Wastewater Treatment and Maintenance Practices, Exams of Water and Wastewater Engineering

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Wastewater Collections Level II

Questions and answers

Wet well probe systems are usually used for---- determination(s) of level. A. Approximate B. Dual point C. continuous D. Single point - .......ANSWERS 🔷🖊 ✔✔D. Single point A foreman's monthly report should include the A. Last time the supervisor read the report B. Number of complaints received and investigated C. number of monthly reports prepared D. Number if qualifiable worker's available - .......ANSWERS 🔷🖊✔✔B. Number of complaints received and investigated. Solids that settle out in the bottom of a wet well are called A. scum B. Colloidal solids C. suspended solids D. Settleable solids - .......ANSWERS 🔷🖊✔✔D. Settleable solids What determines the amount of hydrogen sulfide produced in a sewer? A. BOD concentration B. DO concentration C. pH D. SS concentration - .......ANSWERS 🔷🖊✔✔C. pH

Two pumps of the same capacity operate together with a single main. The discharge will be--- in a typical pump station. A. the same as one pump B. more than one pump, but not twice as much C. twice as much as one pump D. more than twice as much as one pump - .......ANSWERS 🔷🖊✔✔B. more than one pump, but not twice as much Which of the following is an indicator normally used for determination of water pollution? A. Fungi B. Stapylococcus C. Algae D. Coliforms - .......ANSWERS 🔷🖊✔✔D. Coliforms What function does a ground fault circuit interrupter (GFCI) perform when there is an imbalance of current between the hot and neutral conductors of a circuit? A. bypass the ground fault B. grounds the equipment C. opens the circuit D. rebalances the current - .......ANSWERS 🔷🖊✔✔C. Opens the circuit Plastic (PVC) pipe exposed to sunlight requires? A. a protective coating B. Solvent weld fittings C. Special vertical support D. Nothing special - .......ANSWERS 🔷🖊✔✔A. a protective coating The most important factor affecting the useful life of piping is? A. The ability of the materials used to resist internal and external corrosion

B. the depth of the pipe C. the flexibility of the pipe D. the smoothness of the inside of the pipe - .......ANSWERS 🔷🖊✔✔A. The ability of the materials used to resist internal and external corrosion Sewers located adjacent to a ground level storage reservoir are required to be located at least 10 feet from the structure and constructed of watermain-type materials for a distance of at least 50 feet from the storage reservoir. What is the reason for the requirement? A. to prevent a high ground water table adjacent to the reservoir B. to protect the storage reservoir from contamination C. to reduce infiltration into the sewer D. because vitrified-clay sewer pipe is easily broken - .......ANSWERS 🔷🖊✔✔B. to protect the storage reservoir from contamination The best way to track all maintenance work done is through a A. closed circuit TV B. polaroid system C. tape recorder D. work order system - .......ANSWERS 🔷🖊✔✔D. Work order system What is the V-notch weir best suited for measuring? A. large constant flows B. large irregular flows C. small constant flows D. small irregular flows - .......ANSWERS 🔷🖊✔✔C. Small constant flows Which of the following is best qualified to work on an electrical panel? A. maintenance man B. supervisor C. electrician

D. crew leader - .......ANSWERS 🔷🖊✔✔C. Electrician The testing procedure where a solution is added drop by drop until the desired change in a second solution is observed is A. drop addition B. secondary ion addition C. titration D. zwitter ion addition - .......ANSWERS 🔷🖊✔✔C. Titration What are the three basic classes of hazardous atmospheres? A. Gaseous, liquid, combustible B. poisonous, gaseous, toxic C. toxic, perilous, poisonous D. poisonous, explosive, oxygen deficient - .......ANSWERS 🔷🖊✔✔D. Poisonous, explosive, oxygen deficient What is the chemical symbol for sulfuric acid? A. HCI B. H2SO C. CaSO D. SuAc3 - .......ANSWERS 🔷🖊✔✔B. H2SO A sewer blockage has been cleared by rodding. What should be done to the cleared sewer next? A. allow the sewer to rest B. check the sewer for proper exfiltration C. clean the sewer hydraulically to restore full capacity D. clear the sewer with a bucket machine - .......ANSWERS 🔷🖊✔✔C. Clean the sewer hydraulically to restore full capacity

If an air compressor has excessive oil consumption, the most likely cause of the problem would be A. a broken drive coupling B. external oil leaks C. a faulty pump D. worn rotor vanes - .......ANSWERS 🔷🖊✔✔B. External oil leaks Preventative maintenance on an amp-meter includes checking the A. Wiring and contacts for pitting and fraying B. Oil levels and greasing every 6 months C. Alignment and adjusting to proper tolerances D. Dosage and residual rates - .......ANSWERS 🔷🖊✔✔A. Wiring and contacts for pitting and fraying What is the function of the bubbler control in a lift station wet well? A. Aerate the contents of the wet well to prevent septic conditions B. Measure liquid flow rate and regulate pump operations C. Measure liquid flow rate but does not regulate pump operations D. Sense liquid depth in the wet well to regulate pump operations - .......ANSWERS 🔷🖊 ✔✔D. Sense liquid depth in the wet well to regulate pump operations At what time of the day do low flows generally occur? A. Mid-morning B. Afternoon C. Evening D. Late night - .......ANSWERS 🔷🖊✔✔D. Late night Gasoline fires are classified as A. Class A B. Class B

C. Class C D. Class D - .......ANSWERS 🔷🖊✔✔B. Class B Which valve is most suitable for a throttling application? A. Plug valve B. Check valve C. Gate valve D. Butterfly valve - .......ANSWERS 🔷🖊✔✔A. Plug valve A sewer is being rodded to open a stoppage caused by roots. Where is the work usually started from? A. Chimney between manholes B. Dry manholes C. Flooded manholes D. Either manhole - .......ANSWERS 🔷🖊✔✔B. Dry manholes The impeller in a centrifugal pump becomes worn after use. The amount of energy used will be ________ the amount used by a similar new pump. A. The same as B. Less than C. More than D. Six times more - .......ANSWERS 🔷🖊✔✔C. More than Grease fittings on a machinery should be A. Greased only once every six months to prevent over-lubrication B. Greased only with the machinery running to assure thorough distribution of the lubricant C. Replaced with oil cups D. Serviced with the machinery shut off to prevent operator injury - .......ANSWERS 🔷🖊✔✔D. Serviced with the machinery shut off to prevent operator injury.

Causes of accidents include A. Fire hazards B. Kill switches C. Machinery guards D. Railings - .......ANSWERS 🔷🖊✔✔A. Fire hazards Which of the following determines the size of bucket used in a sewer-cleaning operation that uses power bucket machines? A. Capacity of the bucket B. Diameter of the bucket C. Width of the bucket bails D. Overall length of the bucket - .......ANSWERS 🔷🖊✔✔C. Width of the bucket bails Wastewater should be pumped from a wet well A. Based upon the time clock operation B. Four times a day C. Often enough to prevent wastewater from going anaerobic D. Once a day - .......ANSWERS 🔷🖊✔✔C. Often enough to prevent wastewater from going anaerobic Which of the following is the most toxic to biological treatment plant organisms? A. Aluminum B. Calcium C. Copper D. Iron - .......ANSWERS 🔷🖊✔✔C. Copper In a parallel circuit, if one unit is burned out or disconnected, the other unit will A. Become overloaded B. Cease to function

C. Cease to function and then resume when the unit is replaced D. Continue to function - .......ANSWERS 🔷🖊✔✔D. Continue to function A peristaltic pump is a type of A. Centrifugal pump B. Displacement pump C. Peripheral pump D. Reciprocating pump - .......ANSWERS 🔷🖊✔✔B. Displacement pump What is the most important item to check before starting a gasoline engine? A. The gasoline level B. The oil level C. The water level D. The timing - .......ANSWERS 🔷🖊✔✔B. The oil level The velocity of flow in a force main during "pump-on" condition should be about A. 0-1 fps B. 1-3 fps C. 3-6 fps D. 9-12 fps - .......ANSWERS 🔷🖊✔✔C. 3-6 fps Chemicals that may be used for corrosion control are A. lime, alum, permanganate, and soda ash B. Phosphate compounds, baking soda, lime, and soda ash C. Phosphate compounds, caustic soda, alum, and carbon D. Soda ash, activated carbon, and fluorides - .......ANSWERS 🔷🖊✔✔B. Phosphate compounds, baking soda, lime, and soda ash In the fall of the year, there is a 60*F change in temperature and you notice a creaking sound coming from one bearing. What would cause this problem?

A. Grease velocity too low B. Loose bearing cap nuts C. Loose fitting D. Movement between the cartridge and pillow block - .......ANSWERS 🔷🖊✔✔D. Movement between the cartridge and pillow block Maintenance required by liquid or capillary thermometers include checking for A. Corrosion B. Leakage C. Loose connection D. Low fluid level - .......ANSWERS 🔷🖊✔✔B. Leakage When filling the water tank on a high velocity cleaner from a fire hydrant, you should A. Be certain the fill hose extends well into the tank B. Be sure there is an air gap between the fill hose and the water level C. Only fill the tank 75% full D. Open the fire hydrant valve 50% so there will be pressure in the main to fight fire

• .......ANSWERS 🔷🖊✔✔B. Be sure there is an air gap between the fill hose and the water level If there is no spark at the plug of a gasoline engine, the most likely cause of the problem is A. Broken ignition cables B. Carburetor is flooded C. Poor grade gasoline D. Water is in the fuel line of the carburetor - .......ANSWERS 🔷🖊✔✔A. Broken ignition cables The parts of a centrifugal pump include the A. Diaphragm B. Piston

C. Rotor D. Volute - .......ANSWERS 🔷🖊✔✔D. Volute A condition exists where a large volume of flow is pumped against a low head with a centrifugal pump. This results in the motor getting too hot. The operator closes the valve on the discharge side of the pump so that 20% of the original volume of water is being pumped. Under this new contion A. The motor temperature would remain the same B. The motor temperature would be expected to increase C. The motor temperature would be expected to decrease D. It cannot be predicted what would happen to the temperature - .......ANSWERS 🔷🖊 ✔✔C. The motor temperature would be expected to decrease When repairing a pipeline, the depth of the pipeline can be roughly determined by A. Digging with a pick and shovel and checking every 12 inches B. Having an extra person watch the digging to immediately spot the main C. Opening a manhole and observing the depth to the top of the pipe D. Using a level - .......ANSWERS 🔷🖊✔✔C. Opening a manhole and observing the depth to the top of the pipe Which one of the following items does not need to be monitored during operation of an internal combustion engine> A. Air temperature B. Oil pressure C. Oil temperature D. Water temperature - .......ANSWERS 🔷🖊✔✔A. Air temperature Which part of a pipe is the most vulnerable to corrosion from septic wastewater in a gravity system? A. Bell B. Crown C. Flange bolts

D. Invert - .......ANSWERS 🔷🖊✔✔B. Crown To test is a 110 VAC outlet is hot, VOM for A. 100 amps B. 100 VAC C. 250 amps D. 250 VAC - .......ANSWERS 🔷🖊✔✔D. 250 VAC Which of the following should be the most important concern of an operator after a chemical spill? A. Aquatic life B. Clean up procedures C. Health related effects D. Consumer complaints - .......ANSWERS 🔷🖊✔✔C. Health related effects Thermal overload relays in motor starter use heater windings or coils to monitor or sense the A. Ambient temperature in the controller B. Amount of current drawn by the motor C. Operating voltage of the motor D. Temperature drop of the motor - .......ANSWERS 🔷🖊✔✔B. Amount of current drawn by the motor If a gasoline engine has a starting problem, the most likely cause of the problem is A. Dirt in the fuel lines B. Loose connecting rod bearing C. Low crankcase oil D. Sticking inlet valves - .......ANSWERS 🔷🖊✔✔A. Dirt in the fuel lines A centrifugal pump should not be run empty, except momentarily because

A. A serious counter pressure would be built up by excessive vacuum B. It is useless to run a pump without getting water C. The excessive end thrust of the shaft would damage the thrust bearing D. The parts lubricated by water could be damaged - .......ANSWERS 🔷🖊✔✔D. The parts lubricated by water could be damaged If a person comes into contact with chlorine and his/her eyes have been exposed to the gas, you should A. Apply a weak solution of boric acid to the eyes B. Flush eyes with a little water C. Flush the eyes with a lot of water for at least 15 minutes D. Keep their eyes closed and covered with a bandage - .......ANSWERS 🔷🖊✔✔C. Flush the eyes with a lot of water for at least 15 minutes Why do electric motors draw more power when being started than while being operated under normal conditions? A. The pipe friction losses are greater during start-up B. The motor and the attached load have to start moving C. The overload switch has to be deactivated D. Time is required for voltage to activate the magnetic field - .......ANSWERS 🔷🖊✔✔B. The motor and the attached load have to start moving Which of the following does not materially affect the friction loss in a given length of pipe? A. Velocity of the flow B. Roughness of the interior of the pipe C. Number of fittings D. Hardness of the water - .......ANSWERS 🔷🖊✔✔D. Hardness of the water Why would a centrifugal pump packing have a short life? A. There is dirt in the sealing liquid

B. the foot valve is partially clogged C. there is a foreign matter in the impeller D. the speed is too low - .......ANSWERS 🔷🖊✔✔A. There is dirt in the sealing liquid If a chlorinator is connected to the bottom valve of a one-ton cylinder that is 50% full, the chlorinator is withdrawing A. chlorine gas B. liquid chlorine C. liquid gas chlorine depending upon the temperature D. Nothing. There is only 1 connection - .......ANSWERS 🔷🖊✔✔B. Liquid chlorine A dramatic increase in engine cooling water discharge temp indicates a A. lack of filter combustion air B. lack of engine cooling C. lean air/fuel mixture D. low engine vacuum - .......ANSWERS 🔷🖊✔✔B. Lack of engine cooling When operating a wastewater lift station that has two identical pumps, it is best to adjust the controls so that A. one pump stays in operation with the second in reserve B. the pumps alternate in operation C. the pumps run together D. the pump operate alternating every 15 seconds - .......ANSWERS 🔷🖊✔✔B. The pumps alternate in operation What is the best measure of the organic strength of raw wastewater? A. the BOD test B. the pH test C. the residual chlorine test D. the suspended solids test - .......ANSWERS 🔷🖊✔✔A. The BOD test

An increase in the carbon dioxide content in water will A. increase turbidity B. decrease turbidity C. lower pH D. raise pH - .......ANSWERS 🔷🖊✔✔C. lower pH When lubricating electric motors, avoid A. high pressure needle point grease guns B. low viscosity lubricants C. mixing petroleum base grease with silicone base grease D. using automatic relief fittings - .......ANSWERS 🔷🖊✔✔C. Mixing petroleum base grease with silicone base grease Water should never be applied on a chlorine leak because it A. can cause an explosion B. can increase the size of the leak C. forms toxic gases with the water D. reduces the effectiveness of the chlorinator - .......ANSWERS 🔷🖊✔✔B. Can increase the size of the leak Which of the following gases is the most commonly associated with septic wastewater? A. carbon dioxide B. methane C. hydrogen sulfide D. carbon monoxide - .......ANSWERS 🔷🖊✔✔C. Hydrogen sulfide Which of the following pumps delivers liquid chemical solutions the most accurately? A. centrifugal B. diaphragm

C. turbine D. volute - .......ANSWERS 🔷🖊✔✔Diaphragm A preliminary practice used by industry to reduce the quantity of industrial wastes is A. equipment maintenance B. flow metering C. good record keeping D. recycling - .......ANSWERS 🔷🖊✔✔D. Recycling Which of the following is a positive displacement pump? A. air lift pump B. centrifugal pump C. reciprocating pump D. turbine pump - .......ANSWERS 🔷🖊✔✔C. Reciprocating pump Who is responsible for the failure of a municipal collection system safety program? A. workers in the collection system B. OSHA C. supervisor of the department D. public - .......ANSWERS 🔷🖊✔✔C. Supervisor of the department At times in collection system construction, it is necessary for a sewer line to temporarily drop below grade in order to pass under a creek, valley, or roadway. The device used to carry wastewater below the hydraulic gradient without interrupting flow is called a A. drop manhole B. junction structure C. lift station D. invert siphon - .......ANSWERS 🔷🖊✔✔D. Invert siphon

If the air receiver safety valve on an air compressor activates, the most likely cause of the problem would be A. air leaks B. a broken drive coupling C. a faulty dump valve D. worn rotor vanes - .......ANSWERS 🔷🖊✔✔A. Air leaks If a hard to start diesel engine will not rotate, the most likely cause of the problem would be A. air leaks B. exhaust valves are sticking C. improper lubricating oil viscosity D. low battery voltage - .......ANSWERS 🔷🖊✔✔B. Low battery voltage Centrifugal pump motor overloading may be caused by A. low flow B. low discharge pressure C. high flow D. high discharge pressure - .......ANSWERS 🔷🖊✔✔B. Low discharge pressure What are proteins, carbohydrates, and fats? A. aquatic matter B. ash C. inorganic matter D. organic matter - .......ANSWERS 🔷🖊✔✔D. Organic matter How should an operator clean roots from an 8 inch sewer line? A. Avoid using a rodder since a high velocity jet machine will wash the roots out better B. flush the line and then use a rodder

C. start from the upstream manhole with a full-sized root saw and trap the roots downstream D. use a 4 inch corkscrew going upstream - .......ANSWERS 🔷🖊✔✔C. Start from the upstream manhole with a full-sized root saw and trap the roots downstream A flow of 1 cubic foot per second is A. 2,794 gal/hr B. 3,600 gal/hr C. 6,000 gal/hr D. 27,000 gal/hr - .......ANSWERS 🔷🖊✔✔D. 27,000 gal/hr Why should an operator ground an electric drill? A. to eliminate sparking between the tip of the drill and the material being drilled B. to prevent accumulation of a static charge on the case C. to protect the user if the winding breaks down in the case D. to provide for the continued operation of the drill if the grounded line wire opened

• .......ANSWERS 🔷🖊✔✔C. To protect the user if the winding breaks down in the case What is the maximum allowable velocity in sewers? A. 1 fps B. 2 fps C. 5 fps D. 10 fps - .......ANSWERS 🔷🖊✔✔D. 10 fps What type of bacteria can grow with or without free dissolved oxygen? A. aerobic B. anaerobic C. facultative D. pathogenic - .......ANSWERS 🔷🖊✔✔C. facultative

Closing a valve too quickly causes A. a surge in the line B. no problem in distribution piping C. pipe fittings to become more secure D. dosage calculation problems - .......ANSWERS 🔷🖊✔✔A. A surge in the line The oscillating cutter is sharp and moves freely through stationary cutters without touching them. Solids passing through the screen are only partially cut or shredded. What most likely causes a comminutor problem? A. the oil level in the comminutor gear box is low B. not enough grit chambers are in use C. the cutting adjustment is improper D. the base seal is broken - .......ANSWERS 🔷🖊✔✔C. The cutting adjustment is improper Mechanical seals are being installed in pumps because A. packing requires an undesirable leakage that seals eliminate B. seals prevent cross-connection with the potable water C. seals will take more shaft misalignment that packing D. there is a shortage of good packing available on the market - .......ANSWERS 🔷🖊 ✔✔A. Packing requires an undesirable leakage that seals eliminate Which of the following best measures the rate of flow from a pumping station? A. a disc meter B. an orifice meter C. a parshall meter D. a venturi meter - .......ANSWERS 🔷🖊✔✔A. A venturi meter Which type of pipe material can be permeated by hydrocarbons? A. asbestos cement

B. ductile iron C. polyvinylchloride D. reinforced concrete - .......ANSWERS 🔷🖊✔✔C. Polyvinylchloride A standard O.S. & Y. is? A. An opposing side and wye branch B. a rising stem gate valve C. a special tapping machine D. a union galvanized according to AWWA standards - .......ANSWERS 🔷🖊✔✔B. A rising stem gate valve Which of the following has the greatest effect on the amount of oxygen dissolved in water? A. Chlorine residual B. Suspended solids C. temperature D. volatile acids - .......ANSWERS 🔷🖊✔✔C. Temperature What is most likely to cause corrosion or deterioration of metal and concrete surfaces? A. carbon dioxide B. ethanol C. hydrogen sulfide D. methane - .......ANSWERS 🔷🖊✔✔C. Hydrogen sulfide What is the last item to be checked before leaving a lift station? A. control switches in the right position B. cumulative running time metered C. electric meter reading D. oxygen deficiency meter reading - .......ANSWERS 🔷🖊✔✔A. Control switches in the right position

Which of the following is a major characteristic of wastes from a bakery? A. grease B. minerals C. phenols D. high temperature - .......ANSWERS 🔷🖊✔✔A. Grease Wear Rings are located A. around the seal cage B. around the thrust bearing C. inside the outboard bearing D. on the volute - .......ANSWERS 🔷🖊✔✔D. On the volute