PRACTICE EXAM GRADE III TREATMENT - Division of Water Quality

PRACTICE EXAMGRADE III TREATMENTThe Division ofWater Qualitymakes no claim as the accuracy ofany answers provided herein.October 2001

Class III1. Turbidity in wastewater is caused bya. Colorb. Dissolved calciumc. Hardnessd. Finely divided suspended material2. The gas most commonly associated with septic wastewater isa. Carbon dioxideb. Carbon monoxidec. Hydrogen sulfided. Methane5. Mechanical ventilation of a lift station is required toa. Lower the temperatureb. Reduce chlorine demandc. Eliminate the presence of harmful gasesd. Increase DO in raw wastewater6. A wet well probe is usually used for determination(s) of level.a. Approximateb. Dual-pointc. Continuousd. Single-point7. In electrical circuits a(n) is used to reduce the voltage where necessary.a. Ammeterb. Thermal overloadc. Transformerd. Voloneter8. Which of the following causes the greatest pipe friction loss?a. Decreasing the rate of flowb. Increasing the temperature of wastewaterc. Increasing the velocity of wastewaterd. Decreasing the pressure

19. A centrifugal pump is pumping 200 gpm against a 40-ft total pumping head. Theoutput power of the pump is approximately hp.a. 0.5b. 2c. 15d. 12110. When a fire hydrant is operated, it should bea. Opened enough to have a flowb. Opened fullyc. Opened halfwayd. Regulated to flow required11. A 42-in. diameter pipe is flowing at a rate of 6.5 fVsec. What is the flow in cu ttlsec?a. 17.86b. 35.71c. 62.50d. 521.2512. If the pump bearings on horizontal centrifugal pumps are overlubricated, the mostimportant effect is that the extra lubricanta. Will result in smoother and more efficient operation of the pumpb. Will not make any difference in the operation of the pumpc. Will be wastedd. May cause overheating and possible failure of the bearings13. If packing is not maintained properly,a. Cavitation damage will resultb. Impeller will corrodec. Loss of suction will occur due to air being allowed to enter pumpd. Pump efficiency will increase14. Air flow through a trickling filter when the influent is warmer than the air temperatureisa. Upward through the filterb. Downward through the filterc. Inadequate and may require forced air ventilationd. Improved by decreasing the recirculation15. What is affected first when the aerobic digestion process is starting to deteriorate?a. Supernatant qualityb. Temperaturec. Volatile acid:alkalinity ratiod. Volatile solids concentration16. The reaction of chlorine and ammonia in wastewater produces a compound that iscalleda. Ammonium chlorideb. Chloral hydratec. Chloramined. Hydrazine

17. A malfunctioning gas chlorination system has nonnal gas pressure, no feed rateindicated on rotameter, and no injector vacuum. What is the most likely cause ofthe problem?a. Air leak upstream from the rotameterb. Gas line pluggedc. Injector cloggedd. Pressure-reducing valve diaphragm ruptured18. The most critical criterion for determining when a mixed media filter should bebackwashed isa. Filter effluent qualityb. Flow ratec. Head lossd. Visual inspection of the filter surfacel19. The precipitate in coagulation with alum is,aluminuma. Bicarbonateb. Carbonatec. Hydroxided. Sulfate120. Given the following data, what is the mos[ likely cause of the mechanically cleanedbar screen problem?Data: Above normal water differential across bar screenDrive motor shaft turningDrive sprocket, chain, and rake not movingLess than normal flow on bar screen downstream sideBar screen mode selector in automatic positionNormal seasonal flow (influent) coming into bar screenAlarm systems operating normallya. Low influent (incoming) levelb. Raw wastewater pumping units out of servicec. Sheared pin or disengaged clutch on drive unitd. None of the above21. The correct amount of chemical used to remove turbidity is known as thea. Coagulation rangeb. Combination dosagec. Efficiency ranged. Optimum dosage22. The temperature of anaerobic digester should be changed as slowly as possible toa. Avoid overloading the heat exchangerb. Avoid excess heat lossc. Allow digester walls time to adjustd. Allow bacteria time to adjust

24. The quantity of volatile solids in the content of the incoming sludge is an indirectmeasure of thea. Amount of the sample that will evaporate when standingb. "Food" available for bacteria in the digesterc. Number of bacteria in the digesterd. Primary effluent suspended solids25. What organisms will be found in a balanced, good settling mixed liquor?a. Hagellate and amoeboid organismsb. HagelJates and free-swimming ciliates, but no stalked ciliates and rotifersc. Free-swimming and stalked ciliates, some flagellates, and rotifersd. Nematodes, rotifers, ciliates, flagellates, and amoeboids26. Belt filter presses are operated as a process.a. Batchb. Continuousc. Either one, depending on circumstances27. Given the following data, calculate the desired pounds of mixed liquor suspendedsolids (MLSS) in the aeration tank.Data: Primary effluent suspended solids = 120 mg/LInfluent flow = 2.0 mgdDesired sludge age = 5.0 daysAeration tank = 100 ft x 45 ft x 15 ftInfluent BOD = 235 mg/LEffluent suspended solids = 15 mg/La. 6 ()()() Ibb. 8 ()()() Ibc. 10 ()()() Ibd. 12 ()()() Ib28. Required chemical coagulation doses are commonly determined bya. Jartestsb. Measurements of zeta potentialc. Oxidation-reduction investigationsd. Stoichiometric calculations.29. Given the following data, calculate the average velocity in the channel.Data: 2.5-ft wide channelHow depth is 1.4 ftHow rate is 7.2 mgda. 1.2 ftlsecb. 3.2 ftlsecc. 11.2 ftlsecd. 32.2 ftlsecl30. A 240-gpm mixed media filter operated at a rate of 2 gpm/sq ft is backwashed at arate of 15 gpm/sq ft. How many gallons of wash water were used?a. 5 ()()()b. 5400c. 6 ()()()d. 6200

31. Given the data below, what is the most likely cause of a low DO level in an acti­vated sludge aeration tank with a diffused aeration system problem?Data: Blower air rate output highOrganic load normalHydraulic load normalLow turbulence throughout aeration tanka. Aeration system piping leakingb. Excessive air bubble shearing by diffusersc. Return sludge rate 100 highd. Underaeration because of low blower speedl32. Given the data below, what is the most likely cause of the extended aeration facilityproblem?Data: Blower normalRow normal for dry weatherDO level normalDrop pipe air control valves half openDead spot on surface around one drop pipeDead spot remains when drop pipe air control valve fully opena. Air header pipe cloggedb. Blower discharge pipe cloggedc. Blower intake filter cloggedd. Drop pipe clogged.33. An incubator for the BOD test should be controlled at 0c.a. 15b. 20c. 25d. 3034. Results of the settleable solids test run using Imhoff cones may be used toa. Calculate the Imhoff settling index (lSI)b. Calculate the pounds of primary solids pumped to the digesterc. Indicate the quality of the final effluentd. Calculate the sludge volume index (SVI)35. Calculate the percent volatile solids.Data: 100 mL of sampleCrucible weight = 19.985 0 gCrucible plus dry solids = 20.050 3 gCrucible plus ash = 20.0068 ga. 33%b. 50%c. 67%d. 74%

36. In certain situations, a supervisor encourages the employees to make their owndecisions. This is considered to bea. Against the rules to follow past experiences in decision makingb. Bad form because the supervisor eventually loses controlc. Highly desirable because it encourages employee growth and frees the supervisorfor other tasksd. Passing the buck37. Treatment basin (such as primary sedimentation, grit tank, aeration tank, and finalclarifier) drainsa. Must be higher than the receiving sump to allow for gravity flow out of thebasinb. Must be lower than the receiving sump to allow for gravity flow out of thebasin and into the sumpc. Need not be valved closed if the drain is higher than the receiving sumpd. Need not be maintained because it is always faster to pump a treaunent basindry than allow it to drain to the receiving sump38. Successful communication requires mutuala. Agreementb. Confusionc. Transmissiond. Understanding39. When a great deal of authority is delegated on many levels, an organization may bedescribed asa. Authoritarianb. Centralizedc. Decentralizedd. Unstructured40. What should a new crew leader on a shift do if he/she discovers a better way ofdoing a certain operation?a. Discuss the plan with other shift supervisorsb. Explain the plan and its benefits to the chief operator or plant supervisorc. Implement the pland. Write a letter to the plant supervisor outlining the intended improvements41. Generally, as an individual progresses upward in management, reliance on personaltechnical skilla. Becomes more complexb. Decreasesc. Increasesd. Remains the same42. If the sewer rate is $5.50 for the first 500 cu ft and all wastewater generated overthe minimum is billed at the rate of $0.25 per 100 cu ft, how much would a customergenerating 1 200 cu ft be billed?a. $5.25b. $6.25c. $6.75d. $7.25

43. What equipment should be calibrated in a treatment plant?a. Chemical feedersb. Continuous-recording chlorine residual analyzerc. Continuous-recording pressure gaugesd. All of the above44. Special parts that should be carried by the maintenance worker are usually listed inthea. Machine blue printb. Machine history recordc. Machine manufacturer's manuald. Daily log45. lnfonnation on preventive maintenance procedures, materials, and frequencies forplant structures should be taken from.a. As-built blueprintsb. Experience at the panicular plantc. Lab recordsd. Manufacturer's operation and maintenance manuals46. How can the supervisor document that scheduled maintenance is completed?a. Ask the workersb. Hire someone to inspect completed workc. Use a form that compares work assigned with work completedd. Wait and see if there are any failuresNI

Item # Answer Subject1. D General2. C GeneralTREATMENT III - ANSWERS5. C General6. D Support Systems7.8.9.10.11.CCBBCSupport SystemsSupport SystemsSupport SystemsSupport SystemsSupport Systems12. D Support Systems13.14.15.16.17.18.19.20.CACCCACCSupport SystemsUnit Process/Process ControlUnit Process/Process ControlUnit Process/Process ControlUnit Process/Process ControlUnit Process/Process ControlUnit Process/Process ControlUnit Process/Process Control21. D Unit Process/Process Control22. D Unit ProcessIProcess Control23. D Unit ProcesslProcess Control24.25.BCUnit Process/Process ControlUnit Process/Process Control26. B Unit Process/Process Control27.28.29.30.31.CABBAUnit Process/Process ControlUnit Process/Process ControlUnit Process/Process ControlUnit Process/Process ControlUnit ProcesslProcess Control32. D Unit Process/Process Control33. B Unit Process/Process Control34. B Unit Process/Process Control35.36.37.CCAUnit Process/Process ControlTechnical Supervision/ManagementTechnical Supervision/Management38. D Technical Supervision/Management39. C Technical Supervision/Management40. B Technical Supervision/Management41. B Technical Supervision/Management42. D Technical Supervision/Management43. D Technical Supervision/Management44. C Technical SupervisionlManagement45. D Technical Supervision/Management46. C Technical Supervision/Management