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Wastewater Treatment Exam Questions and Answers, Exams of Advanced Education

A comprehensive set of questions and answers related to wastewater treatment operations. It covers various aspects of wastewater treatment, including solids removal, disinfection, flow measurement, safety procedures, and aeration systems. Valuable for students and professionals seeking to understand the principles and practices of wastewater treatment.

Typology: Exams

2024/2025

Available from 11/08/2024

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eric-kariuki 🇺🇸

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2024 WASTEWATER OPERATOR

TN EXAM WITH CORRECT

ANSWERS

Which of the following is not likely to develop if wastewater remains int eh collection system too long? - CORRECT-ANSWERSAlgae A high sewage pH can result int production of toxic gases due to : - CORRECT-ANSWERSAmmonia What problems do septic conditions in the collection system cause at the treatment plant? - CORRECT-ANSWERSOdor and oxygen demand ___________ motors are often used with turbo blowers in order to meet the blower speed requirements to provide improved efficiency - CORRECT- ANSWERSPermanent magnet Harmonic filters can be used to eliminate - CORRECT-ANSWERSInduced harmonics from VFDs _________ does not occur within a rotary lobe blower, but instead occurs at the blower discharge - CORRECT-ANSWERSAir compression A PM task that is commonly needed on rotary lobe blowers is _____ - CORRECT-ANSWERSV belt inspection and re-tensioning Rotary screw blowers are considered "hybrid" blowers because they use both - CORRECT-ANSWERSPositive displacement and internal compression __________ valves are the most commonly used valves for air isolation and control - CORRECT-ANSWERSButterfly Properly placed expansion joints are important in an air distribution system to _______ - CORRECT-ANSWERSRelieve pain strain caused by thermal expansion The diffuser is the point at which _______ - CORRECT-ANSWERSAir is injected into the process tank Large bubble diffusers require significantly ________ than fine bubble diffusers - CORRECT-ANSWERSLess maintenance and cleaning

Fine bubble diffusers create bubbles that are _________ mm in diameter - CORRECT-ANSWERS1.0-3. ___________ can occur when blower inlet air filters allow too many particles to pass through - CORRECT-ANSWERSAir side diffuser fouling _____________ is a frequent mini cleaning technique where high air flows are sent through membrane diffusers are short periods of time - CORRECT-ANSWERSAir bumping Treatment processes with _________ typically experience slower diffuser bio fouling - CORRECT-ANSWERSHigh SRTs Air transfer efficiency improves after cleaning because of _________ - CORRECT-ANSWERSSmaller bubble size and slower rise rates A variable pressure aeration control strategy uses the pressure resulting from the ____________ to adjust the blower capacity and minimize system pressure - CORRECT-ANSWERSMost open valve Programmable logic controller based control systems improve aeration system efficiently because - CORRECT-ANSWERSFacility flows and loads are always changing An aspect of jet aeration system design that makes maintenance easier is

  • CORRECT-ANSWERSNo moving parts are located inside the process tanks High speed surface aerators - CORRECT-ANSWERSHave the impeller direct coupled to the motor Typical PM tanks for low speed surface aerators may include _________ - CORRECT-ANSWERSChange the oil in the drive and grease the motor Operators can adjust the ___________ to increase/decrease the OTR of a horizontal rotor - CORRECT-ANSWERSSpeed of the shaft rotation Decreasing the depth of a horizontal rotors blade submergence will _________ - CORRECT-ANSWERSDecrease the amount of power needed to operate the horizontal rotor Mixer aerators transfer DO into process tanks primarily by _____________ - CORRECT-ANSWERSShearing bubbles front he sparser ring and mixing them into the process liquid What are the components of mixer aerators - CORRECT- ANSWERSSubmerged mixer body, sparger ring, separate air supply, and platform mounted motor

Mixer aerators not only provide good OTE but also provide - CORRECT- ANSWERSExtra mixing energy along the tank floor Preventative maintenance tasks for mixer aerators include - CORRECT- ANSWERSChanging the oil after the recommended amount of run time Why must wastes be treated before they are discharged into receiving waters? - CORRECT-ANSWERS- Diseased bacteria

  • Affect the dissolved oxygen levels
  • Affect the odor or color of the water
  • Solids accumulation Which processes are used in wastewater treatment to remove contaminants from wastewater? - CORRECT-ANSWERS- Chlorine
  • Primary treatment (removes sludge and scum)
  • Peracetic acid
  • UV light Ozone What are the major types of waste discharge? - CORRECT-ANSWERS- Organic
  • Inorganic Radioactive Why should the discharge of organic wastes into a receiving water concern operators? - CORRECT-ANSWERSIt could cause oxygen depletion Which major contagious diseases could be spread by inadequately treated wastewater? - CORRECT-ANSWERS- Giardiasis (giardia) Cryptosporidiosis (Crypto) Why are nutrients in the discharge of treated wastewater a concern? - CORRECT-ANSWERS- It could contain nutrients that encourage excess algae and plant growth It could affect dissolved oxygen levels What is organic waste? - CORRECT-ANSWERSWaste material that may come from animal or plant sources What is inorganic waste? - CORRECT-ANSWERSWaste material that is only slightly affected by the actions of organisms What are total solids? - CORRECT-ANSWERSInclude all solids present in the wastewater; including suspended and dissolved both organic and inorganic What device is used to measure settleable solids in mL/L? - CORRECT- ANSWERSSettleometer

How is organic content of water measured? - CORRECT-ANSWERSBOD, COD, and TOC What is BOD? - CORRECT-ANSWERSThe measure of dissolved oxygen consumed by aerobic organisms while stabilizing decomposable organic matter under aerobic conditions What is COD? - CORRECT-ANSWERSThe measure of oxygen-consuming capacity of organic matter in wastewater What is TOC? - CORRECT-ANSWERSThe measure of concentration of organic carbon in water, including both soluble and particulate forms What is one of the primary functions of a wastewater treatment plant? - CORRECT-ANSWERS- Removal of solids from the wastewater List the various types of solids removed by wastewater treatment plant - CORRECT-ANSWERS- Total

  • Dissolved
  • Suspended
  • Organic
  • Inorganic Suspended solids are composed of what two parts? - CORRECT- ANSWERSSettleable and Non settleable Which wastewater treatment process does not contribute significantly to the reduction of pathogens in the wastewater plant effluent? - CORRECT- ANSWERSDigestion The general types of disinfection include - CORRECT-ANSWERSHeat treatment, radiation treatment, and chemical treatment Disadvantages to the use of ultraviolet radiation in the disinfection of wastewater include: - CORRECT-ANSWERSHigh costs, scattering of the UV irradiation by turbidity particles in the water, coating the tubes with grease and slime What chemicals are used as disinfectants? - CORRECT-ANSWERSBromine, ozone, chlorine and chlorine compounds, iodine What chemical has these characteristics: dark reddish-brown liquid; vaporizes at room temperature; penetrating, suffocating odor - CORRECT- ANSWERSBromine What chemical has these characteristics: forms characteristic vapor on changing gas-lustrous, black solid- chlorine like odor - CORRECT- ANSWERSIodine

What chemical has these characteristics: bluish, toxic gas with a pungent odor, produced electrically or photochemically - CORRECT- ANSWERSOzone Chlorination is the preferred disinfection alternative because of what? - CORRECT-ANSWERSLower cost, greater flexibility In distilled water the amount of free chlorine residual is ______________ related to the dose of amount of chlorine added - CORRECT- ANSWERSAdversely There are two forms of free chlorine residual: - CORRECT- ANSWERSHypochlorite acid and hypochlorite ion Hypochlorite ion is ______________ effective a disinfectant as hypochlorous acid - CORRECT-ANSWERSNot as The most effective form of chlorine residual is - CORRECT- ANSWERSHypochlorous acid The least effective form of chlorine residual is - CORRECT-ANSWERS If a lift station pump will not start what do you check? - CORRECT- ANSWERSBroken and loose terminal connections Shaft binding or sticking Motor shorted or burned out The amount of iron salts fed to the collection system should be increased whenever the: - CORRECT-ANSWERSHydrogen sulfide level increases Where should the flow meter sensor be located at the parshall flume? - CORRECT-ANSWERSAt a specified location in the convergence of the flume What/where is the palmer bowlus flume used in wastewater? - CORRECT- ANSWERSPrimary application: pipelines, round bottom channels, manholes where it is often preferred because the cost and ease of installation that can minimize construction expense Which of the following statements is not true concerning the operation of a magnetic flow meter? - CORRECT-ANSWERSIt operates partially full What methods can be used to check the performance of a flow meter? - CORRECT-ANSWERSMeasure area and velocity in an open channel Measure how long it takes to fill a 55 gallon drum Measure how long it takes to fill a tank

On what type of treatment process do hydraulic flow variations have the greatest impact? - CORRECT-ANSWERSActivated sludge What is important to understand about the impact of high flow on treatment units? - CORRECT-ANSWERSAs flow increases, detention time decreases What is the first indication that a strong toxic industrial substance has entered the activated sludge plant? - CORRECT-ANSWERSIncrease in oxygen concentration in the aeration basin Which type of cave in protection provides the best and most practical way to protect workers in deep excavations? - CORRECT-ANSWERSDrag shields and shoring How do manholes, lift stations, and other features associated with collections/treatment systems would be viewed from a risk assessment point of view? - CORRECT-ANSWERSVulnerabilities Which of the following is an offensive smelling gas found in wastewater treatment plants? - CORRECT-ANSWERSMercaptan Workers in a sludge composting operation should wear respiratory protection because the compost can give off: - CORRECT- ANSWERSAirborne sludge particles What safety equipment should an operator use in areas containing gaseous and particulate contaminants? - CORRECT-ANSWERSSupplied air respirator Which type of fire extinguisher should be used for an electrical fire? - CORRECT-ANSWERSClass C An accident prevention program in generate involves which of the following sets of steps? - CORRECT-ANSWERSRecognition of hazards, evaluation of hazards, and control of hazards How often should fire extinguisher be recharged? - CORRECT- ANSWERSAfter every use Which of the following can poison the atmosphere in a room and should always be handled with special care? - CORRECT-ANSWERSMercury What is the danger level as defined by federal refs, to individuals whose normal noise exposure might equal or exceed this dangerous level - CORRECT-ANSWERS8 hour (TWA) of 85 decibels Widely fluctuating hydraulic flows may require which of the following? - CORRECT-ANSWERSFlow equalization

If you noticed poor solids settling in the clarifier and solids overflow into the chlorine contact chamber, what would you do if the dilated settleometer showed improved settling?? - CORRECT-ANSWERSIncrease sludge wasting As temperature decreases under normal conditions which are the following effect - CORRECT-ANSWERSBiological activity slows down, viscosity of the H2O increases, solids settle slow How does a water temperature decrease affect aerobic biological processes? - CORRECT-ANSWERSDecrease in solids settling efficiency More oxygen in the solution Fine screens typically consist of wedge wire, perforated plate, or closely spaced bars with openings in what range? - CORRECT-ANSWERS0.06 - 0.25 inches One advantage of rotating screens over stationary screens is that rotating screens generally - CORRECT-ANSWERSDo not dam the flow What is the purpose of injecting diffused air into aerated grit chambers? - CORRECT-ANSWERSTo lower the specific gravity of water What is accomplished by an aerated grit chamber? - CORRECT- ANSWERSGrit is removed Grit is washed Wastewater is freshened When using cyclones at the end of a grit removal process what will cause a decrease in grit removal efficiency in the cyclone? - CORRECT- ANSWERSCyclone inlet pressure too low. Increase the inlet pressure by adjusting the grit pump discharge What should an operator do if the communicator is not operating properly? - CORRECT-ANSWERSCheck the motor and look for blockage Cut off the electricity Lock out and tag the breaker Place the bar screen into service How often should communicators be operated? - CORRECT- ANSWERSContinuously How can you control the velocity in a grit channel in order to achieve velocities within a range of 0.7 to 1.4 ft/ sec? - CORRECT-ANSWERSLine the sides with bricks or blocks to change the cross-sectional area Use proportional weirs Vary the number of channels in service in a multiple channel installation

What is primary clarifiers designed to remove? - CORRECT- ANSWERSSettleable solids Unless there is equal flow distribution between two clarifiers, increasing the RAS will - CORRECT-ANSWERSCause an uneven surface loading rate between two clarifiers How does an increase of the flow rate to primary clarifiers affect the detention time and surface loading rate? - CORRECT-ANSWERSDetention time decreases, and loading rate increases Which of the following expresses the formula for the surface overflow rate per day for a settling tank? - CORRECT-ANSWERSThe volume of flow divided by the surface of the tank What test should be performed to see if a clarifier is short circuiting? - CORRECT-ANSWERSPerform a temperature profile of the clarifier How do decreases in temperature affect aerobic biological processes? - CORRECT-ANSWERSDecrease in settling efficiency For which of the following trickling filter problems would you not increase the recirculation rate? - CORRECT-ANSWERSIcing Which of the following is an advantage that synthetic media trickling filters have over rock media trickling filters? - CORRECT-ANSWERSGreater void spaces How would increasing recirculation rates affect the D.O. Content of trickling filter effluent? - CORRECT-ANSWERSIt would increase it When operating an attached growth nitrification process, what five day BOD to nitrogen to phosphorous ratio should be maintained? - CORRECT- ANSWERS100:5: What is a mechanical problem caused from excessive speeds of the distributor of a trickling filter? - CORRECT-ANSWERSDamage to the bearing races of the turntable How do you control the flies around a trickling filter? - CORRECT- ANSWERSCarefully applying insecticides Cleaning around the filter, including pruning grass and shrubbery Flooding the filter weekly When determining the hydraulic loading rate on a trickling filter, the influent flow plus the recirculation rate are used in the calculation. Make sure hydraulic loading remains within the design hydraulic range. What is the typical recirculation rate to influent flow in these calculations? - CORRECT-ANSWERS1:1 up to 2.

During daily operation of a trickling filter, why should the minimum recirculation rate be used whenever possible? - CORRECT-ANSWERSTo conserve energy and maximize plant operation costs and to promote better settling in clarifiers The rotating speed of an air driven rotating biological contactor is controlled by: - CORRECT-ANSWERSAeration rate If the appearance of a RBC becomes white, what is the most likely cause?

  • CORRECT-ANSWERSA type of bacteria that feeds on sulfur compounds is thriving What is the possible course of correction action if RBC turns white? - CORRECT-ANSWERSPre-aerate wastewater influent Add sodium nitrate or hydrogen peroxide in influent Put another RBC unit online Which of the following tests gives the best measure of the microorganisms in the activated sludge process? - CORRECT-ANSWERSMLVSS During cold weather, the biological activity of an activated sludge plant can be subsequently altered. Which procedure best compensates for the problem? - CORRECT-ANSWERSIncrease the MLSS beyond those that are normally maintained during warm temperatures When the F/M ratio is increased, what happens to the sludge age? - CORRECT-ANSWERSDecreases The amount of air suppplied to an aeration tank must be adequate to? - CORRECT-ANSWERSMaintain D.O. At the center of the floc Sphaerotilus natans bulking in the secondary clarifiers can be maintained by: - CORRECT-ANSWERSEnsuring the D.O. Is 2 to 4 ppm in the aeration tank For which is the reasons is intentional daily wasting required in an activated sludge plant: - CORRECT-ANSWERSAs a major method for holding desireable F/M ratio by removing the excess growth Reduce to the lowest of solids in effluent When the return sludge rate is an activated sludge process is too low what happens? - CORRECT-ANSWERSThere will be an insufficient organisms to meet the waste load entering the aerator Activated sludge describes a process by which waterborne wastes are converted into: - CORRECT-ANSWERSBiomass

Mixed liquor suspend solids growth occurs primary from: - CORRECT- ANSWERSNew cell production by the microorganisms MLVSS is a better test for process control than MLSS because it does not measure: - CORRECT-ANSWERSinorganic suspended solids If given an advance warning of a spill of high organic strength waste, what should the operator do: - CORRECT-ANSWERSAdjust the blowers to 100% Decrease the wasting rate At start up or after an upset, which types of microorganisms will predominante in the mixed liquor? - CORRECT-ANSWERSAmoeboids and flagellates A predominance of which of the following organisms may cause bulking? - CORRECT-ANSWERSFilaments Which of the following indicates a good settling quality of activated sludge? - CORRECT-ANSWERSSVI in the range of 50- Which of the following is a problems associated with nitrification in a suspended growth reactor? - CORRECT-ANSWERSHydrogen ion concentration The settleability test conducted on MLSS is an estimate of how well solids will settle in which of the following units? - CORRECT-ANSWERSSecondary clarifier What can the operator do if the plant is experiencing rising sludge in the secondary clarifier as a result of denitrification? - CORRECT- ANSWERSReduce the air at the end of the aeration tank to 0.2 - 0.5 mg/L for a few hours An active sludge in the aeration tank with an abundant available food supply will have a relatively: - CORRECT-ANSWERSHigh oxygen uptake and slow settling rate How long would you allow an activated sludge process to react and stabilize after a major process change? - CORRECT-ANSWERSAt least 1 week What type of activated sludge plant can handle a high organic shock load?

  • CORRECT-ANSWERSStep feed Which of the following is NOT a type of nitrogen removal system? - CORRECT-ANSWERSSand filtration How many pounds of oxygen is required to oxidize 1 pound of ammonia to nitrate? - CORRECT-ANSWERS4.

Alum is added to the secondary clarifiers of an activated sludge plant to remove? - CORRECT-ANSWERSPhosphates Which of the following is NOT a water quality characteristic that should be measured in the receiving waters and in the plant effluent? - CORRECT- ANSWERSChloride According to the state of TN water quality standards, the effluent flow from a wastewater treatment plant shall not change the pH of the receiving stream more than: - CORRECT-ANSWERS1.0 units per 24 hours What is a reason to pump sludge from the primary clarifier to the digester several times a day? - CORRECT-ANSWERSMaintain better conditions in the clarifier To permit thicker sludge to be pumped To prevent cloning To prevent temporary over loading of the digester What is the most critical factor in controlling the anaerobic digester operation? - CORRECT-ANSWERSVolatile acids/alkalinity relationship Which of the following is NOT a reason for withdrawing sludge slowly from an anaerobic digester? - CORRECT-ANSWERSTo keep super ate the from over loading the plant What could be a cause of "washing out" of the belt on a belt filter press? - CORRECT-ANSWERSBelt binding Belt speed too low Hydraulic load too high Polymer dosage insufficient Why should the contents of a primary digester be mixed? - CORRECT- ANSWERSTo distribute food in the tank What are causes of an anaerobic digester floating cover tilting? - CORRECT-ANSWERSWeight distribution not even; adjust movable ballast or weights to level cover. What is the minimum D.O. That should be maintained in a aerobic digester under loading conditions? - CORRECT-ANSWERS1.0 mg/L How can you get a drier cake on a belt press? - CORRECT- ANSWERSDecrease the speed of the belt What is the 40lbs part 503 class B fecal coil form pathogen requirement limits before biosolids can be land applied? - CORRECT- ANSWERS2,000,000 colony forming units per gram of total solids - dry weight

What is the 40 cfr part 503 class A fecal coliform pathogen requirement limits before biosolids can land applied? - CORRECT-ANSWERS<1,000 MPN per gram of total solids - dry weight What is the monitoring frequncry for analysis of pollutants, pathogens, vector attraction based on the amount of biosolids annually disposal or usage in metric tons (503 regulations) - CORRECT-ANSWERSGreater than 0 but less than 290 analyses is 1 year 290 but < 1500 analyses is 4/year 15,000 analyses is 12/ year According to TDEC rule regarding NPDES permits, a loss of MLSS suspended solids of 30% or more from the aeration basin to the receiving stream due to improper operation of from peak flows causes by I/I - CORRECT-ANSWERSWashout According to the rules which govern water and wastewater operators, when found guilty of falsifying records, an operator will lose his/her license for how many years until they will be eligible to reapply? - CORRECT- ANSWERS5 years When must all monthly discharge monitoring reports be submitted to the state? - CORRECT-ANSWERSPostmarked no later than the 15th of each month What are four true statements concerning washouts? - CORRECT- ANSWERSA written report must be submitted to the state within 5 days It is the loss of MLSS of 30% or more It must be reported to the state within 24 hours by telephone It refers ONLY to the MLSS in the aeration tank According to the regulations of the State of TN under what conditions can a certified operator operate more than one water and /or wastewater system? - CORRECT-ANSWERSIf the systems are in reasonable proximity to one another his/her certificate qualifies him/her to operate both systems According to TN regulations when renewing an NPDES permit how long before the permit expiration date must the owner submit their application? - CORRECT-ANSWERSNo later than 180 days According to TN regulations regarding NPDES permits the intentional diversion of waste water away from any portion of a treatment facility is called a: - CORRECT-ANSWERSBypass According to the CODE OF FEDERAL REGULATIONS, what is the approved method for measuring and reporting pH on the NPDES report? - CORRECT- ANSWERSElectro metric

According to TN regulations regarding NPDES permits, any individual sample cannot exceed what value in fecal coil form number per 100 ml - CORRECT-ANSWERS Which of the following laws govern operator certification in TN? - CORRECT-ANSWERSWater and wastewater operator certification act Sand filters can be cleaned by: - CORRECT-ANSWERSBackwashing at correct rates Dosing with chlorine for mud balls, algal and slim growths If clogged: shut down sand filter and acid wash the sand filter with hydrochloride acid or muriactic acid for around 8-12 hours Types of membrane filtration include: - CORRECT-ANSWERSMicrofiltration Ultrafiltration Nanofiltration Reverse osmosis What is the filtrate called that passing through a membrane filter? - CORRECT-ANSWERSPermeate The rate of mass flow permeate passing through the membrane is called: - CORRECT-ANSWERSFlux The ability of a filter to prevent the passage of solid particles to pass through is called: - CORRECT-ANSWERSRejection or retention A malfunctioning gas chlorination system has a normal gas pressure, zero feed rate on the rotometer, and no injector vacuum. Wha this the most likely cause of this problem? - CORRECT-ANSWERSClogged injector The mesh covering a chlorination vent line should be: - CORRECT- ANSWERSA non corrodible fine mesh screen should be placed over the discharge ends all of vent lines. All vent lines shall discharge to the outside atmosphere above grade and at location least susceptible to vandalism What may cause a marked increase in the chlorine demand in the chlorine contact chamber? - CORRECT-ANSWERSIntermediate oxidation state of nitrogen between ammonia and nitrate nitrogen How are pathogenic bacteria destroyed or removed from wastewater? - CORRECT-ANSWERSBy destruction through chemical treatment By natural die off in an unfavorable environment By physical removal through sedimentation or filtration A few days after high flow conditions, and high organic loading to the plant, and with the chlorination equipment set at the correct feed rate, the

effluent chlorine residual is too low and the fecal coliflor count int he effluent is too high. What is the probably cuase? - CORRECT- ANSWERSSolids accumulation in the chlorine contact chamber Chlorine gas is : - CORRECT-ANSWERSHeavier than air Where must the effluent chlorine residual be sampled according to the NPDES permit? - CORRECT-ANSWERSAfter the chlorine contact chamber and any dichlorination During dichlorination what would happen if you ever overfeed sulfur dioxide? - CORRECT-ANSWERSOverdosing can cause a drop in effluent DO, a drop in pH, and an increase in effluent BOD/COD If disinfecting with ozone what is the required contact time? - CORRECT- ANSWERS10-30 minutes How much chlorine must be added to wastewater to produce disinfection?

  • CORRECT-ANSWERSEnough chlorine to satisfy the demand plus the desired residual that will last through the contact period At what concentration does chlorine become fatal in a few breaths? - CORRECT-ANSWERS1000 mg/L What PPE does the chlorine institute recommend for emergency response to a chlorine release when liquid chlorine is not involved? - CORRECT- ANSWERSLevel B PPE A malfunctioning gas chlorination system has normal gas pressure, and no injector vacuum. What is the most likely cause of the problem? - CORRECT-ANSWERSInjector clogged There is a chlorine leak on a 1 ton cylinder. With proper emergency training you should: - CORRECT-ANSWERSRoll the tank until the leak is pointed up What is the most important function of algae in a facultative lagoon? - CORRECT-ANSWERSTo produce oxygen in the daylight What is the color of a properly functioning facultative lagoon that receives domestic sewage? - CORRECT-ANSWERSDeep green Routine pH and dissolved oxygen analyses are probably the most important tests to be performed on a stabilization pond. What kinds of values would an operator expect late in the afternoon before dark? - CORRECT-ANSWERSHighest values of the day What is the most effective in preventing a cross connection? - CORRECT- ANSWERSAir gap

What is a cross connection? - CORRECT-ANSWERSA direct connection between portable water supply and a non potable water supply Motors up to 100 hp should not be started more than - CORRECT- ANSWERS4-5 times per week What kind of pipe is most resistant to corrosion? - CORRECT- ANSWERSPolyvinyl chloride Power couplings between drives and driven parts of a machine should be:

  • CORRECT-ANSWERSKept in alignment What prevents internal leakage in a centrifugal pump? - CORRECT- ANSWERSWear rings At a pump station equipped with centrifugal pumps, what caused the discharge pressure suddenly to increase and the discharge quantity to suddenly decrease? - CORRECT-ANSWERSA discharge valve was closed What happens to flow from a centrifugal pump when the pressure is lost from the discharge end? - CORRECT-ANSWERSCavitation in the pump because of line breaks resulting in low flows What is the electrical pressure available to cause a flow of current when an electrical circuit is closed called: - CORRECT-ANSWERSVoltage Which is not corrosive? - CORRECT-ANSWERSCarbon monoxide Electrical wiring used in business structures has different colors to distinguish them. What color would a ground wire be? - CORRECT- ANSWERSGreen What is included in preventative maintenance of electric motors? - CORRECT-ANSWERSChecking temperature of motor Keeping the motor free of dust, dirt, and moisture Lubricating bearings When a pump is running, how should the packing leak? - CORRECT- ANSWERSShould leak only slightly What is included in the maintenance of gate valves? - CORRECT- ANSWERSOperating inactive valves to prevent sticking Refacing leaking valve seats Tightening or replacing the stem stuffing box packing What is used to determine if the gate valve seats fit properly? - CORRECT- ANSWERSPrussian blue

What causes most bearings failures on turbine or centrifugal blowers? - CORRECT-ANSWERSToo much grease Bearings are often heated for ease of installation. To prevent damage to the bearing, the temperature should not exceed what temp? - CORRECT- ANSWERS300 degreees Fahrenheit The best way an operator can determine when the air filters on aeration blowers need cleaning is to: - CORRECT-ANSWERSMeasure the differential pressure between inlet and discharge side of the filter What is a good indication that the filter in the air distribution system needs to be cleaned or changed? - CORRECT-ANSWERSManometer reading increases more than two or three inches from initial reading When repacking gate valves that is in service, what should the operator do to minimize leaks? - CORRECT-ANSWERSBefore repacking open valve wide open to draw the stern collar tightly against the bonnet for both non- rising stem valves and rising stem valves How should threaded air diffusers be attached to the headers? - CORRECT- ANSWERSManually screw them on until finger tight If you were preparing to paint a pipe around a tank, what should be done?

  • CORRECT-ANSWERSSandblast or wire brush and paint immediately BOD samples must deplete at least how many mg/L to have a valid test? - CORRECT-ANSWERS2.0 mg/L What should be used as a reference concerning NPDES sampling and preservation procedures? - CORRECT-ANSWERSCode of federal regulations title 40 part 136 Which of the BOD samples will require adding seed? - CORRECT- ANSWERSChlorinated EFF Before making dilutions, a BOD sample must be adjusted to what temp? - CORRECT-ANSWERS20 degrees C What is used to standardize a pH meter? - CORRECT-ANSWERSKnown buffer solutions A single sample of water collected at a particular time and place which shows the character of the water at the time and place of collection is a _______ sample - CORRECT-ANSWERSGrab If immediate analysis is not possible how must samples of ammonia nitrogen be preserved? - CORRECT-ANSWERSAdding H2so4 to pH Refrigeration at 4 degrees Celsius

What receiving water characteristics must be measured immediately after the sample is collected? - CORRECT-ANSWERSTemperature, pH, and dissolved gases The temperature of fecal coliflor incubator using the membrane procedure may vary throughout the unit from the standard valve to no more than? - CORRECT-ANSWERS.2 degree C What is used when conducting the VSS test? - CORRECT-ANSWERSGlass fiber filter What units are used to report the results of a settleable solids test? - CORRECT-ANSWERSMl/L What is the difference between the BOD test and the CBOD test? - CORRECT-ANSWERSA nitrification inhibitor is added What is the correct procedure for emptying a volumetric pipette? - CORRECT-ANSWERSAfter outflow stops,touch the tip of the pipette to the wet surface of the receiving vessel The lab just received new pipette. What should be done first? - CORRECT- ANSWERSDip them in avid What is a pipette that has a frosted band there the top that indicated that the small amount that remains after delivery is to be blown out? - CORRECT-ANSWERSSerological In accordance with TN regulations and NPDES permits, what three laboratory methods are approved to detect total chlorine residuals at the 0,05 mg/L - CORRECT-ANSWERSAmo pero metric back titration, DPD color metric, specific ion electrode According to the code of federal regulations what is not an approved method for reporting the chlorine test on the NPDES report? - CORRECT- ANSWERSDPD color comparator What substance is added to the distillate when performing the ammonia test to ensure the distillation apparatus is not contained with ammonia? - CORRECT-ANSWERSNesslers reagent Why is 10N sodium hydroxide added to the sample before analysis when testing for ammonia using the electrode method? - CORRECT- ANSWERSThe pH needs to be above 11 What is a description of an SVI of 300? - CORRECT-ANSWERSThe solids are settling very slowly in the clarifier

What is used to distinguish fecal coliflor bacteria from total coliflor bacteria? - CORRECT-ANSWERSGrowth on M-FC media at 44.5 degrees Celsius (+/- 0.2 degrees ) In preparing a calibration curve for a spectrophotometer what is plotted on the horizontal axis? - CORRECT-ANSWERSConcentration According to TN regulations regarding NPDES permits any individual sample cannot exceed what value in fecal coliflor concentration per 100 ml? - CORRECT-ANSWERS H2SO4 is the formula for? - CORRECT-ANSWERSSulfuric acid What is one gram equivalent of reactant per lit of solution called? - CORRECT-ANSWERSNormal solution Which calculations are methods of grouping measurements and describing the results with a single number? - CORRECT- ANSWERSArithmetic mean Geometric mea Median or mode Standard deviation What chemical is used to standardize the acid Titian's used in the alkalinity test? - CORRECT-ANSWERSSodium carbonate What lab process uses a metal added to a sample and boils the sample to collect the condensation to continue testing of the free sample of interferences? - CORRECT-ANSWERSPreliminary distillation What is used to measure the residual ultraviolet radiation? - CORRECT- ANSWERSThere is no residual What is nitrate changed to when mixed with cadmium? - CORRECT- ANSWERSNitrite For laboratory analysis why are duplicate and or replication samples performed concerning quality control? - CORRECT-ANSWERSPrecision Reflux time for COD is how long? - CORRECT-ANSWERS2 hours A gas cylinder valve should only be opened ____ turn so it can be closed quickly in an emergency - CORRECT-ANSWERSOne quarter Chlorine leaks can be located quickly by: - CORRECT-ANSWERSUsing the vapor only from a squirt bottle filled with ammonia solution The chlorine contact chamber should be drained and cleaned at least: - CORRECT-ANSWERSAnnually

Ultraviolet light disrupts DNA by: - CORRECT-ANSWERSCausing the formation of thymine dimers As effluent turbidity increases: - CORRECT-ANSWERSE. Coli concentrations are likely to increase The fire extinguisher is safe for use on ordinary combustible fires, like those fueled by paper or wood - CORRECT-ANSWERSClass A The fire extinguisher is safe for use on flammable liquids like grease, gasoline, and oil, and most often uses CO2 to suppress fires: - CORRECT- ANSWERSClass B The fire extinguisher is safe for fires that are electrically energized: - CORRECT-ANSWERSClass C The fire extinguisher is safe for combustible metals like magnesium and titanium: - CORRECT-ANSWERSClass D The fire extinguisher used to combat kitchen fires: - CORRECT- ANSWERSClass K Phosphorous accumulating organisms use VFAs in the anaerobic zone to do what: - CORRECT-ANSWERSConvert internal storage products What is an indicator of good EBPR performance? - CORRECT- ANSWERSHigh phosphorous content of MLSS One reason a WWTP may decide to use UV over chlorine for disinfection might be: - CORRECT-ANSWERSConcern over chlorine saftey A vial from MPN test is cloudy from bacterial growth. Shows gas production and glows blue under a black light what is true? - CORRECT- ANSWERSThe test is positive for total coliforms and E. Coli Chlorine and hypochlorite break down water to form - CORRECT- ANSWERSHypochlorite acid and hypochlorite ion EPA recommends that the E. Coli concentration in recreational waters be kept on average below: - CORRECT-ANSWERS126CFU/100 ml Fusible plugs are designed to melt at what temperature - CORRECT- ANSWERS158-165 F A 1 ton chlorine container has this many fusible plugs - CORRECT- ANSWERS6 plugs

For a Venturi to function correctly - CORRECT-ANSWERSPressure and flow rate must be high enough to produce a vacuum This type of water is the most difficult to disinfect: - CORRECT- ANSWERSCold, high pH The IMLR does what? - CORRECT-ANSWERSReturns nitrate to the anoxic zone ORP is affected by: - CORRECT-ANSWERSWater quality and temp This marks the end of denitrification when ORP is used to monitor an SBR - CORRECT-ANSWERSNitrate knee When either alum or ferric chloride is added to wastewater - CORRECT- ANSWERSAlkalinity is consumed One reason alum may be added upstream of the primary clarifier is to: - CORRECT-ANSWERSImprove clarifier performance Luxury uptake of phosphorous occurs - CORRECT-ANSWERSIn the presence of nitrate or oxygen What biochemical reaction takes place in the anaerobic zone: - CORRECT- ANSWERSRelease of phosphorous Growth and reproduction of PAO primarily takes place - CORRECT- ANSWERSWhen PHB is consumed Phosphorous that is removed from an EBPR process - CORRECT- ANSWERSIs sequester in the WAS The organisms capable of both fermentation and luxury uptake of phosphorous - CORRECT-ANSWERSTetraphaaera About how long does it take for the PAO to complete uptake of FVAs when they are in anaerobic zone? - CORRECT-ANSWERS15-45 mins This process control parameter is the least important in sustaining nitrification in activated sludge process - CORRECT-ANSWERSHDT Nitrogen gas produced during denitrification - CORRECT-ANSWERSEnds up in the atmosphere For denitrification to occur what conditions must exist? - CORRECT- ANSWERSOrganic carbon DO can inhibit denitrification at concentrations as low as: - CORRECT- ANSWERS0.3 mg/L

Activated sludge processes that denitrify - CORRECT-ANSWERSGenerates less sludge than those who don't For every 1 mg/L NO3-N converted to nitrogen gas this must alkalinity is recovered - CORRECT-ANSWERS3.57 mg/L as CA CO3 Denitrification of 1 mg NO3 N recovers the equivalent of ______ mg/L of DO in the treatment process - CORRECT-ANSWERS2.86 About this much BOD is needed to convert 1 mg/L of nitrate-nitrogen to nitrogen gas - CORRECT-ANSWERS4 mg/L Primary clarifiers can affect denitrification by : - CORRECT- ANSWERSChanging the BOD to nitrate-nitrogen ratio What must occur first? - CORRECT-ANSWERSConvert ammonia to nitrite Denitrification rates will be highest at this location - CORRECT- ANSWERSPre-anoxic zone Denitrification is likely to occur in the secondary clarifier blanket when - CORRECT-ANSWERSIt is the middle of the day Nitrate is sometimes added to the collection system to: - CORRECT- ANSWERSControl odors After biological treatment is complete, most of the remaining phosphorous will be present as: - CORRECT-ANSWERSOrthophosphate the AOB obtain their energy from - CORRECT-ANSWERSAmmonia Ph affects the AOB by: - CORRECT-ANSWERSReducing the availability of NH3 Nitrifying bacteria convert ammonia to nitrate under - CORRECT- ANSWERSAerobic conditions The operator of an activated sludge process knows from past experience that the water temp in the aeration basin will drop from 72F to 59F between august and December. What process changes should be made? - CORRECT-ANSWERSIncrease the SRT gradually based on water temp A RBC process consist of four wheels operated in series. Where in the process is nitrification most likely to take place - CORRECT- ANSWERSFourth wheel An activated sludge process with an SRT for 6 days receives an abnormally high ammonia load. The blowers are unable to deliver enough

air and DO concentration in the basin drops to 1 mg/L. What may occur next? - CORRECT-ANSWERSChlorine consumption will increase When supernatent the from an anaerobic digester is returned to the activated sludge process in the middle of the day - CORRECT- ANSWERSEffluent ammonia concentrations may increase A domestic WWTP receives the majority of its wastewater from a fruit process and canning factory. The WWTP has an ongoing issue with slimy, viscous, gray foam, to fix the problem they need to: - CORRECT- ANSWERSAdd missing nutrients Excessive fines from septage receiving or solids handling process generate a pumice like foam because - CORRECT-ANSWERSFines dont flocculate well This condition results when MLSS fails to flocculate and leaves behind a turbid supernatent - CORRECT-ANSWERSDispersed growth Which two chemicals may be added to activated sludge for filament control - CORRECT-ANSWERSChlorine and PACI This term is used to describe the total amount of chemical to the treatment process - CORRECT-ANSWERSDose When should chlorine addition to an activated sludge process be stopped?

  • CORRECT-ANSWERSWhen only empty sheaths remain What chemical is most effective for controlling M. Parvicella - CORRECT- ANSWERSPoly aluminum chloride Chlorine is often applied directly to nocardiafoam instead of the RAS line because: - CORRECT-ANSWERSFilaments concentrate in the foam If the MLSS concentration gets too low this condition may result in - CORRECT-ANSWERSStraggler floc If a secondary clarifier is already overloaded with solids turning up the RAS flowrate will: - CORRECT-ANSWERSIncrease the blanket depth What nitrogen compound is not typically found in influent wastewater - CORRECT-ANSWERSNitrite Gas bubbles generated in the sludge blanket may cause: - CORRECT- ANSWERSAshing or clumping A key indicator that denitrification is taking place in a circular secondary blanket is: - CORRECT-ANSWERSSludge collecting between scum baffle and weir

An operator has just finished the daily walk through of the activated sludge process. They decided to increase the RAS flow slightly. What did the operator observe that resulted in the decision: - CORRECT- ANSWERSClarifier blankets deeper than 2 ft During start up when sludge seed is not available, influent wastewater is preferred over primary effluent because: - CORRECT-ANSWERSGreater populations of microorganisms MLSS should not be wasted from the process for the first time until: - CORRECT-ANSWERSMinimum start up concentration has been reached An operator notices that one area of activated sludge basin is particularly turbulent. The most likely cause is: - CORRECT-ANSWERSDamaged or missing diffuser An activated sludge basin is covered with large amounts of CRISP WHITE FOAM this indicates - CORRECT-ANSWERSStart up conditions An activated sludge process has 3 identificar secondary clarifiers. Sludge blanket depths are each at 1ft, 1.2ft, and 3ft. What is the most likely cause for the difference? - CORRECT-ANSWERSUneven flow distribution feeding the clarifiers In the settleometer test the SSV at 30 minutes is an indicator of: - CORRECT-ANSWERSSludge compaction This type of container should be used for the settleometer test: - CORRECT-ANSWERSMallory settleometer Settled sludge may rise back up to the top of the settleometer for this reason: - CORRECT-ANSWERSDenitrifying and production of nitrogen gas The primary difference between an OUR and a SOUR test is: - CORRECT- ANSWERSSOUR corrects for sludge concentration The SOUR test measures : - CORRECT-ANSWERSHow fast microorganisms consume oxygen MLVSS are used for OUR and SOUR testing rather than MLSS becuase - CORRECT-ANSWERSThe MLVSS test measures live organisms An operator is conducting a walkthrough of their facility and they notice billowing clouds of sludge at the edges of the secondary clarifiers. What is the most likely cause: - CORRECT-ANSWERSHydraulic surge

The DO concentration in the activated sludge basin increases from 2 to 6 mg/l what is the most likely cause? - CORRECT-ANSWERSToxic material in the influent When starting up a new facility how long does it typically take for start up foam to go away? - CORRECT-ANSWERS2-4 days Brown foam should be removed from the activated sludge basin and clarifier surfaces to: - CORRECT-ANSWERSReduce the numbers of filament outs bacteria This foaming filamentous bacteria tends to cause problems during colder weather - CORRECT-ANSWERSM. Parvicella The MLSS gradually turning from light tan to black over several hours. DO concentration are normal and excess foaming is not present. No side streams were entering the basin during this time. What could have caused the color change? - CORRECT-ANSWERSPowdered activated carbon The surface of the activated sludge basin and clarifier are covered with brown foam. Micro exam shows that there are almost no filaments in the foam. What must be true? - CORRECT-ANSWERSThe SRT is long and the F/M is low. The influent BOD load is unchanged. SRT is increasing. What must be true? - CORRECT-ANSWERSGrowth rate is decreasing The SRT is currently 12 days. If the SRT is decreased to 8 days. What will happen to the f/m - CORRECT-ANSWERSIt will increase Maintaining a constant MLSS concentration as a process control strategy approximates constant SRT when: - CORRECT-ANSWERSinfluent BOD and TSS loads are nearly constant The minimum sludge age needed to produce well flocculated MLSS is around - CORRECT-ANSWERS2-3 Days White foam is associated with - CORRECT-ANSWERSSRT lower than 2 days For filamentous bacteria to proliferate in activated sludge environmental conditions must support their growth and: - CORRECT-ANSWERSSludge age must be long enough Why do many WWTP facilitates see the SVV decrease in the summer and increase in the winter - CORRECT-ANSWERSWater temp affects settling velocity If the MLSS has an SVI greater than 200 ml.g it is defined as: - CORRECT- ANSWERSBulking

The maximum MLSS concentration for most activated sludge system is limited by: - CORRECT-ANSWERSClarifier capacity To prevent the growth of the filament Sphaerotilus Nathan's, low DO must be avoided and the SRT should be kept below about: - CORRECT- ANSWERS9 days When DO concentrations are low, certain types of filaments grow faster than the floc forming bacteria because: - CORRECT-ANSWERSFloc former growth slows down What concentration will prevent the growth of low DO filaments - CORRECT-ANSWERS2 mg/L The SVI has increased over the last week from 120-180. A micro exam reveals many H. Hydrossis filaments. The operator should: - CORRECT- ANSWERSIncrease DO concentration This process variable is typically what limits the clarifier capacity - CORRECT-ANSWERSSLR (solids loading rate) If the SLR is too high: - CORRECT-ANSWERSBlanket depth will increase Last week the SVI was 120 this week the SVI increased to 210. The operator may need to - CORRECT-ANSWERSReduce the SLR RAS flow rates should be kept as low as possible while meeting treatment goals to: - CORRECT-ANSWERSAvoid sending excess water to solids handling process One advantage of flow pacing the RAS pumps to the influent flow is: - CORRECT-ANSWERSNearly constant RAS concentration Sludge settleability has deteriorated over the last 2 weeks and the clarifiers are building deep blankets. The operator turns up the RAS to remove the sludge from the clarifier faster but instead of going down the blankets get even deeper. This is because: - CORRECT-ANSWERSSOR is too low The secondary clarifier at a small facility is overloaded. There are no other clarifiers available. A short term solution may be to: - CORRECT- ANSWERSAdjust SVI with chemicals An operator notices large patches of white biofilm on an RBC in the first stage of treatment train. This indicates: - CORRECT-ANSWERSLack of oxygen