D2 water distribution test questions and answers graded A+

D2 water distribution test questions and answers graded A+ What is the primary purpose of the SDWA? To create uniform national standards for drinking water quality Who sets Maximum Contaminants Levels (MCLs)? USEPA What are some of the duties of the EPA? Sets MCLs, delegates enforcement of SDWA to state agencies, provides grant funds, monitors state activities, provides continued research What is state primacy? Giving the authority to the state to implement and enforce regulations True or False: State requirements must be at least as stringent as those set by USEPA True. A public water system is a system that supplies piped water for human consumption and that has at least ___ service connections or serves ___ or more persons for ___ or more days of the year. 15, 25, 60 What is an nontransient, noncommunity public water system? Give an example of one. Establishments with their own private water systems that serve an average of 25 persons that do not live at the location, but the same people use the water for more than 6 months per year. Example: school or factory What is a transient, noncommunity public water system? Give an example of one. Establishments with own water system and serve at least 25 persons a day but these people only use the water occasionally and for short periods of time. Example: Motel or Park What is a community public water system? Give an example of one. Establishments with their own water supply that serve more than 15 homes. Example: HOA, or municipal water utilities Which of the public water systems are required to only monitor for nitrate, nitrite, and microbiological contamination? transient, noncommunity What does the National Primary Drinking Water Regulations (NPDWRs) specify? MCLs or a treatment technique requirement for contaminants that may be found in drinking water and could have an adverse health effect on humans What does the National Secondary Drinking Water Regulations (NPDWRs) specify? water contaminants that may adversely affect aesthetic qualities of the water such as taste, odor or color When must an agency post a public notification? When the water system violates any of the operating, monitoring or reporting requirements or if they exceed the MCL Lead and Copper Rule (LCR) Requires that samples be collected at customers taps after the water has remained undisturbed in the water piping for at least 6 hrs True or False: system operators are required to regularly collect and test water samples. true True or False: Water quality cannot change after it enter the distribution system. false -blending, season, operational changes What are the 4 methods of collecting samples? Grab sample, composite sample, time composite sample, flow-proportional composite sample What is a grab sample? A single sample at a single location What is a composite sample? A series of grab samples at one place and at different times What is a time composite sample? Equal volumes at regular intervals What is a flow proportional composite sample? Adjusting the sample size proportional to the flow How do you select a sample point? As close to the main as possible True or false: It is required for samples to be taken from groundwater under the direct influence of surface water. true What are Sanitary Surveys? On site annual inspection of a water system's facilities and operation. What are some the requirements that the State establishes to ensure proper water system operation? Operator Certification, sanitary surveys, enforcement What are the 3 main areas of concern to distribution operators? microbiological safety, disinfection by products, lead Total coliform rule to require surveillance of total coliform bacteria When you have a positive sample for coliform you need to take another test within ___hrs? 24 What are the different disinfectants? physical and chemical What is hardness? the measure of the concentration of calcium and magnesium in water What type of iron bacteria causes red water, taste and odors, clogged pipes and pump failure? Gallionella What is the secondary drinking water standards suggest the limit of iron be in water? 0.5mg/L Does very hard or very soft water cause scaling to form in plumbing fixtures and cooking water? hard water What must the turbidity be equal to or less than in measurements taken each month? 0.5 ntu What chemical is not harmful to humans but stains washed clothes and plumbing fixtures black? manganese What is necessary to prevent backsiphonage and the entry of contaminants? continuous positive pressure What are the 4 water quality safeguards? continuous positive pressure, maintenance of chlorine residual, cross connection control, frequent testing What is a DPD? a chlorine residual test that is quick and simple and can easily be performed at points in the system other than the regular sampling points if there is any question of water quality What are the main concerns for water quality of water entering the distribution system? iron and manganese from well water what are the 3 main objectives for system operations? quality, pressure and flow what forms Disinfection By Products?(DBP) THM between chlorine in water and organic matter Who does the Interim Enhanced Surface Water Treatment Rule apply to? systems less than 10,000 and systems using surface water. includes provisions to conduct sanitary surveys What is the Long Term Enhanced Surface Water Treatment Rule? applies to a population of 10,000 or more, it strengthens microbial controls for small systems, seeks to prevent exposure to excess levels of DBPs, Initial Distribution System Eval , Lead and Copper Rule What can affect water quality within the distribution system? water age, presence of nutrients, corrosion, lead and copper What can affect water quality outside from the distribution system? cross connections, construction and maintenance and intentional contamination Can you improve water quality when designing your water system? yes Can you improve water quality on a day to day basis? yes How can you improve water quality on a day to day basis? storage turnover, preventative flushing, cleaning mains, booster disinfection (on the spot) How are distribution systems inspected? pressure and flow tests, watching for leaks What are some water main cleaning techniques? air purging, swabbing, pigging, metal scapers Unidirectional flushing what is a especially useful for? a flushing technique that requires the closing of all main valves and draws from a relatively clean source and discharges from a single hydrant at the end. Especially effective in removing sediment and biofilm Air purging More effective for smaller mains- spurts of air. air-water mixture will remove all but toughest scale Swabbing Foam plugs that are forced through a pipe by water pressure to remove slime, soft scale and loose sediment Pigging Stiff, Bullet shaped foam plugs that are forced through a main using water pressure Metal Scrapers A series of units that is pushed through the main by water pressure acting against pusher cones. When are lining water mains appropriate? When there seems to be corrosion altered water quality and it seems best to coat the pipe to prevent further corrosion What are the 2 types of lining mains? Cement-mortar lining and sliplining What are some conditions that increase corrosiveness of soil? high moisture content, poor aeration, low electrical resistivity, high chloride or sulfate content, presences of sulfide, presences of anaerobic bacteria. Name 4 types of water systems surface water, groundwater, purchased water, rural water. How many valves should be installed at each main intersection? At least 2 What can dead end mains cause? Degraded water quality, fire hydrants only drawing from one direction, low flow rate & pressure How should hydrants be spaced? Every 350-600ft depending on the density of the area served What are the fire flow requirements for main sizes in residential areas? minimum 6 or 8 inches Where is the best location for valves at street intersections? Opposite the ROW line for the intersecting street What is the primary factor in determining the size of water mains, storage tanks, and pumping stations for water systems serving a population of fewer then 50,000? Fire protection requirements Average day demand annual total water produced/ 365 days Per capita water use annual total water production/ population served maximum day demand highest demand over the span of 24 hrs of the same day peak hour demand water use during the highest 1-hour period during the year What should normal working pressure in a distribution system be? 35-65 psi The Uniform Plumbing Code requires that water pressure not exceed 80psi The minimum pressure at ground level at all points in the distribution system under all flow conditions must be 20 psi What is the water velocity limit for normal operations about 5ft/s 1 psi = ? ft head 2.31 1 ft head = ? psi 0.433 What are some factors that make a difference in the type of pipe used? Water Hammer, External Pressures, Corrosion Resistance, C-Value, Compatibility with existing materials, economy, local conditions, state/ local regulations, weather, earthquakes, fire protection, sunlight What are the 2 types of service pipes? Transmission Pipe & Distribution Mains Transmission Mains from source to distribution (ductile iron material most common) Distribution Mains From distribution to customer (cast-iron most common) What are some types of ductile iron pipe joints? flanged, mechanical, push-on, ball and socket, restrained What type of joints are often used in exposed locations such as treatment plants and pumping station? Flanged (Pipe installation is to be rigid and pipe must be restrained from movement What type of joint has special bells fitted with rubber gaskets? Mechanical Joint What type of joint is the most popular type for main installation because they are inexpensive and easy to install? Push-on Joints What type of valves are start/stop valves? Gate valves What type of valves are the most common, cheaper and easier to control? Butterfly valves What type of valves flows in only one direction? Check Valve Which type of valves should not be used for throttling flow for prolonged periods because vibration of gates will eventually wear and damage valve? Gate and Butterfly Which type of pipe is designed to withstand high pressure forces? Pressure Regulating and Relief Valves What are the 4 types of gate valves used in the distribution system? hydrant auxiliary valves, tapping valves, horizontal gate valves, bypass valves What type of valve controls flow to an elevated tank? altitude valve Which type of valve allows for air to escape? Air-and-vacuum relief valves What are the 4 types of valve operators? electric operators, hydraulic actuators, pneumatic actuators and manual operations What are 5 uses for Hydrants? fire fighting, flushing water mains, flushing sewers, filling tank trucks, construction What are some problems caused by hydrant operations? Sediment and water hammer What type of hydrant is mainly used in freezing weather? Dry-Barrel What type of hydrant is filled with eater at all timed? Wet-Barrel What type of hydrant is equipped with a main valve and small drain valve at the base that allows the barrel to drain when the main valve is closed? Dry-Barrel Is a wet top hydrant or dry top hydrant sealed to reduce the possibility of the treads becoming fouled from sediment or corrosion? Dry-Top Hydrant What type of hydrant is equipped with an entire standpipe and head that are below ground and are accessible through a cover flush with the surface Flush Hydrants What are the 3 types of dry-barrel hydrant main valves? standard compression, slide gate and toggle What is the main purpose of water storage? To equalize supply and demand What are some other purposes of water storage? convenience, balancing pumping requirements, decreasing power costs, emergency and fire requirements, surge relief, increasing chlorine detention time, blending What are the 4 types of storage facilities elevated tanks, standpipes, reservoirs, hydropneumatic storage systems What are some types of elevated tank equipment? riser pipe, overflow pipe, drain connection, air vent, access hatches, ladders, obstruction lighting What is the common service line size and meter size? 1'' line with 3/4'' meter Curb stop the main shut off before the meter What is the difference between a Arch-pattern curb box and a Minneapolis Style Curb box? An arch-patter curb box key sits loosely on top and can be easily misaligned. An Minneapolis style curb box have threads that screw onto the curb box and eliminates misalignment What type of water service tap is the preferred method because the main is still pressurized? wet tap A tap should be __degrees from the top of the main 45 A tap should be in the shape of a ??? S-curve What is the the utilities responsibility? (From where to where?) From the main to the curb stop Which meter is the most commonly used meter in residential areas? (they accurately measure low flow) positive- displacement meters The terms Nutating Disk and Rotary Vane are commonly associated with what type of meter? positive displacement meter Under what type of circumstances will meters under-register? If the meter is not sized correctly or if the meter is old What is a yoke? It acts as a riser and provides structure to install the meter What are some types of current meters? Turbine, multijet, propeller Proportional meter Has a restriction in the pipeline that forces a portion of the flow to pass through a small meter What type of meter is characterized by a defined throat within a meter body and measures the increase in flow velocity in the throat? Venturi Meter What type of meter uses transducers to generate and receive sound pulses across the flow of water? Ultrasonic meter What type of meter consists of a large turbine meter and a small bypass meter? Compound Meter How often should 5/8 inch meters be tested? Every 10 years True or False: Larger meters do not need to be tested more often. False. They need to be test every 5 years Backpressure The condition in which a foreign substance can enter because user's water system at a higher pressure than public water system Backsiphonage The condition in which a negative/ below atmospheric pressure within a water system What are some types of backflow control devices? Air gaps, reduced pressure-zone backflow preventers, double check valves, vacuum breakers, complete isolation What are the 2 types of vacuum breakers? atmospheric and pressure What are the 2 types of pumps? Velocity pumps and positive displacement pumps Which type of pump the most common pump and moves water by propeller at high velocity? velocity pump Which type of pump has a rotating impeler within a pump case? Centrifugal pump Which type of pump can handle high volumes and must be installed submerged at all times? Axial-flow/ propeller pumps which type of pump has an impeler that is shaped so that centrifugal force will move high volumes of water with solids? Mixed-flow pumps Which type of pump is a type of centrifugal pump and is furnished in multiple stages to obtain high pressure @ 90-95% efficiency? Vertical Turbine Pumps Which type of pump is a centrifugal pump that is at ground surface to generate high velocity water that is directed to wells? Jet pumps What are the 2 types of Centrifugal Pump designs? Volute and Diffuser What are the types of small centrifugal pumps? close-coupled and frame-mounted pumps what are the types of large centrifugal pumps? double suction pumps and two-staged pump Static Water Levels Natural water surface Pumping Water Level Water Level after the pump has been operating for a period of time Drawdown Pumping WL- Static WL Cone of Depression The depressed water surface surrounding the well when the well pump is in operation Residual Drawdown Lowered water level below the original natural level that remains after pumping has been stopped for a period of time Well Yield How much water drawn by pump Specific Capacity Well Yield/ Drawdown Static Pressure Water doesn't flow Dynamic Pressure Add Energy to the water system Velocity Speed that Water is Moving True or false: one of the most common and most debilitating types of injury related to material handling is back injury True If an excavation is __ft or more deep, cave in protection is required under any soil conditions. 5 ft Workers should be instructed on proper handling of hypochlorites and should wear ____ and _____when working with it Eye goggles and gloves What is the height to which water will rise in wells located in an artesian aquifer called? Piezometric surface Zone of influence Distance that the cone of depression affects the normal water level What are two purposes of well grouting? 1) prevent surface water pollution 2) to protect the casing from corrosion, restrain unstable soil and rock formations and seal off any aquifers with poor water quality Surface area of cylinder formula SA=2(pi)r(h)+2(pi)r^2