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Class D Water Exam Illinois| Already Passed
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For a water storage tank, cathodic protection is only effective for the: tank areas covered by water For a water storage system, the purpose of an altitude valve is to prevent: overflows Before using a water storage tank that has been disinfected, water from the tank must not show the presense of: coliforms High trihalomethane (THMs) levels may cause: cancer A finished water with a negative Langelier Index may be: corrosive Water with pH scale less than 7 is considered: acidic pH scale of 7 is considered neutral pH scale of 8-14 is considered? basic How many gallons of water are in 1 cubic ft?
7.48 gallons How many gallons of water are in 15 cubic ft? 15 x 7.48 = 112.2 gallons How many cubic ft of water is 20 gallons? 20/7.48 = 2.67 cubic ft 1 gallon of water equals how many lbs? 8.34 lbs 16 gallons of water is how many lbs? 16 x 8.34 = 133.44 lbs A 180 ft water tower would show what psi on the gauge located at the base? 180/ 2.31 = 77.92 psi Pump cavitation is most likely to occur when: the top of the water source level is lower than the impeller 1 pound per square inch is equal to how many feet of elevated water? 2.31 feet For most centrifugal pumps, if the total dyanmic head decreases, the pump will: pump water at a faster rate in gpm. (less head to push against) The velocity of water is measure in:
(19,625 cubic ft/1hr) x (7.48 gal/1 cubic ft) = 146,795 gal per HR 60 mins = 1 HR 146,795/60= 2,446.58 GPM The IEPA requires that routine bacteria samples be taken and analyzed how often? Every month When taking a bacteria sample, the sample bottle should be filled with water: to the 100mL line While taking a bacteria water sample, what should also be done at the same time and location? chlorine residual test What is a chlorine residual and what does it show? The actual amount of chlorine remaining in the water to act as a disinfectant. Indicates that a sufficient amount of chlorine was added to the water to inactivate bacteria and some viruses. If coliform bacteria are found in a water sample. This indicates that: repeat samples should be taken. human or animal feces are present. Sodium thiosulfate is added to Bac-T sampling bottles in order to: neutralize any chlorine in the sample For bacteria contamination, if repeat samples are required, they should be taken: within 24 hours
Which backflow preventer is most likely to be installed as part of a water service line for a single family home? dual check If practical, water mains should be how far above sewer lines? 18 inches Which water meter is most likely to be used for a single family home? Displacement meter Older water meters for a single family home are most likely to? under register Water storage system that uses compressed air to increase water pressure: Hydropneumatic During pump operation, should water lubricated pump packing leak? Yes, at a steady dripping rate A dry chemical that is 65% available chlorine is being used to provide a 50 mg/l disinfection dosage to a completely full 95,000 gallon water storage tank. Approximately how many pounds of chemical are need? 61 lbs dry chemical use pounds formula 95,000= 0.095 MG
A negative Langelier Index means the finished water is: corrosive A Langelier Index of 0 (zero) means the finished water is: stable A water with a pH of 8 would be considered to be: basic A positive Langelier Index can be produced by adding: caustic soda (Sodium Hydroxide NaOH) The action level for lead is: 0.015 mg/l Lead and Copper testing is done on samples from residential kitchens or baths after: after the water has been standing in the line for at least 6 hours The action level for copper is: 1300 ug/l (parts per billion) (or 1.3 mg/l) A bacteria water sample must be mailed so that the labe analysis can begin no later than: 30 hours after the sample was collected
To determine if water is safe to drink in regard to bacteria content, a lab takes a minimum of: 24 hours If a water sample shows the presence of coliform bacteria, how many repeat samples should be taken? 3 repeat samples If a water sample shows the presence of coliform bacteria, what follow up testing is done on the sample? E. Coli test If the E. Coli test is positive, what has been indicated from the sample? Recent contamination from human or animal waste A boil order should be issued whenever the following type of water contamination is suspected: Bacteria contamination During a boil order, drinking or culinary water should be boiled for at least: 5 minutes When collecting a total coliform sample, it is considered good practice to: hold the cap with the threads facing down (less chance of airborne bacteria contamination)
Water high in nitrates can cause? Methemoglobinemia (Blue Baby Disease Total Dynamic Head is: The sum of all the energy needed to move water from one elevation to another. Includes static head, velocity head, and head loss due to friction What is a primary indicator of bearing failure on a water pump? Noise from pump What is atmospheric pressure at sea level? 14.7 psi What is the difference between a Primary and Secondary standard in drinking water? Primary Standards are a threat to public health. Secondary standards are not. The Safe Drinking Water Act defines a public water system that supplies piped water for human consumption as one that has... 15 Service connections or serves 25 or more people for 60 or more days a year What can be done to prevent cavitation from occuring? Reduce the suction lift What gauge is used to perform hydrant flow testing? Pilot Gauge What is applied to electrodes place in the water of a water storage tank?
DC Current When flushing a water main in response to a water quality complaint, always flush at what velocity? Low velocity At what depth is trench protection equipment required? trench depth 5' or greater What is the maximum psi downstream of a service meter? 80 psi If a gauge reads 49 psi at the base of tower, how high is the water level in the tower? 113 feet 49 x 2. What should the pressure gauge at the base of a tower read, if the water level is 90 feet above the gauge? 38.96 psi 90/2. An overflow pipe from a water storage tank should end: 12 to 24 inches above the ground Closing a hydrant too fast will cause: water hammer
under the packing Pump wear rings are located on or close to the impeller Wat part may be the cause of a pump producing less gallons per minute? wear rings A lantern ring would be located in the: stuffing box During pump operation, water lubricated mechanical seal should? not leak any water Water flow from a stuffing box may be controlled by: tightening or loosening the packing gland The purpose of a slinger ring is to: keep water from running down the shaft and into the motor When a pump is primed? air is replaced by water inside the volute The purpose of a pump foot valve is to? keep the pump primed A pump foot valve would be located? near the bottom of the suction piping Before starting a centrifugal pump:
the volute should be full of water What device keeps water from returning to the pump and causing the shaft to rotate in reverse? check valve When increasing the hertz on a VFD by adjusting the potentiometer, what will be the result? more gpms When starting a positive displacement pump, how should the operator adjust the valves? suction open and discharge open For an operating pump, the suction side gauge reads 8.7 psi and the discharge gauge reads 30.5 psi. What is the total dynamic head against this pump?
30.5-8.7=21.8 psi 21.8 x 2.31 = 50. For an operating pump, the suction gauge reads 9.5 inches of Hg and the discharge gauge reads 30.5 psi. What is the total dynamic head against this pump?
9.5 x 1.13' = 10.7'
79,269 gallons 30 x 30 x .785 x 15 x 7. The purpose of the an air line on a well is to? determine the water level The drawdown of a well is determined by: the difference between the statis and pumping level
