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Advanced Wastewater Study Guide

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Wastewater Public Utilities Quiz on Advanced Wastewater Study Guide, created by Dean Lampman on 01/03/2019.
Dean Lampman
Quiz by Dean Lampman, updated more than 1 year ago
Dean Lampman
Created by Dean Lampman over 5 years ago
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Resource summary

Question 1

Question
What does it mean when a belt filter press is washing out?
Answer
  • Water is overrunning the sides of the belt
  • Sludge is squeezing out from between the belt
  • The unit is being cleaned
  • The effluent line is clogged

Question 2

Question
In the five-stage bardenpho process, what occurs after the microorganisms pass from the first anoxic zone into the first aeration basin?
Answer
  • WAS is pumped from the aeration basin back to the head of the plant
  • A percentage of the mixed liquor is returned to the first anoxic zone
  • All of the mixed liquor passes directly into the second anoxic zone
  • All of the mixed liquor passes directly into the secondary clarifier

Question 3

Question
What kind of problems arise in the clarifier when the sludge is overstabilized?
Answer
  • Sludge settles too slowly and is hard to keep in the clarifier
  • Sludge settles too quickly causing high effluent turbidity due to pin floc
  • Sludge settles too slowly and may turn septic in the return sludge system

Question 4

Question
First stage BOD is also known by what term?
Answer
  • Nitrogenous BOD
  • Carbonaceous BOD
  • Metabolic BOD
  • Oxidation

Question 5

Question
What term is used to describe the liquid that leaves a centrifugal thickener through the effluent line?
Answer
  • Concentrate
  • Elutriation
  • Centrate
  • Precipitate

Question 6

Question
Why are primary clarifiers not very effective for removing BOD?
Answer
  • Most BOD is soluble and cannot be removed by sedimentation
  • Most BOD is insoluble, but not heavy enough to settle
  • Primary clarifiers cannot handle high organic loads
  • None of these answers

Question 7

Question
When denitrification is occurring, the microorganisms use methanol as a carbon food source. Where do they obtain the oxygen necessary to metabolize the methanol when there is no free oxygen present?
Answer
  • The microorganisms do not need oxygen to metabolize
  • From the nitrate ion
  • From the ammonia-nitrogen
  • From the gaseous nitrogen

Question 8

Question
Which modification of the activated sludge process is best suited for nitrification?
Answer
  • Complete mix
  • Extended Aeration
  • Step Feed
  • Contact Stabilization

Question 9

Question
Microorganisms that are in an anaerobic environment are then transferred to a proper environment containing food and oxygen where they take in excess amounts of phosphorus. What is this intake of excess phosphorus called?
Answer
  • Endogenous respiration
  • Luxury uptake
  • Anaerobic respiration
  • Absorption

Question 10

Question
What is the term used for water that is contained within the cell mass of sludge?
Answer
  • Bound water
  • Hard water
  • Molecular Water
  • Free Water

Question 11

Question
Which of the following has an ammonia odor?
Answer
  • Mercaptans
  • Indole
  • Skatole
  • Hydrogen Sulfide

Question 12

Question
What can be said about belt speed in a gravity belt filter thickener?
Answer
  • A. As belt speeds increases, the belt area in contact with the influent sludge increases
  • B. As belt speed increases, the belt area in contact with the influent sludge decreases
  • C. Belt speed should be as slow as possible without washing out the belt
  • Both A and C

Question 13

Question
In what order are the basins arranged in the five-stage Bardenpho process?
Answer
  • Anaerobic, anoxic, aeration, anoxic, aeration
  • Anoxic, anaerobic, aeration, anoxic, aeration
  • Aeration, anoxic, anaerobic, aeration, anoxic
  • Aeration, anaerobic, anoxic, aeration, anoxic

Question 14

Question
What type of thickener would work best when treating primary sludge?
Answer
  • Centrifuge
  • Gravity
  • Flotation
  • All of the above

Question 15

Question
Where should screen be located?
Answer
  • As close as possible to where the waste is being produced
  • As far as possible from where the sludge is being produced
  • As close to the plant influent as possible
  • At the aerator influent

Question 16

Question
When calculating how much activated sludge is being wasted, what must always be accounted for?
Answer
  • Solids lost in effluent
  • Solids in influent
  • DO in Aerator
  • Solids lost in effluent and solids in influent

Question 17

Question
What effect would increasing the return sludge aeration time have on the SVI?
Answer
  • Decrease
  • Increase
  • No change
  • Increase then decrease

Question 18

Question
When chlorine is added to water containing ammonia, the ammonia reacts with the hypochlorous acid and forms:
Answer
  • Nitrogen gas
  • Alkalinity
  • Chloramines
  • Nitrates

Question 19

Question
If air input to the aerator has not been increased and there is a significant increase in DO residual, what does this indicate and which process control adjustment should be made?
Answer
  • Increased MLVSS/increase wasting and increase RAS
  • Toxic shock load/increase wasting and decrease RAS
  • Toxic shock load/increase wasting and increase RAS
  • Increased MLVSS/decrease wasting and decrease RAS

Question 20

Question
How deep should sludge be when using a sand drying bed?
Answer
  • 6-12 inches
  • 1-3 inches
  • 12-18 inches
  • 2-4 feet

Question 21

Question
When wastewater has a pH on the low side of 6.5, what property will the wastewater's solid particles have?
Answer
  • High settleability
  • Low settleability
  • Negative ionic charges
  • Positive ionic charges

Question 22

Question
What may be added to wastewater when nutrient levels are too low to support the microorganisms?
Answer
  • Nitrogen and phosphorus
  • Ammonia and phosphoric acid
  • Sodium acetate
  • All of these

Question 23

Question
If the pH of wastewater drops low enough to inhibit nitrification, what has occurred and what should be done to fix the problem?
Answer
  • Too much alkalinity / Recarbonate to achieve proper pH
  • Not enough alkalinity / Add lime to achieve proper pH
  • Low DO / Increase air rate
  • High DO / Decrease air rate

Question 24

Question
At what DO would sulfate be reduced to sulfide?
Answer
  • 0 mg/L
  • 1.0 mg/l
  • 2.0 mg/l
  • >2.0 mg/l

Question 25

Question
While operating a vacuum filter, the operator finds that the sludge cakes are too wet. What would be the best course of action?
Answer
  • Decrease vacuum
  • Decrease chemical conditioning
  • Decrease influent flow
  • Decrease drum speed

Question 26

Question
What conditions can cause forming?
Answer
  • High MCRT values
  • High MLSS
  • High concentration of filaments
  • All of these

Question 27

Question
The DO should be kept at _______ in the first anaerobic and anoxic zones when using the Bardenpho process?
Answer
  • 2.0 mg/l
  • 1.5 mg/l
  • 0.5 mg/l
  • 0 mg/l

Question 28

Question
When treating high organic loads, what process control adjustment should be made?
Answer
  • Decrease RAS
  • Increase RAS
  • Increase wasting
  • Decrease DO

Question 29

Question
What can cause belt blinding when operating a belt filter press?
Answer
  • Polymer undressing
  • Polymer overdosing
  • Loose belts
  • Belt speed too high

Question 30

Question
Why is the amount of food available to the microorganisms allowed to decrease during aerobic digestion?
Answer
  • To cause denitrification
  • To cause nitrification
  • To encourage endogenous respiration
  • To decrease turbidity

Question 31

Question
Why must special care be taken to avoid agitation of the wastewater during the denitrification process?
Answer
  • To avoid allowing free oxygen to enter the wastewater
  • To maintain aerobic conditions
  • To avoid disturbing the microorganisms
  • To decrease turbiditiy

Question 32

Question
Organisms that can only use molecular oxygen are called?
Answer
  • Anaerobes
  • Facultative
  • Obligate aerobes
  • Strict anaerobes

Question 33

Question
When is produced during nitrification that may reduce buffering capacity of the alkalinity and cause a subsequent lowering of the pH?
Answer
  • Hydrogen ions
  • Hydroxyl ions
  • Carbon dioxide
  • Acid

Question 34

Question
What term describes organisms that use inorganic materials for energy and growth?
Answer
  • Heterotrophic
  • Eutrophic
  • Autotrophic
  • Anaerobes

Question 35

Question
Emergency basins and storage tanks should be kept:
Answer
  • Full at all times
  • Filled half way
  • Empty or almost empty
  • Full during high flows

Question 36

Question
What may be indicated by a low respiration rate value?
Answer
  • Low F/M ration
  • High MLVSS
  • Short MCRT
  • Low F/M Ratio and High MLVSS

Question 37

Question
How much chlorine is required to oxidize 1 mg/L of ammonia-nitrogen to nitrogen gas?
Answer
  • 4 mg/L
  • 10 mg/L
  • 12 mg/L
  • 14 mg/L

Question 38

Question
Why does pH increase in most aeration systems?
Answer
  • Alkalinity is increased
  • Carbon dioxide is stripped from the wastewater
  • Microorganism activity increases
  • DO is increased

Question 39

Question
What chemical may be used to increase DO when mechanical aeration is insufficient?
Answer
  • Ammonia
  • Phosphorus
  • Nitrogen
  • Hydrogen peroxide

Question 40

Question
What kind of problems may arise in the clarifier when sludge is understabilized?
Answer
  • Sludge settles too slowly and is hard to keep in the clarifier
  • Sludge settles too quickly causing high effluent turbidity due to pin flocs
  • Sludge settles too slowly and may turn septic in the return sludge system
  • Sludge settles too slowly and is hard to keep in the clarifier and Sludge settles too slowly and may turn septic in the return sludge system

Question 41

Question
If a drop in pH occurs in an aerobic digester due to nitrification, what process control adjustment can be made to supress the growth of nitrifying bacteria?
Answer
  • Increase air rate and detention time
  • Decrease air rate and detention time
  • Decrease influent flow and increase detention time
  • Increase influent flow and air rate

Question 42

Question
If ammonia-nitrogen levels are too high, what process control adjustments can be made to correct this?
Answer
  • Decrease DO
  • Decrease MCRT
  • Increase DO
  • Increase WAS

Question 43

Question
For every milligram of ammonia - nitrogen converted to nitrate - nitrogen, how much alkalinity is consumed?
Answer
  • 7.1 mg as CaCO3
  • 4.5 mg as CaCO3
  • 4.0 mg as CaCO3
  • 2.5 mg as CaCO3

Question 44

Question
At which temperature would the generation of H2S form?
Answer
  • < 40° F
  • 65° F
  • 75° F
  • > 85° F

Question 45

Question
At which pH is all sulfide present only in the gaseous H2S form?
Answer
  • > 9
  • 8.3
  • 7.5
  • 4.5

Question 46

Question
When sludge becomes too thick it may become resistant to pumping and cause:
Answer
  • Bound water
  • Coning
  • Bulking
  • Pin Floc

Question 47

Question
What chemicals can be used to condition sludge for dewatering?
Answer
  • Ferric chloride
  • Polymer
  • Lime
  • All of these

Question 48

Question
What is a selector?
Answer
  • A device used to divert wastewater to various tanks
  • A valve that regulates that flow of influent to the clarifier
  • A computerized system that automatically controls the distribution of influent
  • Compartments within a reactor that each favor the growth of certain organisms over others

Question 49

Question
What is the term for the process of removing odors by absorption?
Answer
  • Stripping
  • Scrubbing
  • Sponging
  • Scouring

Question 50

Question
How does thermal sludge conditioning aid in dewatering?
Answer
  • By precipitating the sludge
  • By release bound water
  • By destroying microorganisms
  • By floating the sludge

Question 51

Question
Where is the BEST point of application when breakpoint chlorination for nitrogen removal?
Answer
  • After the filters
  • Between the secondary clarifiers and filters
  • At the plant influent
  • In the aeration basin

Question 52

Question
What is one probable cause of low OUR values?
Answer
  • High F/M ratio
  • Low MCRT
  • Toxic shock load
  • Young sludge

Question 53

Question
What is the recommended level of DO for proper nitrification?
Answer
  • 0.5 mg/L - 1.0 mg/L
  • 1.0 mg/L - 1.5 mg/L
  • 1.5 mg/L - 2.0 mg/L
  • 2.0 mg/L - 4.0 mg/L

Question 54

Question
What is the best way to remove limestone buildup in pipes and pumps?
Answer
  • Acid
  • Hot water
  • Caustic soda
  • Alum

Question 55

Question
What is the typical DO range in pure oxygen system?
Answer
  • 4-10 mg/L
  • 1-5 mg/L
  • 2-4 mg/L
  • 1-10 mg/L

Question 56

Question
What is substrate
Answer
  • A chemical used by an organism to support its growth
  • The effluent from a centrifuge
  • A clear liquid left over after sludge is dewatered
  • A type of sludge residual

Question 57

Question
In the 5 stage Bardenpho process, what occurs in the first stage?
Answer
  • Microorganisms enter the aeration basin where they take in large amounts of phosphorus
  • Microorganisms enter the first anoxic zone where they begin denitrification
  • Microorganisms enter the anaerobic zone where they release their phosphorus
  • Microorganisms enter the first anoxic zone where they release their phosphorus

Question 58

Question
What happens when pressurized air saturated liquid is released at atmospheric pressure during flotation sludge thickening?
Answer
  • Sludge floats to the surface
  • Sludge settles
  • Denitrification
  • Nitrification

Question 59

Question
Which microorganisms may predominate when nitrogen and phosphorus levels are low?
Answer
  • Filamentous
  • Ciliates
  • Amoebas
  • Rotifers

Question 60

Question
Which microorganisms can cause bulking and foaming?
Answer
  • Filamentous
  • Rotifers
  • Ciliates
  • Protozoa

Question 61

Question
Polymers that have a positive charge are called?
Answer
  • Cationic
  • Anionic
  • Nonionic
  • Polyionic

Question 62

Question
What is the optimal pH when using alum to remove phosphorus?
Answer
  • 6.0
  • 8.0
  • 10.0
  • 11.0

Question 63

Question
The difference in pressure above and below the media of a gravity filter is called?
Answer
  • Head loss
  • Pressure differential
  • Flow rate
  • Concentration polarization

Question 64

Question
What term describes the condition where an oxygen deficient condition exists, but chemically bound oxygen such as nitrate is present?
Answer
  • Anaerobic
  • Aerobic
  • Anoxic
  • Endogenous

Question 65

Question
What is an indication of alum sulfate (Alum) overdosing?
Answer
  • Low pH
  • Cloudiness caused by high turbidity and suspended solids
  • High pH accompanied by pin floc
  • Low pH and cloudiness caused by high turbidity and suspended solids

Question 66

Question
Approximately how many pounds of oxygen are required to nitrify one pound of ammonia-nitrogen?
Answer
  • 2.5 lbs
  • 3.7 lbs
  • 4.6 lbs
  • 5.0 lbs

Question 67

Question
What is the proper term for the substance that may form in digested sludge lines and on the rotating components of centrifuges?
Answer
  • Centrate
  • Concentrate
  • Struvite
  • Precipitate

Question 68

Question
How deep should the sludge blanket be in gravity thickener?
Answer
  • 1-3 ft
  • 2-5 ft
  • 3-4 ft
  • 5-8 ft

Question 69

Question
Which microorganisms prefer lower pH levels around 6.0?
Answer
  • Phosphorus removal microorganisms
  • Volatile fatty acid removal microorganisms
  • Nitrifiers
  • Phosphorus removal microorganisms and nitrifiers

Question 70

Question
What is the lowest concentration of hydrogen sulfide that can be detected by the human nose?
Answer
  • 1.0 ppb
  • 0.5 ppb
  • 1.5 ppb
  • 2.0 ppb

Question 71

Question
High respiration rate values may indication?
Answer
  • Understabilzed organic matter
  • Overstabilzed organic matter
  • Low MLVSS
  • Low F/M ration

Question 72

Question
Which of the following is biodegradable and easily treated?
Answer
  • Emulsified oils & greases of vegetables and animal origin
  • Oils & greases of mineral origin
  • Heavy metals
  • H2S

Question 73

Question
Which of the following may be caused by excessive wasting?
Answer
  • High MLVSS
  • High MCRT
  • Low F/M ratio
  • High F/M ratio

Question 74

Question
Where is the best place to add chlorine when using it to control odors?
Answer
  • In the collection system ahead of the plant
  • In the primary clarifier
  • In the aerator
  • In the plant effluent

Question 75

Question
What process control adjustment should be made when there are a large number of amoeboids and flagellates present?
Answer
  • Increase wasting
  • Decrease wasting
  • Increase MCRT
  • Decrease DO

Question 76

Question
Organisms that can only use bound sources of oxygen are known by what term?
Answer
  • Obligate aerobes
  • Facultative
  • Anaerobic

Question 77

Question
Wasting is done from the RAS and the volatile content in the aerator changes. If the volatile content of the RAS is increasing, what adjustment should be made to the WAS flow rate?
Answer
  • No change
  • Increase
  • Decrease
  • Stop all wasting

Question 78

Question
What is the order in which microorganisms break down compounds containing oxygen?
Answer
  • Carbon dioxide, molecular oxygen, nitrate, sulfate, oxidized organics
  • Molecular oxygen, oxidized organics, carbon dioxide, nitrate, sulfate
  • Molecular oxygen, nitrate, sulfate, oxidized organics, carbon dioxide
  • Nitrate, molecular oxygen, sulfate, oxidized organics, carbon dioxide

Question 79

Question
Wasting is done from the RAS, and the volatile content in the aerator remains constant. If the volatile content of the RAS is decreasing, what should be done to the WAS flow rate?
Answer
  • No change
  • Increase
  • Decrease
  • Stop all wasting

Question 80

Question
Which is an organic gas that has an offensive skunk-like odor?
Answer
  • Mercaptans
  • Indole
  • Skatole
  • H2S

Question 81

Question
When is the best time to measure the sludge blanket depth in a clarifier?
Answer
  • During minimal flows
  • During maximum flows
  • At night when it's cool
  • Any time

Question 82

Question
What is the minimum DO that must be present in order for obligate aerobes to function properly?
Answer
  • 0.5 mg/L
  • 1.0 mg/L
  • 1.5 mg/L
  • 2.0 mg/L

Question 83

Question
When using a belt filter press to dewater sludge, water is forced between the belts and:
Answer
  • Pumped to the effluent line
  • Pumped with the RAS
  • Collected in filtrate trays
  • Allowed to evaporate

Question 84

Question
What are some of the properties of alum?
Answer
  • It reduces alkalinity and supports bacterial growth
  • It is very acidic
  • It increases alkalinity and pH
  • It reduces alkalinity and supports bacterial growth and it is very acidic

Question 85

Question
If the nitrate level in the effluent of the first anoxic basin during the 4 stage Bardenpho process is too high, what process control adjustment should be made?
Answer
  • Increase influent flow rate
  • Increase recycle rate
  • Increase air rate
  • Decrease recycle rate

Question 86

Question
What type of microorganism accomplishes denitrification by converting nitrate to nitrogen gas?
Answer
  • Autotrophic
  • Heterotropic
  • Eutropic
  • Thermotropic

Question 87

Question
Why do pH levels drop during nitrification
Answer
  • Acid formers predominate
  • Nitrate is acidic in nature
  • Alkalinity is destroyed
  • High sludge age

Question 88

Question
Why must pH of water be raised to between 10.8 and 11.5 during ammonia stripping?
Answer
  • To reduce microorganism population
  • So that all of the ammonia ion is converted to ammonia gas
  • To strengthen the buffering capacity
  • For odor control

Question 89

Question
When using odor removal towers to control odors, the pH of the wastewater being treated should not drop below:
Answer
  • 10.0
  • 8.0
  • 7.0
  • 6.0

Question 90

Question
What is the desired water column pressure in pure oxygen system?
Answer
  • 4"-6"
  • 2"-8"
  • 3"-10"
  • 1"-4"

Question 91

Question
What may be indicated by a high residual DO and low oxygen uptake rate in an anaerobic digester?
Answer
  • Toxic substances are present
  • Low pH
  • Low detention times
  • Toxic substances are present, Low pH, and Low detention times

Question 92

Question
How can lime be recovered for reuse?
Answer
  • Gravity belt press
  • Flocculation
  • Centrifuges
  • Floatation

Question 93

Question
What are nitrosomonas and nitrobacter?
Answer
  • Heterotophs that metabolize organic substances such as nitrate
  • Microorganisms that predominate in young sludge
  • Autotrophs that metabolize inorganic substances such as carbon dioxide and bicarbonate alkalinty
  • Two forms of nitrogen

Question 94

Question
What may be indicated by a high chlorine demand in the plant effluent when the plant requires nitrification?
Answer
  • Elevated nitrate levels
  • An imbalance of nitrobacter and nitrosomonas polulations
  • High pH levels
  • Elevated nitrate levels and an imbalance of nitrobacter and nitrosomonas polulations

Question 95

Question
When using the MCRT to determine process control adjustments, how long should you wait before making further changes if the desired MCRT is seven days?
Answer
  • 3 days
  • 10 days
  • 2 to 3 weeks
  • 4 to 6 weeks

Question 96

Question
What should an operator do when a high organic waste load enters the plant?
Answer
  • Decrease RAS flows and air input
  • Decrease WAS flow and air input
  • Increase RAS flow and air input
  • Increase WAS flow and air input

Question 97

Question
At what pH will carbon dioxide be stripped from water?
Answer
  • 8.0
  • 9.0
  • 10.0
  • 11.0

Question 98

Question
What is the recommended ratio of BOD: Nitrogen:Phosphorus (B:N:P) required for a treatment process?
Answer
  • 100:5:1
  • 100:50:10
  • 10:5:1
  • 100:20:10

Question 99

Question
What process control adjustments should be made when greater nitrification is required?
Answer
  • Increase MCRT
  • Decrease sludge age
  • Decrease pH
  • Decrease MCRT

Question 100

Question
When removing odors using the electrolytic process, electrons convert the salt in the brine to:
Answer
  • Chlorine
  • Calcium carbonate
  • Sodium hypochlorite
  • Calcium hypochlorite

Question 101

Question
How deep should the sludge blanket be in the clarifier when using the activated sludge process?
Answer
  • 0.5 - 1 ft
  • 3 - 5 ft
  • 1 -3 ft
  • > 5 ft

Question 102

Question
Which modification of the activated sludge process uses two aeration tanks in which one of the tanks is used for seperate reaeration of the return sludge?
Answer
  • Extended aeration
  • Step feed aeration
  • Contact stabilization
  • Pure oxygen aeration

Question 103

Question
The use of metal salts for optimum enhanced chemical phosphorus removal is highly dependent on pH. Therefore, where is the optimum point for application of metal salts?
Answer
  • After denitrification when alkalinity levels are highest
  • Before denitrification because of the gain in alkalinity that occurs during anoxic reduction of nitrate-nitrogen
  • After nitrification because of the alkalinity depletion during the nitrification process
  • Before denitrification because of the gain in alkalinity that occurs during anoxic reduction of nitrate-nitrogen and after nitrification because of the alkalinity depletion during the nitrification process

Question 104

Question
For every pound of organic matter used by bacteria cells, approximately how many pounds of new bacteria cells are produced?
Answer
  • 2.5 lbs
  • 1.5 lbs
  • 0.5 lbs
  • > 2.5 lbs

Question 105

Question
What is a common problem associated with ammonia stripping?
Answer
  • Scale buildup on pipes and pumps
  • Strong odors
  • Increased pH
  • Microorganisms are destroyed

Question 106

Question
What condition must exist for proper nitrification?
Answer
  • Low BOD
  • Available oxygen
  • A detention time of at least 4 hours
  • Low BOD, Available oxygen, and A detention time of at least 4 hours

Question 107

Question
What percent of oxygen is present in air?
Answer
  • 20.9%
  • 22%
  • 23.5%
  • 19.6%

Question 108

Question
Odors can be controlled by ________ the pH
Answer
  • Raising then lowering
  • Lowering
  • Lowering then raising
  • Raising

Question 109

Question
What process control adjustment can be made to minimize denitrification in a clarifier?
Answer
  • Decrease RAS
  • Decrease WAS
  • Increase RAS
  • Increase DO

Question 110

Question
Why is the COD test not recommended for wastewater's containing high salt concentrations?
Answer
  • Algae may interfere with the test
  • Brine contains high organic levels
  • Chloride may interfere with the chemical reactions
  • Salt has no effect on COD tests

Question 111

Question
If cake solids that are produced by a gravity belt thickener are too wet, what adjustments should be made?
Answer
  • Decrease belt speed and or increase belt tension
  • Increase belt speed and or decrease belt tension
  • Increase belt speed and or increase belt tension
  • Decrease belt speed and or decrease belt tension

Question 112

Question
For every pound of ammonia-nitrogen that is oxidized during nitrification, how many pounds of alkalinity are destroyed?
Answer
  • 4.6 lbs
  • 7.2 lbs
  • 8.3 lbs
  • 10.0 lbs

Question 113

Question
Why must sludge be removed from a gravity thickener at a faster rate during warmer temperatures?
Answer
  • To prevent denitrification
  • To prevent sludge from rising
  • To prevent incomplete nitrification
  • To prevent denitrification and to prevent sludge from rising

Question 114

Question
Which of the following is the easiest to dewater?
Answer
  • Primary sludge
  • Secondary sludge
  • Digester sludge
  • Waste activated sludge

Question 115

Question
After microorganisms take in and store large amounts of phosphorus they are transferred to an anaerobic environment. What effect does this have on microorganisms?
Answer
  • They settle to the bottom of the tank and are removed
  • They release their stored phosphorus
  • They immediately die and are wasted
  • They continue to absorb phosphorus

Question 116

Question
The first 75% of phosphorus precipitation occurs before the pH drops below?
Answer
  • 10.0
  • 8.0
  • 7.0
  • 6.0

Question 117

Question
What term is used to describe the clogging of the filter medium in a microscreen or vacuum filter?
Answer
  • Polarization
  • Blinding
  • Plugging
  • Breakthrough

Question 118

Question
What instrument is used to measure the amount of water draining through soil?
Answer
  • Rotameter
  • Venturi
  • Lysimeter
  • Winkler probe

Question 119

Question
What is the methanol to nitrogen ratio that should be maintained when denitrification is required?
Answer
  • 1:2
  • 2:1
  • 3:1
  • 5:1

Question 120

Question
If an anaerobic selector is being used to achieve phosphorus removal and the the next priority is denitrification, what would be the next selector necessary to achieve this?
Answer
  • Aerobic
  • Anoxic
  • Same selector (Anaerobic)
  • Any of the above

Question 121

Question
For optimal phosphorus removal, pH should not drop below?
Answer
  • 4.0
  • 6.0
  • 8.0
  • 11.0

Question 122

Question
What condition must exist for ammonium to be converted to gaseous ammonia so it can be removed by ammonia stripping?
Answer
  • pH must be raised to the 10.5-11.5 range
  • pH must be lowered to 6.0
  • DO must be increased
  • Nitrobacter must be present

Question 123

Question
What is the term used to describe the boundary layer between two substances?
Answer
  • Concentrate
  • Interface
  • Substrate
  • Coning

Question 124

Question
What adverse effect can high levels of ammonia have on receiving waters?
Answer
  • Oxygen depletion
  • Increase DO
  • Algal blooms
  • Oxygen depletion and algal blooms

Question 125

Question
Which is an example of suspended growth denitrifaction?
Answer
  • Rotating biological contractor
  • Trickling filter
  • Extended aeration
  • None of the above

Question 126

Question
When operating an Advanced Treatment facility using chemical treatment for solids removal, you discover high flows entering the system. You should?
Answer
  • Inspect the chemical feeders to determine if the chemicals being added do NOT cause a great increase/decrease in pH
  • Plan on reducing the sludge removal system from the clarifier
  • Prepare to feed a greater quantity of chemicals
  • Watch for chemical overdoses that could produce toxic conditions in the biological

Question 127

Question
When using polymer in a gravity thickening process for sludge, when would more polymer dosages be required? When the:
Answer
  • Hydraulic loading rate increases
  • Hydraulic loading to the unit decreases
  • Sludge selector speed is decreased
  • Solids loading to the unit decreases

Question 128

Question
When bacteria laden with phosphorous are faced with apparent death, they:
Answer
  • Absorb phosphorous from wastewater in large quantities
  • Absorb phosphorous from wastewater slowly
  • Begin to reproduce to save the species
  • Release phosphorous from their cell structure in large quantities

Question 129

Question
Head loss in a gravity filter is determined by?
Answer
  • Eff. turbidity minus Inf. Turbidity
  • Flow minus the weir overflow rate
  • Inf. Turbidity minus Eff. Turbidity
  • Measuring the water pressure above and below the filter media

Question 130

Question
What dosage of chlorine can be fatal in just a few breaths?
Answer
  • 50 ppm
  • 100 ppm
  • 250 ppm
  • 1000 ppm

Question 131

Question
What statement best describes at which speed a belt filter press should be operated?
Answer
  • The area of the belt determines the speed
  • The ideal belt speed is the slowest the operator can maintain without washing out the belt
  • The concentration of the sludge eff. determines the speed
  • The material of which the belt is made determines the speed

Question 132

Question
What steps should the operator take if "washing out" occurs while operating a belt filter press?
Answer
  • Decrease tension on belt
  • Decrease wash water rate
  • Increase sludge rate and belt speed
  • Lower flow rate and increase belt speed

Question 133

Question
A problem with plastic pipe laterals resting on the surface in a spray irrigation system is?
Answer
  • The pipe can deteriorate due to exposure to sunlight
  • Snakes and other lethal animals can lurk under the pipe
  • The pipe will whip violently during system operation
  • Distribution of the effluent will not be as effective

Question 134

Question
FDEP approved continuous on-line analyzing of reclaimed water effluent includes analyzing for:
Answer
  • CBOD5
  • pH, chlorine, and turbidity
  • D.O. and temperature
  • Fecal Coliform and Total Coliform

Question 135

Question
Lime is used more frequently for phosphorous removal than Aluminum Sulfate because Aluminum Sulfate:
Answer
  • Does not settle as rapidly in clarifiers
  • Is more expensive than lime
  • Raises the pH too much
  • Requires anaerobic conditions and lime does not

Question 136

Question
What process control adjustment should be made when a 30 minute settleometer test shows fast solids settling leaving pin-point floc? Increase the:
Answer
  • Aeration rate
  • MLSS
  • RAS rate
  • WAS rate

Question 137

Question
According to Chapter 62-600, FAC, Domestic Wastewater facilities, the basic disinfection requirement (using chlorine) is a :
Answer
  • 0.5 mg/L total chlorine residual after 15 minutes contact time at average daily flow
  • 0.5 mg/L minimum total chlorine after 15 minutes contact time at peak hourly flow
  • 0.5 mg/L minimum total chlorine residual after 30 minutes contact time at maximum daily flow
  • 1.0 mg/L total chlorine residual after 15 minutes contact time at maximum daily flow

Question 138

Question
In an aerobic digester, excessive air rates can contribute to?
Answer
  • An increase in the activity of biomass
  • Foaming problems
  • High solids carry over
  • Reduction of the activity of biomass

Question 139

Question
A common operational problem that can occur with ammonia stripping towers involves:
Answer
  • Asphyxiation if personnel remain in the tower too long
  • Corrosion due to the chemical reaction forming acids
  • Reduction of capacity due to media breakdown
  • Scale formation due to calcium carbonate build-up

Question 140

Question
What causes a loss of vacuum in a vacuum filter?
Answer
  • Change in effluent characteristics
  • Drum speed too low
  • Filter media misalignment or tear
  • Insufficient conditioning

Question 141

Question
According to Chapter 62-620, FAC, Wastewater Facility Permitting, the permittee shall retain treatment facility operating records for how many calendar years?
Answer
  • 2 years
  • 3 years
  • 10 years
  • 15 years

Question 142

Question
In lakes and deeper rivers, cold waters tend to slip below warmer waters because?
Answer
  • Warmer waters always rise to the top due to atmospheric pressure
  • Thermo clines force them to
  • Cold water is heavier or has a greater density
  • Caused by wind action at the surface

Question 143

Question
According to Chapter 62-602, FAC, Drinking water and Domestic wastewater treatment plant operators. The operator must report to the department any serious plant breakdown or condition causing or likely to cause any discharge not in compliance with the treatment plant permit within how many hours of the occurrence?
Answer
  • 6 hours
  • 12 hours
  • 24 hours
  • 48 hours

Question 144

Question
The plant EFF coliform count has failed to meet the required standards for disinfection. The supply of disinfectant is not the problem. There is adequate chlorine residual. To confirm the cause, it is most relevant to check the:
Answer
  • Chlorine in the stream mixing zone
  • Chlorine Contact Chamber for short circuiting
  • Chlorine Contact Chamber for solids scouring
  • Total chlorine residual analysis

Question 145

Question
How is the Fecal Coliform parameter evaluated?
Answer
  • The concentration is estimated by using the (MLN) Likely number method
  • The concentration is estimated by the TBEL method
  • The concentration is estimated by using the most probable number (MPN) method or the membrane filter (MF) method
  • The value is determined by microscopic examination

Question 146

Question
When reading the level of a column of liquid in a graduated cylinder, burette or manometer, you should?
Answer
  • Fill the glassware to 10 centimeters below the lip of the glassware and record
  • Hold a solid color sheet of paper behind the glassware and record the level to the nearest 10 millimeters
  • Record the level of the bottom of the meniscus of the liquid being measured
  • View the liquid level from an elevation equal to the liquid level and read the top of two liquid level lines

Question 147

Question
According to Chapter 62-601, FAC, Domestic W/W treatment plant monitoring, after July 1, 1993, the tests for on-site parameters pH and chlorine residual shall be performed by or under the direction of ?
Answer
  • A certified laboratory or a certified operator
  • Plant laborers
  • Plant Technicians
  • The permittee

Question 148

Question
What should be the pH in a rapid-mix basin for a maximum phosphorous removal efficiency when using lime?
Answer
  • 5.0
  • 6.0
  • 8.3
  • 11.0

Question 149

Question
Secondary clarifiers are showing straggler floc lost over weirs. Microscopic exam shows few free swimmers, majority of flagellates. SVI is increasing. What visual observation and test results would you expect?
Answer
  • Dark foam, increasing F/M and SRT, decreasing turbidity
  • Light brown foam, decreasing F/M and SRT, decreasing turbidity
  • Light brown to white foam, increasing F/M, dalling SRT and increasing turbidity
  • White foam, decreasing F/M, falling SRT, increased turbidity

Question 150

Question
The plant EFF coliform count has failed to meet the required standards for disinfection. The supply of disinfectant is not the problem. There is adequate chlorine residual. The best solution is to?
Answer
  • Chlorinate to breakpoint
  • Decrease the flow to the steam mixing zone
  • Increase the chlorinator capacity
  • Install additional baffling

Question 151

Question
Which statement is correct concerning confined spaces?
Answer
  • Confined spaces are defined as those that concurrently provide difficult access and/or exit combined with inadequate or deficient ventilation.
  • Monitoring the atmosphere within a confined space is required each hour and is logged into the confined space log book
  • You may enter a confined space only when oxygen levels are above 20%
  • You may process in a confined space only if air contamination exists

Question 152

Question
If a sand drying bed has a problem with the media becoming clogged, what should the operator do first?
Answer
  • Have the contractor replace all the media but leave the gravel intact
  • Investigate the type of sand being used and recommend a different type
  • Rake the surface of the bed, removing the upper 2 to 3 inches of sand, and replace the sand with fresh sand
  • Remove the sand, wash it, check the under-drain, then replace the sand

Question 153

Question
What should be the pH in a rapid-mix basin for maximum phosphorous removal efficiency when using lime?
Answer
  • 5.0
  • 6.0
  • 8.3
  • 11.0

Question 154

Question
What is the most common method of EFF disposal?
Answer
  • Evaporation/Percolation ponds1
  • In deep wells
  • In receiving waters
  • Land disposal

Question 155

Question
What would be the usual approach to measure the impact of a discharge to receiving waters?
Answer
  • Analyze the plants performance evaluations
  • Compare the in-plant measurements measurements to down stream receiving waters
  • Review the Grab sample measurements
  • Take a measurement in the upstream, unaffected area, and compare to a down stream affected area

Question 156

Question
What does not represent a potential hazard of working in a wastewater treatment laboratory?
Answer
  • Burns
  • Electrical shock
  • Hypothermia
  • Infectious materials

Question 157

Question
An instrument used in a laboratory that measures the intensity of color or particular wavelength is a ?
Answer
  • Color standard
  • Nephelometer
  • Spectrophotometer
  • Turbidimeter

Question 158

Question
A gravity filter experiences rapid build-up of head loss. What could be a probable cause?
Answer
  • Applied water flow rate too low
  • Incomplete backwash cycle
  • Media breakthrough
  • Turbidimeter

Question 159

Question
What problems may develop during the injection of reclaimed wastewater into deep wells?
Answer
  • Contamination of groundwater
  • Lowering of groundwater table
  • Saltwater intrusion
  • Severe hydraulic overload

Question 160

Question
According to state regulations, a wastewater plant shall maintain a pH in the effluent after disinfection within what range?
Answer
  • 2.5 - 4.5
  • 4.5 - 6.0
  • 6.0 - 8.5
  • 8.5 - 10.5

Question 161

Question
In chapter 62-699, FAC, Treatment Plant Classification and Staffing, wastewater treatment plants are classified in order to prescribe the lowest class of certified operators who will be permitted to operate the treatment plant. This classification system is based on what (2) factors?
Answer
  • Design flow and treatment type
  • Flow and treatment efficiency
  • Population and flow
  • Population served and treatment type

Question 162

Question
Two inorganic gases giving off the most offensive odors and which is a main concern of operators when controlling odors are?
Answer
  • Ammonia and skatole
  • Hydrogen sulfide and ammonia
  • Mercaptans and indole
  • Methane and ammonia

Question 163

Question
The recovery of a stuck anaerobic digester can be accelerated be neutralizing the acids with a caustic material like?
Answer
  • Aluminum sulfate
  • Calcium hypochlorite
  • Lime
  • Sodium hypochlorite

Question 164

Question
When operating an advanced treatment facility using chemical treatment for solids removal, you discover high flows entering the system. The first step you should take is to?
Answer
  • Inspect the chemical feeder for proper output
  • Prepare jar tests to determine dosage that will be good for increased detention
  • Prepare jar tests to determine dosage that will be good for decreased detention time
  • Run influent turbidity tests hourly to see if the turbidity is actually increasing

Question 165

Question
Even though a process control test is accurately performed, which one of the following could result in meaningless findings?
Answer
  • The ambient temperature being several degrees cooler than normal
  • The analyst not being certified
  • The sample not being representative of the process stream being sampled
  • The use of class A glassware instead class B glassware

Question 166

Question
It takes about 22% less O2 to process 1 lb of carbonaceous waste than 1 lb of nitrogenous waste. What does this indicate?
Answer
  • Additional DO is required to nitrify
  • Carbonaceous material should be add to the MLVSS
  • Carbonaceous wastes take longer to digest
  • Nitrogenous wastes are easily oxidized

Question 167

Question
To determine the location and amount of lowest dissolved oxygen downstream from a wastewater effluent discharge, it is necessary to?
Answer
  • Conduct an annual measurment survey
  • Conduct an oxygen profile of the stream
  • Conduct an oxygen profile of the treatment plant
  • Observe the aquatic life

Question 168

Question
A sand and gravel filter had been working well, but eventually head loss occurred. Performance did not improve significantly following backwashing. What is the most probable cause?
Answer
  • The backwash water overloaded the system
  • The backwash time was too short
  • The backwash time was too long
  • There was excessive auxiliary scour

Question 169

Question
The floating cover on a primary anaerobic digester appears to be tilting. Inspection of the rollers indicates that they are not the problem. Probing the annular space results in finding a thick scum accumulation. What should be done at this point?
Answer
  • Attach a crane cable to one side and lift the corner
  • Decrease the mixing so the scum will be broken up
  • Use chemicals or degreasing agents, then hose down the scum bucket through the inspection ports
  • Immediately drain the tank before an explosion takes place

Question 170

Question
Nitrification in the activated sludge process?
Answer
  • Decreases alkalinity and increases pH
  • Decreases alkalinity and pH
  • Increases alkalinity and pH
  • Increases alkalinity and decreases pH

Question 171

Question
Which statement is most correct concerning dissolved oxygen content in water?
Answer
  • An increase in water temperature causes an increase in DO
  • Decreases in dissolved oxygen content in receiving water is immediately noticed
  • An increase in temperature causes a decrease in dissolved oxygen concentration
  • Temperature has no effect on dissolved oxygen concentrations

Question 172

Question
Rapid accumulation on the surface of a single media sand filter results in very rapid head loss. The solution is ?
Answer
  • Improve prior clarification
  • Increase chemical coagulation
  • Reduce filter backwash time
  • Reduce the filter air scrubbing time

Question 173

Question
In the microscopic exam of the mixed liquor, you observe a dominance of rotifers and nematodes. What would this be indicative of?
Answer
  • Bulking sludge that settles slowly leaving straggler floc
  • Old sludge that settles rapidly, leaving pin floc
  • Rising sludge that settles rapidly, leaving fluffy floc
  • Young sludge that settles slowly, leaving pin floc

Question 174

Question
When using break-point chlorination for ammonia removal, how many ppm of chlorine are needed to remove 1 ppm of ammonia?
Answer
  • 1
  • 5
  • 8
  • 10

Question 175

Question
Misalignment of a driver and a driven piece of equipment can cause?
Answer
  • Premature bearing failure
  • Excessive wear of the slip rings
  • The packing to leak
  • Valve chatter

Question 176

Question
Effluent quality has changed from excellent to poor. A microbial study indicates a decrease of stalked ciliates and rotifers. Now, the predominance is free swimming and flagellates. This observation indicates that the ?
Answer
  • MCRT is decreasing
  • MCRT is increasing
  • Process is moving toward a more stable condition
  • Treatment efficiency is increasing

Question 177

Question
In a suspended growth reactor used for Denitrification
Answer
  • A carbon food source is needed for proper metabolism of the organisms
  • A dissolved oxygen level of at least 2.0 mg/L should be maintained in the aeration tank at all times
  • Nitrate is first converted to ammonium, then to nitrite
  • Nitrite is first converted to nitrate then ammonium

Question 178

Question
The strategy of allowing chlorinated water to stand for 24 to 48 hrs in the rapid sand filter and thoroughly backwashing media is a remedy for?
Answer
  • Curing breakthroughs
  • Remove dissolved air which causes air binding
  • Removing grease and oil from the filter wells
  • Removing mud balls

Question 179

Question
When a 5 min observation of the settlability test indicates fast settling (e.g., 500 ml), what process change should be made?
Answer
  • Decrease the RAS
  • Increase the aeration and RAS
  • Increase the aeration
  • Increase the wasting rate

Question 180

Question
For ammonia stripping to be successful:
Answer
  • Nitrosmonas and Nitrobacters must be present
  • Chemicals must be added to convert nitrogen to nitrate
  • The pH must be raised to approximately 10.8 to 11.5
  • The wastewater to be treated must be stripped of its dissolved oxygen content first

Question 181

Question
Water quality criteria for wastewater reclaimed for public access includes:
Answer
  • Complete lack of BOD
  • High level disinfection
  • No dissolved inorganic solids
  • 50 mg/L TSS

Question 182

Question
What is the optimum temperature range for the nitrification process?
Answer
  • 70 ° and 100 ° F
  • 60 ° and 90 ° F
  • 65 ° and 85 ° F
  • 10 ° and 20 ° F

Question 183

Question
CO2 is stripped at pH below ___ and retained at a pH above ___
Answer
  • 7.0 and 10
  • 6.0 and 11
  • 8.3 and 9.5
  • 8.3 and 8.3

Question 184

Question
How much lime is required per ton of primary sludge?
Answer
  • 100-200 lbs / ton
  • 80-90 lbs / ton
  • 150-175 lbs / ton
  • 175-250 lbs / ton

Question 185

Question
What happens to phosphorus in a plant effluent when mixed with lime?
Answer
  • Phosphorus, calcium and hydroxyl ion compounds are formed
  • Phosphorus carbonate precipitate is formed
  • Phosphorus will cause a reaction that lowers the pH
  • Phosphorus will form a soluble sludge

Question 186

Question
What is utilized as a carbon source?
Answer
  • Nitrogen
  • Phosphorus
  • Methanol
  • Aerobic bacteria

Question 187

Question
In a centrifuge series, centrate from the ____ centrifuge contains most of the phosphorus?
Answer
  • First
  • Second
  • Third
  • Last

Question 188

Question
Using ION exchange for nitrogen removal; what is the name of the resin used?
Answer
  • Clinoptilolite
  • Zemalite
  • Miller lite
  • Red line resin

Question 189

Question
Supplemental phosphorus can be provided by using what items?
Answer
  • Phosphoric acid
  • Ammonia
  • Phosphate fertilizer
  • Phosphoric acid and Phosphate fertilizer

Question 190

Question
Filters should be back washed at what type of flow?
Answer
  • Slow so the filter material stays put
  • Fast just keeping the filter media in the bay
  • Adequate to fluidize the media
  • Fast just letting a small amount of media material to be washed away

Question 191

Question
What types of carbon food sources may be used in denitrification fixed film reactor to promote biological metabolism?
Answer
  • Hydrogen sulfide, primary effluent, source of high carbon food
  • Nitrate, primary effluent, source of high carbon food
  • Magnesium, primary effluent, source of high carbon food
  • Methanol, primary effluent, source of high carbon food

Question 192

Question
What may be used as a phosphorous supplement?
Answer
  • Dissolved triple superphosphate, phosphate fertilizer, phosphoric acid
  • Aqueous ammonia, anhydrous ammonia
  • Seed sludge
  • Cationic Polymers

Question 193

Question
What may be used as a nitrogen supplement?
Answer
  • Dissolved triple superphosphate, phosphate fertilizer, phosphoric acid
  • Aqueous ammonia, anhydrous ammonia
  • Seed sludge
  • Cationic Polymers

Question 194

Question
Methanol is?
Answer
  • An alcohol compound which can be ingested in small amounts without harm
  • A common component of many alcoholic beverages
  • Composed of hydrogen, oxygen, carbon and nitrogen - CH3OH
  • A fuel additive and it is highly flammable

Question 195

Question
What do autotrophic nitrifiers use as a carbon source?
Answer
  • Bicarbonate alkalinity
  • Lime
  • Algae
  • Nitrobacter bacteria

Question 196

Question
When denitrification is occurring, the microorganisms use methanol as a carbon food source. Where do they obtain the oxygen necessary to metabolize the methanol when there is no free oxygen present?
Answer
  • The microorganisms do not need oxygen to metabolize methanol
  • From the nitrate ion
  • From the ammonia-nitrogen
  • From the gaseous nitrogen

Question 197

Question
What may be added to wastewater when the nutrient levels are too low to support the microorganism population?
Answer
  • Nitrogen and phosphorus
  • Ammonia and phosphoric acid
  • Sodium acetate
  • All of the above

Question 198

Question
When treating high organic loads, what process control adjustments should be made?
Answer
  • Decrease RAS
  • Increase RAS
  • Increase wasting
  • Decrease DO

Question 199

Question
The DO should be kept at ____ in the first anaerobic and anoxic zones when using the Bardenpho process?
Answer
  • 2.0 mg/l
  • 1.5 mg/l
  • 0.5 mg/l
  • 0 mg/l

Question 200

Question
Why is the amount of food available to the microorganisms allowed to decrease during aerobic digestion?
Answer
  • To cause denitrification
  • To cause nitrification
  • To encourage endogenous respiration
  • To decrease turbidity
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