WasteWater Operator class C exam practice review 100% Complete and Verified 2024/2025, Exams of Water and Wastewater Engineering

Download WasteWater Operator class C exam practice review 100% Complete and Verified 2024/2025 and more Exams Water and Wastewater Engineering in PDF only on Docsity!

WasteWater Operator class C exam

practice review 100% Complete and

Verified 2024/

When Chlorine is combined with water what type of pipe should be used? A. Ductile iron B. Asbestos concrete C. PVC D. Carbon Steel C. PVC A good settling sludge would consist of what type of protozoa? A. Rotifers and nematodes B. Amoebas and Flagellates C. Stalked ciliates and mastagoria D. Free swimmers and stalk ciliates D. Free swimmers and stalk ciliates What is Phenolphylein used for in titration A. Oxidizer B. Indicator C. Acid reducer to lower pH D. Applicator B. Indicator Your plant has an influent of 220 BOD and 163 TSS, and an effluent of 10 BOD, and 6 TSS. What is the BOD removal efficiency in your plant? A. 92% B. 94% C. 95% D. 96% C. 95%

You suspect your anaerobic digester is going sour. What is the best way to verify its condition? A. pH B. Foam type C. VA/ALK ratio D. DO C. VA/ALK ratio Before operating any piece of equipment what should be done? A. Lock out Tag out (remember, safety first!) B. Read O & M manual C. Read manufacturers manual D. Notify supervisor C. Read manufacturers manual Detritus is noticed in your grit channel. What is the problem? A. Velocity too fast with short D/T B. Velocity too low with long D/T C. Short circuiting D. Density currents B. Velocity too low with long D/T What is considered normal operation of an aerobic digester? A. Fill react B. Skim off foam when needed C. Settle and Decant as needed D. Feed only during low flow or constant when the sun is out C. Settle and Decant as needed A plant with a flow of 1 MGD should be monitored A. Continuously B. Intermittently C. Daily D. Every four hours depending on surface load A. Continuously What do total solids consist of?

A. Dissolved and settleable B. Floatable and settlable C. Suspended and dissolved D. Settlable and nonsettleable C. Suspended and dissolved What would cause excessive wear on bearing? A. Misalignment B. Reduced Oil due to low viscosity C. Blow seal D. Over tubercation A. Misalignment Amperometric titration is used to measure A. Dissolved solids B. Chlorine residual C. Colloids D. Emulsions B. Chlorine residual What growth phase is an aerobic digester operated in. A. Log B. Lag C. Endogenous respiration D. Declining phase C. Endogenous respiration If excessive pressure builds up in a chlorine tank due to excessive heat. What will prevent explosions? A. Valve seat adjustments B. Heat reducing valve C. Fusible plug D. Check valve C. Fusible plug You notice that your bearings are excessively hot on a pump, why? A. Ambient temperature too high

B. Over lubrication C. Oil seal blown D. Discharge rate too low B. Over lubrication Where can you gain access for collection system maintenance? A. Lift station B. Force main C. Man hole D. Gravity main C. Man hole Low DO and nutrient deficiency will promote the growth of what? A. Rotifers B. Filamentous bacteria C. Spirillium D. Amoebas B. Filamentous bacteria When charging a lead-acid type battery for a composite sampler, what dangerous gas could be produced? A. Hydrogen B. Oxygen C. Hydrogen sulfide D. Cyanide A. Hydrogen What is the best method in dealing with a chemical spill? A. Contain and clean up B. Saw dust and kitty litter C. Foam congaing super trimethyl bromine D. Flood with water A. Contain and clean up There is septic wastewater entering your primary clarifier. What is the problem? A. Aerobic conditions in the collections system B. Lift station pumps operating on short cycles

C. Anaerobic conditions in the collections systems D. High flows due to a low MCRT C. Anaerobic condition in the collections system Which of the following substances is highly viscous and very slippery? A. Calcium hypochlorite B. Calcium oxide C. Potassium permanganate D. Polymer D. Polymer If you pump green sludge to a drying bed what chemical should be applied? A. Polymer B. Lime C. Cl D. Alum B. Lime Chlorine leaks can be detected by? A. ISCBA B. Ammonia solution with Q-Tip C. Alcohol vapor D. Spray with mist of water B. Ammonia solution with Q-Tip What takes place in the stabilization tank in a contact stabilization plant? A. Adsorption B. Clarification C. BNR D. Absorption D. Absorption Why is an aerobic digester covered? A. Hold in gas B. Protect for contaminants C. Reduce radiation D. Protect from cold weather

D. Protect from cold weather Which of the following would you not use a grab sample on? A. BOD B. DO C. pH D. Temp A. BOD Staffing is based on what? A. Budget B. Flow and type of treatment C. City Hall D. Chief operator B. Flow and type of treatment What condition does an operator have the least amount of control over? A. Flow B. Wasting Rate C. F/M ratio D. Temp D. Temp Why would you chlorinate the RAS line? A. Remove struvite B. Lower the pH of incoming C. Control Filamentous bacteria D. Meet chlorine demand C. Control Filamentous bacteria What is the most common type of pond? A. Anaerobic B. Aerobic C. Facultative D. Polishing C. Facultative

The ash content in lab procedures is the same as? A. Organic solids B. Volatile solids C. Inorganic solids D. Total solids C. Inorganic solids Denitrification will cause what? A. Straggler floc B. Rising sludge C. Methane production D. Low MLSS B. Rising sludge If a 220 volt, 3 phase motor is running backwards what should you do? A. Switch the two leads B. Return pump for a refund C. Check the polarity magnets D. Check static pressure A. Switch the two leads Coliform count fails to meet standards your chlorine supply is not the problem. What is? A. Short circuiting and low contact time B. Chlorine has become stale C. High temps D. Lack of disinfectant bacteria A. Short circuiting and low contact time What type of material should be used for transporting samples? A. Glass B. Polyethylene C. Graduated cylinders D. Burette B. Polethylene How does temperature effect disinfection?

A. Lower the temp the better the disinfection B. Has no effect C. Higher the temp the better the disinfection D. Depends on the constant altitude C. Higher the temp the better the disinfection The advantage of an anaerobic digester over an aerobic digester is? A. Less solids B. Increased power consumption C. Decrease power consumption D. Easier to operate C. Decrease power consumption How long should you wait after you make a process change before making another change? A. 7 hours B. 10 days C. When the operator thinks it's necessary D. 1 week D. 1 week Determine the MCRT using the following: Known: Aerator volume = 323,000 gal Final clarifier vol. = 150,000 gal Flow = 2 MGD Waste flow = 20,000gal MLSS = 2,400 mg/L Waste sludge SS = 6400 mg/L Final eff. SS = 16 mg/L A. 3.3 days B. 4.8 days C. 2.7 days D. 4.1 days B. 4.8 days What is needed to calculate the F/M ratio? A. BOD mg/L and MLSS mg/L

B. BOD in Ibs and MLVSS in Ibs C. BOD mg/L and MLVSS in Ibs D. BOD in Ibs and MLSS mg/L B. BOD in Ibs and MLVSS in Ibs What type of ponds are used after a trickling filter, activated sludge, or RBC plant? A. Facultative pond B. Aeration Pond C. Anaerobic pond D. Polishing pond D. Polishing pond Concert 27* C to Fahrenheit A. 81. B. 80. C. 106. D. 86. B. 80. Determine the sludge age for an activated sludge plant with the following: Known: Aerator tank vol. = 500,000 gal Flow = 5.25 MGD PE SS = 72 mg/L MLSS = 2350 mg/L A. 6.5 days B. 4.2 days C. 3.1 days D. 5.2 days C. 3.1 days You have excessive billowing white sudsy foam on the surface of your aerator. What is the cause? A. MLSS too high B. F/M too high C. F/M too low D. MLVSS too high B. F/M too high

The settleometer settles fairly slowly. You have shiny dark foam on the surface of the aerator. What is the problem? A. MCRT too high B. MCRT too low C. Sludge age too low D. WAS too high A. MCRT too high The removal of nitrogen and phosphorus are? A. Useful in the growth of algae B. Advanced secondary treatment C. General practice in extended aeration D. Prevents anaerobic conditions B. Advanced secondary treatment What would cause a pump to fail to discharge? A. Excessive gravity B. Tubercation C. Suction lift too high D. Proper lubrication C. Suction lift too high Chlorine is not coming out. Another cylinder is hooked up with the same problem occurring. What is the problem? A. Educator submerged B. Icing C. Manifold line is blocked D. POA too far C. Manifold line is blocked How would you measure the amount of load being applied from the digester to the head works? A. Total solids test B. BOD C. COD D. DPD A Total solids test

Why is a vacuum/pressure relief valve used on an anaerobic digester? A. Prevent methane gas from reaching the heat exchanger B. Prevent CO2 from being released to the atmosphere C. Prevent negative and positive pressure D. Increase digester capacity C. Prevent negative and positive pressure What would cause the most damage to a centrifugal pump? A. Grit B. Cavitation C. Velocity too low D. Intermediate operation B. Cavitation The rock in trickling filters is placed? A. In a uniform manner B. Small to large C. With large voids D. On system tile under drains D. On system tile under drains If you have a sudden increase of BOD by 50% or a BOD>400. What is this termed? A. Under loaded aerator B. Overloaded clarifier C. Increased inorganic load D. Increased organic load D. Increased organic load Coliform bacteria are used for what? A. Process control changes B. Indicators of possible presence pathogenic organisms C. Prevent disease D. Remove Co2 residual in sample bottle B. Indicators of possible presence pathogenic organisms Where does the effluent from the aerator go?

A. Secondary clarifier B. Primary clarifier C. Solids handling D. Digester A. Secondary clarifier A decrease in temperature will have what effect on disinfection? A. Require longer contact time B. Require shorter contact time C. Increase rate of disinfection D. Have no effect on disinfection A. Require longer contact time Cl2 combined with ammonia forms what? A. Hydrochloric acid B. Chloroammonia acid C. Chloramines D. Hypochlorous acid C. Chloramines At what pH would disinfection be at its greatest? A. 9 B. 7 C. 6. D. 5 D. 5 It can be said that: A. The higher the pH, the greater the disinfection B. The lower the pH, the great the disinfection C. The lower the disinfection the lower the pH D. PH and disinfection are not related B. The lower the pH, the great of disinfection What is the distance between manholes? A. 300-600 ft B. 450-700 ft

C. 300- 500 ft D. Depends on the population of the given area C. 300-500 ft You have an RBC unit with the following parameters, what is the organic loading in Ibs per 1, cu/ft? Known: Q = 1.4 MGD Sol. BOD = 100 mg/L Surface Area = 500,00 s/f A. 2.5 Ibs B. 2.3 Ibs C. 2.8 Ibs D. 4.8 Ibs B. 2.3 Ibs What is the disadvantage of a hypochlorinator? A. Lowers the pH and increases the disinfection B. Lowers the pH and decreases the disinfection C. Increases the pH and decreases the disinfection D. Increases the pH and increases the disinfection C. Increase the pH and decreases the disinfection What chemical would be used on a sample to be used for TSS test? A. Sodium Thiosulfate B. DPD C. Nitriver D. Nothing D. Nothing What TSS test is most critical for plant operation? A. TSS in air-bay B. TSS in aerobic digester C. TSS on primary clarifier D. TSS in anaerobic digester A. TSS in air-bay

What is a quick test to check sludge condition? A. BOD B. COD C. Autoclave D. Settleometer D. Settleometer What is the funnel called that is used along with the vacuum apparatus when doing solids testing? A. Buchner funnel B. Filter funnel C. Micro funnel D. Straining funnel A. Buchner funnel What would be most harmful to the population of microorganisms? A. High toxicity, strong acids, strong bases B. Warm temperatures, high DO C. Cold temperatures, low DO D. Neutral pH A. High toxicity, strong acids, strong bases What is the best range of parameters for the activated sludge process? A. 2 ppm DO, pH 7.0, 80-95* F B. 1 ppm DO, pH 6.5, 60 - 70* F C. 4 ppm DO, pH 5.0, 80-90* F D. 3 ppm DO, pH 7.5, 45-65* F A. 2 ppm DO, pH 7.0, 80-95* F What is the breakdown of nitrate to nitrogen gas called? A. Nitrification B. Denitrification C. Autotriphication D. Anaerobic decomposition B. Denitrification

What 2 stages are in an anaerobic digester? A. Fill and Decant B. Acid formation and gas formation C. VA/ALK and Redox D. Over feed and under feed B. Acid formation and gas formation What is the benefit of step feed aeration? A. Re-aeration tank stability B. Treat higher flows in less space C. Absorption in contact tank D. Anoxic zones enhance denitrification B. Treat higher flows in less space What is classic sludge bulking caused from? A. Young sludge B. Old sludge C. High MLSS D. Long MCRT A. Young sludge What should be the maximum allowable level of TSS and BOD in the eff. of a domestic w/w facility in accordance with FAC? A. 20 TSS, 20 BOD or 80% removal B. 30 TSS, 30 BOD or 90% removal C. 20 TSS, 30 BOD or 90% removal D. 20 TSS, 20 BOD or 90% removal D. 20 TSS, 20 BOD or 90% removal What does CBOD mean? A. Chemical Biological Oxygen Demands B. Carbonaceous Biochemical Oxygen Demand C. Carbonic Biological Oxygen Demands D. Chlorinated Biochemical Oxygen Demand B. Carbonaceous Biochemical Oxygen Demand

What is the min. depth of a pond? A. 6 ft B. 10 ft C. 4 ft D. 3 ft D. 3 ft What can happen if more than 40 Ibs of chlorine is withdrawn from a 150 Ib tank in a 24 hr period? A. Reliquification B. Increased pressure C. Freezing of the lines D. Budget increase C. Freezing of the lines What the two main gasses produced b an anaerobic digester? A. Methane & Carbon Monoxide B. Co2 & CH C. Methane & Co D. Hydrogen Sulfide & Oxygen C. Methane & Co When working in a man hole, what would be the biggest danger? A. Falling debris B. Cave-ins C. Asphyxiation D. Carcinogens C. Asphyxiation In a pond, what will happen to the pH during the day time? A. Decrease B. Remain constant C. Increase D. Fluctuate A. Decrease Cathodic protection is used for what purpose?

A. The prevention of corrosion to metals B. To avoid electrical shock C. Increase safety D. Protect utilities from lawsuits due to unsafe environments A. The prevention of corrosion to metals In an anaerobic digester, when the VA/ALK ratio starts to increase, what will be noticeable? A. An increase in Co2 & decrease in pH B. A decrease in Co2 & increase in pH C. Optimum operation D. an increase in Co2 & increase in pH A. An increase in Co2 & decrease in pH What should you do if your samples come to the lab and have settled to the bottom? A. Discard B. Mix them well C. Re-Sample D. Run tests B. Mix them well What are some similarities between methane and H2S? A. Flammable, explosive, colorless B. Flammable, explosive, odorless C. Rotten egg order, yellowish color, combustible D. Blue flam, non toxic, lighter than air A. Flammable, explosive, colorless What causes the most wear to an impeller? A. High velocities B. No water C. Grit D. Constant head C. Grit If a pump will not start and you have power at the breaker, what is the next logical step? A. Call the power company B. Check for blown fuses

C. Install new wiring D. Inspect power relay B. Check for blown fuses What affect does Cl2, acid, and Co2 have on pH? A. Raise B. Neutralization C. No affect D. Lower D. Lower As an operator, how do you control the anaerobic digestion process? A. Microbial population and temperature B. H2S and methane concentration C. Temperature and rate of raw sludge feed D. Methane and Co2 production C. Temperature and rate of raw sludge feed What is a true statement about recording data? A. Bar and line graphs are the most accurate B. There are many techniques to record data C. Pie charts are most common D. Data recording is not important B. There are many techniques to record data According to FAC Ch. 62-600, Domestic WasteWater Facilities, your job s an operator during major process breakdowns is to? A. Maintain competent documentation and record keeping B. Report to the DEP within 24 hours after the problem is fixed C. Call the fire department D. Shut down the plant immediately A. Maintain competent documentation and record keeping Short circuiting in a primary clarifier can be prevented by? A. Scum troughs B. Vertical mixers

C. Baffles D. Chain flights C. Baffles What do you do if you experience a plant upset due to a hydraulic overload? A. Decrease DO B. Increase RAS C. Increase WAR D. Decrease WAS to maintain microorganisms population D. Decrease WAS to maintain microorganisms popultion You have dark foam, high MLSS, slow settlings sludge with a clear effluent, you should? A. Increase WAS, decrease RAS B. Maintain 1-3 ft sludge blanket, monitor MLSS, increase DO if necessary C. Decrease DO, decrease WAS, increase RAS D. Raise MCRT, sludge age and SDI B. Maintain 1-3 ft sludge blanket, monitor MLSS, increase DO if necessary If the blades on the comminutor become dull, this can cause? A. Pumps to become clogged with rags B. Excessive flows C. Increased efficiency D. Grit to settle out slower A. Pumps to become clogged with rags After removing the roof of the chlorinator storage, building during the summer, the Cl2 stop feeding, what is the cause? A. The CPRV became clogged B. The tank got hotter than the manifold C. The external pressure reducer failed D. The tank is empty B. The tank got hotter than the manifold What do total suspended solids consist of? A. Settleable and dissolved B. Settleable, dissolved, and suspended

C. Settleable and suspended D. Dissolved and suspended C. Settleable and suspended The pH in your plant is decreasing, effluent turbidity is increasing, and the sludge is rising in the clarifier. What is the problem? A. Hydraulic overload B. High F/M C. Over wasting D. Denitrification D. Denitrification The TSS of the digester supernatant should be calculated because? A. The DEP requires you to B. To measure the solids load on the plant C. To calculate the VA/Alkalinity ratio D. It's a good indication of methane concentration B. To measure the solids load on the plant How do you calculate the F/M ratio? A. Effluent BOD Ibs., divided by the MLVSS Ibs. B. Influent BOD mg/L, divided by the MLVSS Ibs. C. Influent COD Ibs., divided by the MLVSS Ibs. D. Influent BOD Ibs., divided by the MLVSS mg/L C. Influent COD Ibs., divided by the MLVSS Ibs. If an activated sludge plant becomes upset, what is the most important and least time consuming operation an operator should do to discover the cause? A. Check the plant data for the previous 3 weeks B. Run BOD, DO, suspended solids, and pH tests on the system C. Check collection system D. Check effluent BOD and Cl2 residual A. Check the plant data for the previous 3 weeks A colored dye solution is added into the raw wastewater entering a primary settling tank. The dye color was noticeable in the effluent in 15 min and all of the color had passed through the tank in 40 min. What does this indicate?

A. Wastewater is passing through the tank too fast for effective settling B. Optimal detention time is being achieved C. This tank has a detention time of 40 min. D. This tank design has a detention time of 55 min. A. Wastewater is passing through the tank too fast for effective settling