Water Distribution Chapter 1 Questions and Answers 100% Correct., Exams of Water Resources Planning and Management

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Water Distribution Chapter 1 Questions

and Answers 100% Correct.

Chlorination is the most common means of disinfection used today to protect the public's health - ANSWER-True As water mains and reservoirs become older, they require less and less maintenance. - ANSWER-False Routine water quality monitoring of distribution systems consists of collecting samples at remote locations in the system and testing for chlorine residual and coli forms - ANSWER-True Existing contaminant limits mar be modified is EPA's ongoing research reveals new information about the effects of a particular substance - ANSWER-True Reservoirs that are not heavily used can be a source of taste, odor, and contamination problems - ANSWER-True When someone contacts you complaining that their drinking water looks muddy, taste bad, or smells bad, you need not be concerned. - ANSWER-False The lack of circulation in a dead end creates nearly ideal conditions for degrading water quality - ANSWER-True Ground waters are more susceptible to contamination than surface waters. - ANSWER- False A water supply that us satisfactory in quality for one purpose might be entirely unsatisfactory for another - ANSWER-True Chloramines are considered a more powerful disinfectant than chlorine. - ANSWER- False Under what conditions may water mains be located adjacent to sewer lines? - ANSWER-When physical conditions or soil conditions prevent minimum separation distances from being met How can corrosion be prevented on the insides of cement or metal pipes? - ANSWER- Line with asphalt or coal tar coatings

What influences the knowledge and skills required to work as a water distribution system operator in a given system? - ANSWER-The size and type of water distribution system What are organics? - ANSWER-Chemical substances that are based on the element carbon Why are chloramines more effective against biofilms than chlorine? - ANSWER-More persistent Why have drinking water quality standards been prepared and used? - ANSWER-Tp provide the needed quality control and ensure the acceptability of the product Why is water quality monitoring of distribution systems important? - ANSWER-to identify when and where water quality changes occur in the system. When water lines are being repaired, how can possible contamination of the water line be prevented? - ANSWER-Keep the hole dewatered What are pathogens? - ANSWER-disease causing organisms What is the primary responsibility of a water treatment plant? - ANSWER-to produce a safe and palatable water What is considered the greatest water quality nuisance? - ANSWER-Corrosion and precipitation of iron What types of consumer complaints can result from hydrant testing and flushing programs? - ANSWER-Dirty water complaints What is the purpose of adequate and reliable records? - ANSWER-To document the effectiveness of the operation What is every operators responsibility with regard to safety? - ANSWER-Be sure that the facilities are a safe place to work and that everyone follows safe procedures What should you do after investigating a drinking water complaint? - ANSWER-Notify the person who complained of the results and what corrective action was or will be taken What is the term for the treated water storage facilities at water treatment plants? - ANSWER-Clear wells What does the term water quality describe? - ANSWER-The composite chemical, physical, and biological characteristics of a water supply

What is one of the best results from a well-guided tour of water system facilities? - ANSWER-Gaining support to obtain the funds necessary to run a good operation What conditions in water main dead ends can produce carbon dioxide, methane, and sulfide odors? - ANSWER-Anaerobic What is backsiphonage? - ANSWER-a form of backflow caused by a negative or below atmospheric pressure within the water supply piping What could be the cause of milky water? - ANSWER-Air Who are a water supply systems ultimate consumers? - ANSWER-Homes Industrial water users Businesses Why may ground water require treatment? - ANSWER-To remove excessive hardness to remove iron and manganese to remove taste and odor causing substances What are possible causes of water quality degradation in water storage facilities? - ANSWER-1.Contamination entering through improperly maintained covers 2.Small animals that gain access through improperly screened overflows 3.Inadequate disinfection of reservoirs after construction or repairs 4.Failure in the side walls of below ground reservoirs 5.Materials introduced to uncovered reservoirs How may large variations in flow through a distribution system adversely affect water quality? - ANSWER-1.Low circulation and stagnant water can result in the growth of organisms, formation of sediments and corrosion products, depletion of oxygen, and increased taste and odors 2.Turbulence can entrain air into the supply causing milky water, which is objectionable to consumers

3. Changes in water velocity and flow reversals can result in sediments being stirred up and carried along until they reach the consumer Which items are typical duties of a water distribution system operator? - ANSWER- 1.Lay, connect, test, and disinfect water mains 2.Tap into water mains 3.flush and clean water mains 4.excavate trenches and install shoring 5.place barricades , signs, and traffic cones around work sites to protect operators and the public Which diseases are transmitted by internal parasites in water? - ANSWER- Cryptosporidiosis Giardiasis

Which types of constituents have limits under primary drinking water standards? - ANSWER-inorganic chemicals organic chemicals microorganisms disinfection byproducts Which factors may cause water quality degradation - ANSWER-Dead ends biological growth and activity time in the system cross connections corrosion Which supervision and administration tasks might be included in a water distribution system operators duties? - ANSWER-Giving advice on future planning keeping adequate reliable records giving advice on budget requirements training new operators encouraging operators to strive for higher levels of certification Which activities are potential safety hazards for water distribution system operators? - ANSWER-Painting facilities without adequate ventilation excavating for the installation or repairs of pipes working in traffic What are some components of a water distribution system? - ANSWER-Service lines meters network of pipes valves fire hydrants Which items are possible contamination sources for open reservoirs? - ANSWER- Atmospheric contaminants animals, including birds and rodents vandalism illegal bathing and fishing windblown contaminants Which operating procedures can result in water quality degradation in a distribution system? - ANSWER-Poorly performed water quality monitoring and flushing programs inadequate cross connection control insufficient surveillance to determine whether the protective features for storage facilities and mains are still adequate tolerance of low or negative pressures in the distribution system inadequate disinfection after repair or installation of new facilities

What are some critical elements of an effective water distribution system O&M Program? - ANSWER-1.developing a valve exercise program to ensure the proper setting and operation of valves

2. developing and maintaining an active corrosion control program 3.instituting an annual cleaning and lining program 4.developing a program to eliminate as many of the dead ends in the distribution system as possible Why is the iron precipitated by the iron bacteria Crenothrix of special concern in water distribution systems? - ANSWER-1. Reduces pipe carrying capacity 2.produces color in water
3. Forms deposits in pipes How can chemicals used at water treatment facilities cause water quality problems? - ANSWER-Chlorinating water containing organic materials results in the formation of THMs Which criteria must a domestic water supply meet to be considered of good quality? - ANSWER-Of such a chemical composition that it may be distributed without undue corrosive or scale forming effects on the water distribution system Under what conditions would water quality not change in the distribution system? - ANSWER-If the system were inert to water How can water in below-ground reservoirs be subject to contamination? - ANSWER- 1.from flooding by surface storm waters 2.from windblown contamination 3.from materials that enter through failures in the side walls 4.from vandalism