Wastewater Treatment Operator Certification Exam 2023-2024 | Actual Exam, Exams of Water Resources Planning and Management

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Wastewater Treatment Operator Certification

Exam 2023 - 2024 | Actual Exam Questions and

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What is common practice in an activated sludge process? A) Waste all activated sludge B) Sludge age of 14 days for conventional system C) Recirculate activated sludge (RAS) D) Limiting DO to increase the mircoorganism population -----CORRECT ANSWER------ --C) Recirculate activated sludge (RAS) (v.2 pg 20,21) Prior to entering a permit required confined space, what should you verify? A) a standby person should be at the entrance to the confined space. An additional person is not required B) A standby person should be within 30 feet of the confined space. C) A standby person should be within 50 feet of the confined space. D) A standby person should be located outside the entrance to the confined space, while another person should be within sight or call of the standby person. ----- CORRECT ANSWER--------D) A standby person should be located outside the entrance to the confined space, while another person should be within sight or call of the standby person. (v.2 pg 270) What is a common way to determine the organic strength of wastes in the influent? A) Test for the biochemical oxygen demand B) Test for the biological oxygen demand C) Test for the volatile solids reduction D) Test for the carbon and hydrogen concentrations -----CORRECT ANSWER--------A) Test for the biochemical oxygen demand (v.1 pg 505) What should you do if you are mildly exposed to chlorine gas? A) Breathe heavily to inhale clean air B) Cough to release chlorine from lungs C) Immediately evacuate the contaminated area, remain calm, keep warm, breathe lightly, and avoid coughing

D) Keep your body as cool as possible -----CORRECT ANSWER--------C) Immediately evacuate the contaminated area, remain calm, keep warm, breathe lightly, and avoid coughing (v.1 pg 377) If the lab results show that the plant influent sample has a COD of 100 mg/l and the BOD of 300 mg/l, which of the following is most likely true? A) Lab results appear incorrect B) Carbon concentration is very high C) Organic content is unusually high D) COD seems excessive -----CORRECT ANSWER--------A) Lab results appear incorrect (v.2 pg 541) If a primary clarifier is placed out of service, then how should a plant with at least two trickling filters operate the system? A) Operate the filters in parallel B) Divert the influent to several trickling filters C) Operate the filters in series D) Maintain existing operation without changing filter arrangement -----CORRECT ANSWER--------C) Operate the filters in series (v.1 pg 191) What is the main reason for preventing a direct connection between potable water pipe and a stuffing box (packings) of a wastewater pump? A) Wears out the glands quicker B) Glands should not be wet C) Potable water will rapidly destroy the stuffing box D) Cross Connection -----CORRECT ANSWER--------D) Cross Connection (v.2 pg 414) Which of the following is true about algae in a pond? A) During the daytime, the algae will release carbon dioxide B) During the daytime, the algae will release oxygen for the aerobic bacteria C) Algae uses sunlight to produce hydrogen sulfide D) Photosynthesis helps algae create carbon monoxide -----CORRECT ANSWER-------- B) During the daytime, the algae will release oxygen for the aerobic bacteria (v.1 pg

What are the main sources of domestic sewage in the collection system? A) Canals

B) Surface flow C) Ocean outfall D) Households and commercial establishments -----CORRECT ANSWER--------D) Households and commercial establishments (v.1 pg 33) What is the methane content in a properly operation anaerobic digester? A) 30 to 35% by volume B) 1 to 2% by volume C) 65 to 70% by volume D) 15 to 20% by volume -----CORRECT ANSWER--------C) 65 to 70% by volume (v.2 pg

What will the addition of chlorine gas do to the pH of wastewater? A) Moderately increase pH B) pH will not be affected C) Significantly increase the pH D) Decrease the pH -----CORRECT ANSWER--------D) Decrease the pH (v.1 pg 349-

What is the purpose of a Parshall flume? A) measure turbidity B) measure flowrate C) measure settling rate D) measure solids content -----CORRECT ANSWER--------B) measure flowrate (v.1 pg

What is the typical removal efficiency of settable solids in a primary clarifier? A) 95 to 99% B) 40 to 60% C) 20 to 50% D) 10 to 15% -----CORRECT ANSWER--------A) 95 to 99% (v.1 pg 129) Which of the following is true about pumping scum from a primary clarifier? A) Pumping scum is less problematic during colder weather. B) Scum rarely leads to plugged pipelines due to its viscous nature.

C) Scum causes more piping problems than other substances pumped at a wastewater treatment plant. D) Scum causes the least amount of piping problems among all the substances pumped at a wastewater treatment plant. -----CORRECT ANSWER--------C) Scum causes more piping problems than other substances pumped at a wastewater treatment plant. (v.2 pg

What might cause thick billows of white sudsy foam in the aeration tank? A) MLSS is too high B) Temperature in the aeration tank is too low C) Old sludge D) MLSS is too low -----CORRECT ANSWER--------D) MLSS is too low (v.2 pg 53,75) What does the "M" in F/M ratio represent? A) MLSS in aeration tank B) The influent BOD loading rate into the aeration tank C) The mixed liquor volatile suspended solids in the aeration tank D) The mass of inorganic solids in the aeration tank -----CORRECT ANSWER--------C) The mixed liquor volatile suspended solids in the aeration tank (v.2 pg 16) In general, how will warmer temperature affect the settling rate of solids in a clarifier? A) Decrease settling rate B) Increase the settling rate C) Temperature will not affect the settling rate D) Worsen the settling rate -----CORRECT ANSWER--------B) Increase the settling rate (v.1 pg 134) What could happen if the digester gas is mixed with air (85 to 95% by volume)? A) Cause an explosion B) Improve efficiency of digestion C) The bacteria will become aerobic and increase VSR D) The digester becomes safer to operate due to less toxic gas in the system ----- CORRECT ANSWER--------A) Cause an explosion (v.2 pg 158) How will algae impact the chlorine demand in the pond effluent? A) Slightly decreases chlorine demand

B) Does not affect chlorine demand C) Significantly decreases chlorine demand D) Increases chlorine demand -----CORRECT ANSWER--------D) Increases chlorine demand Which of the following is true about positive displacement pumps? A) It is a type of centrifugal pump B) Suction valve should be closed when the pump is started C) It must never be started with the discharge valve closed D) Adds head to liquid using several impellers -----CORRECT ANSWER--------C) It must never be started with the discharge valve closed (v.2 pg 435) What is true about the F/M ratio? A) MLVSS data in not required to determine the F/M ration B) Volume of the secondary clarifier is not needed to determine the F/M ratio C) The amount of COD or BOD entering the aeration tank does not have to be known to calculate the F/M ratio. D) The amount of organisms in the aeration tank is not needed to calculate the F/M ratio -----CORRECT ANSWER--------B) Volume of the secondary clarifier is not needed to determine the F/M ratio (v.2 pg 58) Which of the following is one of the basic rules of laboratory work? A) Do not leave keys in equipment or vehicles at any time B) Patrol the facilities frequently, and look for suspicious activity or behavior C) never pipet hazardous material with your mouth, even if the pipet has be sterilized D) Lock out and tag out relevant mechanical and electrical equipment before starting any maintenance activity. -----CORRECT ANSWER--------C) never pipet hazardous material with your mouth, even if the pipet has be sterilized (v.2 pg 493) What is the recirculation ratio for a trickling filter? A) Q_r/Q B) Q/Q_r C) Q/Q_r+Q D) Q_r+Q/Q -----CORRECT ANSWER--------A) Q_r/Q Which of the following is true about COD and BOD?

A) They are direct measurements of organic content in the influent B) They measure the inorganic content of the influent C) They represent the amount of filamentous bacteria in the influent D) They are indirect measurements of the organic content in the influent -----CORRECT ANSWER--------D) They are indirect measurements of the organic content in the influent What is the purpose of the grit channel? A) Remove dissolved and non-settleable organics B) Remove heavy inorganic wastes C) To allow activated sludge to settle D) Remove substances that float and readily settle from the wastewater as part of primary treatment -----CORRECT ANSWER--------B) Remove heavy inorganic wastes (v.1 pg 84) Which of the following is true about the extended aeration process? A) Bugs get more food B) Wasting is not necessary C) It does not produce as much waste sludge as the other processes D) It is very different from the conventional activated sludge process -----CORRECT ANSWER--------C) It does not produce as much waste sludge as the other processes (v.1 pg 257) What is the correct formula for solids in raw wastewater? A) Non-volatile solids + Suspended solids= Total solids in the influent B) Dissolved solids + Settable solids= Total suspended solids C) Colloids + Dissolved solids = Total suspended solids D) Non-settleable solids + Settable solids= Total suspended solids. -----CORRECT ANSWER--------D) Non-settleable solids + Settable solids= Total suspended solids (v. pg 22) What is the "freeboard" in a waste stabilization pond? A) Operational depth of the pond B) Wooden inlet and outlet structures C) Wooden baffles D) Vertical distance from normal water surface to the top of the levee -----CORRECT ANSWER--------D) Vertical distance from normal water surface to the top of the levee (v.1 pg 519)

What is one of the requirements for a BOD test? A) The BOD bottle should be completely filled to the top B) The BOD bottles must be 100 ml in size C) Samples should be incubated at 30 degrees Celsius D) Stoppers should not be installed on the bottles to ensure proper air flow to the samples -----CORRECT ANSWER--------A) The BOD bottle should be completely filled to the top (v.2 pg 574) What should be scheduled every 3 months for a flamer arrester in an anaerobic digester? A) Replacement B) Maintenance C) Flow Test D) Temperature Test -----CORRECT ANSWER--------C) Flow Test (v.2 pg 162) Why is it important to maintain a horizontal weir in a clarifier? A) Prevent sludge bulking B) Prevent short circuiting C) Prevent gasification D) Prevent excessive slime growth -----CORRECT ANSWER--------B) Prevent short circuiting (v.1 pg 131) What are mostly removed in the grit channel? A) Biomass B) Organics C) Dissolved solids D) Sand, eggshells, cinders, and heavier particulate matter -----CORRECT ANSWER---- ----D) Sand, eggshells, cinders, and heavier particulate matter (v.1 pg 84) How often should an anaerobic digester be fed? A) Several times a day B) Once a day C) Twice a week D) Five times per week -----CORRECT ANSWER--------A) Several times a day (v.2 pg

What is the health effect of carbon dioxide? A) Vomiting B) Migraine C) Can lead to asphyxiation D) Rapid heart beat -----CORRECT ANSWER--------C) Can lead to asphyxiation (v.2 pg

Which of the following enters the headworks of a treatment plant? A) Effluent B) Supernatant C) WAS D) Influent -----CORRECT ANSWER--------D) Influent (v.1 pg 33) Which gas diminishes your sense of smell? A) Hydrogen B) Hydrogen Sulfide C) Nitrogen D) Ethane -----CORRECT ANSWER--------B) Hydrogen Sulfide (H_2S) (v.2 pg 268) What type of microorganisms can use nitrate as a source of oxygen? A) Aerobic bacteria B) Anaerobic bacteria C) Facultative bacteria D) Zoogleal -----CORRECT ANSWER--------C) Facultative bacteria (v.1 pg 254) What is the equivalent of 1 mg/L A) 1 ppb B) 10 ppm C) 10 ppb D) 1 ppm -----CORRECT ANSWER--------D) 1 ppm (v.1 pg 468) Select the most accurate statement about extended aeration.

A) The bugs are retained in the aeration tank much shorter than the conventional activated sludge system. B) Extended aeration produces the most waste sludge compared to other sludge processes C) An oxidation ditch is usually operated in extended aeration mode, and is used for small flows D) Extended aeration is the least common type of package plant treatment process ----- CORRECT ANSWER--------C) An oxidation ditch is usually operated in extended aeration mode, and is used for small flows (v.1 pg 269) What is equivalent to organic solids? A) Volatile Solids B) Fixed Solids C) Suspended Solids D) Colloids -----CORRECT ANSWER--------A) Volatile Solids (v.1 pg 546) What should be done if a large amount of organic matter is found in the grit channel? A) Decrease the velocity of the wastewater B) Inject sodium hydroxide at the headworks C) Raise the pH D) Increase the velocity of the wastewater -----CORRECT ANSWER--------D) Increase the velocity of the wastewater (v.1 pg 87) Which flowrate should you use to calculate the hydraulic loading to a trickling filter? A) Plant inflow B) Plant inflow minus recirculated flow C) Plant inflow plus recirculated flow D) Recirculated flow -----CORRECT ANSWER--------C) Plant inflow plus recirculated flow (v.1 pg 199) What is the difference between the sludge from a primary clarifier and secondary clarifier? A) Secondary sludge is denser than primary sludge B) Primary sludge is denser than secondary sludge C) Specific gravity of secondary sludge is larger than that of a primary sludge D) Primary sludge has a smaller specific weight than secondary sludge -----CORRECT ANSWER--------B) Primary sludge is denser than secondary sludge (v.1 pg 109)

Which process includes a blower? A) Trickling filter B) Waste stabilization pond C) Chlorine contact tank D) Activated sludge -----CORRECT ANSWER--------D) Activated sludge (v.2 pg 28) How does an activated sludge system remove waste from wastewater? A) Physical Treatment B) Chemical Treatment C) Biological Treatment D) Radiological Treatment -----CORRECT ANSWER--------C) Biological Treatment (v. pg 16) Which of the following best describes pre-chlorination? A) Mainly used for disinfection and requires a large amount of chlorine residual in the wastewater at the chlorine contact chamber. B) Addition of chlorine to wastewater a the entrance to the plant, and used for odor control, BOD reduction, grease removal, and aid sedimentation C) Injection on a well-clarified effluent D) Describes a type of chlorination to address sludge bulking -----CORRECT ANSWER- -------B) Addition of chlorine to wastewater a the entrance to the plant, and used for odor control, BOD reduction, grease removal, and aid sedimentation (v.1 pg 354) When would you expect reduced algae population and less oxygen released into a pond? A) Fall and winter, when the weather is cool and sunlight is reduced B) Summer, when there is abundant sunlight C) Spring, when the weather transitions from cool to warm D) When photosynthesis is very effective and at its peak -----CORRECT ANSWER-------

• A) Fall and winter, when the weather is cool and sunlight is reduced (v.1 pg 309) What is the first step of the lockout/tagout procedure? A) Shut down the equipment if it is operating B) Operate the energy isolating device so that the equipment is isolated form its energy source C) Lockout the equipment with assigned lock or tag

D) Notify all affected employees that a lockout or tagged system is going to be used and the reason why. -----CORRECT ANSWER--------D) Notify all affected employees that a lockout or tagged system is going to be used and the reason why (v.2 pg 274) What type of process is the activated sludge system? A) Anaerobic B) Anoxic C) Aerobic D) Ionic -----CORRECT ANSWER--------C) Aerobic (v.1 pg 46) What will happen if too much raw sludge is added to the digester? A) pH will increase due to the increase in sodium hydroxide B) Acid fermenters will predominate and lower the pH C) pH will not be affected D) Methane fermenters will thrive -----CORRECT ANSWER--------B) Acid fermenters will predominate and lower the pH (v.2 pg 184) What might cause sludge to rise in a clarifier? A) Gasification from aging sludge B) pH is too high C) Sludge withdrawal rate is too high D) Photosynthesis -----CORRECT ANSWER--------A) Gasification from aging sludge (v.1 pg 129) What happens when carbon dioxide is removed from a pond? A) Decreased pH B) pH is not affected C) Increased pH D) Sudden increase in H_2S -----CORRECT ANSWER--------C) Increased pH (v.1 pg

How much dissolved oxygen should be in a conventional activated sludge system if good effluent is being produced? A) 6 to 8 mg/l B) 0.5 to 1 mg/l C) 4 to 6 mg/l

D) 2 to 4 mg/l -----CORRECT ANSWER--------D) 2 to 4 mg/l (v.2 pg 53) What is the typical concentration of mixed liquor suspended solids in a conventional activated sludge process? A) 50 to 1,000 mg/l B) 1,000 to 4,500 mg/l C) 4,500 to 5,500 mg/l D) 5,500 to 6500 mg/l -----CORRECT ANSWER--------B) 1,000 to 4,500 mg/l (v.2 pg 54) The temperature of the plant influent is A) Slightly warmer than tap water B) Slightly colder than tap water C) Much cooler than tap water D) Much warmer than tap water -----CORRECT ANSWER--------A) Slightly warmer than tap water The purpose of disinfection is to A) kill all microorganisms in the wastewater B) Stabilize the pH C) Destruction or inactivation of pathogenic bacteria D) Oxidize the minerals in the effluent -----CORRECT ANSWER--------C) Destruction or inactivation of pathogenic bacteria (v.1 pg 353) What must you do before entering a room with harmful concentration of chlorine gas in the air? A) Read the O&M manual B) Wear self-contained breathing apparatus (SCBA) C) Prepare the fire extinguishers D) Cover your mouth and spray aqueous ammonia in the room. -----CORRECT ANSWER--------B) Wear self-contained breathing apparatus (SCBA) (v.1 pg 375) What does black sludge at the bottom of a secondary clarifier located downstream of a trickling filter signify? A) Pumping rate is excessive B) Pumping duration is too long C) Detention time is too short

D) Sludge has stayed in the secondary clarifier too long -----CORRECT ANSWER-------- D) Sludge has stayed in the secondary clarifier too long (v.1 pg 138) Which of the following is not true about hydrogen sulfide? A) Hydrogen sulfide is flammable B) Hydrogen sulfide is explosive under certain conditions C) Hydrogen sulfide is lighter than air D) Hydrogen sulfide is toxic -----CORRECT ANSWER--------C) Hydrogen sulfide is lighter than air (v.2 pg 268,505) What type of treatment if primarily used to thicken sludge instead of dewater the sludge? A) DAF B) Sludge drying bed C) Centrifuge D) Vacuum filters -----CORRECT ANSWER--------A) DAF (v.2 pg 219-227) Why should sludge at the bottom of a clarifier be removed in a timely manner? A) To improve the performance of the grit channel B) To maintain a consistent volume of sludge in the drying bed C) To minimize the formation of Chloramines D) To prevent sludge gasification, which causes the sludge to float -----CORRECT ANSWER--------D) To prevent sludge gasification, which causes the sludge to float (v. pg 130) What is the purpose of sludge digestion? A) Convert primary and secondary sludge to mostly hydrogen sulfide B) Increase efficiency of the DAF C) Reduce the volume of the sludge and stabilize the solids D) increase solids volume -----CORRECT ANSWER--------C) Reduce the volume of the sludge and stabilize the solids (v.2 pg 148) Which of the following is true about trickling filters? A) It is mostly an anaerobic process

B) The three main parts of a trickling filter are media, distribution system, and underdrain C) In computing BOD loading, it is standard practice to include the BOD of the re- circulated effluent D) Filter ponding is usually due to inadequate organic loading -----CORRECT ANSWER--------B) The three main parts of a trickling filter are media, distribution system, and underdrain (v.1 pg 169) Which of the following could cause foaming in an anaerobic digester? A) Temperature is kept constant B) Feeding sludge at a regular, short interval C) Digester is well-mixed D) Organic overload -----CORRECT ANSWER--------D) Organic overload (v.2 pg 187,207) Which of the following parameters should be monitored several times a week in a pond? A) TDS B) MLSS C) Dissolved oxygen, temperature, and pH D) MLVSS -----CORRECT ANSWER--------C) Dissolved oxygen, temperature, and pH (v.1 pg 315) Which is true about the temperature in an anaerobic digester? A) Temperature in a digester should not be changed by more than 1 degree Fahrenheit per day. B) Temperature must be changed significantly according to the sludge loading rate. C) Temperature at the bottom should be higher than at the top of the digester. D) Mesophilic digestion required a temperature between 105 to 108 degrees Fahrenheit. -----CORRECT ANSWER--------A) Temperature in a digester should not be changed by more than 1 degree Fahrenheit per day (v.2 pg 191) The effectiveness of disinfection is determined by: A) The Chlorine residual concentration B) The Chlorine demand C) The Chloramine concentration in the effluent D) The coliform concentration in the effluent -----CORRECT ANSWER--------D) The coliform concentration in the effluent (v.1 pg 353)

An increase in the acid/alkalinity ratio for an anaerobic digester means A) The digester is in an ideal condition B) The carbon dioxide content is decreasing C) Acid concentration is increasing or alkalinity is decreasing D) pH of the sludge in the digester is increasing -----CORRECT ANSWER--------C) Acid concentration is increasing or alkalinity is decreasing (v.2 pg 191) Which of the following will not cause short circuiting in a clarifier? A) Uneven weir settings B) Flow line of launder is low C) Damaged or missing inlet baffles D) Velocity of wastewater is greater in some sections than in others -----CORRECT ANSWER--------B) Flow line of launder is low (v.1 pg 125,135) A grab sample is most suited for these constituents A) BOD B) TSS C) Suspended Solids Concentration D) Residual Chlorine -----CORRECT ANSWER--------D) Residual Chlorine (v.2 pg 499) The organic loading to a trickling filter is expressed as A) lbs BOD/day/1000 cuft B) lbs BOD/day/1000 sqft C) lbs BOD/day/sqft D) lbs BOD/1000 gallon -----CORRECT ANSWER--------A) lbs BOD/day/1000 cuft (v. pg 199) How often should the sludge at the bottom of a clarifier be pumped? A) Once a week B) Bi-weekly C) Frequently throughout the day D) Once every three days -----CORRECT ANSWER--------C) Frequently throughout the day (v.1 pg 130) Which of the following will not affect the settling characteristics in a clarifier?

A) Temperature B) Short Circuit C) Detention Time D) Depth of launder -----CORRECT ANSWER--------D) Depth of launder (v.1 pg 134-

The best way to evaluate the effluent TSS concentration from a plant is to A) Check the grab sample at peak flow B) Check the composite sample of TSS C) Check the grab sample at low flow D) Check the grab sample during average flow -----CORRECT ANSWER--------B) Check the composite sample of TSS (v.1 pg 128) Which of the following is not associated with an aeration tank? A) RAS B) WAS C) RBC D) MCRT -----CORRECT ANSWER--------C) RBC (v.2 pg 56,59) What creates hydrogen sulfide? A) Excessive aeration B) Surface active agents C) Organic matter under aerobic condition D) Decomposing organic matter under anaerobic condition -----CORRECT ANSWER---- ----D) Decomposing organic matter under anaerobic condition (v.2 pg 299) A pond with a detention time of less than three days will perform similar to A) Sedimentation tank B) Aeration tank C) Trickling Filter D) RBC -----CORRECT ANSWER--------A) Sedimentation tank (v.1 pg 299) Which type of Bacteria is used for a Trickling Filter? A) Anaerobic bacteria B) Anoxic bacteria

C) Aerobic bacteria D) Facultative bacteria -----CORRECT ANSWER--------C) Aerobic bacteria (v.1 pg 46) Which of the following is not associated with a trickling filter? A) Media B) Filamentous bacteria C) Zoogleal Film D) Recirculation -----CORRECT ANSWER--------B) Filamentous bacteria (v.1 pg 169) What is an MCRT? A) A calculation that indicates the tendency of activated sludge solids to thicken B) A measure of food provided to bacteria in an aeration tank. C) The amount of volatile suspended solids in the mixed liquor of an aeration tank D) An expression of the average time a microorganism will spend in an activated sludge process. -----CORRECT ANSWER--------D) An expression of the average time a microorganism will spend in an activated sludge process. (v.2 pg 59) WasteWater Sources & Characteristics: What is the most common reason for a wastewater to contain intermittent large amounts of sand, gravel, and grit? ----CORRECT ANSWER--------storm events WasteWater Sources & Characteristics: Combined wastewater is defined as ----CORRECT ANSWER--------sanitary wastewater and stormwater runoff WasteWater Sources & Characteristics: In general, the solids content in wastewater is about ----CORRECT ANSWER-------- 0.1% WasteWater Sources & Characteristics: In general, what is the % of suspended solids in the total amount of solids ---- CORRECT ANSWER--------30%

WasteWater Sources & Characteristics: Generally, the % of dissolved solids in the amount of total solids is about ----CORRECT ANSWER--------70% WasteWater Sources & Characteristics: Which type of organisms would most probably be associated with poor treatment or young biomass ----CORRECT ANSWER--------amoebas WasteWater Sources & Characteristics: Which type of organisms would most probably be associated with very clear plant effluent. low BOD and low amounts of suspended solids ----CORRECT ANSWER-------- stalked cilates Basic WasteWater Treatment: Aerobic bacteria will reproduce and live in an environment that contains only ---- CORRECT ANSWER--------oxygen Basic WasteWater Treatment: Anaerobic bacteria will reproduce and live only in an environment that completely lacks ----CORRECT ANSWER--------free or dissolved oxygen Basic WasteWater Treatment: The biochemical oxygen demand (BOD) test usually has a specific time of ---- CORRECT ANSWER--------5 days Basic WasteWater Treatment: An Imhoff cone measures ----CORRECT ANSWER--------volume of settleable solids Basic WasteWater Treatment: Septic conditions are caused by ----CORRECT ANSWER--------anaerobic bacteria

Basic WasteWater Treatment: Scum is usually removed in the _____treatment stage ----CORRECT ANSWER-------- primary Basic WasteWater Treatment: When domestic wastewater enters natural waters, what species deplete most of the oxygen ----CORRECT ANSWER--------aerobic bacteria Basic WasteWater Treatment: Once the oxygen is depleted in a natural body of water, which organisms take over? ---- CORRECT ANSWER--------anaerobic Basic WasteWater Treatment: The major gas produces by anaerobic decomposition is ----CORRECT ANSWER-------- methane Wastewater Treatment Facilities: Another name for promary treatment is ----CORRECT ANSWER--------sedimentation Wastewater Treatment Facilities: Digester gas is_______when mixed with air the the proper proportions ----CORRECT ANSWER--------extremely explosive Wastewater Treatment Facilities: A pond that is used to treat raw wastewater is called ----CORRECT ANSWER--------a waste stabilization pond Wastewater Treatment Facilities: A pond that has an aerobic top layer and an anaerobic bottom layer is called ---- CORRECT ANSWER--------a facultative pond

Preliminary Treatment: What is the angle of the bars on a manually cleaned bar screen? ----CORRECT ANSWER--------30 degrees Preliminary Treatment: What is the angle of the bards on a mechanically cleaned bar screen ----CORRECT ANSWER-------- 45 - 60 degrees Preliminary Treatment: What is the ideal wastewater velocity in FPS through a screen channel? ----CORRECT ANSWER--------1.5ft/s Preliminary Treatment: What is the ideal wastewater velocity in FPS for grit removal in a grit chamber ---- CORRECT ANSWER--------1.0 ft/s Preliminary Treatment: In general, what is the water content of screen material ----CORRECT ANSWER-------- 80% Preliminary Treatment: What is the wastewater velocity range in FPS for grit removal in a grit chamber? ---- CORRECT ANSWER--------0.7 - 1.4 ft/s Racks, screens, comminutors and Grit removal: Which one of the following chemicals gives water its greatest capacity to neutralize acids? ----CORRECT ANSWER--------hydroxide Racks, screens, comminutors and Grit removal:

The bar rack is used ----CORRECT ANSWER--------when the bar screen is out of service Primary Sedimentation: Typically, what is the average detention time for wastewater in a primary clarifier? ---- CORRECT ANSWER--------2 hr Sedimentation and Flotation: Name one gas this irritates the "eyes" ----CORRECT ANSWER--------chlorine Primary Sedimentation: Activated sludge clarifiers accept material to be settled from ----CORRECT ANSWER---- ----an aeration tank Primary Sedimentation: According to CWA, secondary treatment is defines as a wastewater plant producing an effluent that has no more than____total suspended solids and no more than_____BOD5 ----CORRECT ANSWER--------30 mg/L, 30 mg/L Primary Sedimentation: The color of bio film on a rotating Biological Contactor would appear____under normal operating conditions ----CORRECT ANSWER--------gray Activated Sludge: A primary effluent and returned activated sludge mixture is called ----CORRECT ANSWER--------waste activated sludge Activated Sludge: The mixture of organisms and solids in water that is removed from the settling tank is called ----CORRECT ANSWER--------mixed liquor

Activated Sludge: Under normal operating conditions, what color is activated sludge ----CORRECT ANSWER--------dark chocolate brown Activated Sludge: What test(s) could an operator use to make process changes immediately if a problem develops ----CORRECT ANSWER--------COD test Activated Sludge: The main "workers" in the activated sludge process are ----CORRECT ANSWER-------- bacteria Activated Sludge: A yellow gas flame from a digester's waste gas burner may indicate a poor quality gas with a ----CORRECT ANSWER--------high CO2 content Waste Treatment Ponds: Ponds used in series after primary wastewater treatment are sometimes called ---- CORRECT ANSWER--------oxidation ponds Waste Treatment Ponds: The most common type of pond is ----CORRECT ANSWER--------facultative pond Waste Treatment Ponds: Which one of the following nuisance organisms is controller simply by the water surface being disturbed by wind or currents? ----CORRECT ANSWER--------mosquitoes Waste Treatment Ponds: When is the Dissolved Oxygen in a waste pond the lowest? ----CORRECT ANSWER---- ----sunrise

Odor Control: What would be the most likely solution in the influent to a wastewater treatment plant has an H2S order? ----CORRECT ANSWER--------add treatment chemicals Phosphorus Removal: That is the main reason why wastewater treatment plants remove phosphorous from their effluent before discharging to a lake or river? ----CORRECT ANSWER--------the reduce the growth of algae Disinfection: What is the color of liquid chlorine? ----CORRECT ANSWER--------amber... Disinfection: How many times heavier than air is chlorine gas? ----CORRECT ANSWER--------2.5 times Disinfection: Free available chlorine consists of ----CORRECT ANSWER--------dissolved chlorine gas, hypochlorous acid, and hypochlorite ion Disinfection: The fusible plug on a chlorine cylinder will start to melt at approximately? ----CORRECT ANSWER--------160 degree F Wastewater Solids Processing: This solids retention treatment method usually has 20 days of retention time: ---- CORRECT ANSWER--------aerobic digestion Wastewater Solids Processing:

The solids treatment methods processes solids in a sealed unit: ----CORRECT ANSWER--------anaerobic digestion Wastewater Solids Processing: The solids treatment method produces methane gas that can be used in other plant processes: ----CORRECT ANSWER--------anaerobic digestion Wastewater Solids Processing: This solids treatment method cures the final product and then it may be applied to farmlands ----CORRECT ANSWER--------composting Wastewater Solids Processing: The solids treatment method uses evaporation but also requires a great deal of labor. ---

• CORRECT ANSWER--------sand drying beds Wastewater Solids Processing: The solids treatment method uses a partially submerged rotating drum ----CORRECT ANSWER--------vacuum filter Wastewater Solids Processing: These solid treatment methods use a coagulant polymer and pressure ----CORRECT ANSWER--------belt filter and plate Sampling, testing & reporting Tests such as pH, temperature and dissolved oxygen should always be performed within____after collection ----CORRECT ANSWER--------15 min Sampling, testing & reporting When calibrating a pH meter, the buffers used should bracket the expected pH and ______ ----CORRECT ANSWER--------be at least 2 pH units apart

Sampling, testing & reporting A test method for determining dissolved oxygen is the______ ----CORRECT ANSWER-- ------azide modification for the Winler titration method Sampling, testing & reporting How long can a dissolved oxygen sample wait for analysis using the modified Winkler method, if it is preserved with sulfuric acid? ----CORRECT ANSWER--------8 hr Sampling, testing & reporting BOD5 samples can be preserved by ----CORRECT ANSWER--------storing them in a refrigerator above freezing and up to 4 degrees C Sampling, testing & reporting The maximum holding time for preserved BOD5 samples is ----CORRECT ANSWER---- ----2 days Sampling, testing & reporting Which one fo the following tests is least likely to effectively help an operator control a waste plant's process? ----CORRECT ANSWER--------BOD 5 Sampling, testing & reporting The maximum holding time for a preserved total suspended solids sample is: ---- CORRECT ANSWER--------7 days Sampling, testing & reporting Generally, the state regulatory body must be notified of all unusual or extraordinary discharges by telephone within: ----CORRECT ANSWER--------24 hours Sampling, testing & reporting