AOS Practice Exam WWC 1-2_4.0.pdf

WASTEWATER COLLECTION OPERATOR CERTIFICATION PRACTICE EXAM GRADES 1 & 2  TIPS TO REMEMBER WHEN TAKING YOUR EXAM 1. Become familiar with the need-to-know criteria of the ABC exam you plan to take. You can find this on-line at: http://www.abccert.org/testing_se...

WASTEWATER COLLECTION OPERATOR CERTIFICATION PRACTICE EXAM GRADES 1 & 2  TIPS TO REMEMBER WHEN TAKING YOUR EXAM 1. Become familiar with the need-to-know criteria of the ABC exam you plan to take. You can find this on-line at: http://www.abccert.org/testing_services/need_to_know_criteria.asp Make time to study every day for at least two months prior to taking your exam. Attending one day certification prep classes does not guarantee you will pass your exam. 2. Purchase additional study material & courses from reputable organizations such as: a. California State University, Sacramento (CSUS) Foundation, Office of Water Programs; https://www.owp.csus.edu b. Water Environment Federation (WEF); http://www.wef.org c. American Water Works Association; Operators | American Water Works Association (awwa.org) 3. Allow plenty of time to drive to the exam site. Don’t forget your I.D. 4. Read every question carefully to determine exactly what is being asked. Some questions are written in a manner that may mislead you and may contain more info than necessary. 5. Never make a choice based on the frequency of previous answers. For example, if the last two or three answers have been A, it does not mean that the answer to the next question will also be A. 6. If you are not sure of the answer, try to eliminate as many of the choices as possible and make an educated guess. 7. Do not panic when you don’t know the answer. You may find that other questions on the exam will give you clues to the answer you were looking for. 8. Pace yourself, don’t spend too much time on one question. If you complete the exam and still have time left, go back and review the questions you did not know the answers to. 9. Remember, you do not need to score 100% on the exam. You can pass with a score of 70% or higher. Fear of failing the exam could distract you from the questions. Relax as much as possible. 10. Write out your math questions before using your calculator. This helps eliminate errors and helps you re-check your math. Sometimes drawing a shape related to the math problem e.g., a circular tank, rectangular basin, etc. will help you better visualize the problem. AOS WWC 1-2 PRACTICE EXAM | 4.0 1. What is the slope of a 10-inch sewer pipe that drops 6 inches over a distance of 150 ft? a. 0.3% b. 0.6% c. 1.5% d. 25% 2. How many gallons of sewer can a 6-inch diameter pipe that is 1-mile-long hold? a. 10,800 gal b. 5,500 gal c. 7,750 gal d. 250,000 gal 3. How many pounds of chlorine per day are required for a wastewater plant that is treating 5,000,000 GPD and dosing 10 mg/L? a. 417 lbs b. 815 lbs c. 250 lbs d. 330 lbs 4. A dye is detected 200 feet downstream 2.5 minutes after it is poured into an upstream manhole of a 12-inch sewer main. What is the velocity of the flow in feet per second? a. 2.0 ft/sec b. 3.0 ft/sec c. 1.3 ft/sec d. 2.8 ft/sec 5. How many cubic yards of earth are excavated from a trench 36 inches wide, 6 feet deep, and 300 feet long? a. 152 b. 185 c. 200 d. 466 AOS WWC 1-2 PRACTICE EXAM | 4.0 6. What is the dosage in mg/L for a treatment plant that uses 318 lbs/day of chlorine and treats 23.4 ft3/s? a. 2,542 mg/L b. 0.40 mg/L c. 175.4 mg/L d. 2.5 mg/L 7. What is the removal efficiency of a chemical odor scrubber with an inlet H2S concentration of 300 mg/L and discharge concentration of 5 mg/L? a. 15% b. 29.5% c. 98.3% d. 59% 8. How many gallons per foot are held in a lift station wet well with a diameter of 8 feet, and a depth of 15 feet? a. 375 gal/ft b. 500 gal/ft c. 626 gal/ft d. 283 gal/ft 9. Determine the pump capacity in GPM if a wet well measuring 4’ wide, 6’ long is lowered 4 feet in 10 minutes? a. 91 gpm b. 85 gpm c. 62 gpm d. 71 gpm 10. Calculate the detention time in hours of a primary clarifier that has a diameter of 90 feet, a depth of 12 feet, and an influent flow of 9.0 MGD. a. 0.5 hrs b. 1.5 hrs c. 3.0 hrs d. 36 hrs AOS WWC 1-2 PRACTICE EXAM | 4.0 11. A machine can be an effective tool when used to remove sewer stoppages in emergency situations. a. Pigging b. Bucket c. Flushing d. Rodding 12. Which of the following types of cleaning equipment is most commonly used when responding to an emergency stoppage service request for an overflowing manhole? a. Hand rods and power rodders b. Hand rods and high-velocity cleaners c. Power rodders and bucket machines d. High-velocity cleaners and bucket machines 13. Which of the following rodding tools is used to pilot a hole through a pipe experiencing heavy roots, grease, or solids? a. Sand corkscrew b. Auger c. Porcupine d. Spring blade cutter 14. The is specified by the manufacturer for a single vehicle, and it must not be exceeded when the vehicle is fully loaded. a. Adjusted vehicle weight (AVW) b. Gross vehicle weight (GVW) c. Adjusted vehicle weight rating (AVWR) d. Gross vehicle weight rating (GVWR) 15. Which of the following may result from an improperly constructed sewer lateral? a. Sewer odors entering a residential building b. Excessive infiltration entering the upstream manhole c. Corrosion caused by septic conditions within the mainline sewer d. A sewer main blockage caused by a protruding tap AOS WWC 1-2 PRACTICE EXAM | 4.0 16. Horizontal directional drilling and pipe jacking are examples of what type of method? a. Trenchless pipe replacement b. Open cut pipe installation c. Service connection repair d. Pipeline renewal 17. Examples of cleaning methods include hand rodding, power rodding, and bucketing. a. Hydraulic b. Pneumatic c. Mechanical d. Operational 18. is a method designed to support the walls of a trench and consists of a framework composed of wood and/or metal. a. Sheeting b. Shielding c. Shoring d. Sloping 19. Pressure transducers, ultrasonics, and bubblers are used to determine what component of sewer flow? a. Depth b. Inflow and infiltration c. Chemical composition d. Temperature 20. Which of the following are common sense procedures to prevent electrocution when working on electrical equipment? a. Wear metal-framed eyeglasses, jewelry, or brass belt buckles. b. Complete the work quickly, using both hands. c. Use rubber mats, rubber boots, leather gloves, or other forms of isolation between you and the ground. d. Before conducting work, test for oxygen deficiency/enrichment and flammable or explosive conditions. AOS WWC 1-2 PRACTICE EXAM | 4.0 21. Variable-frequency drive (VFD) pumps. a. Do not need maintenance as often as other pumps b. Are more complex and require specialized skills to maintain c. Can be used without a motor control center d. Have chemical battery backup 22. When is it more appropriate to conduct low-pressure air testing on sewers than conducting water tests? a. In steep terrain b. During wet weather c. In areas with high groundwater tables d. Before sewer laterals are connected to the main line 23. What is a swing or ball check valve on the discharge line of a pump used for? a. Prevent cavitation during low-flow periods b. Serve as an isolation valve during pump maintenance c. Eliminate the need for a wye fitting d. Provide positive shutoff from the force main when the pump is off 24. Electrical current is measured in. a. Volts b. Kilovolt amperes c. Watts d. Amps 25. are required to avoid the risk of accidental operation of related equipment while working on an electrical system. a. Air relief valves b. Fusible links c. Lockout/tagout procedures d. Confined space entry permits 26. The minimum permissible oxygen level required for a work space is. a. 19.5% b. 21.5% c. 80% d. 100% AOS WWC 1-2 PRACTICE EXAM | 4.0 27. What type of level sensing technology does not come in contact with flow during normal operation? a. Ultrasonic b. Capacitance c. Bubbler system d. Float ball 28. A variable frequency drive will regulate pump flow by adjusting the pump's. a. Total dynamic head b. Speed c. Pressure d. Efficiency 29. What should you look for when inspecting a pump impeller? a. Paint thickness b. Material of construction c. Chips or broken tips d. Size 30. When monitoring flow in an open channel that experiences surcharge conditions, what type of flow monitoring device will provide the most accurate measurements? a. Inline flow meter b. Area-velocity c. Parshall flume and a depth pressure sensor d. Magnetic flow meter 31. Variable-frequency drives are used in pumping stations to. a. Keep the pump revolutions per minute (rpm) at a constant rate b. Match the discharge rate to the influent rate c. Vary the wet well level to prevent buildup d. Turn the pumps on and off frequently AOS WWC 1-2 PRACTICE EXAM | 4.0 32. When using a hydraulic cleaning machine, which of the following provides the most effective cleaning? a. High pressure and fast reel speed b. Low pressure and moderate reel speed c. Low pressure and fast reel speed d. High pressure and moderate reel speed 33. The type of valve used to prevent water from flowing backwards through a pump is called a(n) valve. a. Anti-siphon b. Gate c. Check d. Ball 34. Which type of motor used in a wet well-only pumping station? a. Squirrel cage b. Wound rotor c. Induction d. Submersible 35. Face shields, gloves, and steel-toed work shoes are known as a. Personal protection equipment b. Anti-bacterial protection equipment c. Wastewater-resistant equipment d. Sewer safety uniform 36. The bottom of the inside of a sewer pipe is called the. a. Channel b. Crown c. Invert d. Segment 37. Regular cleaning of areas in the sewer system that have frequent blockages is called maintenance. a. Emergency b. SSO c. Corrective d. Preventive AOS WWC 1-2 PRACTICE EXAM | 4.0 38. One thousand parts per million (ppm) of hydrogen sulfide gas is classified as a. Lower explosive limit (LEL) b. Immediately dangerous to life or health (IDLH) c. Upper explosive limit (UEL) d. Time weighted average (TWA) 39. A large pumping station that has separate chambers for the wastewater and the pumps is called a pumping station. a. Submersible b. Pneumatic ejector c. Suction lift d. Drywell 40. Inverted siphons are used to go under obstructions such as. a. Rivers, highways, and utilities b. Tree roots and poor soil c. Mountains and river gorges d. Private property and groundwater tables 41. Which of the following situations may result if there is too much distance between a hand rod power drive and the manhole rod guide tube during hand rodding operation? a. A loop can form in the rod, the rod can break, and someone can get injured by the broken rod. b. A sudden surge of stored wastewater can shoot through the rod tube when a stoppage is broken loose. c. The rod can be pushed through the pipe too quickly, and roots and other mate­ rial may remain in the pipe. d. The rod can seize in the palm of the operator's hand and cause severe injury. 42. When reading an atmospheric analyzer, the operator should make sure the oxygen percentage reading is between. a. 12.6 and 15.9% b. 16.2 and 19.1% c. 19.5 and 23.5% d. 24.5 and 26.5% AOS WWC 1-2 PRACTICE EXAM | 4.0 43. Why is emergency maintenance of lift stations less desirable than other types of maintenance? a. Different personnel need to perform emergency maintenance because of labor union rules. b. There are potential regulatory consequences and the likelihood of substantially higher costs. c. Personnel will have higher morale. d. Bypass pumping equipment is required for emergency maintenance only. 44. Why should force main air release valves be routinely checked and maintained? a. Air constantly comes out of solution and needs to be relieved. b. Air valve access chambers require periodic cleaning. c. Force mains typically require resizing to accommodate different flows. d. Air valves control air flow into the pumps. 45. To detect early signs of trouble related to pump performance, periodic cleaning and a simple should be performed. a. Ultrasonic test b. Vibration analysis c. Look-feel inspection d. Oil analysis 46. Smoke testing should be performed on a sewer pipe. a. When groundwater is high to locate broken or leaking pipes b. On a windy day so the public will not call the fire department c. At a lift station to find an electrical defect d. When groundwater is low to find defects 47. Using a closed-circuit television (CCTV) camera before removing roots or debris with a hydraulic cleaning nozzle can reveal what serious problem? a. Pipeline has corrosion or structural flaws. b. Service taps directly across from each other in a mainline pipe. c. The sewer main has an internal drop into the manhole. d. The downstream pipe size is smaller than the pipe to be cleaned. AOS WWC 1-2 PRACTICE EXAM | 4.0 48. A capacity, management, operations, and maintenance (CMOM) program will. a. Prevent all sanitary sewer overflows (SSOs). b. Improve the performance of the collection system. c. Ensure a utility can increase rates for service. d. Comply with the U.S. Environmental Protection Agency (U.S. EPA) regulation. 49. Which one of the following is not a basic pipe material commercially available for gravity sewer construction? a. Ductile iron b. Copper c. Polyethylene d. Polyvinyl chloride 50. Which method is used for manhole renewal in structures that are unsound? a. Fiberglass reinforced plastic pipe b. High-density polyethylene sheets c. Spiral-wound in situ pipe d. Cured-in-place liner 51. If the public sewer main is experiencing a sanitary sewer overflow (SSO), then corrective action needs to be taken. Any materials discovered in the line should be removed from the if possible. a. Downstream manhole b. Upstream manhole c. Bar screen at the treatment plant d. Nearest pumping station 52. Identify the following related activity that can be combined with predictive, scheduled, and corrective maintenance at a lift station: a. Supervisory control and data acquisition b. Work management c. Risk analysis d. Preventive AOS WWC 1-2 PRACTICE EXAM | 4.0 53. Pumps typically are categorized as either. a. Kinetic energy pumps or negative-displacement pumps b. Kinetic energy pumps or positive-displacement pumps c. Hydraulic energy pumps or positive-displacement pumps d. Direct energy pumps or positive-displacement pumps 54. Short-lived transient pressure conditions in force mains and pressure pipes is known as. a. Water hammer b. Normal flow c. High velocity d. Reverse flow 55. In a sewer lift station, electric motors are designed for either current or current. a. Right or left b. Positive or negative c. Alternating or direct d. Direct or indirect 56. What is the "Ten State Standards" minimum ventilation requirement in a dry well of a sewer lift station? a. 30 air changes per hour intermittently or six air changes per hour continuously b. 20 air changes per hour intermittently or nine air changes per hour continuously c. 35 air changes per hour intermittently or 12 air changes per hour continuously d. 25 air changes per hour intermittently or 10 air changes per hour continuously 57. What does SCADA stand for? a. Supervisory contact and data acquisition b. Supervisory control and data alternative c. Supervisory center and display availability d. Supervisory control and data acquisition AOS WWC 1-2 PRACTICE EXAM | 4.0 58. Pump capacity is typically expressed in. a. Gallons per minute (gpm) or million gallons per day (mgd) b. Feet per second (ft/sec) or pound-force per square inch (psi) c. Feet per second squared (ft/sec2) or pound-force per square inch (psi) d. Pound-force per square inch (psi) or shaft power (horsepower [hp]) 59. What is the range of the optimum velocity in force mains? a. 1 and 2 ft/sec b. 3 and 5 ft/sec c. 6 and 7 ft/sec d. 8 and 10 ft/sec 60. A lightning arrester is. a. A protective device for limiting the high surge voltages on equipment by releasing a surge current to the atmosphere b. A protective device for limiting the high surge voltages on equipment by releasing a surge current to the ground c. A protective device for limiting the high surge voltages on equipment by releasing a surge current to the electric grid d. A protective device for limiting the low surge voltages on equipment by releasing a surge current to the electric grid 61. The term “static head” is defined as. a. The amount of energy produced by a pump at high velocity b. The difference in elevation between the bottom of the wet well and the centerline of the pump c. The positive and negative displacement of the discharge pipe d. The vertical distance from a specific point of the water surface when the water is not moving AOS WWC 1-2 PRACTICE EXAM | 4.0 62. When does cavitation in a pump occur? a. When the net positive suction head (NPSH) required by the pump at the eye of the impeller is less than the NPSH available in the system b. When the negative pressure of the inlet drops below the atmospheric pressure of the fluid being pumped c. When the absolute pressure at the eye of the impeller is less than the vapor pressure of the fluid being pumped, causing the fluid to boil and form vapor bubbles d. When the absolute pressure at the eye of the impeller is higher than the vapor pressure of the fluid being pumped, causing the fluid to boil and form vapor bubbles 63. Air-release valves should be considered for installation at on discharge piping. a. Midpoint b. High points c. Discharge manhole d. Straight level point 64. Hydrogen sulfide is generated in collection systems when. a. Chlorine is added after long stretches of gravity sewers b. Iron salts are mixed with the sulfides in wastewater c. Oxygen is not present in the wastewater flowing through the system d. Hydrogen peroxide is added to a pumping station wet well 65. Wastewater is conveyed from a building to a low-pressure small-diameter force main sewer system using a. a. Screw pump system b. Vacuum pump system c. Grinder pump system d. Air lift pump system 66. Hydrogen sulfide can be removed by passing wet well exhaust through a vessel containing wood chips mixed with organic matter such as compost. This odor control unit is known as a. a. Chemical scrubber b. Biofilter c. Carbon filter d. Anthracite filter AOS WWC 1-2 PRACTICE EXAM | 4.0 67. Measuring devices such as weirs, flumes, or area velocity meters are often permanently or temporarily installed in gravity flow pipes to measure. a. Nutrient concentrations b. Flow c. Pressure d. Energy use 68. A lift station has a wet well and a dry well. On/off float switches are used to activate fixed speed pump(s). During the pumping cycle, just before the pump turns off, a noise occurs in the centrifugal pump that sounds like marbles or gravel trapped in the volute. This happens each cycle. What is the likely cause? a. Cavitation b. Excess torque c. Packing too tight d. Excess fluid flow 69. A primary advantage of a vacuum sewer system is that. a. There are few moving parts in contact with the wastewater b. There is no electrical consumption c. The life cycle costs are low d. The water use required for flushing is low 70. What is the most important concern after a discharge of hazardous material into a wastewater collection system? a. Finding out who caused the discharge b. Determining where to buy the proper cleanup equipment c. Minimizing health risks d. Preventing odors 71. When a complaint call is received from a customer, the steps to efficiently resolve the issue would be to first prepare a thorough record of the call and then. a. File the report for future reference. b. Respond to the complaint as soon as possible. c. Check with the city manager before responding. d. Refer the customer to a contract/professional who can help. AOS WWC 1-2 PRACTICE EXAM | 4.0 72. Besides infiltration/exfiltration, which of the following is related to a cracked sewer line? a. Odor problems. b. Root intrusion. c. Increase in the flow rate through the pipe. d. An increase in hydrogen sulfide gas. 73. If a collection system is subject to a large amount of inflow and infiltration, what may occur if the line is surcharged? a. Pressure may cause a rupture in the pipe b. Exfiltration may occur at a joint or crack c. An overflow may occur at a manhole d. All of the above 74. Rotating operators to different crews or types of work should be done to. a. Determine how easy it is for new operators to operate equipment b. Promote operators that are capable to get work done c. Improve efficiency in the department d. Prevent operators from being promoted 75. The individual responsible for signing the confined space entry permit before entry and canceling it following entry is known as the. a. Attendant b. Entry supervisor c. Safety officer d. Superintendent 76. An oxygen alarm reading of less than 19.5% on a gas detector during confined space entry is known as a(n) reading. a. Oxygen-enrichment b. Lower explosion limit c. Oxygen-deficiency d. Hazardous substance AOS WWC 1-2 PRACTICE EXAM | 4.0 77. When identifying a confined space, the Occupational Safety and Health Administration (OSHA) standard requires the employer to. a. Limit access and egress b. Eliminate dark and damp areas c. Identify employee job duties d. Establish a verbal procedure for issuance, use, and cancellation of entry permits 78. The numerical designation for neutrality when measuring pH is. a. 0 b. 2 c. 7 d. 10 79. Who is the only person who should remove the lockout/tagout devices when finished working on electrical systems? a. The supervisor b. The person who assigned the work c. The person who installed the devices d. The helper 80. When sloping of an excavation made in Class B soil is not possible because of limited work space, what is the minimum depth at which shoring is always required? a. 3 ft b. 4 ft c. 5 ft d. 7 ft 81. The term given to the person responsible for inspection and evaluation of the safety of a trench or excavation is. a. Supervisor b. Competent person c. Excavator d. Superintendent AOS WWC 1-2 PRACTICE EXAM | 4.0 82. In a 7-ft deep trench, what is the maximum distance allowed for a worker to reach a means of egress? a. 10 ft b. 15 ft c. 25 ft d. 30 ft 83. Under what conditions is hydrogen sulfide gas usually produced? a. Aerobic conditions b. Anaerobic conditions c. High temperature conditions d. Humid conditions 84. How is a collection system map prepared? a. Information from the "as built" plans are drafted onto the property map b. A contractor provides copies of the construction plan c. Maps are obtained from the county assessor's office d. The USGS prepares all maps for municipalities 85. Name an economical and quick method of determining if a new sewer line is straight and unobstructed. a. Lamping b. Hydro testing c. Exfiltration / infiltration testing d. Weir method 86. What is the most likely reason for fluctuating flows in a sewer line? a. Fluctuating flow is normal b. A lift station may not be working c. A pump may be inoperable d. There is an obstruction in the line 87. Which of the following gases will an atmospheric instrument NOT monitor? a. Hydrogen sulfide b. Oxygen c. Flammable hydrocarbons d. Nitrogen AOS WWC 1-2 PRACTICE EXAM | 4.0 88. Which of the following items is considered optional information on a collection system master map? a. Manhole surface elevation b. Soil conditions c. The length of the sewer line d. The direction of flow 89. Which of the following procedures should be carried out to repair a leak in a gravity sewer line? a. Call an underground service alert and locate utilities before digging b. Find the utilities with a pipe locator c. Insure the site before digging d. Perform the work and repair damaged utilities 90. Which term best describes liquid waste leaking out of a sewer pipe? a. Exfiltration. b. Infiltration c. Transpiration d. Seepage 91. Under what conditions may untreated sewage be bypassed from a sewage treatment facility? a. Untreated sewage from a sewage treatment facility shall not be bypassed b. If the facility has an Aquifer Protection Permit c. If the facility is a Grade 4 facility d. If the facility notifies the Department 92. What type of cross-connection should be installed between a public water system and a wastewater treatment plant? a. A cross-connection using a pressure vacuum breaker backflow prevention assembly b. A cross-connection using a double check valve backflow prevention assembly c. A cross-connection using a reduced pressure principle backflow prevention assembly d. A person shall not install or maintain a connection between any part of a sewage treatment facility and a potable water supply AOS WWC 1-2 PRACTICE EXAM | 4.0 93. Hydrogen sulfide gas smells like. a. dead fish. b. fuel gas. c. rotten cabbage. d. rotten eggs. 94. Why are gasoline and volatile solvents objectionable when present in a sewer? a. they produce an explosion hazard. b. they tend to cause the solids to vaporize. c. they will coagulate floatables and cause stoppages. d. none of the above. 95. Leakage of seal water around the packing on a centrifugal pump is required because it acts as a(n). a. adhesive. b. coolant. c. lubricant. d. vapor barrier. 96. What must be checked before entering a manhole? a. atmosphere in manhole. b. equipment. c. proper barricades or warning devices around manhole. d. all of the above. 97. In sewer maintenance, what is a pig? a. a ball forced through a sewer line. b. a power rod. c. any foul smelling equipment. d. the hydraulic rodding truck. 98. Wearing rings are installed in a pump to. a. concentrate wear on an economically replaceable part. b. hold the shaft in position. c. keep the impeller in place. d. wear out rings instead of sleeves. AOS WWC 1-2 PRACTICE EXAM | 4.0 99. A lantern ring is a. a. metal ring for lowering an explosive-gas detector candle into manholes and wet wells. b. shaft coupling that has been completely worn through in spots or that has "daylighted." c. spacer ring in a pump packing gland to improve seal water distribution. d. type of coupling for joining pipes that will not be covered or put in the dark for at least 5 days. 100. Mechanical ventilation of a lift station is required to. a. lower temperatures to reduce production of hydrogen sulfide. b. reduce chlorine demand. c. reduce corrosion. d. increase D.O. in raw wastewater. AOS WWC 1-2 PRACTICE EXAM | 4.0