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distribution exam
card set to study for water distribution exams
| Question | Answer |
|---|---|
| Turbidity | The cloudy appearance of water caused by the presence of suspended and colloidal matter. |
| Head | The vertical distance, height, or energy of water above a reference point. |
| Raw Water | Water in its natural state before any treatment. |
| A Distribution System | Consists of a network of pipes, valves, fire hydrants, service lines, meters and pump stations. |
| Backflow | A reverse flow condition, created by a difference in water pressures, that causes water to flow back into the distribution system, from a source or sources other than the intended source. |
| Backsiphonage | A form of backflow caused by a negative or below atmospheric pressure within a water system. |
| What are the two major sources of of water supply? | Groundwater and surface water. |
| Early planning and budgeting will contribute greatly to the smooth operation of a distribution system? True or False | True |
| What is palatable water? | Water at a desirable temperature that is free from objectionable taste, odors, colors and turbidity. |
| What are the two causes of backflow through a cross-connection? | Back pressure and Backsiphonage. |
| A connection between a drinking water system and an unapproved water supply or between a storm drain system and sanitary collection system. Is called? | A cross-connection |
| What form of chlorine is most effective against biofilms? | Chloramines |
| How often should reservoirs be inspected? | At least twice a month. |
| Carelessness and negligence contribute to most workplace accidents? True or False | True |
| What is the responsibility of water treatment plant operators? | Produce safe and pleasant drinking water. |
| Peak Demand | The maximum momentary load placed on a water treatment plant, pumping station, or distribution system. |
| What are two of the six types of water storage facilities? | Any: clear well, elevated storage tank, standpipe, ground-level service storage reservoir, hydro-pneumatic/pressure tank, surge tank. |
| A group of bacteria found in the intestines of warm-blooded animals, plants, soil, air and water? | Coliform |
| What is a hydrant's primary function? | Fire Protection |
| Altitude Valve | A valve that automatically shuts off the flow into an elevated tank when the water level reaches a predetermined level. |
| A pump consisting of an impeller fixed on a rotating shaft that is enclosed in a casing, with inlet and discharge connections? | Centrifugal Pump. |
| Cathodic protection | An electrical system for prevention of rust, corrosion, and pitting of metal surfaces, that are in contact with water, wastewater, or soil. |
| Name three types of maintenance used to maintain the distribution system. | Preventive, Predictive, Corrective. |
| What do turbidity units [TU's] measure in water? | Cloudiness of wtaer. |
| What is the main function of a Distribution storage facility? | To take care of daily demands and peak demands. |
| Surge arrestors | Help control unusual velocity changes. |
| Why should reservoirs be covered? | To reduce the possibility of contamination. |
| Clear Well | Type of storage facility used for storing filtered water from treatment plants. |
| Where should a water system store nameplate data? | With equipment records. |
| Dissolved Oxygen | Substance in water that increases the rate corrosion in storage facilities. |
| Value that indicates the smoothness of the interior of a pipe? | C Factor |
| Appurtenance | Machinery, appliances, structures and other parts of the distribution main necessary to system operation. ex... hydrants. |
| Water Hammer | When a valve is opened rapidly, the rise and fall pressure can cause serious damage to the system. |
| Static Head | Vertical distance from a reference point to the water surface, when the water is not moving. |
| Why should construction of dead-end water mains be avoided? | Prevent the development of undesirable tastes and odors. |
| Type of valve that has a movable disc as large as the diameter of the pipe? | Butterfly Valve |
| First choice of methods to protect pipe from corrosion? | Proper use of noncorrosive metals and mechanical coatings. |
| When installing a water main parallel to sanitary sewer, what is the recommended horizontal separation, in feet? | 10 feet |
| Velocity meter types? | Turbine, propeller, venturi, electronic, insertion |
| Displacement meter types [low flow]? | Nutating-disc, piston |
| Hydrant Uses? | fight fires, flush pipelines, and to provide water for construction needs or water trucks. |
| What is the primary function of a water meter? | Measure and display the amount of water passing through it. |
| Nutating-disc meter | The most commonly used meter on small diameter domestic water services. |
| The two most commonly used types hydrants in distribution systems? | Dry-barrel and Wet-barrel |
| List five types of valves: | Rotary, butterfly, plug, gate, and globe |
| List water main pipe types: | Ductile-iron, cast-iron, steel, concrete, asbestos-cement and plastic [PVC] |
| What health issues does Turbidity cause? | Reduces effectiveness of chlorine against disease causing organisms. |
| List four possible causes of taste and odor problems within the distribution system? | High chlorine residual, biological growths, microorganisms and dead end mains or tanks. |
| What is preventive maintenance? | The repair or adjustment of equipment and facilities, that is done before deterioration takes place. |
| What is corrective maintenance? | Maintenance that is necessary when a problem already exists. ex... main break |
| Compound Meters | Used when water flow fluctuates widely. Compound meters are a combination of displacement and velocity type meters, to track the high and low flow. |
| Corporation Stop | A water service shut off valve located at the water main, buried cannot be operated from street level, no valve box. |
| Curb Stop | A water service shut off valve located on the water service, located near the curb between the main and the building it serves. |
| Emergency response plans must be developed in response to failures of pumps, mains, and tanks? True or false | True |
| Cathodic protection is regarded as a substitution for the use of a proper interior coating or application of chemical inhibitors? True or False | False |
| A small amount of packing gland leakage helps cool the pump shaft and reduce premature packing wear and scored shaft sleeves? True or false | True |
| Chlorinated waters used to disinfect a storage tank may be discharged to any surface waters without obtaining approval from the appropriate water pollution control agencies? True or False | False |
| When a water storage tank is taken out of service, provisions must be made so that the distribution system will be able to meet the water demands of its customers? True or False | True |
| Corrosion only occurs on the inside of the metal surface of a storage facility? True or False | False |
| Where are backflow prevention devices normally installed when used? | Backflow prevention devices, when used, are normally installed at the service directly downstream of the meter. |
| What factors should be considered when selecting a suitable backflow device for a given situation? | Degree of hazard, probability of backflow occurring, complexity of the piping system, and probability of the piping being modified. |
| What is the objective of distribution system maintenance? | Ensuring proper equipment operation and maintenance will keep the system operating smoothly and extend the useful life of the system. |
| How often should valve boxes be inspected? | Valve boxes and other valve appurtenances should be inspected at least annually to determine if they are damaged, filled with dirt, or covered by pavement. |
| When should air release valves/ air-vacs be inspected? | After rains or floods to ensure they are not submerged in drainage waters or storm water and that they work properly. |
| Tuberculation | Formation of small mounds of corrosion, inside of iron pipe, these tubercles increase the roughness on the inside of the pipe, this restricts water flow and decreases the C factor of the pipe. |
| Prime | The action of filling a pump casing to remove the air. Most pumps must be primed before startup or they will not pump water. |
| Pitot tube | An instrument used to measure fluid, liquid or air velocity by means of the differential pressure between the tip [ dynamic ] and side [ static ] openings. |
| Hydraulic Gradient | The slope of the grade line. This is the slope of the water surface of the groundwater table, or the slope of the water pressure for pipes under pressure. |
| What types of joints are commonly used for ductile-iron pipe? | Mechanical, push-on joints, flanged, restrained, flexible and sleeve joints. |
| What types of joints are used to join steel pipe? | Bell and Spigot [ welded, or rubber gasket type ], Harness Joint, Carnegie Shape Rubber Gasket Joint, Butt-Welded Joint, Butt Strap Joint for Welding. |
| What are the three basic design configurations for a distribution system? | Arterial- Loop system, Grid system, and Tree system |
| Where are bacteriological samples for coliforms taken? | At points that are representative of the conditions in the distribution system. |
| A chlorine residual of about 0.2 mg/L measured at the extremities of the distribution system is a good indication, of what? | That an acceptable free chlorine residual is present in all other parts of the system. |
| A water supplier should try to maintain minimum pressure of what, at all points of the distribution system? | A minimum pressure of 35psi with an absolute minimum of 20psi even during fire flows. |
| Commercial districts, psi range? | 75psi and higher are used, but should exceed 100psi. |
| How can a frozen water main be thawed out? | Electrical thawing methods, hot water, or blowing steam into frozen pipes. |
| Why is the freezing of service lines a greater problem than with mains? | They have less ground cover and are smaller in diameter. |
| What precaution should be taken when thawing pipe using electrical methods? | Remove any electrical grounds that are connected to the pipe in that building. |
| Cavitation? | Formation and collapse of a gas pocket or bubble on the blade of an impeller or gate of a valve, with terrific force that knock metal particles off causing pitting, accompanied by loud noises that sound like a pounding hammer on the impeller or gate. |
| What information should be recorded on a water quality complaint form? | Date and time, location, complete description of the probelm. |
| What factors could cause taste and odor complaints in a local area of a distribution system? | Chlorine residuals above or below normal, low flow due to low demands ex.. dead end mains, or a cross connection. |
| When should should fire hydrants be inspected? | Twice a year and after use |
| What happens when a dry barrel hydrant is operated with the valve partially open? | The drain will partially open, water will seep through the drain, saturate the drain field, and could result in damage due to freezing. |
| How are meter registers driven? | mechanically or magnetically |
| Why are coupons installed in water mains? | Steel coupons are installed in metal pipe mains to indicate the rate of corrosion. |
| How can water utilities avoid serious valve operating problems? | By creating a comprehensive program of valve inspection, exercising, and maintenance. |
| Why should valves be exercised regularly? | Determine if the valve works, extend valve life, help clean encrustations from the valve seats and gates. |
| What is the purpose of a sanitary sewer survey? | Purpose of a survey is to detect all health hazards and to evaluate their present and future importance. |
| List the common physical characteristics of water. | observable color, turbidity, temperature, taste, odor. |
| Why are coliform bacteria used to measure the bacteriological quality of water? | Coliform tests are used because the test indicates the fecal contamination where specific disease-causing organisms are not easily isolated and identified. |
| Who must comply with the safe water drinking act [ sdwa ] regulations? | All public water systems must comply. |
| What are the provisions to prevent contamination of water sources in the sdwa? | (1) the contaminant might have adverse health effects; (2) there is substantial likelihood that the contaminant will occur in public water systems at levels of public health concern; and (3) its regulation will reduce public health risk |
| In a distribution system what elements should be considered for a surveillance program. | Vandalism, storm damage, reservoirs, underground and above ground storage tanks, pump stations and valves. |
| What has caused more waterborne disease outbreaks in the united states than any other reported factor? | Cross Connections. |
| Samples are routinely collected from a distribution system for kinds of tests? | Coliform bacteria, Turbidity, Total trihalomethanes, Chlorine residual, Physical quality (tastes and odors), Lead and Copper |
| Why do utilities attempt to maintain chlorine residuals throughout the distribution system? | To protect public health, control coliform, after growths, and to serve as an indicator that the water is free from contamination. |
| What types of cross connection control devices are recommended where there is a health hazard? | Air gap separation, Reduced pressure principle backflow device |
| Why should a distribution system be under continuous positive pressure at all times? | To meet customer needs and to prevent contamination from backflow. |
| What types of checks should be performed on bearings? | Temperature, noise, and proper lubrication. |
| What type of pipe maintenance is performed by distribution system operators? | Repairing, Flushing, Cleaning, Disinfecting, and Relining. |
| What causes pipe deterioration? | On the inside because of water corrosion and erosion, and on the outside due to corrosion from aggressive soils and moisture. |
| Where can Leaks originate? | Weakened joints or fitting connection, or from damaged or corroded parts of a pipe. |
| Why are water audits conducted? | When no specific reason can be found for a significant water loss in the system. |
| How can buried nonmetallic pipes be located? | using a probe and driving it into the ground until you find the pipe, placing a tracer wire which is traceable by locators on top of the pipe before it is buried. |
| What is wet tapping? | A procedure for making a service connection while the water main is under pressure. |
| Water carries biological life forms which can cause diseases? True or False | True |
| Chlorine disinfects water much faster at a ph around 8.0 than ph of 7.0? True or False | False |
| Longer contact times are required to disinfect water at higher temperatures? True or False | False |
| The use of hypochlorite to treat potable water achieves the same result as chlorine gas? True or False | True |
| A precipitate on valves dissolves when calcium and chloride ions combine? True or False | False |
| Chlorine gas tends to raise the ph and hypochlorite tends to lower ph in water? True or False | False |
| Public water supplies are normally chlorinated to the breakpoint? True or False | True if free chlorine is used in the distribution system. False if chloramination is used in the distribution system. |
| When a new well is completed, it is necessary to disinfect the well, pump, and screen? True or False | True |
| The chlorine injection should never be on the intake side of the pump because it will cause corrosion problems in the pump? True or False | True |
| Always add acid to water, never in the reverse? True or False | True |
| Coliform tests results should be positive when the chlorination system is operating properly? True or False | False |
| What is disinfection? | Selective destruction or inactivation of pathogenic organisms. |
| Why has there been increased interest in disinfectants other than chlorine? | Because of the carcinogenic compounds that chorine may form. |
| What is a limitation of using ultraviolet rays for disinfection of waters conveyed in distribution systems? | Lack of measurable residual |
Created by:
bjuice73