California Wastewater Grade 3 Exam Prep FREE Sample Exam

A pump coupling guard was removed so the coupling could be inspected. The inspection is finished and the pump is needed. What comes first?

The pump is run for a trial shift without the guard to confirm it runs true

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The guard is refitted securely before the pump is returned to service

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The guard is left off because the coupling area is rarely visited by anyone

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The guard is propped beside the pump as a reminder to refit it next week

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Over one day, 13,260 pounds of solids are applied to a primary clarifier whose surface area is 1,560 square feet. What solids loading rate does that produce?

8.5 lb/day/sq ft

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6.63 lb/day/sq ft

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10.63 lb/day/sq ft

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11.05 lb/day/sq ft

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During the storm peak, solids are washing into the primary clarifiers faster than usual and blankets are climbing. Besides evening out the flow, what withdrawal move helps?

Stop sludge withdrawal entirely so the blankets can compact in place

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Increase sludge withdrawal to keep the blankets from building too deep

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Withdraw scum only, and leave the sludge blankets untouched for now

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Drain one clarifier completely and let the others take the whole flow

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A clarifier’s effluent carries a fine turbidity made of tiny, dense floc particles even though most of the sludge settles. The floc in the basin looks small and compact rather than open and fluffy. Which condition fits?

Pin floc, the small compact floc associated with an over-aged sludge

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Filamentous bulking, which always produces a large, open, slow-compacting blanket in the clarifier

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Dispersed growth, in which no floc particles of any size ever form in the mixed liquor sample

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Sludge washout, in which whole formed floc is carried over the weirs only during storm flows

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Each time operators raise MLSS to hold more treatment capacity, the secondary clarifier begins carrying solids over well before its hydraulic limit is reached. What governs how much inventory this system can hold?

The weir overflow rate alone, since hydraulic figures are the only loading a clarifier ever experiences and the solids applied to its surface each day have no bearing on performance at all

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The length of the aeration basin, which fixes the inventory regardless of clarifier performance

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The dissolved oxygen setpoint, which determines how many solids the clarifier can settle per hour

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The solids loading on the secondary clarifier, which limits the solids flux the clarifier can pass downward

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A microscopic examination of mixed liquor shows abundant stalked ciliates, firm floc with few filaments, and very few free-swimming organisms. How should the operator read this?

A stable, older, well-oxidizing system in good operating condition

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A young, dispersed sludge that needs its wasting rate cut sharply today

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A bulking sludge in which filamentous organisms are taking over the floc

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A septic mixed liquor that needs immediate chlorination of the return sludge

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During inspection of a drained filter cell, the operator finds balled clumps of media and solids, bare patches where media depth is low, and cracks at the bed surface. Which set of classic bed defects is present?

Sloughing, ponding, and icing of the media surface during cold weather

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Denitrification, luxury uptake, and precipitation within the media bed

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Ripening, breakthrough, and short-circuiting of the underdrain system

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Mudballs, media loss, and cracking or shrinkage of the filter bed

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A digester’s volatile acids have climbed for several days, alkalinity and gas production are falling, and the feed log shows the volatile-solids loading was recently stepped up sharply. What is the best first response?

Increase the feed rate further so the methane-forming organisms receive more food and recover faster

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Raise the digester temperature well above its normal heated range to speed up the slowed organisms

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Stop mixing entirely and let the digester rest undisturbed until the volatile acids consume themselves

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Cut back the feed, hold heating and mixing steady, and reseed if suitable seed sludge is available

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How many pounds of chlorine are needed to dose 0.28 million gallons of effluent at 2.4 mg/L?

0.67 lb

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11.21 lb

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2.80 lb

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5.60 lb

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What physically happens in a pond at seasonal turnover?

Cooling surface water becomes denser than the water below and sinks, mixing the pond's layers and stirring settled material back through the water column

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The pond's algae suddenly die off and release their oxygen

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Wind pushes the entire pond volume through the outlet in one surge

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The bottom sludge layer floats to the surface as a single mat

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To judge how much load one treatment stage is actually removing, which analyses does the operator pair?

The stage's influent and effluent analyses for the same period, compared against each other

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Two effluent analyses taken a month apart, with the difference between them reported as the stage's removal performance

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The influent analysis and the chemical feed record

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The effluent analysis and the flow totalizer reading alone

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During performance testing, a pump delivers 850 gpm against a total head of 115 ft while its driver supplies 42 brake horsepower. What is the pump efficiency?

24.68%

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58.77%

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170.14%

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0.59%

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California Wastewater Grade 3 Exam Prep FREE Sample Exam — Fixed Set

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