Water Distribution Exam Questions and Answers 100% Pass

Water Distribution Exam Questions and Answers 100% Pass A noisy or vibrating valve may be an indication of what? Cavitation The selective destruction or inactivation of pathogenic organisms is Disinfection Pathogenic organisms can be removed from water, killed, or inactivated by Filtration The most commonly used distribution system disinfection is Free chlorine A greenish- yellow gas with a penetrating and distinctive odor, two and a half times heavier than air is Chlorine A brief session to discuss aspects of a job and safety Tailgate safety meeting The most common means of disinfecting drinking water used today to protect the public's health? Chlorination What is the responsibility of water distribution system operators? Ensure safe and pleasant drinking water is delivered to everyone's tap A valve that automatically shuts off the flow into an elevated tank when the water level in the tank reaches a predetermined level. Altitude valve A pump consisting of an impeller fixed on a rotating shaft, that is enclosed in a casing, and having an inlet and a discharge connection would be called Centrifugal pump What is the MAIN purpose of a water storage facility? To provide sufficient supply of water to average daily demands on the water supply system When is the best time to take a storage tank out of service? When consumption is lowest Gauges are commonly used on which side of a pump? Discharge side A condition which atmospheric or dissolved molecular oxygen is present in the aquatic environment is called Aerobic What is palatable water Pleasing to the senses (tastes, odors, colors, and turbidity) All trenches must be effectively shored at ____ ft. or deeper 5ft OSHA defines____________ as a person capable of identifying existing hazards in the surroundings, or working conditions which are unsanitary, hazardous or dangerous to employees, and who has authorization to take prompt corrective measures to eliminate the hazards. Competent person Instead of shoring, a trench may be sloped at what ratio? 2 :1 In what direction should the bell of a pipe be pointed when laying pipe downhill? Uphill When should the first lift of backfill be compacted when laying pipe? Up to the horizontal centerline of the pipe What is the most common type meter used for domestic services? Nutating Disc The combination of the displacement type (low flow) and velocity type (high flow) meters are called a _____________ meter. Compound meter In what year was the Safe Drinking Water Act passed? 1974 What is the available chlorine of calcium hypochlorite? 65% A reverse flow condition, created by a difference in water pressures which causes water to flow back into the distribution system is referred to as what? Backflow The maximum height in which water will rise in a perfect vacuum above a free surface of water is: 33.9ft Backflow that is caused by a sub atmospheric or negative pressure within a water system is known as: Backsiphonage A backflow prevention assembly that consists of two independently acting approved check valves together with a hydraulically operating, mechanically independent pressure differential relief valve located between the check valves would describe a Reduce pressure principle assembly The unobstructed vertical distance through free atmosphere from the tip of a supply outlet or faucet supplying water to a tank or other receiving vessel and the flood level rim of the receptacle is called a/an: Air gap About ____% or more of the storage capacity of the distribution system should normally be reserved for fire demand and emergency use. 35% Sodium Hypochlorite contains approximately ______% available chlorine. 5 to 15% Who is responsible for setting drinking water standards and ensuring their enforcement? U.S. EPA What year was the Safe Water Drinking Act amended? 1986 A new well must be disinfected at the well, pump and screen with a ____mg/l solution. 50 Before disinfecting mains you must first ______ them. Flush When flushing mains you must flush with a minimum velocity of at least ____ft/sec. 2.5 The maximum rate of chlorine removal from a 150lb cylinder is ___lbs per day or freezing will occur. 40 The 1991 Uniform Fire Code states that the exhaust fan for chlorine must be taken from A point within 12 inches from the floor Death can occur after a few deep breaths at what exposure rate? 1000ppm A __________ has limited means for entry or exit, is not designed for continuous occupancy and is large enough that an employee can enter to perform work. Confined space Before entering a confined space you must first ________. Test atmosphere How far above the excavation must a ladder extend? 3 ft How often must excavations be inspected? Daily What are clear wells? Storage facilities for treated water at water treatment plants What is the most common means of disinfecting drinking water used today to protect the public's health? Chlorination Why do surface waters require treatment? To remove, kill, or inactivate disease causing organisms What do turbidity units measure? The cloudiness of water The U.S. National Primary Drinking Water Regulations is regulated at which level Federal What is the absolute minimum pressure a water main should be taken down to before a boil water advisory is issued? 20 psi What are the separations of water and sewer lines when being laid in the ground? 10' horizontal and 1' vertical What is the most common form of cross connection? A garden hose Continuous pressure is considered to be: Constant water system pressure of 20 psi A phrase used in determining whether the substance in a non-potable system is toxic or non-toxic: Degree of hazard The most common consumer complaint is: Red water A chemical with a pH of 12.0 is considered: Basic