Water distribution system operation and maintenance Exam with correct detailed solutions

Water distribution system operation and maintenance Exam
|| || || || || || ||




with correct detailed solutions
|| || ||




Intrusion of seawater into ground water basins results from __________ - ✔✔Overpumping
|| || || || || || || || || || ||




fresh water
|| ||




What is stratification in lakes and reservoirs? - ✔✔Formation of separate layers of
|| || || || || || || || || || || || ||




temperature, plant life, or animal life. || || || || ||




What causes the elevation and slope of water tables and artesian pressure levels to change? -
|| || || || || || || || || || || || || || ||




✔✔Seasonal variations in the water supply.
|| || || || || ||




How extensive should the treatment be for reclaimed water? - ✔✔Depends on potential
|| || || || || || || || || || || || ||




exposure to the public. || || ||




The water distribution system must have sufficient capacity to meet __________ plus
|| || || || || || || || || || || ||




___________ and __________ throughout the system. - ✔✔Maximum water demands,
|| || || || || || || || || ||




firefighting requirements, maintain adequate pressures
|| || || ||




What is one difference between primary and secondary drinking water regulations? -
|| || || || || || || || || || || ||




✔✔Primary regulations are mandatory limits while secondary regulations are guidelines.
|| || || || || || || || ||




What is palatable water? - ✔✔Water at a desirable temperature that is free from
|| || || || || || || || || || || || || ||




objectionable tastes, odors, colors and turbidity. || || || || ||




Factors that may cause water quality degradation are ____________ - ✔✔Cross
|| || || || || || || || || || ||




connections, corrosion, biological growth and activity, high temperature,unusual flows,
|| || || || || || || || ||




time in system, dead ends, age of facilities or operational procedures.
|| || || || || || || || || ||

,Once groundwaters are contaminated, it normally takes a considerable amount of time
|| || || || || || || || || || || ||




before they recover because of _________ - ✔✔The slow movement of water in the ground.
|| || || || || || || || || || || || || ||




What are 2 causes of back flow through a cross connection? - ✔✔Back pressure and back
|| || || || || || || || || || || || || || || ||




siphonage.



Which form of chlorine is most effective against biofilms? - ✔✔Chloramines
|| || || || || || || || || ||




Careless operating procedures that contribute to the degradation of water quality in a
|| || || || || || || || || || || || ||




distribution system include _______ - ✔✔Inadequate cross connections controls, poorly
|| || || || || || || || || ||




performed water quality monitoring and flushing programs, tolerance of low or negative
|| || || || || || || || || || || ||




pressures in system, insufficient surveillance of storage facilities and mains, inadequate
|| || || || || || || || || || ||




disinfection after repair or installation, disregard for hazards of installing facilities in close
|| || || || || || || || || || || || ||




proximity to water lines || || ||




What influences the potential for corrosion in metal or asbestos pipe that is lined with
|| || || || || || || || || || || || || || ||




asphalt or coal tar? - ✔✔Integrity of the coating
|| || || || || || || ||




How often should reservoirs be inspected? - ✔✔At least 2 times per month.
|| || || || || || || || || || || ||




Why are uncovered reservoirs often prohibited? - ✔✔They are subject to contamination
|| || || || || || || || || || || ||




from many sources.
|| ||




What is an important aspect of a tank inspection and maintenance program? - ✔✔Ensuring
|| || || || || || || || || || || || || ||




adequate turnover of water in the tank. || || || || || ||




Why should an O&M (operation and maintenance) program include exercising valves? -
|| || || || || || || || || || || ||




✔✔To ensure proper setting and operation.
|| || || || ||

, What is the responsibility of water treatment plant operators? - ✔✔To produce safe and
|| || || || || || || || || || || || || ||




pleasant drinking water. || ||




What do most states require for someone to work as a water treatment plant operator? -
|| || || || || || || || || || || || || || || ||




✔✔An operator certificate or license.
|| || || ||




What contributes to most treatment plant accidents? - ✔✔Carelessness and negligence.
|| || || || || || || || || ||




One of the benefits of storing water in a distribution system is that the system __________
|| || || || || || || || || || || || || || || ||




and __________ are improved and stabilized, providing better ____________ to customers.
|| || || || || || || || || || ||




- ✔✔Flows, pressures , service
|| || || ||




Which type of storage facility is used for filtered water from water treatment plants? -
|| || || || || || || || || || || || || || ||




✔✔Clear well ||




What is the primary purpose of elevated tanks? - ✔✔To maintain adequate and fairly
|| || || || || || || || || || || || || ||




uniform pressure to a service area. || || || || ||




Why should reservoirs be covered? - ✔✔To reduce the possibility of contamination
|| || || || || || || || || || ||




How do surge arrestors protect piping systems from hydraulic transients? - ✔✔By
|| || || || || || || || || || || ||




controlling unusual velocity changes || || ||




Selection of a storage facility or tank depends on the systems __________ and the
|| || || || || || || || || || || || || ||




____________ where it will be installed. - ✔✔Individual needs, type of terrain || || || || || || || || || || ||




What is an advantage of using surge control valves in a water distribution system? -
|| || || || || || || || || || || || || || ||




✔✔Easy to fit into plant. || || || ||