Question 7 of 50

How does a conventional gravity sewer normally move wastewater?

Inject compressed air at each manhole to push wastewater downstream

Maintain a vacuum throughout the service connections and collection main

Operate pumps at individual property connections to move wastewater to the main

Use pipe slope so wastewater moves downhill under the force of gravity

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Question 8 of 50

Which is a typical source of domestic wastewater entering a sanitary collection system?

Surface water flowing through a creek that crosses the service area

Stormwater runoff entering a roadside drainage inlet during rainfall

Sanitary flow from toilets, sinks, showers, and similar building fixtures

Groundwater seeping through soil toward a naturally saturated aquifer

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Question 9 of 50

Why can exposure to untreated domestic wastewater be a public-health concern?

Sewer travel makes most disease-causing organisms harmless before treatment

Health risk occurs only after wastewater is discharged to a receiving stream, not during collection work

It may contain disease-causing microorganisms that can expose workers or the public

The main concern is odor; untreated domestic wastewater normally has little biological hazard

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Question 10 of 50

Which Texas agency issues wastewater discharge permits and licenses wastewater operators?

Texas Commission on Environmental Quality (TCEQ)

Texas Department of State Health Services (DSHS)

Texas Water Development Board (TWDB)

Railroad Commission of Texas (RRC)

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Question 11 of 50

Which item is a physical characteristic of wastewater?

Temperature

Biochemical oxygen demand

Chlorine residual

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Question 12 of 50

What is the basic function of a lift-station wet well?

Maintain constant discharge pressure regardless of incoming wastewater flow

Store emergency fuel for the lift station's standby power equipment

Remove grit and screenings before wastewater enters the collection system

Collect incoming wastewater temporarily so pumps can cycle as the level changes

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Question 13 of 50

What is the basic purpose of an advance warning sign at a sewer work zone?

Warn road users about changed conditions before they reach the work area

Guide road users along a detour after they have entered the work zone

Mark the point where normal traffic conditions have already resumed

Regulate who has the right-of-way at the exact work-space boundary

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Question 14 of 50

A dye slug travels 600 feet through a sewer in 5 minutes. What is the average velocity?

300 feet per minute

120 feet per minute

3,000 feet per minute

60 feet per minute

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Question 15 of 50

Before an employee enters a sewer manhole that is treated as a permit-required confined space, what is a basic safety requirement?

Have a coworker watch from the surface instead of testing the atmosphere

Open the cover for several minutes and enter if no strong odor remains

Use a nearby engine fan as ventilation and enter without an entry evaluation

Test the atmosphere and follow the required confined-space entry procedure

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Question 16 of 50

A pump moves wastewater at 250 gallons per minute for 40 minutes. Approximately how many gallons are pumped?

10,000 gallons

16,000 gallons

6,250 gallons

8,000 gallons

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Question 17 of 50

Before servicing powered sewer-cleaning equipment, what is the purpose of lockout/tagout?

Keep road users separated from workers and equipment in a temporary work zone

Prevent access to moving machine parts by keeping fixed equipment guards in place

Protect the worker from contact hazards by using the required personal protective equipment

Prevent unexpected startup or hazardous-energy release while maintenance is performed

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Question 18 of 50

When loosening a hex-head bolt during equipment maintenance, why should the operator use the correct-size wrench?

Use locking pliers on the bolt head if the correct wrench is not immediately available

Use a smaller wrench at an angle so it grips the corners more tightly

Reduce slipping, fastener damage, and the chance of hand injury during the task

Use an oversized open-end wrench so the handle can be pulled from a steeper angle

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Question 19 of 50

What is the basic purpose of routine sewer cleaning?

Replace the need to inspect structural condition or repair damaged pipe

Remove accumulated material that can restrict flow or contribute to blockages

Increase solids concentration so wastewater travels faster through the sewer

Convert a gravity sewer segment into a pressurized wastewater force main

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Question 20 of 50

Which inspection method provides a visual recording of the inside condition of a sewer pipe?

Smoke testing from a controlled access point

Dye tracing from a suspected connection

Atmospheric testing at a manhole opening

Closed-circuit television (CCTV) inspection

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Question 21 of 50

One crew is performing scheduled cleaning while another reports an active sanitary sewer overflow. If the same vacuum truck is needed for both, what is the most appropriate priority?

Send the truck to whichever site is closer without considering the overflow's public-health impact

Split the vacuum truck's time between both jobs even if overflow containment is delayed

Use the vacuum truck for the active overflow response, then reschedule routine cleaning

Finish the scheduled cleaning first because planned work should not be interrupted by unplanned events

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Question 22 of 50

Why can a large discharge of untreated, biodegradable wastewater cause fish stress or kills in a receiving stream?

The organic load reduces water temperature enough to stress fish

Microbial decomposition can consume dissolved oxygen needed by aquatic life

The main effect is increased suspended solids, while dissolved oxygen remains unchanged

Bacteria release oxygen while decomposing organic matter, causing dissolved oxygen to rise

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Question 23 of 50

Which activity is an example of preventive maintenance?

Inspect and lubricate equipment on a planned schedule before a failure occurs

Clear a blockage only after a high-level alarm occurs

Replace a bearing after it fails and stops the equipment

Repair a damaged drive component after it breaks during operation

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Question 24 of 50

What is a common purpose of smoke testing a sanitary sewer system?

Locate openings, defects, or improper connections where introduced smoke escapes

Measure oxygen and toxic-gas concentrations before confined-space entry

Create a video record of cracks and roots inside the sewer pipe

Trace the flow path from one suspected drain to a downstream manhole

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Question 25 of 50

Why does Texas regulate wastewater discharges to waters of the state?

To assign ownership of municipal collection systems to a state agency

To protect waters of the state from uncontrolled wastewater discharges

To set one statewide sewer rate that local utilities must charge

To determine the construction grade of local gravity sewer projects

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Question 26 of 50

A sewer segment has repeated grease-related stoppages. Which basic operating response is most appropriate?

Clean only the downstream manhole because grease will eventually collect there

Increase reactive jetting pressure after each blockage but keep the same cleaning interval

Wait for a complete stoppage before cleaning so the problem location is easier to confirm

Use preventive cleaning and address the recurring grease source before another blockage

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Question 27 of 50

A circular sewer pipe has an inside diameter of 24 inches. What is its cross-sectional area? Use π = 3.14.

3.14 square feet

1.57 square feet

6.28 square feet

12.56 square feet

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Question 28 of 50

Why is a vacuum unit often used with high-pressure sewer jetting?

Recover loosened debris from the manhole rather than moving it farther downstream

Increase the water pressure available at the jet nozzle during the cleaning pass

Pull the jet hose through the sewer when the nozzle cannot move on its own

Cool the jetting pump by circulating wastewater through the vacuum tank

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Question 29 of 50

What is the main purpose of cones or other channelizing devices in a temporary work zone?

Give utility vehicles automatic priority over other road users

Provide all required advance warning without the need for any signs

Guide road users along a defined path around or through the work area

Mark the underground location of the sewer being repaired

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Question 30 of 50

A trench is 60 feet long, 3 feet wide, and 4 feet deep. Approximately how many cubic yards of soil are excavated? Use 27 cubic feet = 1 cubic yard.

80.0 cubic yards

26.7 cubic yards

53.3 cubic yards

13.3 cubic yards

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Question 31 of 50

What is the purpose of a service lateral in a typical sanitary sewer system?

Raise wastewater to a higher elevation when gravity flow cannot continue

Collect flow from many laterals and carry it through the collection network

Connect an individual building or property sewer to the public collection main

Provide surface access to the sewer for inspection and maintenance

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Question 32 of 50

A new gravity sewer project is being designed. At the Class I level, which statement about Texas design criteria is most accurate?

They establish minimum standards that the project design and construction must address

They become relevant after the sewer project has already been completed and placed in service

They are optional recommendations when a utility does not use an engineer

They make the collection operator responsible for all engineering calculations

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Question 33 of 50

A crew opens a sewer manhole and notices a rotten-egg odor. What is the safest conclusion?

Ventilation makes odor a reliable substitute for atmospheric monitoring

The atmosphere is safe if the rotten-egg odor fades after several minutes

A strong rotten-egg odor confirms that oxygen concentration is acceptable

Hydrogen sulfide may be present, and odor is not a reliable safety test

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Question 34 of 50

What is a pipe laser or survey level commonly used for during gravity-sewer construction?

Test the trench atmosphere for oxygen, combustible gas, and toxic gas

Check and maintain the sewer pipe's intended line and grade during installation

Compact backfill around the installed pipe to reduce future settlement

Locate buried utilities before excavation by detecting underground signals

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Question 35 of 50

Which practice best reduces biological exposure after handling wastewater-contaminated equipment?

Wash hands after removing gloves and before eating, drinking, or touching the face

Skip handwashing if the gloves did not tear during the task

Wash hands when wastewater contamination is visible on the skin

Clean the outside of the gloves, then handle food while still wearing them

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Question 36 of 50

Why is proper bedding placed beneath a newly installed gravity sewer pipe?

Eliminate the need for properly assembled joints and gaskets

Raise wastewater temperature to improve gravity flow through the new sewer

Create temporary storage around the pipe for peak wet-weather flow

Provide uniform pipe support and help maintain the intended line and grade

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Question 37 of 50

What is the purpose of level controls in a typical wastewater lift station?

Manually isolate a pump so it can be removed from service for repair

Prevent reverse flow through the discharge line after a pump stops

Monitor motor winding temperature and shut the motor down if it overheats

Start and stop pumps in response to rising and falling wastewater levels

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Question 38 of 50

Why is the correct lubricant used on collection-system equipment?

Mix different lubricants when equipment is noisy so one can compensate for the other

Apply as much lubricant as possible to prevent any chance of dry operation

Reduce friction, heat, and wear according to the equipment's lubrication requirements

Use the same grease on every bearing so maintenance inventory is simpler

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Question 39 of 50

A sidewalk must be temporarily rerouted around a sewer repair. What is the basic traffic-control goal?

Route pedestrians through the work space as long as cones separate them from workers

Provide a clear, continuous pedestrian route that avoids the work space and traffic hazards

Close the sidewalk at the work area without providing a usable alternate route

Direct pedestrians into the roadway without a protected path when the sidewalk is closed

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Question 40 of 50

Why should a collection utility record the location and cause of sewer stoppages?

Use the records as a substitute for follow-up inspection or condition assessment

Identify recurring trouble locations and plan preventive cleaning or repair

Use the records mainly to assign responsibility to the crew that handled each stoppage

Schedule cleaning only by calendar date without considering recurring problem locations

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Question 41 of 50

What is the main purpose of a check valve on a pump discharge line?

Manually isolate the pump from the discharge line for maintenance

Relieve excessive discharge pressure by opening to a lower-pressure path

Measure the wastewater flow rate through the discharge piping

Prevent reverse flow through the discharge line after the pump stops

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Question 42 of 50

Why is backfill commonly compacted around and above a repaired sewer trench?

Seal gasketed pipe joints against infiltration by increasing soil pressure around them

Limit future settlement and help support the pipe and restored ground surface

Correct a pipe that was installed off grade by forcing it into position with compacted soil

Replace the need for proper bedding and haunch support beneath and beside the pipe

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Question 43 of 50

What is the basic function of a sewer main in a gravity collection system?

Receive flow from connected laterals and convey it through the collection network

Provide surface access for inspection and cleaning at a sewer junction

Lift wastewater to a higher elevation when gravity flow is not practical

Connect one individual building sewer to the public collection main

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Question 44 of 50

What is the main purpose of a sewer cleanout?

Raise low-elevation wastewater and discharge it into a downstream sewer

Collect flow from many service laterals and convey it through the sewer network

Provide full-size access for personnel and equipment at major sewer junctions

Provide an access point for cleaning or clearing a sewer or service lateral

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Question 45 of 50

Which tool is specifically suited to cutting roots that have grown into a sewer line?

A high-pressure jet nozzle intended mainly to scour loose deposits

A vacuum hose used to recover debris from a downstream manhole

A CCTV crawler used to inspect the pipe after cleaning is complete

A mechanical root cutter designed to cut intrusive roots

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Question 46 of 50

According to OSHA trench-safety guidance, what is the primary hazard of trenching and excavation work?

A cave-in or collapse of the trench wall

An oxygen-deficient or toxic atmosphere in the excavation

Being struck by material or equipment near the excavation

Contact with an unmarked underground utility

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Question 47 of 50

A crew introduces a harmless dye into a suspected drain and later observes the dye in a sanitary manhole. What did the test help determine?

Locate surface openings by watching where introduced smoke escapes

Measure leakage from a new pipe by monitoring a controlled pressure test

Create a continuous video record of the inside wall of the sewer

Confirm the flow path or connection between the drain and the sanitary sewer

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Question 48 of 50

A crew discovers an unexpected unsafe condition at a sewer work site. What is the best management decision?

Continue the task at reduced speed while the supervisor is notified

Keep one employee in the hazard area to watch conditions while the rest of the crew continues

Document the condition for the next safety meeting before changing the work plan

Stop or secure the affected work and control the hazard before continuing

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Question 49 of 50

Which statement correctly describes a basic difference between a trickling filter and an activated sludge process?

A trickling filter uses suspended solids; activated sludge grows attached biomass on fixed media

A trickling filter uses attached growth on media; activated sludge uses suspended biological solids

Both processes rely on settling and do not depend on biological activity

Activated sludge passes wastewater over fixed media, while a trickling filter keeps biomass suspended

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Question 50 of 50

Which activity is an example of sewer rehabilitation rather than routine sewer cleaning?

Rodding a localized blockage from an accessible service lateral

Flushing loose deposits from the pipe with high-velocity water

Vacuuming debris that has collected in a downstream manhole

Installing a structural liner inside an existing deteriorated sewer

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