Water distribution practice test D1 /D2 Questions & Answers

The only absolutely reliable method of backflow prevention is the use of - ANSWERSAir Gap The bubbles formed in a positive multiple tube fermentation test are - ANSWERSCarbon Dioxide The maximum rate of withdrawal of gas from a 150lb chlorine cylinder in 24-hours is - ANSWERS40 lbs If you encounter a liquid chlorine leak in a one tone container, what action should you take first, to reduce the severity of the leak? - ANSWERSRotate the container to place the leak at the top The most commonly used water disinfectant in the United States is - ANSWERSChlorine When collecting a distribution system sample, the water should be allowed to run for a period of time prior to sample collection. How long - ANSWERSAs long as necessary to permit cleaning of service line Sample bottles wich are furnished by a certified laboratory for collection of bacteriological samples - ANSWERSAre ready to use The difference between water pressure upstream and downstream of a pump when it is not in operations is know as the - ANSWERSTotal static head A device that automatically shuts off flow in an elevated storage tank when the water level in the tank reache a preset level is termed a - ANSWERSAltitude valve In an occupied trench requiring personal egress what is the maximum allowable distance between a worker and an exit letter - ANSWERS25 feet A water bearing formation in the soil is referred to as - ANSWERSAn aquifer The distance between the static water level and the pumping water level is termed the - ANSWERSDrawdown To prevent the entry of surface contamination into a well is the purpose of - ANSWERSSanitary seal The presence of coliform bacteria in a distribution system - ANSWERSIndicates that pathogenic organisms may be present also The most common valve type in water distribution system is the - ANSWERSGate valve A Venturi is a device used to - ANSWERSMeasure water flow Backspin is occurring after well shut down this indicates - ANSWERSA faulty check valve A ph reading of 6.0 units indicates the water sample is - ANSWERSSlightly acidic Chlorine gas - ANSWERSIs heavier than air The change in what're demand during the course of a day is called - ANSWERSDiurnal variation Catholic protection is a system used for - ANSWERSMetallic corrosion inhibition The elevation of the free surface in a water table well wich is not running is called - ANSWERSStatic water level The maximum momentary load placed on a water supply system is known as - ANSWERSPeak demand Most below ground level storage tanks are constructed of - ANSWERSConcrete Hey bacteriological sampling bottle should be - ANSWERSFilled carefully to leave a small air space When fully open, wich of the following will have the lowest friction loss - ANSWERSGate valve Enclosed, open, and smi closed are terms used for the designation and selection of - ANSWERSImpellers