Wastewater Operator Level 1 Practice Test

These questions are part of the practice quiz. Start practicing

• What is the greatest hazard when entering a confined space at a plant?
• What is one advantage of a COD test over a BOD test?
• Why is a good housekeeping program important in a wastewater plant?
• In most activated sludge plants the waste activated sludge is pumped to waste sludge handling facilities.
• Which set of measurements is typically used to assess effluent quality after treatment?
• Which outcome is directly associated with insufficient dissolved oxygen in the aeration basin?
• What does MLSS stand for in wastewater context?
• What is a common consequence of excessive sludge wasting?
• Why is maintaining adequate DO in an aeration basin important?
• What does the acronym MPN stand for in wastewater testing?
• BOD can be removed from the incubator after 5 days plus or minus how many hours?
• Which maintenance issue can cause overheating of mechanical equipment?
• Which statement best describes the difference between domestic wastewater and industrial wastewater?
• Why does grit settle out better in aerated grit chambers?
• What does BOD5 measure in wastewater and why is it important?
• A plant receives 2.5 MGD and has a rectangular aeration basin of 30 m by 12 m by 4 m. What is the approximate detention time in hours?
• What is the primary byproduct produced during anaerobic digestion of sludge?
• Why is odor control important at a wastewater treatment plant?
• In the CT concept, what does t represent?
• In a healthy activated sludge process which of the following organisms will most likely be found in the greatest numbers?
• What is the typical effect of increasing the aeration time in an activated sludge basin?
• What is energy recovery in wastewater treatment?
• Which statement best describes the relationship between pH and basic or acidic conditions?
• Which early-stage treatment step is used to freshen wastewater and remove oils before biological treatment?
• Which component of MLSS represents the active biomass?
• Accidents can be reduced by thinking safety.
• What is a typical acceptable pH range for biological wastewater processes?
• What is the function of an influent pump station?
• Which parameter is most directly used to control the rate of biological treatment in an activated sludge system?
• Which parameter is commonly used to monitor the biological treatment process in the mixed liquor?
• Which parameter is measured by TSS in wastewater testing?
• What is the typical reason for grit removal in an inlet works?
• What is composite sampling and why is it used in wastewater analysis?
• Grab sampling and composite sampling differ in what way?
• What does SRT stand for and why is it important in activated sludge?
• Why are lockout/tagout procedures essential during maintenance?
• Which maintenance issue is associated with overheating of mechanical equipment?
• Filamentous bulking of activated sludge may be controlled temporarily by...
• Turbidity is primarily a measure of which parameter?
• Grit removal in wastewater treatment is primarily intended to remove what type of material?
• What residual is routinely monitored to verify disinfection in wastewater effluent?
• In aeration tanks, the typical DO range for activated sludge is?
• Raw or untreated wastewater contains materials that will either settle to the bottom or float to the water surface readily when the wastewater velocity is allowed to become very slow.
• In a rectangular sedimentation basin, what is the primary function of the scum trough?
• What is the role of a residuals management plan?
• Since reaction rates are lower during the winter, the operator of an activated sludge plant will usually...
• What could happen if hold time exceeded?
• What is a common cause of low dissolved oxygen in aeration tanks?
• Which organism type is most commonly observed in healthy activated sludge?
• Which statement best describes permit compliance in wastewater operations?
• For a combined sedimentation-digestion unit what is the purpose of inflow measurement?
• A high SVI indicates which of the following?
• Which of the following describes common approaches to odor control in wastewater plants?
• BOD5 testing measures the oxygen consumed by biological oxidation over how many days?
• The COD test provides faster results than the BOD test because:
• The primary function of coagulants and polymers in treatment is to:
• What is the difference between GPM and MGD, and how are they used in plant design?
• Name a common safety hazard associated with pumping stations.
• What is the primary purpose of a wastewater treatment plant's grit chamber?
• During anaerobic decomposition, which gas is commonly produced?
• If sludge production is reported as lb/day, which conversion approximates kg/day?
• The output from an anaerobic digester can help with which of the following?
• What is a centrifugal pump and when is it preferred?
• In a secondary clarifier, what is the primary function?
• After completing a shift at a wastewater treatment plant, which practice helps prevent spreading contaminants home?
• What is the main function of a secondary clarifier?
• Which statement about safety in wastewater operation is true?
• What is the most common wastewater flow measuring device at a treatment plant?
• Wastewater entering a treatment plant typically is which relative temperature to tap water?
• Why is pH monitoring important in a wastewater plant?
• In a clarifier, how does flow velocity affect settling?
• Which issue signals that aeration may be insufficient in a wastewater treatment system?
• Which device is used to measure flow rate in a wastewater system?
• Head loss in a pipe is most accurately defined as
• What is the primary purpose of a SCADA system in a wastewater facility?
• Anaerobic decomposition of wastewater produces which gas?
• A SCADA system in wastewater operations is used to do which of the following?
• Which byproducts are managed under a residuals management plan?
• Which disinfectant leaves a residual in treated water to provide ongoing disinfection?
• Special care and safety must be practiced when visitors are taken through your treatment plant.
• Convert 2 million gallons per day (MGD) to liters per second (L/s).
• What does pH express?
• The first clarifier that wastewater flows into is called the secondary clarifier.
• What does sludge age refer to in a wastewater treatment process?
• Which test would give the fastest indication of toxicity in an activated sludge process?
• What is the role of a centrifuge in sludge handling?
• What is the primary purpose of dewatering sludge?
• Best operating strategy for feeding primary sludge to an anaerobic digester?
• What is the primary purpose of nitrification in wastewater treatment?
• A basin has a volume of 800 cubic meters and an inflow of 200 cubic meters per hour. What is the hydraulic detention time?
• Composite sampling in wastewater labs is defined as what?
• What is the role of alkalinity in wastewater chemistry?
• What is the purpose of a rectangular sedimentation basin scum trough?
• Why is a sampling plan important for a wastewater plant?
• How do you calculate hydraulic detention time in a basin given volume V and inflow Q (consistent units)?
• Which statement correctly describes unit requirements for calculating HRT?
• What type of device is commonly used to measure flow in sewer lines?
• Which of the following is not a function of a primary clarifier?
• Entrained air frequently contributes to which problem in a wastewater pump system?
• The screening disposal method used by a plant should be assessed for potential adverse impacts on groundwater or surface waters.
• What is the standard unit for reporting sludge production rate in a wastewater plant?
• What is the purpose of pre-aeration?
• Why is a preventive maintenance program essential in wastewater operations?
• What is the formula for Hydraulic Retention Time (HRT) in a tank with known volume?
• Which parameter is used to estimate the strength of wastewater's organic matter?
• What is the purpose of an anaerobic digester in sludge management?
• Tests on clarifier efficiency may be conducted at the plant site where the sample is collected or in the laboratory.
• Which treatment units are designed and operated to remove sludge and scum?
• Normal and abnormal operational procedures as well as start-up and shut-down procedures for barminutors are different from those used for comminutors.
• What is the typical range for dissolved oxygen (DO) in aeration tanks used in activated sludge processes?
• If a chlorine leak is detected, what is the correct sequence of actions?
• In the MPN test, the sample is considered positive when which condition occurs in the Durham tube?
• Which statement about COD relative to BOD is true?
• What does a high Food-to-Microorganism (F/M) ratio usually indicate in an activated sludge process?
• What makes confined space entry hazardous and what permit is used?
• What does DO stand for and why is it critical in activated sludge?
• Which statement best describes permit limits in wastewater regulation?
• What is the purpose of a coagulant or polymer in treatment?
• What is the function of a secondary clarifier in a conventional treatment plant?
• What is the purpose of return activated sludge (RAS) in an activated sludge plant?
• What is the purpose of a chlorine contact tank in disinfection?
• Which statement best describes the effect of flotation technology on fats and oils removal?
• Nitrification is the biological process that converts ammonia to nitrate.
• Why is scum skimmed from the liquid surface of a primary settling tank?
• DO stands for which term?
• What does a high mixed liquor suspended solids (MLSS) indicate in an aeration basin?
• Which of the following is a typical requirement before entering a confined space at a plant?
• What does MLVSS represent and why is it used?
• If you double the contact time while keeping chlorine concentration constant, what happens to CT and disinfection effectiveness?
• Many industrial wastes are highly acidic or alkaline and either condition can interfere with aquatic life, domestic use, and other uses.
• Which statement best describes the impact of discharging industrial wastes on water uses?
• Which sampling method is best for capturing peak pollutant concentrations?
• What are the common methods of disposal of material removed from screens?
• In a clarifier, lower flow velocity helps solids settle out.
• What is a common method for measuring chlorine residual in wastewater?
• How much education does an operator need?
• MLSS content includes which of the following?
• What does BOD5 stand for?
• If filamentous bulking occurs, which practice can temporarily help regain settleability?
• Alkalinity is a measure of the ability of wastewater to...
• What is a waste activated sludge (WAS) stream?
• What range is acceptable for biological wastewater processes?
• Why is DO critical in the aeration basin?
• What is the function of a chlorine contact tank?
• In wastewater analysis, composite sampling is typically used to represent what?
• Reviewing all aspects of the wastewater treatment system to determine potential outcomes during various emergencies is known as which process?
• A process control chart is used for which of the following?
• Which statement about safety during plant tours is most accurate?
• What is the purpose of UV disinfection in wastewater treatment?
• Inflow measurement in a combined sedimentation-digestion unit helps determine which parameter?
• Which parameter is most commonly used to evaluate disinfection effectiveness in plant effluent?
• pH generally will be affected significantly by a clarifier.
• Which factor most directly affects the efficiency of solids settling in a secondary clarifier?
• What is bulking and what is a common cause related to filamentous bacteria in activated sludge?
• How does flow rate relate to head in a pump curve?
• In wastewater systems, which pump is typically used for general flow with moderate head and continuous operation?
• Why must fats, oils, hair, and other light material be removed by flotation?
• What is COD and how does it differ from BOD?
• What is a storm sewer?
• What is the purpose of backwash in a filtration system?
• What is H2S and why is it a concern in wastewater facilities?
• During confined space entry, what is the purpose of atmosphere monitoring?
• Why must some organisms periodically be removed from the activated sludge process?
• If pump head is higher than design, what is a typical corrective action?
• Which statement best describes the difference between a weir and a flume for measuring flow?
• Which permit is used to authorize entry into a confined space?
• Treated wastewater discharge into a small stream used for a domestic water supply and swimming will require considerably more treatment than wastewater discharged into water used solely for navigation.
• What parameter best indicates the strength of organic matter in wastewater?
• Fecal coliform results are reported as MPN per...
• What is the purpose of primary treatment?
• What is the standard incubation duration for BOD tests?
• In a secondary clarifier, what is the purpose of return activated sludge (RAS)?
• A representative sample is necessary to ensure compliance with what?
• If DO drops to 0.5 mg/L in the aeration basin, what issues may arise?
• How would you diagnose a sudden drop in plant effluent clarity?
• What device is used to measure pH in wastewater and what is a typical operating pH range for municipal treatment?
• In a pump curve, what happens to flow as discharge head increases?
• What is nitrification and why is it important?
• What is the typical operating pH range for municipal wastewater treatment?
• In an activated sludge process, what does MLSS stand for?
• What is the primary purpose of an aeration basin in an activated sludge system?
• Which parameter best indicates the organic strength of wastewater?
• Detention time in a basin is defined as the ratio of basin volume to flow rate. If the basin volume is 90 m3 and the flow rate is 30 m3/hour, what is the detention time in hours?
• Which statement best describes grab and composite sampling in wastewater analysis?
• Which chemical is commonly dosed for phosphorus removal in secondary treatment?
• What is industrial pretreatment?
• In the CT concept, what does C represent?
• Inflow measurement in a combined sedimentation-digestion unit is used to determine what parameter?
• Which component is specifically designed to remove grit from wastewater?
• What is the typical effect of increasing pH on chlorine disinfection potency?
• Besides contact time, which factors influence chlorine disinfection effectiveness?
• What are common indicators of poor aeration in an activated sludge system?
• What is a return activated sludge (RAS) stream?
• What is the purpose of a standard operating procedure (SOP) at a water/wastewater plant?
• What does the NPDES regulate?
• Which statement is true about treating wastewater before discharge?
• What does BOD5 measure and why is it important in wastewater treatment?
• Which unit is commonly used to measure volumetric flow rate in wastewater systems?
• What is the purpose of lockout/tagout in plant safety?
• Which statement best describes the primary role of a coagulant or polymer in treatment?
• What does TSS stand for and what does it measure?
• During primary treatment, what is the main goal?
• Which statement about BOD5 is correct?
• What is a positive displacement pump and where is it typically used in wastewater systems?
• What is the function of an aerator in an activated sludge system?
• Why is backup power important for wastewater facilities?
• What is the primary role of SCADA in wastewater operations?
• Which sampling approach provides a more representative picture of wastewater quality over a period?
• Which option best describes how a process control chart is used in plant operations?
• What is the main purpose of denitrification?
• What is the purpose of a wastewater plant digester?
• How does a SCADA system assist wastewater plant operators?
• What is energy recovery in wastewater treatment commonly achieved through?
• What does SVI stand for and what does it measure?
• Before maintenance on electrical equipment, what safety procedure must be followed?
• How do gravity thickening and mechanical thickening differ?
• Which statement best defines aerobic bacteria?
• If a secondary clarifier is not functioning properly, which is likely outcome?
• When evaluating trickling filter operating records operators should adjust the process according to which main principle?
• A grit channel with slower flow velocity than recommended may allow large quantities of organic matter to settle out with the grit.
• MLSS stands for and what does MLSS represent in the aeration basin?
• Why is a disinfectant residual maintained after disinfection?
• Which parameter is used to verify disinfection after treatment?
• Why is chlorine residual monitoring important in disinfection?
• In disinfection, the CT concept defines CT as
• What is a likely effect of high MLSS on aeration efficiency?
• Which unit is used to express plant flow rate as an alternative to GPM in many systems?
• In an activated sludge system, wasting sludge helps to prevent which problem?
• In screening and grit facilities, what is the main purpose of the equipment?
• What is the name for the biological slime growth that develops on the trickling filter media?
• Which microbiological indicator is commonly used to assess treated effluent quality?
• Historically, Americans have shown a great lack of interest in the protection of their water resources.
• How does pH affect chlorine disinfection effectiveness?
• What is the purpose of sludge thickening?
• Operators must do the best they can to remove any substances from wastewater that will unreasonably affect users of receiving waters.
• What is hold time in wastewater sampling?
• For quickly assessing toxicity in an activated sludge process, which test would you perform?
• What is sludge thickening?
• In the activated sludge process, why must some of the activated sludge be wasted?