Waste Water Operator class C exam 2024/2025 Review Questions and Answers correct verified, Exams of Water and Wastewater Engineering

Download Waste Water Operator class C exam 2024/2025 Review Questions and Answers correct verified and more Exams Water and Wastewater Engineering in PDF only on Docsity! Waste Water Operator class C exam 2024/2025 Review Questions and Answers correct verified When Chlorine is combined with water what type of pipe should be used? A. Ductile iron B. Asbestos concrete C. PVC D. Carbon Steel - CORRECT ANSWER-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 - CORRECT ANSWER-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 - CORRECT ANSWER-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% - CORRECT ANSWER-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 - CORRECT ANSWER-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 - CORRECT ANSWER-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 - CORRECT ANSWER-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 - CORRECT ANSWER-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 - CORRECT ANSWER-A. Continuously What do total solids consist of? A. Dissolved and settleable B. Floatable and settlable C. Suspended and dissolved D. Settlable and nonsettleable - CORRECT ANSWER-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 - CORRECT ANSWER-A. Misalignment Amperometric titration is used to measure A. Dissolved solids A. Hold in gas B. Protect for contaminants C. Reduce radiation D. Protect from cold weather - CORRECT ANSWER-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 - CORRECT ANSWER-A. BOD Staffing is based on what? A. Budget B. Flow and type of treatment C. City Hall D. Chief operator - CORRECT ANSWER-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 - CORRECT ANSWER-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 - CORRECT ANSWER-C. Control Filamentous bacteria What is the most common type of pond? A. Anaerobic B. Aerobic C. Facultative D. Polishing - CORRECT ANSWER-C. Facultative The ash content in lab procedures is the same as? A. Organic solids B. Volatile solids C. Inorganic solids D. Total solids - CORRECT ANSWER-C. Inorganic solids Denitrification will cause what? A. Straggler floc B. Rising sludge C. Methane production D. Low MLSS - CORRECT ANSWER-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 - CORRECT ANSWER-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 - CORRECT ANSWER-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 - CORRECT ANSWER-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 - CORRECT ANSWER-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 - CORRECT ANSWER-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 - CORRECT ANSWER-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 - CORRECT ANSWER-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 - CORRECT ANSWER-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 - CORRECT ANSWER-D. Polishing pond Concert 27* C to Fahrenheit A. 81.6 B. 80.6 C. 106.2 D. 86.1 - CORRECT ANSWER-B. 80.6 Determine the sludge age for an activated sludge plant with the following: Known: D. Remove Co2 residual in sample bottle - CORRECT ANSWER-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 - CORRECT ANSWER-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 - CORRECT ANSWER-A. Require longer contact time Cl2 combined with ammonia forms what? A. Hydrochloric acid B. Chloroammonia acid C. Chloramines D. Hypochlorous acid - CORRECT ANSWER-C. Chloramines At what pH would disinfection be at its greatest? A. 9 B. 7 C. 6.5 D. 5 - CORRECT ANSWER-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 - CORRECT ANSWER-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 - CORRECT ANSWER-C. 300-500 ft You have an RBC unit with the following parameters, what is the organic loading in Ibs per 1,000 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 - CORRECT ANSWER-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 - CORRECT ANSWER-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 - CORRECT ANSWER-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 - CORRECT ANSWER-A. TSS in air-bay What is a quick test to check sludge condition? A. BOD B. COD C. Autoclave D. Settleometer - CORRECT ANSWER-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 - CORRECT ANSWER-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 - CORRECT ANSWER-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 - CORRECT ANSWER-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 - CORRECT ANSWER-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 - CORRECT ANSWER-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 - CORRECT ANSWER-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 - CORRECT ANSWER-A. Young sludge 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 - CORRECT ANSWER-B. Check for blown fuses What affect does Cl2, acid, and Co2 have on pH? A. Raise B. Neutralization C. No affect D. Lower - CORRECT ANSWER-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 - CORRECT ANSWER-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 - CORRECT ANSWER-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 - CORRECT ANSWER-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 - CORRECT ANSWER-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 - CORRECT ANSWER-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 - CORRECT ANSWER-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 - CORRECT ANSWER-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 - CORRECT ANSWER-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 - CORRECT ANSWER-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 - CORRECT ANSWER-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 - CORRECT ANSWER-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 - CORRECT ANSWER-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 - CORRECT ANSWER-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. - CORRECT ANSWER-A. Wastewater is passing through the tank too fast for effective settling