Class B Surface Water Operator Exam

Raw-water total organic carbon increases substantially. Why should the operator pay particular attention to where and how chlorine is applied?

Chlorine converts all organic carbon directly into harmless carbonate

Organic precursor material can react with disinfectants and contribute to disinfection-byproduct formation

Higher organic carbon always eliminates chlorine demand

Organic carbon prevents coagulation from occurring at any pH

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During cold weather, a filter backwash at the usual flow rate produces noticeably less bed expansion than in warm weather. What is the best explanation?

Colder water is more viscous, so a greater backwash rate may be needed to obtain the same media expansion, within design limits

Colder water has no effect on backwash hydraulics

The filter must be dosed with additional coagulant during backwash

Cold water always causes media to expand more at the same flow

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Finished water leaving a surface water plant has very low alkalinity and its pH changes easily during treatment and distribution. What operational concern is most directly suggested?

The water is guaranteed to form protective scale

The water necessarily contains excessive hardness

The water has poor buffering capacity and may be chemically unstable

The water cannot be disinfected with chlorine

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Raw-water conditions change and chlorine demand increases. The plant must maintain the same target disinfectant residual. What relationship should guide the operator's response?

Dose must account for both chlorine demand and the desired residual

Demand becomes zero whenever turbidity is low

Residual always equals demand minus dose

The only acceptable response is to double the chlorine dose

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A Class D operator at a surface water plant notices rapidly increasing settled-water turbidity and wants to change the coagulant dose. Under the TCEQ operating rule, when may the Class D operator make that process adjustment?

Only after receiving approval by telephone from any licensed water operator

Whenever the change is less than 10 percent of the current dose

Whenever the operator documents the reason in the plant log

When a Class C or higher surface water operator is present and has issued specific instructions for the adjustment

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A filter reaches terminal headloss much sooner than normal, but its effluent turbidity remains low. Which condition should the operator investigate first?

Low distribution-system pressure

Insufficient chlorine contact time in the clearwell

Excess solids loading to the filter from pretreatment or clarification

Excess storage-tank turnover

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A clearwell develops a warm upper layer and a cooler lower layer with poor turnover. Residual is also lower in the stagnant zone. What is the most appropriate operational response?

Increase the tank level and reduce turnover

Add coagulant directly to the clearwell

Improve mixing and turnover so stored water is less stratified and stagnant

Stop monitoring residual until the temperature becomes uniform

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Immediately after a filter is returned to service following backwash, the effluent turbidity is temporarily higher than the plant's normal filtered-water turbidity. What practice best limits the effect on finished water?

Use filter-to-waste when the plant is equipped for it and return the filter to service only after performance stabilizes

Increase coagulant dose at the raw-water intake for exactly five minutes

Send the initial filtrate to the clearwell regardless of turbidity

Stop measuring turbidity until the filter ripens

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A plant changes to a higher polymer dose and soon observes smaller, sticky floc, increased filter headloss, and no improvement in settled-water turbidity. What is the best response?

Continue increasing polymer until the filter run length returns to normal

Decrease backwash frequency

Increase finished-water pH without testing

Return to controlled jar testing and optimize the polymer/coagulant dose instead of assuming more chemical is better

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A bacteriological sample is collected from a chlorinated distribution system. Which practice is appropriate?

Use the sterile bottle as provided, including the dechlorinating agent when supplied, and avoid contaminating the cap or bottle opening

Fill the bottle from a garden hose that has been lying on the ground

Add extra chlorine to the bottle after collection

Rinse the sterile sample bottle with tap water before filling

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An earthy-musty taste-and-odor event appears in the source reservoir. Which treatment strategy is commonly evaluated for adsorption of many taste-and-odor compounds?

Adding sodium thiosulfate to the raw water

Powdered activated carbon with an appropriate dose and contact opportunity

Reducing all mixing in coagulation

Increasing filter media size

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The SCADA display suddenly shows a large increase in filtered-water turbidity, but a properly collected grab sample measured on a verified bench turbidimeter remains normal. What is the best immediate response?

Investigate the online analyzer, sample flow, and calibration before changing the treatment process

Make a large coagulant change based only on the SCADA value

Disable all turbidity alarms

Increase chlorine dose to correct the instrument reading

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Near the end of a filter run, effluent turbidity begins increasing even though headloss is still below the usual terminal value. What is the most appropriate response?

Increase clearwell level to dilute the turbidity

Treat the rising turbidity as possible breakthrough and remove the filter from service for evaluation/backwash

Lower the raw-water coagulant dose immediately

Continue the run until the normal headloss limit is reached

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A plant manager is assigning a complex process change to a newly promoted operator. Which supervisory approach is best?

Perform the work personally and avoid delegating technical tasks

Define the objective and limits, confirm the operator's competence, provide the needed resources, and require follow-up on results

Give the operator full responsibility without guidance to test initiative

Delegate the task but withhold the expected operating target

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A laboratory is measuring a finished-water pH near 7.6. Which calibration practice best supports a reliable pH result?

Skip calibration if the meter display is stable

Calibrate once per year with distilled water

Calibrate with appropriate standards that bracket or closely surround the expected sample pH

Use only a pH 10 buffer because it has the highest value

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A surface water treatment plant is operated during an unstaffed period. Which condition is necessary under the TCEQ operator-coverage rule?

Continuous turbidity and disinfectant-residual monitors must be tied to automatic plant shutdown and alarms that summon operators

A security camera must continuously record the filter gallery

A Class D operator must be available by telephone within 30 minutes

Only a continuous raw-water turbidity monitor is required

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Customers in a high-elevation pressure zone experience low pressure only during peak demand, while plant discharge pressure and lower-zone pressure remain normal. What should be investigated first?

Raw-water coagulant concentration

Laboratory incubator temperature

The hydraulic capacity and controls serving the high-elevation zone, including booster pumping and pressure-zone operation

Filter-media effective size

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An electric motor that drives a rapid-mix unit is being opened for maintenance. What is the most important step before hands enter the equipment?

Ask the control-room operator not to start the mixer

Place the control switch in the OFF position only

Reduce the mixer speed to its minimum setting

Isolate hazardous energy and apply the facility's lockout/tagout procedure

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One sedimentation basin is removed from service, plant flow remains unchanged, and settled-water turbidity rises although floc formation looks normal. What is the most likely operational cause?

The remaining basins have a higher hydraulic loading rate and less effective settling capacity

The laboratory pH meter is reading low

The chlorine demand of the raw water has decreased

The filters are producing too much backwash water

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A clearwell has a usable volume of 600,000 gallons and the plant flow is 2.0 MGD. Ignoring baffling, what is the theoretical detention time?

12.0 hours

7.2 hours

18.0 hours

3.0 hours

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A surface water plant uses aeration to help stabilize water that contains excess dissolved carbon dioxide. What effect is the operator generally trying to achieve?

Add alkalinity by converting oxygen directly into bicarbonate

Remove carbon dioxide so pH can rise and corrosiveness can decrease

Increase dissolved carbon dioxide to lower pH

Create chlorine demand before coagulation

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A utility's master meter shows substantially more water entering a pressure zone than the sum of customer meters, and minimum-night flow has also increased. What is the best next step?

Increase chlorine dose until the meter balance improves

Reduce coagulation pH

Verify meter accuracy and begin a targeted water-loss/leak investigation

Assume the difference is normal and take no action

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After a treatment change, the utility observes lower finished-water pH, lower alkalinity, and increasing metal release complaints. What is the best next step?

Increase distribution flushing only and leave treatment unchanged

Lower finished-water pH further to reduce scaling

Increase chlorine dose until the metal complaints stop

Evaluate water stability and corrosion-control chemistry, then adjust treatment based on the findings

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After a flocculator-speed increase, the operator sees large floc form and then break into smaller particles before sedimentation. Which adjustment is most appropriate?

Increase flocculation intensity further

Bypass the flocculation basin

Increase filter backwash rate

Reduce excessive flocculation shear and restore an appropriate mixing regime

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A new treatment chemical is delivered to a public water plant. Before employees handle it, what action best supports an effective hazard-communication program?

Remove the manufacturer label and replace it with the plant's inventory number

Store the chemical first and provide training only if an exposure occurs

Make the safety data sheet accessible, confirm proper labeling, and train affected employees on the chemical's hazards and protective measures

Require only supervisors to know the chemical hazards

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Why should a chlorine-residual sample normally be analyzed promptly after collection?

Prompt analysis is needed only because pH always falls to zero

Chlorine residual is unaffected by storage time

Chlorine residual can change as reactions continue in the sample

The sample becomes radioactive after several minutes

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A turbidity sample gives an unexpectedly high result, and the sample cell has visible fingerprints and a small air bubble. What should the analyst do first?

Report the result because the instrument produced a number

Clean the sample cell, remove bubbles without changing the sample, and repeat the measurement using proper technique

Add chlorine to the sample and measure again

Dilute the sample with tap water

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A strong chlorine odor and detector alarm indicate a possible chlorine-gas release. What is the best immediate action for an operator who is not part of a trained emergency-response team?

Enter quickly with a cartridge respirator to close the valve

Evacuate to a safe location, keep others out, and initiate the facility's emergency response procedure

Open the chlorine-room door to increase natural ventilation

Turn off the gas detector so it does not distract responders

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A surface water plant is producing 3.6 MGD. What is the average flow in gallons per minute?

2,000 gpm

3,600 gpm

1,250 gpm

2,500 gpm

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A Texas surface water system serves 1,600 connections. Which staffing arrangement meets the minimum operator-license levels described by TCEQ for a surface water system of this size?

One Class B or higher surface water operator and one Class C or higher surface water operator

One Class C surface water operator only

Two Class D water operators who have completed Surface Water Production I and II

One Class A operator from any water-license specialty

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Plant flow drops by 35 percent, but a manually set chlorine feed rate remains unchanged and the residual begins climbing. What is the most appropriate operational response?

Turn off residual monitoring until flow returns

Increase the chlorine feed rate further

Reduce or pace chlorine feed to the actual flow and residual target while continuing to verify disinfection requirements

Keep the same feed rate because chlorine dose is independent of flow

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A 100 mL water sample requires 12.0 mL of 0.020 N acid to reach the alkalinity titration endpoint. What is the alkalinity as mg/L CaCO3?

60 mg/L

240 mg/L

24 mg/L

120 mg/L

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A supervisor finds that an experienced operator has begun skipping a required instrument-calibration check because 'the meter has been stable for months.' What is the best supervisory response?

Stop the shortcut, reinforce the required procedure, determine whether retraining or corrective action is needed, and verify future compliance

Move the calibration record to another employee without discussing the behavior

Wait until the instrument produces an obviously bad reading before intervening

Allow the shortcut because the operator is experienced

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Ammonia unexpectedly enters the treatment stream. After chlorine is applied, the free-chlorine residual is much lower than expected and combined chlorine appears. What is the best explanation?

Chloramines can form only when no chlorine is present

Chlorine is reacting with ammonia and forming chloramines, increasing the chlorine requirement before a free residual can be established

The result proves the turbidity meter is out of calibration

Ammonia prevents any chlorine reaction from occurring

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A distribution area develops red-water complaints after a change in finished-water chemistry. Which response is most appropriate?

Evaluate water stability and corrosion conditions, correct the underlying chemistry as needed, and use flushing as a supporting action

Increase coagulant dose in the distribution system

Use flushing only and ignore the treatment change

Lower pH further to dissolve more pipe scale

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A large transmission-main valve is closed rapidly and operators hear a sharp pressure surge in the system. What is the best operational lesson?

Operate large valves and pumps in a controlled manner to limit sudden velocity changes and water hammer

Increase finished-water turbidity before valve operation

Water hammer occurs only in open channels, not pressurized pipe

Close valves faster so the surge lasts less time

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A plant maintains the same free-chlorine residual and contact time, but water temperature drops substantially. What should the operator recognize?

Disinfection reactions generally slow at lower temperature, so the required CT condition may become harder to achieve

Lower temperature always makes chlorine infinitely more effective

The chlorine residual automatically doubles when temperature drops

Temperature affects only turbidity, not disinfection

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In a vacuum-operated gas chlorinator, what is the primary function of the ejector (injector)?

Store liquid chlorine under pressure

Use flowing water to create the vacuum that draws chlorine gas into solution

Remove hardness by precipitation

Measure filter turbidity

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A storm causes raw-water turbidity to increase sharply while alkalinity decreases. Settled-water turbidity begins rising even though the coagulant feed rate has not changed. What is the best first process-control response?

Run jar tests using current raw water and evaluate coagulant dose and pH/alkalinity conditions

Increase finished-water chlorine residual to compensate for poor clarification

Increase filter backwash frequency without changing coagulation

Reduce sludge withdrawal from the clarifiers

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What is the principal operational value of a jar test during a raw-water change?

It directly determines pump horsepower

It allows controlled comparison of treatment conditions such as coagulant dose and pH before making a full-scale change

It measures distribution-system pressure

It replaces all finished-water compliance monitoring

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A chemical-feed pump display indicates 30 lb/day, but a calibrated drawdown test shows an actual output of 22 lb/day. What should the operator do before simply increasing the setpoint?

Ignore the difference if finished-water turbidity is currently low

Increase the setpoint by 50 percent without another measurement

Verify feeder calibration and the cause of the difference between indicated and actual feed

Assume the drawdown test is wrong because the controller is electronic

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A plant is experiencing poor coagulation, and jar tests show good floc at the current coagulant dose only when the test water pH is adjusted downward. What does this result most strongly indicate?

The chlorine contact basin is too large

The filters must contain the wrong media size

The raw-water flow meter is necessarily inaccurate

Full-scale coagulation performance is being limited by an unfavorable pH condition

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A plant treats 4.0 MGD and applies chlorine at a dose of 2.2 mg/L. Approximately how many pounds of chlorine are required per day?

73.4 lb/day

18.4 lb/day

146.8 lb/day

36.7 lb/day

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Before a crew begins replacing a chemical-feed line, what is the most useful focus for a tailgate safety session?

Assigning the fastest worker to complete the highest-risk task

Identifying the specific job hazards, required controls, PPE, and emergency actions for the work about to begin

Reviewing last month's production totals

Discussing only hazards that have caused an injury at the plant before

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An elevated finished-water storage tank occasionally overflows, but the SCADA level indication still shows 70 percent full. What is the best first diagnostic action?

Verify the actual tank level independently and investigate the level-sensing/control system before changing pump capacity

Increase the high-level alarm setpoint so the alarm occurs less often

Assume the overflow pipe is undersized

Reduce coagulant dose at the treatment plant

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A plant's settled-water turbidity is consistently good, but filtered-water turbidity is deteriorating on only one filter while the other filters remain stable. What is the best diagnostic direction?

Shut down every filter because all filters must have the same cause

Focus on a problem specific to that filter, such as media condition, underdrain/backwash performance, valves, or instrumentation

Assume the raw-water source has changed because one filter is affected

Increase coagulant dose for the entire plant immediately

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With free-chlorine disinfection, finished-water pH rises significantly while temperature, residual, and contact time remain unchanged. What is the most important disinfection effect to recognize?

Higher pH eliminates chlorine demand in all waters

pH has no relationship to free-chlorine chemistry

Higher pH always converts all chlorine to hypochlorous acid

The fraction of hypochlorous acid generally decreases as pH rises, which can reduce free-chlorine disinfection effectiveness

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A raw-water pump develops a gravel-like noise, vibration, and declining flow while suction pressure becomes unusually low. What condition should be investigated first?

Cavitation caused by inadequate suction conditions or a suction-side restriction

Excessive chlorine residual in the clearwell

High alkalinity in the finished water

Filter media loss during backwash

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A pump delivers 1,500 gpm against 120 ft of total dynamic head. If the pump efficiency is 75 percent, approximately what brake horsepower is required?

45 hp

34 hp

81 hp

61 hp

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A clarifier sludge blanket is rising and solids are beginning to carry over into the effluent. Which operational action is most directly indicated?

Increase filter run length

Increase sludge removal and evaluate whether hydraulic or solids loading is exceeding the basin's capacity

Lower the finished-water chlorine residual

Reduce sludge withdrawal so the blanket can compact further

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