Massachusetts Wastewater Operator Grade 6 Practice Test

These questions are part of the practice quiz. Start practicing

• Which type of waste is prohibited from being sent to a wastewater treatment facility?
• What phenomenon occurs during endogenous respiration in wastewater treatment?
• If BOD removal rates in a primary clarifier drop to 15%, what is the most likely cause?
• In a two-step anaerobic digestion process, which digester is heated and mixed?
• What is the maximum % error in accuracy permitted for a flow measuring device in an open channel?
• To avoid panic, how should chlorine tanks be opened?
• If a chlorine line connected to the bottom valve of a 1-ton container results in gas instead of liquid, what is a likely cause?
• The biofilm on a rotating biological reactor should be what color and shade?
• What type of valve excels in applications of throttling the flow of fluids?
• At what point should fecal coliform samples be tested after collection without preservatives?
• Which condition is detrimental to the nitrification process in an anoxic zone?
• What does an SVI of 250 or more indicate in a settleometer?
• When are monthly reports due to the MA DEP?
• Without preservatives, a fecal coliform sample can wait to be tested for how many hours?
• How much does gaseous chlorine expand in volume compared to liquid chlorine?
• How long can FOG samples be stored properly?
• What test is used to determine coagulant levels for solids removal?
• What does the presence of a broken injection check valve signify in a chlorine feed system?
• How long can a BOD bottle be removed from the incubator if it is within the acceptable time range?
• What occurs to the chlorine demand of water after nitrification happens?
• How often should air masks used in wastewater treatment operations be inspected?
• What is the primary purpose of using alkaline chemicals like lime in treatment processes?
• When using polymer in a DAF unit, what % solids recovery should the operator expect?
• How is the term "accuracy" defined?
• Suction lift refers to the negative pressure on which side of a pump?
• Which measurement device is suitable for an open channel with low flow conditions?
• What is a volute in the context of pumps?
• What unusual property might a treatment facility expect in its influent from the canning industry?
• What is the purpose of using UV light in wastewater treatment?
• What temporary solution can help control filamentous bulking in activated sludge?
• What is the primary function of DAF (dissolved air flotation) systems?
• What is a common cause of nocardia formation in wastewater treatment?
• At what temperature does a drying oven of a furnace typically operate?
• After digestion, what typically happens to the bulking agent added to sludge?
• What effect does waste decomposition have on pH levels in wastewater systems?
• What is the primary component of the treater's solid waste after anaerobic digestion?
• What happens to a three-phase motor if one phase were to fail?
• How is water hardness defined?
• What effect does rising DO levels above 0.5 mg/L have in an anoxic zone?
• What is the most responsible component for the economical operation of a centrifuge?
• What is the typical settling characteristic of very old sludge?
• What could be a likely cause for two large bubble compressors in a wastewater treatment plant switching over constantly?
• What is amperometry?
• What contributes to effective sludge treatment in wastewater management?
• Which type of pump is typically started with its discharge valve closed?
• High acid production in an anaerobic digester could result in what condition?
• Where can you find regulations for sludge discharge and lab procedures?
• What issue can cause liquid chlorine to flow back into its storage tank?
• True or False: Chlorine cylinders must be stored in the same room as chlorinators.
• Which of the following is not typically a responsibility of a wastewater operator?
• What type of organism is indicated by the presence of stalked ciliates in activated sludge?
• What could cause an abnormal increase in BOD levels in wastewater?
• What temperature range is optimal for thermophilic digestion?
• What are the consequences of failing to process water samples quickly for DO, pH, and temperature?
• What is a requirement for installing couplings in wastewater operations?
• Why is it important to monitor the pH in wastewater treatment systems?
• For UV treatment systems, how frequently must quartz sleeves be cleaned?
• What are the three types of aeration basins in order of lineage of the Bardenpho process?
• What is struvite?
• Within which temperature range does mesophilic digestion occur best?
• At what temperature are anaerobic digesters typically operated?
• How is a molecule classified if it has a positive electrical charge?
• What is the primary purpose of using breakpoint chlorination?
• What happens first if a chlorine gas system loses its Venturi effect?
• Which of the following will not be measured in the total chlorine residual?
• Which parameter is crucial for determining the efficiency of activated sludge systems?
• How many fusible plugs are present on a one-ton chlorine container?
• What chemical can be used to identify a chlorine gas leak, and what color will the gas produced be?
• What is a possible cause of low chlorine residual if dosing is correct?
• What happens to the microbial growth rate as sludge ages?
• Which condition would likely indicate a need to neutralize a digester?
• When can methane gas become both explosive and flammable?
• What effect does adding polymer have on sludge in the dewatering belt-press process?
• If solids are rising in the secondary clarifier, which process is likely occurring?
• What is one significant effect of excess nutrients in wastewater?
• Which condition may lead to the formation of struvite in wastewater treatment?
• How quickly should samples for DO, pH, and temperature be processed after capture?
• What is a potential environmental hazard caused by uncontrolled nitrate in wastewater?
• What is the function of an eductor tube in a chlorine container?
• What percentage of oxygen is recommended in dilution water for a BOD test?
• What does an overwhelming presence of rotifers in sludge indicate?
• What is the human threshold of hydrogen sulfide gas?
• How should the operating temperature be adjusted in an anaerobic digester?
• What safety hazard is associated with high-pressure water pumps?
• What is the most common impeller design used in wastewater centrifugal pumps?
• What effect does a toxic substance have on BOD readings?
• What most significantly affects the sedimentation process in primary clarifiers?
• What is the primary benefit of removing BOD from wastewater?
• In wastewater treatment, what type of system often uses anaerobic digesters?
• What are the two types of gaseous poisoning with chlorine called?
• What is the highest percentage part of the gases produced by an anaerobic digester?
• What is the term for a condition where clear supernatant is pumped through the sludge blanket of a gravity thickener?
• What is the volatile acid to alkalinity ratio for a properly operating anaerobic digester?
• What adjustment should be made in the aeration basin when ammonia levels are unusually high?
• What does the operation of a centrifugal pump depend on?
• Which bacteria are responsible for converting nitrite (NO2) to nitrate (NO3)?
• What is the volume reduction percentage when sludge is incinerated?
• What might indicate that a digester is experiencing issues with solids concentration?
• By what percentage can anaerobic digesters reduce volatile solids in wastewater?
• What is one function of sodium bisulfite in wastewater treatment?
• The presence of which gas is dangerous when mixed with the emissions from an anaerobic digester?
• How much alkalinity is returned to the Mixed Liquor Suspended Solids (MLSS) for each pound of nitrate used in the denitrification process?
• How long do solids typically remain in an anaerobic digester?
• Which wavelength of UV light is required for effective disinfection of bacteria?
• What is the term for a centrifugal pump operating against a closed discharge valve?
• What is the order of parameters to test for before entering a confined space?
• How long are maintenance records required to be kept?
• As the amount of carbon dioxide in wastewater increases, what happens to the pH?
• What type of fire extinguisher is suitable for a gasoline fire?
• Four 8 inch pipes carry the same volume as which of the following?
• What is a typical distance to check flow measurement upstream of a weir?
• What should be done after a centrifugal pump is started with a closed discharge valve?
• For every 10 degrees C increase, how does the metabolic activity of bacteria in the activated sludge process change?
• Why are centrifugal pumps started with their discharge valves closed?
• From where is suction lift measured?
• How much pressure in psi does each foot of head correspond to?
• Which factor is crucial in sludge incineration processes?
• What is a likely cause of influent from the collection system having consistently low pH?
• What is a common adjustment rate for temperature in an anaerobic digester?
• For how long can preserved BOD samples be kept?
• What is the appropriate flow measuring device for a pressurized pipe pumping from a lift station?
• Which of the following defines anaerobic conditions?
• What does a gravity belt thickener most represent?
• How long can an ammonia nitrogen sample be preserved at 4 degrees C on sulfuric acid?
• What is the purpose of measuring the reaction of organisms to an unknown stimulus in a lab test?
• The presence of nitrite in wastewater raises the demand for what chemical?
• Foaming in an anaerobic digester typically occurs due to?
• Where should the pressure relief valve be located in a chlorine or sulfur dioxide evaporator?
• Which of the following best describes the role of anaerobic digesters in wastewater treatment?
• What is a common method used to monitor the health of a digester?
• Which of the following is indicative of a safe chlorine gas system?
• What is the primary purpose of throttling an outlet valve on a pump?
• What ideal velocity should influent have in a grit chamber?
• How does a rise in DO levels affect denitrification in an anoxic zone?
• What are psychoda commonly known as?
• What is the main function of bicarbonate in wastewater treatment?
• How should 150-pound chlorine containers be stored and moved?
• What type of sewer system carries domestic and industrial wastes?
• What is a common impact of waste from metal-plating industries on influent?
• What are conductivity tests used to measure?
• What is the allowable fecal coliform number upstream of a WWTP typically recognized?
• What might be an indicator of problems with a chlorine system if gas is emitted instead of liquid?
• What is the purpose of a diffuser in a centrifugal pump?
• Which type of bacteria is more resistant to chlorination?
• Chlorine and hypochlorite in water produce which compounds?
• What is the consequence of having too much nitrite in incoming water regarding chlorine residual?
• What is the first stage in the basic processes of anaerobic digestion?
• What could be the issue if water pumps at a plant are making loud banging noises, shaking severely, and running very hot while at 100% capacity?
• What is the flow rate measuring device located upstream of the converging wall?
• At what temperature should preserved samples be stored?
• What can be done to control the population of filter flies on a trickling filter?
• What does an SVI of 180 indicate in a settleometer?
• What is the maximum total suction lift recommended?
• What type of solids cannot be removed from effluent filtration systems like sand filters?
• Which test measures the rise of sludge particles in the DAF process?
• When using lime to remove phosphorus, what is the optimal pH level?
• What does MCRT stand for in wastewater treatment?
• What is one primary operational characteristic of a well-functioning aeration basin?
• Which class of organism in wastewater is most resistant to chlorine disinfection?
• What component is essential for liquid chlorine withdrawal from a container?
• What type of filament indicates very old sludge with denitrifying characteristics?
• What is the time frame for industrial discharge to meet pretreatment specifications?
• What is the role of alkalinity in wastewater treatment?
• Using breakpoint chlorination, how many parts of chlorine are required to remove one part of ammonia?
• What does the presence of amoebas in sludge indicate?
• What is the main purpose of an emergency scrubber system in a wastewater treatment facility?
• What is the characteristic of young sludge with respect to rotifers?
• What is the only type of equipment permitted to be stored in a chlorine cylinder gas feed room?
• What does an SVI of 80 or less indicate in a settleometer?
• What is the ideal volatile solid reduction percentage aimed for in anaerobic digestion?
• What are the three compounds used in wastewater treatment that increase alkalinity?
• How can an operator effectively cure a sour digester?
• What does the acronym SOUR stand for?
• What is the effect of cold temperatures on the flow of water?
• What is phenolic waste, and how is it typically removed from wastewater?
• What are the primary sources of phosphorous in municipal wastewater?
• Which contaminants are noted to have the lowest pollutant limits?
• In what type of wastewater treatment process is ammonia typically removed?
• What chemical is typically used to neutralize leaking chlorine gas?
• What does MPN stand for in the context of fecal coliform measurement?
• What effect does sunset have on DO levels in stabilization ponds?
• What does a closed impeller design in centrifugal pumps help achieve?
• What is the primary function of the second tank in a two-step anaerobic digestion process?
• What role does the rise rate test play in wastewater treatment?
• What chemical is commonly used for conditioning sludge in a belt filter press?
• Which sewer system includes surface, drain, and storm run-off?
• What issue might a bubbler system indicate if it has a low wet well level but shows a high level reading?
• What is a typical food-to-microorganism (F/M) ratio for conventional activated sludge?
• What is a common indicator of an ineffective anaerobic digester?
• How much BOD does an average person contribute to collected wastewater daily?
• When using an SCBA (self contained breathing apparatus), how should the bypass valve be set?
• Which factor can lead to the formation of smaller flocs in wastewater treatment?
• What time of day will dissolved oxygen (DO) levels be highest in un-aerated stabilization ponds?
• Why is it important to monitor fecal coliform in biosolids?
• What is the required storage condition for preserving fecal coliform samples?
• What is a characteristic of pneumatic pumps related to their operating environment?
• What happens to viscosity as the temperature increases?
• How does a belt thickener measure the rate of sludge loading?
• Which two chemicals are typically used to de-chlorinate water?
• What is the duration for completing the BOD test?
• What distinguishes a conventional activated sludge process from an advanced wastewater treatment process?
• What are common causes of a sour digester?
• What does the Chemical Oxygen Demand (COD) test measure?
• In wastewater treatment, which pollutant is primarily removed in advanced processes?
• What happens to the discharge of a centrifugal pump when the head is increased?
• How often should maintenance be scheduled for wastewater treatment pumps to ensure proper operation?
• What is the difference between a closed circuit and an open circuit?
• How can an operator permanently increase the F:M ratio in the activated sludge process?
• What is the pH requirement for lime stabilization to meet Class B stabilization standards within the first two hours?
• What happens to detention time and surface overflow rate when plant influent flow decreases?
• What should be done if a diaphragm pump is not delivering the correct amount of chemical?
• Which activated sludge process can remove CBOD, nitrify, and denitrify all in the same reactor tank?
• What is the cause when a mechanical blower keeps turning on and off due to high pressure?
• Coliform bacteria presence indicates what in water treatment?
• What is the fecal coliform limit for Class A biosolids?
• What chemical should be used to preserve an ammonia nitrogen sample?
• What device is commonly used to measure the flow of a gas?
• Which type of bacteria is used to convert ammonia nitrogen in the activated sludge process?
• What is the common name for the molecule O3?
• What wastewater component diminishes the effectiveness of UV treatment as its concentration increases?
• What chemical is used to test for phosphorus in effluent?
• If a centrifugal pump with high flow and low static head begins overheating, what should the operator do?
• What is the maximum filling percentage for chlorine cylinders and containers by law?
• In which part of a wastewater treatment process is an electromagnetic meter most often used?
• What is the purpose of backwashing a filter?
• When cadmium cyanide complexes are oxidized, which form of cadmium precipitates out of the solution?
• What is the chemical formula for sulfur dioxide?
• In the event of a hazardous spill, where should an operator refer for guidance?
• Which substances can be added to a digester to neutralize a sour condition?
• What role does sodium hydroxide play in emergency scrubber systems?
• In a trickling filter, which order of media occupies the lower portion from top to bottom?
• What is the principal waste product produced by oil production processes?
• What is the maximum time a BOD test can be preserved if cooled to the appropriate temperature?
• What impact does fats, oils, and grease have on wastewater treatment processes?
• What is the temperature equivalent of 70-74 degrees C in degrees F?
• Wastewater that is oily and contains toxic organics is most likely from which type of bath?
• What likely causes higher fecal coliform numbers downstream of a wastewater treatment plant (WWTP)?
• What characterizes the presence of thiothrix in sludge?
• What chemical is commonly used in a wet scrubber system to address hydrogen sulfide (H2S) gas?
• What is the maximum total suspended solids (TSS) level in the effluent of a gravity thickener for optimal operation?
• At what temperature range do fusible plugs melt?
• What occurs to water as it passes through a centrifugal pump?
• What is a potential consequence of a centrifugal pump running deadhead for an extended period?
• What effect does higher water temperature have on dissolved oxygen levels in water?
• What is typically the main byproduct of anaerobic digestion?
• Where should head measurements be taken using a v-notched weir?
• What can an operator add to quickly increase the presence of larger flocs?
• What is the ideal ratio of Carbon, Nitrogen, and Phosphorus for the activated sludge process?
• What maintenance task is essential for preventing overheating in pumps?
• What does the Winkler method test for?
• Where can you find regulations for sampling and record storage?
• Which chemicals are most commonly used to condition sludge at the Attleboro WWTP?
• If the chlorine residual is falling, what action should be taken if ice is forming on the chlorine regulator?
• Gaseous chlorine is how many times heavier than air?
• In case of an emergency, how should the valve of a chlorine tank be closed?
• Which piece of equipment serves as an example of a rotary lobe pump in the Attleboro WWTP?
• Which type of effluent is typically treated by tertiary filters?
• When using a weir, where should an operator check for accuracy of flow measurement?
• Which parameter is crucial for evaluating the performance of a wastewater treatment facility?
• Which process involves the conversion of ammonium to nitrate and requires oxygen?
• What noise level in the workplace requires the implementation of a hearing protection program according to OSHA?
• What does a TSS level above 100 mg/L in gravity thickener effluent indicate?
• Where should an operator sample for Nocardia bacteria?
• How does increased temperature affect water's ability to carry dissolved oxygen?
• What do progressive cavity pumps resemble in design?
• What is a pneumatic pump typically used to transport?
• In a centrifugal pump, what happens to the head if the discharge increases?
• Which acid is stronger, hypochlorous acid or hydrochloric acid?
• What are the three most common gases tested for before entering a confined space?
• What is commonly added to wastewater to improve sludge thickening?
• During back washing of a mixed media filter, what is the expected bed expansion percentage?
• What is the difference between autotrophic and heterotrophic bacteria?
• What two chemicals are used for de-chlorination?
• Which is the correct order of bacteria classifications based on temperature ranges, from colder to hotter?
• What does a higher sludge age in an activated sludge process generally indicate?
• How much heavier is liquid chlorine compared to water?
• What factor is crucial for maintaining a healthy anaerobic digester?
• What issue may arise from using too much polymer in a belt filter press?
• How are heavy metals typically removed from wastewater?
• A yellow flame in the gas burner of an anaerobic digester indicates?
• In which type of wastewater treatment is the removal of fats, oils, and grease crucial?
• What is a characteristic of a positive displacement pump?
• What is the best indicator of health in anaerobic digesters?
• What is the maximum allowable error for measuring flow in an open channel?
• Which type of pump is best suited for delivering a specific amount of chemical?
• Which chemical is used to remove phosphorus from wastewater as a precipitate?
• Before using tertiary filters, such as sand filters, what is a necessary action?
• What does "unity of command" in management mean?
• How long is an NPDES permit valid for before it must be renewed?
• If a bubbler system has a high wet well level but shows a low level reading, what could be the problem?
• Where would a pressure reducing valve be located on a chlorine evaporator?
• What indicates poor settling in sludge?
• If a dissolved air flotation unit is turned off, when should the drain valves be opened?
• As the temperature decreases, what happens to the viscosity of water?
• What process occurs in the absence of oxygen and results in denitrification?
• What issue is indicated if higher BOD samples are yielding higher oxygen uptake readings?
• How is a molecule classified that contains a negative electrical charge?
• Which process is mainly responsible for the removal of nitrogen in wastewater treatment?
• What is the minimum pH level for lime stabilization after the first 2 hours?
• What does food waste lack that makes it a poor influent for proper biological growth on a trickling filter?