Wastewater Class B Texas questions with correct answers, Exams of Water and Wastewater Engineering

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Wastewater Class B Texas

1. Which of the following is the primary goal of a wastewater treatment plant? A) To remove odors B) To reduce the total volume of wastewater C) To remove contaminants and return clean water to the environment D) To store wastewater for future use Answer: C) To remove contaminants and return clean water to the environment
2. In the activated sludge process, the primary purpose of the aeration tank is to: A) Remove solids B) Provide oxygen to microorganisms C) Filter out debris D) Separate clear water from sludge Answer: B) Provide oxygen to microorganisms
3. Which of the following chemicals is commonly used in the coagulation process during wastewater treatment? A) Sodium hypochlorite B) Alum (aluminum sulfate) C) Lime D) Calcium carbonate Answer: B) Alum (aluminum sulfate)
4. What is the primary function of a secondary clarifier in a wastewater treatment plant? A) To disinfect effluent B) To separate solid particles from the wastewater C) To add oxygen to the wastewater D) To collect and remove sludge Answer: B) To separate solid particles from the wastewater
5. The term "BOD" in wastewater treatment stands for: A) Biochemical Oxygen Demand B) Biological Organic Disposal C) Bacterial Oxygen Density D) Biotic Organic Degradation

Answer: A) Biochemical Oxygen Demand

6. Which of the following is NOT typically a responsibility of a Class B wastewater operator in Texas? A) Supervising the operation of the treatment plant B) Conducting laboratory analyses of samples C) Performing maintenance on mechanical equipment D) Certifying the wastewater treatment plant’s compliance with state regulations Answer: D) Certifying the wastewater treatment plant’s compliance with state regulations
7. Which type of wastewater treatment method is used to remove larger solids from the wastewater before it enters the treatment process? A) Secondary treatment B) Primary treatment C) Tertiary treatment D) Filtration Answer: B) Primary treatment
8. What is the primary purpose of disinfection in wastewater treatment? A) To remove all solid particles B) To reduce the microbial contamination of the effluent C) To reduce the BOD levels D) To increase the oxygen levels in the water Answer: B) To reduce the microbial contamination of the effluent
9. When calculating the flow rate for a wastewater treatment plant, the unit of measurement typically used is: A) Cubic feet per second (cfs) B) Liters per minute (L/min) C) Gallons per day (GPD) D) Gallons per minute (GPM) Answer: D) Gallons per minute (GPM)
10. What is the ideal pH range for wastewater in an aeration tank? A) 0 - 3 B) 4 - 6 C) 6 - 9 D) 10 - 12

Answer: C) 6 - 911. Which of the following is a common method of sludge disposal at a wastewater treatment plant? A) Incineration B) Injection into deep wells C) Drying and land application D) Evaporation Answer: C) Drying and land application

12. What is the typical detention time in an aeration tank during the activated sludge process? A) 1-2 hours B) 2-4 hours C) 4-8 hours D) 10-12 hours Answer: C) 4-8 hours
13. In a wastewater treatment plant, which of the following is used to remove suspended solids? A) Chlorine disinfection B) Activated sludge C) Primary clarifier D) Aeration tank Answer: C) Primary clarifier
14. The process of nitrification in wastewater treatment primarily involves: A) The conversion of ammonia to nitrites and then to nitrates B) The breakdown of organic solids C) The removal of heavy metals D) The reduction of BOD Answer: A) The conversion of ammonia to nitrites and then to nitrates
15. Which of the following statements about wastewater sludge is correct? A) Sludge is typically 100% organic material. B) Sludge must always be incinerated to ensure proper disposal. C) Sludge is treated to reduce pathogens and volume before disposal. D) Sludge should not be subjected to dewatering processes. Answer: C) Sludge is treated to reduce pathogens and volume before disposal.

16. What is the primary goal of the filtration process in tertiary wastewater treatment? A) To remove dissolved solids B) To remove bacteria and viruses C) To remove remaining suspended solids after primary and secondary treatment D) To increase dissolved oxygen levels in the effluent Answer: C) To remove remaining suspended solids after primary and secondary treatment
17. Which of the following methods is commonly used to disinfect wastewater before it is discharged into the environment? A) Mechanical filtration B) Chlorine disinfection C) Coagulation D) Activated carbon filtration Answer: B) Chlorine disinfection
18. The "MLSS" (Mixed Liquor Suspended Solids) concentration in an aeration tank is a measure of: A) The total volume of water treated B) The amount of oxygen available for microorganisms C) The concentration of organic material in the wastewater D) The concentration of suspended solids in the aeration tank Answer: D) The concentration of suspended solids in the aeration tank
19. Which of the following is a potential consequence of failing to properly disinfect effluent before discharge? A) Increased BOD levels B) Contamination of receiving waters with harmful pathogens C) Higher sludge production D) Decreased nutrient removal efficiency Answer: B) Contamination of receiving waters with harmful pathogens

20. In wastewater treatment, what is the purpose of the "return activated sludge" (RAS) system? A) To recycle treated effluent back into the system B) To increase the oxygen content in the aeration tank C) To maintain a sufficient concentration of microorganisms in the aeration tank D) To remove excess solids from the primary clarifier Answer: C) To maintain a sufficient concentration of microorganisms in the aeration tank
21. Which of the following is a common source of odor at a wastewater treatment plant? A) Chlorine disinfection B) Hydrogen sulfide from anaerobic conditions C) Oxygen from aeration D) Carbon dioxide from respiration Answer: B) Hydrogen sulfide from anaerobic conditions
22. What is the main purpose of a grit chamber in a wastewater treatment plant? A) To remove oils and greases B) To remove sand, gravel, and other heavy particles C) To disinfect the wastewater D) To aerate the wastewater Answer: B) To remove sand, gravel, and other heavy particles
23. Which of the following is an indicator of the effectiveness of wastewater treatment? A) Turbidity B) Total solids concentration C) Total suspended solids (TSS) concentration D) Temperature of the influent Answer: C) Total suspended solids (TSS) concentration
24. Which of the following would most likely indicate a problem with the secondary treatment process?

A) High BOD levels in the effluent B) High pH levels in the influent C) Low total solids in the influent D) Low temperature in the aeration tank Answer: A) High BOD levels in the effluent

25. What is the purpose of the sludge digester in a wastewater treatment plant? A) To reduce the volume of solids B) To filter out debris C) To add oxygen to the effluent D) To remove chemicals from the effluent Answer: A) To reduce the volume of solids26. What does the term "TSS" stand for in wastewater treatment? A) Total Suspended Solids B) Total Saturated Solids C) Thermal Suspended Solids D) Toxin Suspended Solids Answer: A) Total Suspended Solids
26. What is the primary purpose of the trickling filter in wastewater treatment? A) To disinfect effluent B) To provide aeration for microorganisms C) To remove suspended solids from the wastewater D) To remove odors Answer: B) To provide aeration for microorganisms
27. Which of the following is a method of reducing sludge volume in wastewater treatment? A) Chemical coagulation B) Filtration C) Anaerobic digestion D) Aeration

Answer: C) Anaerobic digestion

29. The term "RT" in a wastewater treatment plant refers to: A) Reactor time B) Retention time C) Recovery time D) Reaction time Answer: B) Retention time
30. In a wastewater treatment plant, what is the function of the bar screen? A) To disinfect the effluent B) To remove large debris from the wastewater C) To remove dissolved gases D) To add chemicals to the influent Answer: B) To remove large debris from the wastewater
31. Which of the following substances is often removed during primary treatment but not secondary treatment? A) Organic matter B) Suspended solids C) Nutrients D) Large solids (e.g., sticks, rags) Answer: D) Large solids (e.g., sticks, rags)
32. The "CET" (Critical Elevation Tank) in a wastewater treatment plant is used for: A) Primary settling B) Maintaining water level consistency in the plant C) Disinfection of effluent

D) Aeration of the mixed liquor Answer: B) Maintaining water level consistency in the plant

33. In wastewater treatment, which of the following is the most common method used to remove phosphorous from effluent? A) Chemical precipitation B) Filtration C) Biological removal D) UV disinfection Answer: A) Chemical precipitation
34. The process of "denitrification" in wastewater treatment refers to: A) The conversion of nitrates to nitrogen gas B) The conversion of ammonia to nitrites C) The breakdown of organic solids D) The removal of phosphorus from wastewater Answer: A) The conversion of nitrates to nitrogen gas
35. Which of the following parameters is used to determine the effectiveness of a disinfection process? A) pH level B) Chemical oxygen demand (COD) C) Total residual chlorine (TRC) D) Total dissolved solids (TDS) Answer: C) Total residual chlorine (TRC)
36. In a wastewater treatment plant, which of the following is responsible for adding oxygen to the system for microbial digestion?

A) Chlorine contact chamber B) Aeration tank C) Secondary clarifier D) Trickling filter Answer: B) Aeration tank

37. What is the primary difference between primary and secondary wastewater treatment? A) Primary treatment uses chemicals; secondary treatment does not B) Secondary treatment involves biological processes; primary treatment does not C) Primary treatment is more effective at removing nutrients than secondary treatment D) Secondary treatment removes more solids than primary treatment Answer: B) Secondary treatment involves biological processes; primary treatment does not
38. Which of the following tests is commonly used to measure the effectiveness of biological treatment in a wastewater treatment plant? A) Total Suspended Solids (TSS) B) BOD (Biochemical Oxygen Demand) C) pH levels D) Total Coliform Answer: B) BOD (Biochemical Oxygen Demand)
39. The process of coagulation in wastewater treatment is used to: A) Remove organic matter B) Remove large solids C) Aggregate suspended particles into flocs for easier removal D) Disinfect the effluent

Answer: C) Aggregate suspended particles into flocs for easier removal

40. Which of the following is an indicator of the quality of effluent in wastewater treatment? A) Nitrogen levels B) Alkalinity C) Color D) Total Suspended Solids (TSS) Answer: D) Total Suspended Solids (TSS)
41. Which of the following is the best method for sludge disposal when considering both environmental impact and cost? A) Incineration B) Landfilling C) Land application D) Deep-well injection Answer: C) Land application
42. What does the term "effluent" refer to in wastewater treatment? A) Water used in the treatment process B) The solids removed from wastewater C) The treated water discharged from the plant D) The waste gases released during treatment Answer: C) The treated water discharged from the plant
43. Which of the following is a reason for monitoring and maintaining the pH level of the wastewater treatment process? A) To promote bacterial growth in the aeration tank

B) To ensure proper chemical coagulation C) To maintain proper chlorine levels for disinfection D) To facilitate sludge digestion Answer: B) To ensure proper chemical coagulation

44. Which of the following is an example of a non-point source of pollution that a wastewater treatment plant may encounter? A) Industrial discharge B) Household septic tanks C) Urban stormwater runoff D) Discharge from sewage treatment plants Answer: C) Urban stormwater runoff
45. What is the purpose of the final clarifier in a wastewater treatment plant? A) To remove remaining solids after secondary treatment B) To disinfect the effluent C) To remove dissolved gases from the effluent D) To add oxygen for biological treatment Answer: A) To remove remaining solids after secondary treatment46. In the activated sludge process, what is the primary function of the aeration tank? A) To settle out solids B) To mix and aerate the wastewater to support microbial digestion C) To add chemicals to the wastewater D) To disinfect the effluent Answer: B) To mix and aerate the wastewater to support microbial digestion
46. Which of the following is an example of a secondary treatment process in wastewater treatment?

A) Primary clarifier B) Anaerobic digestion C) Trickling filter D) Bar screen Answer: C) Trickling filter

48. The term "volatile solids" in wastewater treatment refers to: A) Organic solids that can be broken down by microorganisms B) Inorganic solids that do not decompose C) Solids that are removed by filtration D) Solids that remain after incineration Answer: A) Organic solids that can be broken down by microorganisms
49. Which of the following substances is most likely to be removed during tertiary treatment? A) Nitrogen B) Organic matter C) Pathogens D) Phosphorus Answer: D) Phosphorus
50. In a wastewater treatment plant, what is the role of the chlorine contact tank? A) To remove pathogens from the effluent B) To filter out suspended solids C) To aerate the effluent D) To add oxygen to the water Answer: A) To remove pathogens from the effluent

51. What is the main advantage of using UV light for disinfection in wastewater treatment? A) It is less costly than chlorine B) It removes nitrogen from the effluent C) It does not require the addition of chemicals D) It removes suspended solids Answer: C) It does not require the addition of chemicals
52. What is the most common cause of foaming in activated sludge systems? A) Excessive organic loading B) High chlorine concentration C) High levels of suspended solids D) Low temperature in the aeration tank Answer: A) Excessive organic loading
53. The process of “sludge stabilization” refers to: A) The increase in volume of sludge B) The breakdown of organic material in the sludge C) The removal of toxic materials from sludge D) The process of drying the sludge Answer: B) The breakdown of organic material in the sludge
54. Which of the following is a typical characteristic of anaerobic digestion? A) It requires large amounts of oxygen B) It is used to treat wastewater directly C) It reduces the volume of organic solids in sludge D) It produces large amounts of chlorine gas Answer: C) It reduces the volume of organic solids in sludge

55. What is the primary function of a digester in a wastewater treatment plant? A) To remove suspended solids B) To treat and reduce the volume of organic solids in sludge C) To disinfect the effluent D) To add oxygen for microbial activity Answer: B) To treat and reduce the volume of organic solids in sludge
56. What does the term "TKN" stand for in wastewater treatment? A) Total Kinetic Nitrogen B) Total Kinetics of Nutrients C) Total Kjeldahl Nitrogen D) Total Knowledge of Nitrogen Answer: C) Total Kjeldahl Nitrogen
57. Which of the following is an example of a chemical used to control odors in wastewater treatment plants? A) Chlorine B) Ozone C) Activated carbon D) Sodium hydroxide Answer: C) Activated carbon
58. What is the typical purpose of the secondary clarifier in a wastewater treatment plant? A) To disinfect the effluent B) To remove settled solids after biological treatment C) To aerate the effluent D) To add chemicals to the water

Answer: B) To remove settled solids after biological treatment

59. Which of the following is an indicator of the biological activity in an aeration tank? A) Temperature of the influent B) Biochemical Oxygen Demand (BOD) C) Total Coliforms D) Suspended Solids (SS) Answer: B) Biochemical Oxygen Demand (BOD)
60. What is the primary purpose of the anaerobic digester in a wastewater treatment plant? A) To reduce pathogens in the sludge B) To add nutrients to the effluent C) To convert organic solids into biogas and reduce sludge volume D) To remove phosphorous from the wastewater Answer: C) To convert organic solids into biogas and reduce sludge volume
61. Which of the following is the main advantage of using a trickling filter over an activated sludge system? A) Lower energy requirements for aeration B) Better removal of phosphorus C) Higher nutrient removal efficiency D) Increased pathogen removal Answer: A) Lower energy requirements for aeration
62. What does "MLVSS" stand for in wastewater treatment? A) Maximum Liquid Volatile Solids

B) Minimum Liquid Volatile Solids C) Mixed Liquor Volatile Suspended Solids D) Mixed Liquor Solids Suspension Answer: C) Mixed Liquor Volatile Suspended Solids

63. What is the function of a "sludge dewatering" process in a wastewater treatment plant? A) To reduce the volume of sludge before disposal B) To add oxygen to the wastewater C) To disinfect the sludge D) To add nutrients to the effluent Answer: A) To reduce the volume of sludge before disposal
64. What is the primary purpose of using a "bar screen" in the wastewater treatment process? A) To remove dissolved chemicals B) To remove large debris from the influent C) To aerate the wastewater D) To adjust the pH of the influent Answer: B) To remove large debris from the influent
65. Which of the following is the best indicator of how much oxygen is required for microorganisms to treat organic matter in wastewater? A) Total Suspended Solids (TSS) B) Biological Oxygen Demand (BOD) C) pH D) Temperature

Answer: B) Biological Oxygen Demand (BOD)66. The process of "flocculation" in wastewater treatment refers to: A) The conversion of ammonia to nitrites B) The formation of flocs from suspended particles for easier removal C) The addition of chemicals for disinfection D) The removal of dissolved gases from the effluent Answer: B) The formation of flocs from suspended particles for easier removal

67. Which of the following processes is typically used for tertiary treatment to further polish effluent? A) Chemical precipitation B) Filtration C) Biological aeration D) Anaerobic digestion Answer: B) Filtration
68. Which of the following is NOT a common method of sludge disposal? A) Landfilling B) Incineration C) Land application D) Ocean discharge Answer: D) Ocean discharge
69. In a wastewater treatment plant, what is the purpose of the "primary clarifier"? A) To disinfect the effluent B) To remove settled solids from the influent C) To add oxygen to the influent D) To treat and reduce organic matter

Answer: B) To remove settled solids from the influent

70. Which of the following tests is used to measure the amount of oxygen required for the biological degradation of organic matter in wastewater? A) Total Suspended Solids (TSS) B) Biochemical Oxygen Demand (BOD) C) Total Nitrogen (TN) D) Chemical Oxygen Demand (COD) Answer: B) Biochemical Oxygen Demand (BOD)
71. The term "nitrification" in wastewater treatment refers to: A) The conversion of ammonia to nitrite and then to nitrate B) The removal of phosphorus from effluent C) The breakdown of organic solids by anaerobic bacteria D) The removal of suspended solids through filtration Answer: A) The conversion of ammonia to nitrite and then to nitrate
72. Which of the following is an important factor to consider when designing a wastewater treatment plant's aeration system? A) The temperature of the influent B) The level of dissolved oxygen in the effluent C) The pH of the influent D) The type of sludge in the system Answer: B) The level of dissolved oxygen in the effluent
73. What is the function of the "anaerobic digester" in wastewater treatment? A) To remove chlorine from the effluent B) To remove large debris from the influent C) To break down organic material in sludge in the absence of oxygen

D) To aerate the wastewater for microbial digestion Answer: C) To break down organic material in sludge in the absence of oxygen

74. What is the key characteristic of a "secondary clarifier" in wastewater treatment? A) It provides the primary treatment for solids B) It is responsible for removing floating debris C) It allows solids to settle after biological treatment D) It disinfects the effluent Answer: C) It allows solids to settle after biological treatment
75. Which of the following processes is primarily used to remove phosphorous from wastewater? A) Filtration B) Chemical precipitation C) Biological nitrification D) Aerobic digestion Answer: B) Chemical precipitation
76. Which of the following is true about the role of microorganisms in wastewater treatment? A) They remove suspended solids B) They convert organic matter into carbon dioxide, water, and energy C) They add oxygen to the system D) They are responsible for removing phosphorus Answer: B) They convert organic matter into carbon dioxide, water, and energy
77. What is the purpose of adding lime to the sludge in wastewater treatment? A) To reduce pathogens in the sludge

B) To neutralize the pH of the influent C) To remove phosphorous D) To disinfect the effluent Answer: A) To reduce pathogens in the sludge

78. Which of the following is a potential consequence of over-aeration in an activated sludge system? A) Decreased BOD removal B) Increased energy consumption C) Increased nitrogen levels D) Reduced pathogen removal Answer: B) Increased energy consumption
79. What is the primary reason for controlling the pH of wastewater in treatment systems? A) To ensure proper chemical reactions for nutrient removal B) To reduce the BOD of the influent C) To enhance the growth of pathogenic microorganisms D) To prevent the formation of foam in the system Answer: A) To ensure proper chemical reactions for nutrient removal
80. What is the most common method of wastewater disinfection used in the United States? A) UV light B) Ozone C) Chlorine D) Hydrogen peroxide Answer: C) Chlorine

81. What is the purpose of the "effluent" in wastewater treatment? A) To add solids to the treatment system B) To remove treated water from the system C) To add chemicals for disinfection D) To store untreated wastewater Answer: B) To remove treated water from the system
82. Which of the following is a common problem caused by high levels of organic matter in wastewater? A) Increased BOD levels B) Increased nutrient removal C) Reduced aeration requirements D) Decreased nitrogen concentrations Answer: A) Increased BOD levels
83. In wastewater treatment, what is the significance of "solids retention time" (SRT)? A) It controls the amount of solids in the influent B) It determines the amount of time solids are retained in the system C) It is used to calculate the flow rate of influent D) It is used to measure the oxygen demand of wastewater Answer: B) It determines the amount of time solids are retained in the system
84. In which of the following processes are bacteria used to break down organic material? A) Filtration B) Anaerobic digestion C) Chlorination

D) Reverse osmosis Answer: B) Anaerobic digestion

85. Which of the following is NOT typically a part of the primary treatment in wastewater treatment? A) Screening B) Sedimentation C) Coagulation D) Biological treatment Answer: D) Biological treatment
86. The "turbidity" of an effluent sample is used to measure: A) The presence of dissolved oxygen B) The concentration of suspended particles C) The temperature of the effluent D) The pH of the water Answer: B) The concentration of suspended particles
87. What is a potential environmental concern when discharging treated effluent into a river or stream? A) High levels of nitrogen and phosphorous can cause eutrophication B) The effluent may increase the dissolved oxygen levels in the water C) The effluent can remove essential microorganisms from the water D) It may increase the sludge volume downstream Answer: A) High levels of nitrogen and phosphorous can cause eutrophication
88. In a wastewater treatment plant, the "flow equalization basin" is used for: A) Adding chemicals to disinfect the effluent

B) Removing excess solids from the influent C) Equalizing the flow of wastewater to the treatment processes D) Settling solids from the treated effluent Answer: C) Equalizing the flow of wastewater to the treatment processes

89. The term "BOD5" refers to: A) The biochemical oxygen demand measured over five days B) The amount of oxygen required for five types of bacteria C) The five most important pollutants in wastewater D) The amount of oxygen required to treat five gallons of wastewater Answer: A) The biochemical oxygen demand measured over five days
90. What is the primary purpose of the activated sludge process in wastewater treatment? A) To remove dissolved solids B) To treat wastewater by using microorganisms to decompose organic material C) To neutralize acids in the effluent D) To filter out large debris and particles Answer: B) To treat wastewater by using microorganisms to decompose organic material
91. What is the function of the "trickling filter" in wastewater treatment? A) To remove large solids from the influent B) To provide aeration for biological treatment C) To chemically treat the effluent D) To filter out suspended particles using fine mesh Answer: B) To provide aeration for biological treatment

92. Which of the following types of microorganisms are primarily responsible for breaking down organic matter in the activated sludge process? A) Algae B) Protozoa C) Bacteria D) Viruses Answer: C) Bacteria
93. What is the primary purpose of "chlorine disinfection" in wastewater treatment? A) To kill harmful pathogens in the effluent B) To remove nutrients like nitrogen and phosphorous C) To reduce the biochemical oxygen demand (BOD) D) To settle out suspended solids Answer: A) To kill harmful pathogens in the effluent
94. Which of the following is the best method for reducing nitrogen levels in wastewater during treatment? A) Sedimentation B) Biological nitrification and denitrification C) Chemical coagulation D) Reverse osmosis filtration Answer: B) Biological nitrification and denitrification
95. In wastewater treatment, "sludge volume index" (SVI) is used to measure: A) The volume of effluent produced B) The amount of oxygen required for treatment C) The settling properties of activated sludge D) The temperature of the influent

Answer: C) The settling properties of activated sludge

96. The term "septic tank" refers to: A) A type of aeration basin used in wastewater treatment B) A large tank used to settle solids and digest organic matter in small systems C) A tank used to treat nitrogen in wastewater D) A filtering system for tertiary treatment Answer: B) A large tank used to settle solids and digest organic matter in small systems
97. What does the term "total suspended solids" (TSS) refer to in wastewater? A) The dissolved organic matter in the water B) The particles that float on the surface of the water C) The solid particles that are suspended in the water but can settle D) The bacteria responsible for breaking down organic material Answer: C) The solid particles that are suspended in the water but can settle
98. What is the primary goal of secondary treatment in wastewater treatment? A) To disinfect the effluent B) To remove suspended solids and reduce organic matter C) To filter the effluent before discharge D) To add oxygen to the wastewater for aeration Answer: B) To remove suspended solids and reduce organic matter
99. Which of the following is a common issue when wastewater treatment plants experience high inflow and infiltration (I&I)? A) Overloading of the treatment system B) Increased chemical use for disinfection C) Decreased bacterial activity in the aeration tanks