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Which of the following conditions will cause the most wear and damage to a pump impeller?
1. The pump runs dry
2. The speed of the motor is too fast
3. The headpressure is too high
4. There is grit in the inlet entering the pump
What is the standard temperature in the drying oven for the TSS test?
1. 20 to 25ºC
2. 110 to 115ºC
3. 103 to 105ºC
4. 545 to 555ºC
Which problem is the more likely cause of pumps and pipes clogging and requiring cleaning to restore normal flow rates?
1. Poor screenings removal
2. Poor BOD removal
3. Poor TSS removal
4. Poor NH₃ conversion
What is the detention time in a primary clarifier that is 120 feet long, 40 feet wide, 14 feet deep, and the influent flow is 7.5 mgd?
1. 2.3 hours
2. 1.8 hours
3. 1.6 hours
4. 3.1 hours
What procedure should be performed before entering a manhole that has been classified as a permit confined space?
1. Have a trained attendant with you
2. Use a tripod for fall protection
3. Test the air with a gas detector
4. Complete a confined space entry permit
5. All of the above
What is the equivalent in mgd for 35,000 gpd?
1. 0.00035 mgd
2. 1.35 mgd
3. 0.035 mgd
4. 0.35 mgd
What is the surface area of the secondary clarifier?
• Secondary Clarifier Diameter is 50 ft. and the Depth is 12 ft.
1. 7,850 ft²
2. 3,925 ft²
3. 491 ft²
4. 1,963 ft²
How many minutes/day must a pump run, given the following data?
• One (1) piston 14 inches in diameter, and 16 inches long
• The pump runs @ 55 strokes per minute
• The pump delivers 1,000 gallons/day
1. 405 mins/day
2. 3.42 mins/day
3. 17.1 mins/day
4. 1.71 mins/day
When using the proper chemical to identify a chlorine leak, what color will the cloud of smoke be?
1. Green
2. Black
3. Yellow
4. White
Given the following data, how many lbs/day of TSS are entering this plant?
• Plant flow is 350 gpm
• Influent TSS is 250 mg/l
1. 87,500 lbs/day
2. 1,051 lbs/day
3. 729,750 lbs/day
4. 10,491 lbs/day
What are the two (2) major zones of a belt filter press called?
1. Drainage and evaporation
2. Gravity drainage and pressure filtration
3. Pressure shearing and transpiration
4. Liquefaction and expansion
What does the term aliquot mean:
1. Composite sample
2. Grab sample
3. The total volume of sample
4. A portion of a sample
What component is used to convert liquid chlorine into chlorine gas?
1. Expander
2. Evaporator
3. Liquefier
4. Vacuum regulator
What is the main purpose of a trickling filter?
1. To filter out bacteria through sand media
2. To remove large solids particles
3. To oxidize organic material
4. None of the above
What is the RAS flow rate, in mgd, in this activated sludge process?
• Influent Flow is 575,000 gpd
• RAS rate is 55% of Q
1. 300,000 gpd
2. 0.158 mgd
3. 0.316 mgd
4. 0.546 mgd
Which bar screen will capture more debris on its screen?
1. The bar screen that runs all of the time
2. The bar screen that runs on either timer control or level control
3. Capture on the screen has nothing to do with the method of operation
What is the temperature of the incubation for a BOD test?
1. 20ºC
2. 5ºC
3. 20ºF
4. 68ºF
5. Both "a & d"
Which test is better to use for process control of an anaerobic digestion process?
1. pH
2. Acid/alkalinity
3. Total solids
4. Scum blanket
What is the weir overflow rate for the secondary clarifier?
• Influent Flow is 575,000 gpd
• Secondary Clarifier Diameter is 50 ft. and the Depth is 12 ft.
• Secondary Clarifier has a Single Weir Around the Tank's Circumference
1. 5,677 gpd/ft of weir
2. 3,662 gpd/ft of weir
3. 1,831 gpd/ft of weir
4. 7,325 gpd/ft of weir
What is the fecal coliform limit to meet standards for Class B biosolids?
1. 1,000 #/gram TS
2. 10,000 #/gram TS
3. 1,000,000 #/gram TS
4. 2,000,000 #/gram TS
What is the basic principle of a belt filter press?
1. To stabilize volatile solids
2. To destroy microorganisms
3. To increase the sludge volume
4. To remove water from a liquid/solids suspension
What does it mean when there is a lack of any odor coming from a lift station manhole?
1. Dangerous gases may be present because some gases do not emit an odor
2. The oxygen level may still be too low for entrance
3. Some gases deaden the sense of smell
4. All of the above
What 15-minute test will help to identify the concentration of the thickened sludge product on the gravity belt thickener system?
1. Laboratory TSS
2. Settleometer
3. Centrifuge spindown
4. Sludge judge
Which activated sludge growth phase is considered to have the lowest F/M ratio, the highest SRT, the lowest sludge yield, and the worse oxygen utilization efficiency?
1. High rate aeration
2. Extended aeration
3. Conventional aeration
4. Log growth
What is the formula that defines chlorine residual?
1. Demand - supply = residual
2. Supply - demand = residual
3. Supply x demand = residual
4. None of the above
What is it called when sludge and polymer plug the belts of a belt filter press?
1. Blinding
2. Sloughing
3. Cavitation
4. Bulking
What is a typical RAS to Q ratio for an extended aeration activated sludge process?
1. 10% to 25%
2. 25% to 50%
3. 1% to 2%
4. 75% to 100%
What does the "5" mean in the BOD₅ test?
1. That the sample is incubated for 5 days
2. That the sample is maintained at 5ºC during incubation
3. That the sample is collected for 5 days
4. That the sample is held for 5 days before incubation begins
What action should be performed if streaks of sludge appear on the belt of a gravity belt thickener?
1. Clean the washbox nozzles
2. Increase the sludge feed rate
3. Reduce the belt speed
4. Increase the chemical feed rate
Where does denitrification primarily occur?
1. Anoxic zone
2. Fermentation zone
3. Effluent Filtration
4. Aerobic zone
What does this formula represent associated with primary clarifier performance?

IN - OUT ÷ IN x 100 = ?
1. Detention time, hrs
2. Removal Efficiency, %
3. Solids loading rate, lbs/day
4. Surface loading rate, gal/day/ft²
What does an open circuit mean in electrical terms?
1. That power is disengaged ... dead
2. That power is bypassed
3. That power is engaged ... live
4. None of the above
What type of maintenance is performed on a piece of equipment after it breaks?
1. Corrective
2. Preventive
3. Quarterly
4. Emergency
What adjustment should be made if solids are rising in the secondary clarifier accompanied by small nitrogen gas bubbles?
1. Increase aeration D.O.
2. Decrease the RAS rate
3. Decrease the WAS rate
4. Decrease aeration D.O.
How many lbs/day of WAS are removed each day?
• WAS Volume is 14,000 gpd
• WAS Concentration is 1% Total Solids
1. 0.1168 lbs/day
2. 116,760 lbs/day
3. 2,335 lbs/day
4. 1,168 lbs/day
What is the overall concept of a gravity thickener?
1. The thinner the sludge you put in ... the thicker the sludge you take out
2. The thicker the sludge you put in ... the thicker the sludge you take out
3. The thinner the sludge you put in ... the thinner the sludge you take out
4. The thicker the sludge you put in ... the thinner the sludge you take out
What is the total length of weir for the secondary clarifier?
• Secondary Clarifier Diameter is 50 ft. and the Depth is 12 ft.
• Secondary Clarifier has a Single Weir Around the Tank's Circumference
1. 262 feet
2. 105 feet
3. 314 feet
4. 157 feet
What happens to the pH and alkalinity of the sludge after lime is added to it?
1. The pH goes down and the alkalinity goes up
2. The alkalinity goes down and the pH goes up
3. The pH goes up and the alkalinity goes up
4. None of the above
Which is the physical process that follows an aeration tank?
1. Preliminary treatment
2. Tertiary treatment
3. Activated sludge process
4. Secondary clarification
Which activated sludge growth phase is considered to have the lowest F/M ratio, the highest SRT, the lowest sludge yield, and poor oxygen utilization efficiency?
1. High rate aeration
2. Extended aeration
3. Conventional aeration
4. Log growth
What is the F/M ratio of the activated sludge process?
• Influent Flow is 575,000 gpd
• Influent CBOD₅ is 250 mg/l
• Aeration Tank Dimensions are 100 ft. Long, 25 ft. Wide, and 14 ft. Deep
• Aeration MLSS is 3,500 mg/l
• Aeration MLSS is 75% Volatile
1. 0.42
2. 0.21
3. 2.28
4. 0.16
What does "sloughing" mean on the trickling filter?
1. The filter is being bypassed
2. Large pieces of growth are breaking off of the media and flowing out with the filter effluent
3. The media is becoming broken as a result of age and acidic conditions
4. The recirculation rate is very high
Which gases may be found in sewer collection systems?
1. Explosive gases
2. Hydrogen sulfide
3. Methane
4. All of the above
What is the amount of oxygen required to convert 1 ppm of ammonia-nitrogen?
1. 1.0 pounds
2. 7.48 pounds
3. 4.6 pounds
4. 8.34 pounds
Where does the D.O. come from in an unaerated lagoon?
1. Wind blowing across the pond
2. Algae growth
3. Oxygen-producing bacteria
4. The moon
Which time of day will generally produce the highest D.O. in an unaerated stabilization pond?
1. 12 midnight
2. 3 p.m.
3. 4 a.m.
4. 9 a.m.
What type of maintenance is performed on a piece of equipment before it breaks?
1. Corrective
2. Preventive
3. Quarterly
4. Emergency
What is the term when ammonia-N and organic-N are added together?
1. TN
2. NO₃
3. NO₂
4. TKN
What should a shift supervisor do if he or she finds an employee sleeping on the job?
1. Shake the employee and yell at him or her
2. Find out why the employee was sleeping and then follow the prescribed policy for sleeping on the job
3. Fire the employee on the spot
4. Report this to your supervisor
5. Both "b & d"
What does a recirculation rate of 1:1 mean in a trickling filter process?
1. There is 1 mg/l BOD₅ being loaded to 1 ft² of media
2. The total flow applied to the trickling filter is 2 mgd
3. The total flow applied to the trickling filter is twice the volume of the raw wastewater flow
4. The flow applied to the trickling filter is three times the volume of the raw wastewater flow
Which group of bacteria are strictly aerobic and are responsible for nitrification in the activated sludge process?
1. Heterotrophic
2. Carbon eaters
3. Autotrophic
4. Facultative
Which zone produces the largest amount of biological denitrification?
1. Fermentation
2. Anoxic
3. Aerobic
4. Reaeration
What is the equivalent in gpm of a pipe that has 1 mgd flowing through it?
1. 694 gpm
2. 1,440 gpm
3. 133,690 gpm
4. 11.6 gpm
What is the top blanket of sludge called in the DAF process?
1. Subnatant
2. Decant
3. Float
4. Cirilo
Which item of information would not be of major importance if you were developing and presenting a report to your organization's council?
1. Capital improvement program
2. Major equipment maintenance
3. Facility process performance
4. Detailed lab procedures
What happens to the activity rate of activated sludge microorganisms when the temperature increases?
1. It decreases
2. It increases
3. It remains the same
What two laboratory analyses are necessary to calculate the F/M ratio?
1. Aeration MLVSS and influent CBOD₅
2. Aeration MLSS and OUR
3. Aeration MLVSS and effluent CBOD₅
4. Aeration MLSS and influent CBOD₅
Given the following data, what is the SRT of this activated sludge plant?
- Plant flow = 0.575 mgd
- MLSS = 3,500 ppm
- Aeration tank dimensions = 100 ft long, 25 ft wide and 14 ft deep
- WAS volume = 14,000 gpd
- WAS concentration = 1% total solids
- Effluent TSS = 2.5 ppm
1. 12 days
2. 8.5 days
3. 6.5 days
4. 0.15 days
What is the purpose of an Imhoff cone test?
1. To identify total suspended solids
2. To identify settleable solids
3. To identify volatile solids
4. To identify fixed solids
Which is more likely to be of volatile nature?
1. Grit debris
2. Screenings debris
3. Grease
4. Both "b & c"
Which dangerous gas will be more likely to rise near the surface of a manhole?
1. Hydrogen sulfide
2. Methane
3. Nitrogen
4. None of the above
What does the production of foam indicate in an anaerobic digester?
1. That the alkalinity level is too high
2. That the acid production is too low
3. That the acid production is too high
4. This is a normal indication ... all is OK
What does the unit parts per million (ppm) mean?
1. 1 pound per million pounds
2. 1 gallon per million gallons
3. 8.34 pounds per million gallons
4. 1 milligram per liter
5. All of the above
Which best describes the nitrification cycle?
1. Nitrates are converted to ammonia
2. Ammonia is converted to nitrites and then to nitrates
3. Ammonia is converted to nitrates and then to nitrites
4. Nitrites are converted to ammonia and then to nitrates
What happens to the alkalinity in wastewater during the nitrification process?
1. It increases
2. It decreases
3. It does not change
4. It stabilizes at 200 mg/l
What should be done with an employee whose work is below acceptable levels?
1. Fire the employee and look for a replacement
2. Demote the employee without discussion
3. Find a replacement and then fire the employee
4. Talk with the employee and provide additional training
5. After offering assistance, give the employee a deadline to show improvement
6. Both "d & e"
What piece of equipment is used in the volatile solids test?
1. Muffle furnace
2. Desiccator
3. Analytical balance
4. All of the above
Which chemical is commonly used as a source of carbon in a chemical denitrification process?
1. Methanol
2. Methane
3. Sodium Bicarbonate
4. Caustic soda
What is generally required when the sludge blanket is too high on the floor of a gravity thickener?
1. Increase the withdrawal rate of sludge from the gravity thickener
2. Pump more sludge into the gravity thickener
3. Decrease the speed of the drive unit
4. Decrease the withdrawal rate of sludge from the gravity thickener
What is the relationship of gas chlorine to air?
1. Gas chlorine is 1½ lighter than air
2. Gas chlorine is the same weight as air
3. Gas chlorine is 1½ heavier than air
4. Gas chlorine is 2½ heavier than air
If your plant has a flow rate of 1.25 mgd, a chlorine demand of 7.5 mg/l, and you maintain a chlorine residual of 1.5 mg/l, how many lbs/day of chlorine will be used?
1. 93.8 lbs/day
2. 78.2 lbs/day
3. 62.6 lbs/day
4. 52.1 lbs/day
Which term is most related to vector attraction reduction in an aerobic digester?
1. Settleometer
2. Pathogen
3. SOUR
4. F/M
What is the term for water leaking out of a sanitary sewer line?
1. Exfiltration
2. Slip line
3. Combine sewer
4. Infiltration
What is the relationship of liquid chlorine to water?
1. Liquid chlorine is 1½ times lighter than water
2. Liquid chlorine is the same weight as water
3. Liquid chlorine is 1½ times heavier than water
4. Liquid chlorine is 2½ times heavier than water
What is an acceptable surface loading rate for a primary clarifier?
1. 400 to 600 gpd/ft²
2. 800 to 1,200 gpd/ft²
3. 100 to 300 gpd/ft²
4. 5,000 to 15,000 gpd/ft²
Which chemical is not used to remove phosphorus from wastewater?
1. Lime
2. Sodium Hydroxide
3. Ferric chloride
4. Aluminum sulfate
What adjustment may be the best to make if the secondary clarifier, and the settleometer test, show an abundance of small pin floc in the effluent?
1. Decrease the RAS rate
2. Increase the SRT
3. Decrease the WAS rate
4. Decrease the SRT
What process test can be performed in about 10 minutes and identifies the amount of oxygen being consumed by the microorganisms?
1. OUR, mg/l/hr
2. SVI ml/mg
3. SRT, days
4. F/M ratio
What does the unit parts per million (ppm) mean?
1. 1 pound per million gallons
2. 1 gallon per million pounds
3. 8.34 pounds per million gallons
4. 10 milligrams per liter
What adjustment should be made if solids are rising in the secondary clarifier accompanied by large, smelly gas bubbles?
1. Increase aeration D.O.
2. Decrease the RAS rate
3. Decrease the WAS rate
4. Decrease aeration D.O.
Is hydrogen sulfide (H₂S) lighter or heavier than the weight of air?
1. Lighter, it will rise
2. Heavier, it will settle
3. No difference, they are both the same weight
What are the two (2) major gases produced in a properly operated anaerobic digestion process?
1. Methane and carbon dioxide
2. Methane and oxygen
3. H₂S and CH₄
4. Nitrogen and O₂
Which aeration foam may indicate an old sludge condition?
1. Black in color
2. Light brown in color
3. White or very light in color
4. Very dark grey in color
What does hydrogen sulfide (H₂S) smell like at low concentrations?
1. No smell
2. Chlorine
3. Rotten eggs
4. Sulfuric acid
Who benefits from the development of a complete annual report of the facility O&M?
1. The governing body
2. The responsible engineer
3. The health department
4. The facility management
5. All of the above
What is a common spacing between the bars for a fine bar screen?
1. 2 inches
2. ¼ inch
3. 4 inches
4. 1 micron
What is the best method of collecting a sample to be tested for effluent chlorine residual?
1. Composite sample at the inlet of the chlorine contact chamber
2. Grab sample at the outlet of the chlorine contact chamber
3. Composite sample at the outlet of the chlorine contact chamber
4. Grab sample at the inlet of the chlorine contact chamber
What should not be done when working with a liquid chlorine system?
1. Never spray water on the cylinders
2. Never trap liquid between two valves
3. Never attempt to fix a leak by yourself
4. All of the above
What happens to the alkalinity in wastewater during the denitrification process?
1. It increases
2. It decreases
3. It does not change
4. It stabilizes at 200 mg/l
What is it called when all of the demand for chlorine has been satisfied?
1. Breakpoint
2. Combined
3. Mono-chloramine
4. Molecular liberation
What is the volume in gallons of the aeration tank?
•Aeration Tank Dimensions are 100 ft. Long, 25 ft. Wide, and 14 ft. Deep
1. 7,854 gals
2. 261,800 gals
3. 4,679 gals
4. 291,900 gals
What is the volume of 1 cubic foot of water?
1. 8.34 gals
2. 62.4 gals
3. 92.84 gals
4. 7.48 gals
Which lab test requires the use of an analytical balance, a drying oven, filter papers, and a desiccator?
1. TSS
2. TS
3. CBOD₅
4. Settleable Solids
What happens to the pH in an aerobic digester when carbon dioxide is released from the sludge?
1. The pH decreases
2. The pH increases
3. Carbon dioxide does not affect the pH
4. Alkalinity is decreased
What is the solids loading rate on the secondary clarifier?
• Influent Flow is 575,000 gpd
• RAS rate 55% of Influent Flow
• Secondary Clarifier Diameter is 50 ft. and the Depth is 12 ft.
• Aeration MLSS is 3,500 mg/l
1. 13.2 lbs/day/ft²
2. 8.6 lbs/day/ft²
3. 4.7 lbs/day/ft²
4. 9.9 lbs/day/ft²
What is the system called that requires proper documentation associated with the person who collects the samples, the person who receives the samples in the lab, and the lab technician who performs the tests?
1. Sample performance
2. Chain of custody
3. Mapping
4. Sample journal
Which test is not used to indicate the performance of an anaerobic digester?
1. Alkalinity
2. Methane gas production
3. pH
4. Chlorine residual
Which type of sewer system contains both sanitary wastewater and storm water?
1. Domestic wastewater system
2. Combined sewer system
3. Separate collection system
4. Sewer system evaluation survey
What happens to the digester pH if carbon dioxide is trapped in the sludge?
1. The pH decreases
2. The pH increases
3. Carbon dioxide does not affect the pH
4. Alkalinity is increased
Why should air be prevented from entering an anaerobic digester tank?
1. It reduces the gas storage capacity of the tank
2. It interferes with the activity of the aerobic bacteria
3. It lowers the temperature of the digested sludge
4. It can react with the digester gas and create a potential for an explosion
What does it usually mean if gas and rising sludge is occurring in a gravity thickener?
1. Too much sludge is being withdraw from the thickener
2. Not enough sludge is being withdrawn from the thickener
3. The system is fully aerobic
4. This is not the indication of a problem ... it is a normal condition
What causes the sludge to float to the surface in the dissolved air flotation (DAF) process?
1. The addition of lime
2. The addition of polymer
3. The addition of air-saturated recycle water
4. Withdrawing bottom sludge at a fast rate
What is a common volume make-up of gases in a properly operated anaerobic digester?
1. 30% CO₂ and 70% N²
2. 50% CH₄ and 50% CO₂
3. 70% CH₄ and 30% CO₂
4. 25% O₂ and 75% N²
What adjustment is generally necessary when gas and/or solids rise to the surface of a primary clarifier?
1. Increase the amount of primary sludge withdrawal
2. Stop pumping primary sludge
3. Load the primary clarifier at a higher rate
4. Decrease the amount of primary sludge withdrawal
What is the percent TSS removal efficiency in this plant?
• Influent TSS is 200 mg/l
• Effluent TSS is 2.5 mg/l
1. 98.8%
2. 100%
3. 89.6%
4. 82.7%
Which is the biological process that follows primary treatment?
1. Preliminary treatment
2. Tertiary treatment
3. Activated sludge process
4. Secondary clarification
What color should digested sludge be in a properly operated anaerobic digestion process?
1. Black
2. Grey
3. Green
4. Brown
What is the makeup of typical grit debris?
1. Organic material
2. Dissolved solids
3. Inorganic material
4. Volatile solids
What happens to ozone residual when the ozonated effluent has increased COD levels?
1. The ozone residual increases
2. The ozone residual decreases
3. Ozone residual is unaffected by COD
4. None of the above
What is the equivalent in mgd for 78,850 gpd?
1. 0.0007885 mgd
2. 0.7885 mgd
3. 0.07885 mgd
4. 0.007885 mgd
What is a common problem associated with trickling filters?
1. Bulking
2. Ponding
3. Snail growth
4. Liquefaction
What is the BOD test a measure of?
1. Suspended solids
2. Organic content
3. Dissolved solids
4. Alkalinity
Which chemical is used to identify a chlorine leak?
1. Bleach
2. Ammonia
3. Sodium
4. Nitrate
What D.O. range is more likely to allow filamentous bacteria to become more populated as compared to the healthy floc formers in activated sludge?
1. D.O. above 2.0 mg/l
2. D.O. above 4.0 mg/l
3. D.O. between 0.4 to 0.8 mg/l
4. D.O. between 3.0 to 5.0 mg/l
What type of pond has aerobic conditions near the top and anaerobic conditions at the bottom?
1. Fully aerated
2. Anaerobic digestion
3. Fermentation
4. Facultative
What item is important in the development of a maintenance program?
1. Equipment data
2. Maintenance frequencies
3. Repair procedures
4. List of emergency phone numbers
5. All of the above
What is a common method of determining the quantity of chlorine used each day?
1. Read the pressure gauge and calculate loss
2. Read the vacuum gauge
3. Calculate the chlorine demand
4. Read the chlorine scale weight
Which type of bacteria is responsible for stabilization of organic material (CBOD₅) in wastewater?
1. Nitrosomonas
2. Nitrobacter
3. Autotrophic
4. Heterotrophic
What may be the recommended action to perform if the top belt of a belt filter press was flooded, and sludge was leaking off the sides?
1. Increase the sludge feed rate
2. Decrease the belt speed and decrease the washwater pressure
3. Decrease the sludge feed rate or increase the belt speed
4. Adjust the polymer dose rate
5. e. Both "c & d"
What is the term for water seeping into a sanitary sewer line?
1. Exfiltration
2. Slip line
3. Combine sewer
4. Infiltration
What is the surface settling rate for the secondary clarifier?
• Influent Flow is 575,000 gpd
• Secondary Clarifier Diameter is 50 ft. and the Depth is 12 ft.
1. 24,481 gpd/ft²
2. 12.1 gpd/ft²
3. 293 gpd/ft²
4. 73.2 gpd/ft of weir
Which of the following is considered to be the least harmful bacteria?
1. Typhoid
2. Fecal coliform
3. Cholera
4. Streptococcus
Associated with primary clarifier scum, what does FOG mean?
1. Fat Oil Grease
2. Full Organic Gold
3. Firm Oily Gate
4. Fat Old Guy
What is the fecal coliform limit to meet standards for Class A biosolids?
1. 1,000 #/gram TS
2. 10,000 #/gram TS
3. 1,000,000 #/gram TS
4. 2,000,000 #/gram TS
What should be done to protect all personnel when repairs are made to an electrical component?
1. Inform all personnel in the area that the repairs are being made
2. Lock-out the equipment controls
3. Tag the equipment controls
4. Be trained and understand the OSHA requirements for this procedure
5. All of the above
Why is it critical to keep the distribution arm of a trickling filter free from plugging?
1. To prevent overloading the secondary clarifier
2. To encourage sloughing
3. To assure ventilation through the filter
4. To assure uniform application of the wastewater over the media
Which repair kit is used with one-ton chlorine cylinders?
1. “A” Kit
2. “B” Kit
3. “C” Kit
4. “D” Kit
Which aeration foam may indicate a young sludge condition?
1. Black in color
2. Dark brown in color
3. White or very light in color
4. Very dark grey in color
Where does nitrification primarily occur?
1. Anoxic
2. Fermentation
3. Aerobic
4. Anaerobic
What percentage of total suspended solids (TSS) is typically removed in a primary clarifier?
1. 25%
2. 100%
3. 50%
4. 85%
What form of chlorine comes in one-ton containers?
1. Gas from both valves
2. Liquid from both valves
3. Liquid from the top valve and gas from the bottom valve
4. Gas from the top valve and liquid from the bottom valve
What is a typical percent solids in the final cake of a belt filter press?
1. 2% to 4%
2. 30% to 50%
3. 15% to 20%
4. 8% to 10%
What does this formula represent?
π r² x depth, ft. x 7.48
1. Volume of a cone in gallons
2. Volume of a circular tank in gallons
3. Volume of a sphere in gallons
4. Volume of a cone in ft³
What is the main purpose for a comprehensive maintenance program?
1. To give the mechanics something to do
2. To operate all of the plant equipment
3. To allow the plant to operate at its peak performance
4. To repair equipment after breakage
Why is flooding of trickling filter media sometimes recommended?
1. To control filter flies
2. To create a reservoir of stored wastewater
3. To improve the contact of BOD₅ and the organisms on the media
4. To create sloughing
What is the detention time in the aeration tank? (not including RAS flow)
• Influent Flow is 575,000 gpd
• Aeration Tank Dimensions are 100 ft. Long, 25 ft. Wide, and 14 ft. Deep
1. 15.1 hours
2. 10.9 hours
3. 2.2 hours
4. 9.0 hours
What percentage of CBOD₅ is typically removed in a primary clarifier?
1. 25%
2. 100%
3. 50%
4. 75%
What should management do if they see a large increase in the facility monthly power bill?
1. Yell at the operators and tell them to use less electricity
2. Evaluate the practice of starting high horsepower equipment
3. Call the power company and complain
4. Meet with the power company and discuss the options of alternate billing methods
5. Both "b & d"
Which is a common type of level control system?
1. Staff gauge
2. Brush stepper
3. Backpressure valve
4. Bubbler
Which component in the chlorination process is responsible for creating a vacuum condition, which draws the chlorine gas through the chlorinator, and then mixes the gas into a solution?
1. Pressure regulator
2. Vacuum regulator
3. Gas rotometer
4. Gas injector
What are the responsibilities of plant management?
1. To ensure operators are trained
2. To develop performance data records and reports
3. To control budgets
4. All of the above
Which factor affects the operation of a sand drying bed?
1. Climatic conditions
2. Depth of sludge application
3. Degree of sludge stabilization
4. Age of the sludge
5. All of the above
What term is most related to free chlorine residual?
1. Chloramine
2. Fecal
3. Breakpoint
4. Alkalinity
What happens to the trickling filter effluent D.O. when the recirculation rate is increased?
1. It decreases the D.O.
2. It increases the D.O.
3. It has no affect on the D.O.
4. It becomes supersaturated with D.O.
Which chemical is typically used for conditioning the sludge feed applied to a gravity belt thickener process?
1. Lime
2. Polymer
3. Ferric chloride
4. Chlorine
What is the organism growth on the media of a trickling filter called?
1. Filamentous
2. Rotifier
3. Larvae
4. Zoogleal
What is the main cause of water seepage into a sanitary sewer?
1. Poor construction of the collection line, especially at pipe joints
2. Sewer line too deep
3. Sewer line diameter too small
4. Improper cycling of lift stations
What percentage of settleable solids are typically removed in a primary clarifier?
1. 25%
2. 100%
3. 50%
4. 85%
What is a typical percent solids in the thickened sludge product of a gravity belt thickener?
1. 1% to 2%
2. 10% to 15%
3. 20% to 25%
4. 4% to 8%
What is a typically acceptable D.O. in an aerobic digester?
1. 0.01 to 0.05 mg/l
2. No less than 5.0 mg/l
3. 0.5 to 1.5 mg/l
4. 6.0 to 8.5 mg/l
What does H₂S smell like at high concentrations?
1. Rotten eggs
2. Cabbage
3. No smell
4. Sweet orange
What is the fraction, in its least common denominator, for the decimal 0.86?
1. 86 ÷ 100
2. 43 ÷ 50
3. 86 ÷ 50
4. 43 ÷ 100
How many lbs/day of CBOD₅ are entering your plant, given the following data?
• Plant flow is 350 gpm
• Influent CBOD₅ is 250 mg/l
1. 87,500 lbs/day
2. 1,051 lbs/day
3. 729,750 lbs/day
4. 10,491 lbs/day
What is the decimal for the fraction ⅝ ?
1. 0.265
2. 0.562
3. 0.625
4. 1.6
Which component is not part of a centrifugal pump?
1. Check valve
2. Impeller
3. Bearings
4. Rotor
What component of a pump keeps the material in the discharge pipe from emptying out through the pump suction when the pump is off?
1. Pressure relief
2. Check valve
3. Mechanical seal
4. Volute
What is the detention time of a chlorine contact chamber that is 50 feet long, 15 feet wide, 10 feet deep, and has a plant flow rate of 2.1 mgd?
1. About 2 hours
2. About 76 minutes
3. About 39 minutes
4. About 15 minutes
What happens when chlorine liquid is converted to chlorine gas in a pipeline or from a leaking cylinder?
1. It expands about 8.34 times the volume
2. It expands about 7.48 times the volume
3. It expands about 460 times the volume
4. It expands about 2.5 times the volume
What is the makeup of typical screenings debris?
1. Organic material
2. Inorganic material
3. Sand
4. Dissolved solids
What is another term for inorganic solids?
1. Volatile
2. Non-volatile
3. Dissolved
4. Soluble
What is the fundamental concept of aerobic digestion operation?
1. Methane gas is a by-product
2. The overall sludge production is increased
3. High rate, log growth is accomplished
4. Endogenous decay occurs at a faster rate than microbial growth
What is the guideline velocity number to accomplish proper grit removal?
1. 2 fps
2. 1 fps
3. 10 fps
4. 5 fps
What is considered to be a neutral pH?
1. 6.5
2. 14.0
3. 10.0
4. 7.0
Which factors affect the amount of sludge that can be applied to a land application site?
1. Nitrogen and heavy metals
2. Carbon and chlorides
3. Phosphorus and alkalinity
4. pH and BOD₅
What is the principle concept of the gravity belt thickener?
1. Dewaters through pressure shearing
2. Thickens through gravity drainage
3. Thickens through high speed spinning
4. Thickens through pressure filtration
How should manhole covers be lifted?
1. Your fingers
2. A manhole hook
3. A screw driver
4. A hammer
Why does scum float on the surface of a primary clarifier?
1. Because its specific gravity is greater than water
2. It is mainly inorganic material
3. Because its specific gravity is less than water
4. Scum does not float it sinks to the floor of the clarifier
What is the percent BOD₅removal efficiency in this plant?
• Influent CBOD₅ is 250 mg/l
• Effluent CBOD₅ is 3.5 mg/l
1. 98.6%
2. 100%
3. 89.6%
4. 82.7%
What is the equivalent in total percent solids of a sludge sample that has a concentration of 15,700 mg/l?
1. 1.57%
2. 15.7%
3. 157%
4. 0.157%
Which factors affect the operation of an aerobic digester?
1. Oxygen transfer efficiency
2. Dissolved oxygen level
3. Dissolved oxygen level
4. Temperature
5. All of the above
What is the best adjustment to make if the RAS in a secondary clarifier is black and the sludge blanket depth is high?
1. Decrease the aeration D.O.
2. Increase the RAS rate
3. Decrease the WAS rate
4. Increase the SRT
What should be done if a neighbor complains about a plant odor?
1. Meet with the person and explain that you have no control over plant odors
2. Use massive volumes of chlorine in the plant influent to kill the odor
3. Evaluate the odor source and use the best management practice to minimize the odor
4. Use massive amounts of lime in the sludge to sweeten the odor
What does the term "anaerobic" mean in regard to oxygen?
1. Free D.O. and combined oxygen are present
2. Only free D.O. is present
3. Only combined oxygen is present
4. No oxygen is present in any form
Which of the following materials is not commonly used in the construction of a collection system?
1. Vitrified clay
2. Aluminum
3. Ductile iron
4. Precast concrete
What is the term for the collection of one (1) sample in which an analysis is performed?
1. Grab
2. Composite
3. Grab-to-composite
4. Beaker

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Wastewater Operator Study Guide Module 1 ... Practice Quiz ... Happy Studying!Return to the Quiz Home Page by Clicking the Upper Right "x" on Your Browser

Wastewater Operator Study Guide Module 1 ... Practice Quiz ... Happy Studying!
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