Water distribution practice test D1 /D2 Correct 100%

The only absolutely reliable method of backflow prevention is the use of - ANSWER Air Gap The bubbles formed in a positive multiple tube fermentation test are - ANSWER Carbon Dioxide The maximum rate of withdrawal of gas from a 150lb chlorine cylinder in 24-hours is - ANSWER 40 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? - ANSWER Rotate the container to place the leak at the top The most commonly used water disinfectant in the United States is - ANSWER Chlorine When collecting a distribution system sample, the water should be allowed to run for a period of time prior to sample collection. How long - ANSWER As long as necessary to permit cleaning of service line Sample bottles wich are furnished by a certified laboratory for collection of bacteriological samples - ANSWER Are ready to use The difference between water pressure upstream and downstream of a pump when it is not in operations is know as the - ANSWER Total 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 - ANSWER Altitude valve In an occupied trench requiring personal egress what is the maximum allowable distance between a worker and an exit letter - ANSWER 25 feet A water bearing formation in the soil is referred to as - ANSWER An aquifer The distance between the static water level and the pumping water level is termed the - ANSWER Drawdown To prevent the entry of surface contamination into a well is the purpose of - ANSWER Sanitary seal The presence of coliform bacteria in a distribution system - ANSWER Indicates that pathogenic organisms may be present also The most common valve type in water distribution system is the - ANSWER Gate valve A Venturi is a device used to - ANSWER Measure water flow Backspin is occurring after well shut down this indicates - ANSWER A faulty check valve