Class III 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

A sewer replacement crosses an area with a high groundwater table and uncertain soils. How should that condition affect the Class III estimate?

Add a groundwater contingency to equipment cost and retain the base schedule until field pumping is established

Adjust the estimate for dewatering, excavation protection, access limitations, productivity effects, and supported contingency needs

Increase the trench-support allowance for uncertain soils while retaining normal equipment cycles and spoil handling

Add dewatering equipment to the dry-ground estimate while retaining normal excavation support and productivity assumptions

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Question 2 of 50

For atmospheric testing before a permit-required confined-space entry, which testing order follows OSHA requirements?

Toxic gases first, then combustible gases, then oxygen

The order does not matter as long as all readings are taken before entry

Oxygen first, then combustible gases and vapors, then toxic gases and vapors

Combustible gases first, then oxygen, then toxic gases

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Question 3 of 50

A Class III operator is designing a long-term stream survey to evaluate the effect of a wastewater treatment plant discharge. Which design is strongest?

Use fixed upstream and downstream stations but vary sampling locations within each reach to maximize spatial coverage

Use fixed representative upstream and downstream stations with repeated sampling under consistent documented quality-control procedures

Use the permitted outfall as the reference station and compare annual outfall results with a fixed downstream station

Use several downstream stations during unusual plant events and compare them with routine effluent monitoring data

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Question 4 of 50

A collection manager has more corrective work than the available crews can complete this week. Which prioritization method best reflects sound utility management?

Prioritize by repair cost and use asset criticality to rank jobs within each weekly cost band

Prioritize by asset age and complaint frequency and then adjust the list for regulatory significance

Prioritize by work-order age and use service consequence mainly to break ties among similarly aged requests

Prioritize work using failure consequence and likelihood, service impact, regulatory risk, and available resources

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Question 5 of 50

A force-main valve becomes partially restricted, increasing friction loss while the pump speed remains unchanged. What change is expected at the pump operating point?

Required system head decreases and the operating point generally shifts to a higher flow

The pump curve shifts upward because the restriction increases the head produced at each pump flow

Static head increases by the same amount as the added friction loss, leaving the operating flow essentially unchanged

Required system head increases and the operating point generally shifts to a lower flow

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Question 6 of 50

A utility suspects that roof drains and other improper connections are contributing stormwater inflow to a sanitary sewer basin. Which inspection plan is most directly targeted to that problem?

Compare dry-weather treatment-plant flow with final effluent quality and use the basin with the largest difference as the inflow source

Use CCTV to locate pipe defects first and infer direct stormwater connections from the structural condition of the inspected reaches

Compare lift-station motor current during storms with dry-weather current and use the largest changes to locate individual inflow connections

Use smoke testing or targeted dye testing to identify likely direct inflow connections, then verify the suspected sources

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Question 7 of 50

A Class III operator is designing a safety-training program for collection, pumping, and treatment personnel. Which approach is strongest?

Use a common core program for all crews and have each supervisor cover job-specific hazards during routine pre-job briefings

Provide detailed initial training and schedule refresher training primarily after incidents or major procedure changes

Build training around actual job hazards and written procedures, then verify that employees can apply the required controls

Emphasize required PPE, records, and supervisor responsibilities, with hands-on procedure practice assigned during field qualification

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Question 8 of 50

Which basis is strongest for setting preventive-maintenance intervals for collection-system pumps and motors?

Use local failure history as the primary interval basis once several years of operating records are available

Use manufacturer calendar intervals adjusted mainly for equipment age and the maintenance crew's available workload

Use manufacturer guidance as a baseline, then adjust intervals using actual equipment condition and service risk

Use operating-hour intervals adjusted for asset criticality and apply them consistently to equipment of the same model

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Question 9 of 50

What is the principal collection-system purpose of an inverted siphon?

To add pressure head so a gravity sewer can carry wastewater to a higher downstream elevation

To provide a low point where grit and heavy solids can be collected before flow enters a downstream interceptor

To convey wastewater through a depressed section beneath an obstacle where a normal gravity profile cannot be maintained

To provide temporary in-system storage that attenuates peak flow before it reaches a downstream pump station

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Question 10 of 50

During major rain events, the collection system sends a sharp hydraulic surge to the wastewater treatment plant. Which collection-side strategy most directly helps control the quantity of wastewater reaching the plant?

Temporarily lower lift-station pumping rates so the collection system itself stores a larger portion of the storm response

Increase lift-station pumping early in each storm so upstream storage is emptied before peak inflow reaches the stations

Reduce significant infiltration and inflow and use available equalization or storage controls to moderate the hydraulic peak

Route the highest storm flows to the treatment plant first, then use equalization after the peak has passed

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Question 11 of 50

A basin normally carries about 1.4 MGD during dry weather but rises to about 2.8 MGD during rainfall without a comparable increase in customers. What is the most useful Class III interpretation?

The rain-correlated increase indicates that infiltration and inflow may be materially affecting the basin and should be quantified further

The change is most consistent with ordinary diurnal variation, so rainfall should be excluded from the basin flow analysis

The higher wet-weather flow proves the interceptor is undersized even before surcharge levels, capacity, or rainfall response are evaluated

The increase should be attributed to industrial loading unless laboratory strength data show that wastewater quality stayed unchanged during the storm

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Question 12 of 50

Repeated root intrusion is documented at joints in an older sewer. Which operational plan best addresses both the immediate and recurring problem?

Remove the roots with an appropriate control or mechanical method and plan repair or rehabilitation of the defective joints

Apply chemical root control on a fixed interval and defer joint repair while the treatment continues to suppress regrowth

Increase hydraulic flushing frequency and monitor whether the higher cleaning rate delays root-related stoppages at the same joints

Clean the affected reach mechanically and place it on a shorter inspection cycle before deciding whether the joints require rehabilitation

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Question 13 of 50

What distinguishes a force main from a gravity sewer in normal operation?

A force main is a closed conduit that conveys wastewater under pressure supplied by pumping equipment

A force main is a closed conduit that normally remains full but is driven primarily by gravity

A force main is a pressurized conduit in which downstream elevation supplies the primary driving head

A force main is a gravity sewer with a steeper slope selected to maintain high transport velocity

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Question 14 of 50

Which use best reflects the role of SCADA in a wastewater collection system?

Use SCADA mainly as a compliance archive while alarms and operating commands remain outside the system

Use SCADA to convert CCTV defect codes into rehabilitation work orders as the primary inspection function

Use SCADA to monitor remote collection assets and support authorized alarm response and control from a central location

Use SCADA operating data to establish final design sizes for future lift stations and force mains

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Question 15 of 50

A sudden industrial discharge is suspected of sending a high-strength or toxic load toward the treatment plant. What is the best collection-system response?

Hold the suspect wastewater in upstream conveyance where capacity permits and delay plant notification until laboratory identification is complete

Continue normal conveyance while sampling the suspected source, then notify treatment staff if a measurable process response develops

Increase collection-system dilution flow and begin source tracing after treatment-plant influent confirms the suspected load

Coordinate source-control or pretreatment action and alert treatment-plant staff early enough to prepare for the incoming load

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Question 16 of 50

A new wastewater line must be installed within nine feet of a potable-water line because site constraints make greater separation impracticable. What should the Class III design review do next?

Determine the parallel or crossing configuration and relative elevations, then apply the Section 217.53(d) protection required for that case

Place the wastewater line below the potable-water line and use the standard gravity-sewer pipe specification for the remaining separation

Provide an encasement detail at the closest point between the lines and use normal separation requirements elsewhere in the affected reach

Use pressure-rated wastewater pipe for the affected reach whenever the horizontal separation is less than nine feet

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Question 17 of 50

A 6-inch-diameter force main is 2,000 ft long and carries 150 gpm. Using 7.48 gal/ft³, approximately what is the detention time in the force main?

19.6 minutes

13.1 minutes

2.9 minutes

26.2 minutes

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Question 18 of 50

An 18-inch inside-diameter gravity sewer is flowing full at 2.5 ft³/s. Using area = πD²/4 and velocity = flow/area, what is the approximate velocity, and how does it compare with the Texas 2.0 ft/s full-flow design criterion?

0.7 ft/s, which is below the criterion

2.0 ft/s, which exactly meets the criterion

1.4 ft/s, which is below the criterion

3.3 ft/s, which is above the criterion

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Question 19 of 50

CCTV identifies 1,200 ft of structurally deteriorated sewer beneath a heavily traveled street. The utility is comparing open-cut replacement with trenchless rehabilitation. Which Class III estimate is most useful for selecting the approach?

Prefer trenchless work for the traffic condition and retain open-cut replacement as the contingency approach

Compare unit prices per foot and use one common allowance for bypass, traffic control, access, and restoration

Compare mobilization and pipe-work costs first, then estimate bypass and restoration after choosing a preferred method

Compare complete method-specific resource and cost estimates for open-cut and trenchless approaches before selecting the method

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Question 20 of 50

A public works director sets a goal to reduce repeat sewer blockages by 25%. What is the best Class III management action?

Increase total cleaning footage and use monthly feet cleaned as the main performance measure for the goal

Replace the oldest sewers first and use declining average asset age as the main measure of progress

Convert the goal into assignable work and measurable performance, then review repeat-blockage results and adjust the program

Increase monthly work-order closures and use closure rate as the primary indicator of repeat-blockage reduction

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Question 21 of 50

A trench used for sewer repair was inspected at the start of the day, but a heavy rainstorm occurs before the crew reenters. What should happen next?

Have a competent person reinspect soil conditions, water accumulation, access, and the protective system before reentry

Pump accumulated water, check the access ladder, and resume work under the original excavation inspection

Keep the original inspection valid if the protective system has not moved and no soil has visibly fallen

Document the rainfall and perform the next competent-person inspection at the utility's normal shift-change interval

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Question 22 of 50

A Texas utility assigns a foreman to directly supervise a domestic wastewater collection maintenance crew. Which staffing decision best matches TCEQ licensing requirements?

The foreman must hold a wastewater collection license because a wastewater treatment operator license does not qualify for collection supervision

The foreman must hold an appropriate wastewater collection or treatment operator license to directly supervise the maintenance crew

An unlicensed foreman may direct the crew when a licensed utility manager remains available to provide technical advice during the shift

An unlicensed foreman may direct the crew if a Class III operator performs a documented review of the work each week

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Question 23 of 50

A gravity sewer would exceed 10 ft/s when flowing full. What does current Texas Chapter 217 require the design to address?

Select a higher pressure-class pipe to resist the larger internal hydraulic forces created by the design flow

Add downstream flow control to hold normal sewer velocity below 10 ft/s at the design peak

Provide design protection against displacement of the pipe and bedding under the expected high-velocity condition

Flatten the pipe slope enough to reduce velocity while maintaining the same downstream invert and design capacity

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Question 24 of 50

On a graph containing a centrifugal pump curve and the system-head curve, what does their intersection represent?

The shutoff condition where the pump develops its maximum head at zero discharge

The pump's best-efficiency point, which is set by the pump curve and motor selection

The point of maximum system flow, where static head and friction loss are at their minimum combined value

The expected operating point where pump head equals the head required by the system

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Question 25 of 50

A pump's vibration readings have risen steadily over several inspections even though it still meets current flow demand. How should a preventive-maintenance program use this information?

Increase inspection frequency and defer mechanical investigation while flow, temperature, and motor current remain within normal limits

Reduce pump run time by rotating duty more often and use the next scheduled overhaul to investigate the vibration source

Use the rising trend as condition information that can trigger investigation or planned maintenance before functional failure

Continue normal operation until vibration reaches the alarm limit, then schedule inspection at the next planned outage

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Question 26 of 50

A sewer project requires a 1.5-ft-wide by 0.75-ft-deep bedding zone along 1,200 ft of pipe. If 10% extra material is included for handling and field variation, approximately how many cubic yards of bedding should be budgeted?

45 cubic yards

50 cubic yards

55 cubic yards

75 cubic yards

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Question 27 of 50

A Class III operator is preparing a material estimate for replacement of a sewer reach. Which method gives the most defensible quantity?

Apply one contingency percentage to every material category after the drawing-based quantity takeoff is completed

Scale the previous project's material quantities by footage and carry forward its overall contingency percentage

Develop quantities from the measured project scope and add allowances tied to identifiable construction uncertainty

Use drawing quantities as procurement quantities and address fittings or field changes through construction change orders

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Question 28 of 50

Why might a utility use a deep interceptor tunnel as part of a large collection system?

To replace individual building laterals with pressurized service connections that discharge directly into a central deep collection conduit

To serve mainly as protected underground storage for inspection vehicles, bypass pumps, pipe fittings, and other large maintenance equipment

To provide primary sedimentation and biological treatment inside the tunnel before wastewater is discharged to a downstream treatment facility

To intercept and convey substantial flows across a service area where a deep, high-capacity route is operationally advantageous

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Question 29 of 50

A utility plans CCTV inspection of 50,000 feet of sewer. What is the best basis for estimating inspection labor and schedule?

Use a footage-based production rate plus one daily allowance for setup, cleaning, traffic control, and review

Use demonstrated inspection productivity adjusted to actual access, setup, cleaning, traffic-control, and data-review needs

Use one crew-day per mile and add contingency days after the first week of actual field production

Divide the footage among available inspection employees and assign each crew the same daily production target

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Question 30 of 50

A critical trunk sewer is nearly blocked and upstream levels are rising rapidly. What should the operating plan prioritize first?

Improve downstream conveyance first, then return to the trunk restriction if upstream levels continue rising

Reduce controllable upstream pumping and diagnose the obstruction before committing crews and equipment to bypass

Start mechanical removal and stage bypass equipment for deployment if upstream levels approach the overflow threshold

Prioritize safe flow control and restoration of conveyance while protecting people and the environment and monitoring upstream levels

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Question 31 of 50

When preparing a temporary traffic-control plan for a sewer repair in a roadway, what should the planner do before selecting the final signs and channelizing-device layout?

Place the excavation and work vehicles for efficient access, then adapt the nearest standard traffic-control layout

Start with the roadway-class standard application and adjust device locations after confirming shoulder and lane width

Choose the warning sequence from speed and lane count, then resolve pedestrian and bicycle routing during setup

Base the final layout on a site-specific assessment of road users, work activity, duration, and roadway conditions

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Question 32 of 50

A gravity sewer design produces a full-flow velocity of 1.6 ft/s. Based on current Texas Chapter 217 criteria, what should be concluded?

The slope or other design conditions should be revised so full-flow velocity is at least 2.0 ft/s

Convert the reach to pressure sewer service because Chapter 217 does not allow gravity flow below 2.0 ft/s

The design is acceptable if the engineer documents that the lower velocity is adequate for expected solids and routine cleaning

The design is acceptable if the pipe diameter is at least 8 inches

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Question 33 of 50

Several sewer reaches have repeated grease blockages while most of the system has few problems. How should a Class III operator plan routine cleaning?

Use one systemwide cleaning interval and reserve additional cleaning for reaches after they experience another stoppage

Shift repeated-problem reaches to condition-triggered cleaning and use fixed preventive intervals on the remainder of the system

Use blockage and inspection history to increase preventive cleaning frequency on the reaches with recurring grease problems

Increase cleaning frequency on every reach in the affected basin and evaluate source control or rehabilitation after the next annual cycle

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Question 34 of 50

Which element should be built into a pump-maintenance safety procedure before employees begin work on equipment that can start automatically?

Run the pump slowly with guards removed so technicians can inspect rotating parts before shutdown

Silence the alarm circuit but leave the controls energized so technicians can observe the equipment

Post two trained employees at the local start switch and rely on them to prevent accidental operation

Isolation and control of hazardous energy, followed by verification that the equipment cannot start unexpectedly

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Question 35 of 50

A basin averages 1.8 MGD in dry weather and 3.3 MGD during a six-hour wet-weather period. Assuming the 1.5 MGD difference represents rain-related excess flow, approximately how much excess volume entered the system during those six hours?

1,500,000 gallons

825,000 gallons

375,000 gallons

225,000 gallons

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Question 36 of 50

When using a pump curve to estimate discharge from a lift-station pump, which hydraulic value should be determined for the system first?

Total dynamic head, including static head and the applicable friction and minor losses

Motor horsepower at the operating speed, using the rated power to establish the system head for the curve

Force-main friction loss at design flow, using pump shutoff head to account for the elevation difference

Static head between the suction and discharge elevations, using the pump curve to account for friction losses

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Question 37 of 50

What is the main operational value of flow-equalization controls in a wastewater collection system?

To replace multiple lift-station controls with one central level switch

To smooth short-term flow peaks so downstream facilities receive a more manageable hydraulic load

To increase effective sewer capacity by keeping upstream water levels above the pipe crown

To remove dissolved pollutants before wastewater reaches biological treatment at the plant

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Question 38 of 50

Which information is most useful when estimating personnel needed for a planned sewer rehabilitation project?

Apply a published productivity benchmark to total footage and treat traffic-control and bypass staffing as support overhead

Scale the crew from the utility's most recent rehabilitation project in direct proportion to project footage

Set crew size from the target completion date and assign specialized duties from personnel available that week

Estimate staffing from method-specific productivity, work sequence, shift duration, site constraints, and required specialties

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Question 39 of 50

Which monitoring approach gives the strongest basis for estimating wet-weather wastewater volume in a collection basin?

Compare repeated basin flow records with a representative dry-weather baseline and rainfall from multiple storm events

Convert lift-station run time to flow using rated pump capacity and compare the result with monthly average plant flow

Apply a population-based peak factor to dry-weather flow and treat the result as measured wet-weather response

Use the largest measured storm peak and its duration as the basin's representative wet-weather volume

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Question 40 of 50

Why should a Class III preventive-maintenance program maintain detailed work-order and failure records?

Use the records to standardize intervals across similar assets and minimize differences caused by local operating history

Use the records to replace manufacturer recommendations after enough local failures have been documented

Use the records to document scheduled work so condition inspections can be reduced on frequently serviced assets

Use the records to detect recurring failures and refine maintenance schedules, resource plans, and accountability

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Question 41 of 50

Which flow basis is most appropriate when sizing a new gravity collection system under Texas Chapter 217?

Average service-area flow plus a standard peaking factor and future growth, using a separate operational plan for infiltration and inflow

Current peak monitored flow plus estimated infiltration and inflow, using the present service area as the design horizon

Average dry-weather flow plus projected future population, with peak hydraulic conditions checked after the pipe diameter is selected

Peak service-area flow plus expected infiltration and inflow, with the required allowance for future service-area flow

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Question 42 of 50

A sewer reach contains heavy grease and loose sediment but no major structural defect. Which resource plan is most appropriate for routine cleaning?

Use mechanical cutting equipment sized for the pipe so grease, sediment, and any developing root intrusion are removed in one pass

Use hydraulic cleaning suited to grease and loose sediment, with appropriate debris recovery and downstream control

Apply a chemical grease-control program first and schedule physical cleaning after the deposit has been softened

Perform CCTV first to map deposits and use the inspection footage as the basis for deciding whether hydraulic cleaning is necessary

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Question 43 of 50

A collection basin develops recurring odor and septicity complaints. Before budgeting a chemical-control program, what should the Class III operator do?

Diagnose where and why septicity develops before selecting a chemical or operational control program

Select a chemical from estimated sulfide loading and adjust a basinwide dose in response to complaints

Add ventilation at complaint locations and use follow-up sulfide readings to decide whether other controls are needed

Increase cleaning frequency across the basin and evaluate chemical control if complaints remain after cleaning

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Question 44 of 50

A utility must inspect a newly constructed 20,000-ft sewer before acceptance. Which plan best supports a Class III estimate of inspection resources?

Inspect representative reaches in each construction segment and use quality records to estimate the remaining inspection effort

Base inspection labor on the installation schedule and add equipment time for the specified acceptance tests

Use a standard crew-day per mile that incorporates acceptance testing, setup, access, and routine retesting

Translate the specified acceptance scope into crew and equipment time using footage, access, setup, and likely retesting

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Question 45 of 50

A utility operates a Category III wastewater collection system and a Category C wastewater treatment facility. Which staffing conclusion is correct?

Apply the Category C treatment staffing level to both systems because treatment operators may also perform collection-system duties

Use the staffing level of the larger-flow system for both facilities and treat the other classification as a secondary designation

Apply the Category III collection staffing level to both systems because it is the utility's highest collection-system classification

Staff each system to its own classification: Category III collection requirements and Category C treatment-facility chief-operator requirements

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Question 46 of 50

How is the combined performance of two similar centrifugal pumps in series represented?

Add the discharges from both pumps at the same developed head

Add the heads developed by the pumps at the same flow

Divide the total required head equally between the pumps at every possible flow

Use the downstream pump curve and add the upstream pump's shutoff head

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Question 47 of 50

On a 45-mph roadway, current MUTCD guidance is being used to set maximum spacing for channelizing devices. Which pair matches the general guidance for taper and tangent channelization?

45 ft in both the taper and the tangent

90 ft in the taper and 45 ft in the tangent

45 ft in the taper and 90 ft in the tangent

90 ft in both the taper and the tangent

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Question 48 of 50

A trunk-sewer rehabilitation will require temporary bypass pumping. Which basis is most appropriate for planning the bypass equipment?

Size bypass resources for expected peak flow and required head, with suitable routing, redundancy, and failure response

Size bypass pumps for annual average flow and rely on operator response if short-duration peaks exceed capacity

Base bypass capacity on wet-well volume from a similar lift station and adjust during the rehabilitation work

Use the largest utility-owned portable pump and limit upstream pumping whenever bypass capacity becomes constrained

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Question 49 of 50

How is the combined performance curve for two similar centrifugal pumps operating in parallel constructed conceptually?

Add the pump heads at the same discharge

Multiply one pump's head by its efficiency

Subtract system static head from each pump's shutoff head

Add the pump discharges at the same head

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Question 50 of 50

A sewer repair begins with the approved traffic-control setup, but field conditions create a new pedestrian conflict and shorten the available taper. What is the best response?

Continue the work and document the pedestrian conflict for correction on the next similar job

Keep the original setup because changing an approved plan during active work could create additional conflicts for drivers and pedestrians

Reevaluate and adjust the temporary traffic-control setup so the changed conditions are addressed safely and consistently with applicable standards

Remove pedestrian devices and use the extra roadway width to preserve the original vehicle taper

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