Surface Water General Exam Quuestions and Complete Solutions

Surface Water General Exam Quuestions and Complete Solutions Texas Commission of Environmental Quality - Answer: What is the name of the State Agency responsible for enforcing the safe drinking water program in Texas Calcium and Magnesium - Answer: What minerals cause water hardness? Adequate quantity of water adequate water pressure adequate disinfection - Answer: A public water system must at all times provide Aquifer - Answer: A source of groundwater would be water supply is contaminated harmful bacteria may be present possible pathogenic organisms are in the water water is unsuitable for drinking - Answer: Fecal coliform organisms sometimes found in water supplies are in indication that Dysentery - Answer: A disease that may be spread by inadequately disinfected water is calcium hypochlorite - Answer: A common chemical used in the disinfection of a small water supply is a cross connection - Answer: A physical connection between a potable water supply and a house well would be demand - Answer: The amount of chlorine in mg/L that is used up by reacting with iron, organics, or bacteria is called greenish yellow color heavier than air pungent, penetrating odor corrosive - Answer: all of the following are physical characteristic of chlorine gas except? solution feed pump - Answer: Which of the following would be considered a part of a hypo-chlorinator system? flow measuring device - Answer: According to state requirements, all public water supply wells should be provided with a raised concrete sealing block, screened vents and the difference in static and pumping level - Answer: The drawdown of a water well is determined by if it is more acidic or basic - Answer: The pH of water indicates 0-14 - Answer: The pH water is expressed by a scale of numbers ranging from 7.0 - Answer: Water that is considered neutral is expressed on the pH scale at use of an approved, sterile sample container - Answer: Which of the following is a required step in collecting a routine distribution sample for bacteriological testing? turbidity - Answer: Sand filtration will remove which of the following from surface water? taste and odor control - Answer: Activated Carbon is used in a surface water plant primarily for? Alum and ferric chloride - Answer: Which of the following chemicals are commonly used in coagulants in surface water treatment? screened vents approved locking roof hatch overflow pipe with hinged flap device annual inspection and maintenance as needed - Answer: Ground storage tanks are required to be provided with which of the following painting cathodic protection water stabilization - Answer: An elevated storage tank should be protected against corrosion by 35psi - Answer: A public water supply system should maintain residual pressure of 20 psi and a minimum normal operating pressure of 50mg/L - Answer: Before a new or repaired water line is placed into service, it must be properly disinfected by providing a chlorine dosage of ___ and proper detention time. Aquifers - Answer: Water bearing formations beneath the earth's surface that are used as a source of water for public water supplies are determine water levels in the well - Answer: The purpose of an air line on a well is reduce the amount of sand pumped - Answer: The mesh size is an important feature of a well screen because properly sized openings should pH alkalinity temperature chemical dosage - Answer: When treating water, the process of coagulation will be most affected by the When the loss of head gauge indicated between 6-10 - Answer: A rapid sand filter should be backwashed when 0.2mg/L free chlorine residual 0.5mg/L chloramine residual for a surface water supply 0.8mg/L chlroamine residual when using chloramine treatment 0.5mg/L free chlorine residual for a groundwater supply - Answer: Which of the following is an acceptable disinfection residual at the far reaches of the distribution system? 79,300 - Answer: What is the approcimate total volume of a circular tank in gallons, if it is 30 feet in diameter and is 15 feet deep? 25 - Answer: You are setting a chlorinator to provide a dosage of 4.0mg/L. If the daily water usage is 750,000 gallons, the gas chlorinator feed rate should be set at ___ pounds per day. 8.34 lbs - Answer: One gallon of water weighs 0.433 lbs - Answer: One foot of water inside a storage vessel will raise a pressure gauge at the bottom of the vessel by 1,000 feet - Answer: A raw water intake structure may not be constructed within ___ feet of a boat ramp, dock, or marina. vertical turbine submersible - Answer: common types of pumps for use in water wells are hydrological cycle - Answer: ____ is the natural exchange of water between the earth and air 24 hours - Answer: If and when a health hazard contamination event occurs in a public water system, the operator must contact the state regulatory authority within ___ hours by telephone. maintained at adequate pressure pathogen free contains chlorine residual - Answer: Potable water is that of Blue babies - Answer: Excessive nitrates in drinking water can cause a condition that affects infants under the age of 6 months. This condition is known as coagulation - Answer: In surface water treatment the process of causing the fine particles in the water to join together to form larger heavier particles that settle in a clarifier is called jar test - Answer: The test commonly used to determine the chemical dosage for the surface water plant is the _____test. can be filtered with additional treatment cause mudballs and filter plugging - Answer: Suspended solids are the solids portion that coliform - Answer: A public water system is required to take samples of water for bacteriological analysis. The organism that is used as an indicator is called residual - Answer: Chlorine dosage is demand plus desired ______ stand pipe - Answer: A storage vessel that is the same diameter from the ground to the top and is more than 20 feet but less than 85 feet tall is called a 35psi - Answer: Potable water must be stored at an elevation at least 80.85 feet above the highest known connection to provide the minimum operating pressure of ____ psi hydro pneumatic tank - Answer: A water tank that uses compressed air over wtaer to provide pressure is called a 8.0% - Answer: According to the lead and copper rule, pipe and fittings may not contain more than ______ lead or solder and flux may not contain more than 0.2% lead. red - Answer: When testing for chlorine residual DPD is used as an indicator, when DPD is added to water containing chlorine what color does the sample turn? gate valve - Answer: The most common valves used for isolating a water leak in the ______ valve water hammer - Answer: In the distribution system when a valve or hydrant is opened or closed too fast it could result in a centrifugal - Answer: The most commonly used pump in the distribution system is 14,583 - Answer: You are treating 21 MGD water in a surface water plant, how many gallons per minute is this? 250 - Answer: A Texas class D certified operator can operate a public water system up to _____ connections 3 years - Answer: All state of Texas operator license's after issue are good for _____ years. collect another sample at the site that tested positive plus one within 5 connections upstream and one within 5 connections downstream and re submit. - Answer: After analyzing monthly bacteriological samples the operator is notified that one testing point, tested positive. The operator should 5 feet - Answer: Any excavation greater than _____ feet in depth requires the use of OSHA approved shoring equipment or sloping of walls to prevent cave ins. 9 feet - Answer: Waterlines should be installed no closer than ____ feet to any sewer lines or other possible contaminate lines. 166 feet - Answer: At the base of an elevated storage tank a pressure gauge reads 72 psi, how far above the gauge is teh water surface? 7,315 - Answer: How many gallons of water will a storage tank that is 978 cubic feet hold? 65-75% - Answer: Calcium Hypochlorite (HTH) is used as a disinfectant in small systems, what percentage chlorine is this material typically? 3.14 - Answer: When calculating area, one will use the standard for pi, what is the standard accepted numerical value? once every month - Answer: Flushing dead end mains - current state regulations required that all punlic water systems flush dead end mains to assure chlorine residual and water quality. What is the minimum flushing requirement? must confirm to the national sanitation foundation (NSF) standard 60 - Answer: In small systems liquid bleach is an approved method of disinfection, provided the product used meets basic industry standards. What is the current standard bleach must meet in order to be approved for disinfection in a public water system? breakpoint chlorination - Answer: The process of adding enough chlorine to a water supply to complete all reactions with reducing compounds, ammonia, and organic materials so that some free chlorine is left is called internal and external corrosion improper backfill and lack of proper bedding - Answer: The primary reasons for main line failures in the distribution system is prevent water from flowing back through the pump when the pump is off - Answer: Check valves on the discharge side of a pump are used to Trihalomethanes and Haloacetic - Answer: ___________ & ____________ acids are by products of drinking water chlorination. 8 - Answer: There are ____ major underground water aquifers in Texas rapid sand and designed to flow 2 gpm/ft2 - Answer: The most common type of filter in a surface plant today is ____ and is designed to treat and flow at _________ 30% to 50% - Answer: Proper back washing of a sand filter is accomplished when the filter media expands by _______% one sample for every 1000 feet of line - Answer: After disinfection and flushing of super chlorinated new lines and service but prior to placing the line into service, bacteriological samples are required. The current standard is __________ sample for every ____ feet of line. physical air gap - Answer: For cross connection control the TCEQ preferred method is cryptosporidium - Answer: One microorganism in water that is resistant to chlorine is positive displacement multi jet compound propeller - Answer: What are the common types of water meters? Low distribution pressure water outages repeated unacceptable BAC-T samples failure to maintain good Cl2 residual - Answer: What triggers a Boil Water Notice 40 lbs per 24 hours - Answer: The maximum safe withdrawal rate of chlorine for a 150 lb cylinder is acid to water - Answer: When diluting a strong acid, always add __________ to ___________ rather than the reverse. 20.9 - Answer: The normal oxygen content of the atmosphere is _____% 19.5 - Answer: Any atmosphere that is less than ___________% oxygen should not be entered without an approved self-contained breathing apparatus. hypochlorous acid - Answer: When chlorine gas is added to water, what compounds are formed? the safe drinking water act of 1974 - Answer: The most important federal law that impacts the water utility industry is? RV park hotel / motel service station - Answer: An example of a Non-community water system would be? Consumer Confidence Report - Answer: The EPA requires community water systems to provide customers with an annual? 130 gallons - Answer: When designing systems engineers use a rule of thumb of ______ gallons per person per day when more accurate data is not available. 0.6 gpm - Answer: TCEQ requires community water systems to have a minimum production capacity of ____ per connection at peak demand. disinfection - Answer: The most important treatment in water is? safe for human consumption free of disease causing organisms has a chlorine residual - Answer: potable water means the water is change in water source, water quality, and health hazards - Answer: TCEQ requires notification from the operator if changes to the public water system occur such as pumpage and chemical usage date of dead end flushing and storage tanks cleaned microbiological test and chemical tests - Answer: Public water systems in Texas are required to compile and maintain reports showing taste turbidity temperature odor color - Answer: physical characteristic of water include obnoxious and like rotten eggs - Answer: Common gases found in water are hydrogen sulfide, carbon dioxide, and methane. Hydrogen sulfide can be identified by its distinct smell, which is minerals gases corrosives - Answer: Groundwater is generally well filtered and free of turbidity, color, and organics, however it may be high in 50 feet - Answer: Livestock septic tanks must be no closer than ____ to public well. 150 feet - Answer: Underground fuel tanks and septic drainage fields must be at least __________ feet from public well. 500 feet - Answer: Feedlots, sewage treatment plants and landfills must be at least ________ feet from the public well. 12 inches - Answer: Trenches for laying six inch and larger pipe must be at least 18 inches wide and/or __________ wider than the pipe diameter. 24 to 36 inches - Answer: The top of the pipe in a trench must be at least ____ inches from the tip of the ground 4 feet - Answer: In an excavation ___ feet or deeper a means for exit must be provided 3 feet above and 25 feet laterally - Answer: In an excavation if a ladder is used as a means of exit, it must extend ___ feet about the ground and be secured and within ___ feet laterally of anyone in the excavation. 2 operators with c licenses - Answer: A ground system that serves an excess of 1,000 connections must have at least ___ opeartors with ___ license to meet minimum state requirements for public water systems. 144 - Answer: A groundwater well is currently pumping 1000 gallons per minute. Convert 1000 gpm to millions gallons per day. 7.0 and corrosive - Answer: It is desirable for the pH of treated water to be above ________, otherwise ________ conditions will exist. 4.0mg/L - Answer: Fluorides are naturally occurring in some groundwater. Fluorides in drinking water should not exceed _____ mg/L. iron - Answer: Red water of red stains may be caused by ______ levels in the water. 30 - Answer: When chemicals are used at a water treatment plant, a _____ day supply should be kept on hand at all times to comply with state standards. aeration - Answer: The presence of iron in water is most commonly treated by potassium permanganate - Answer: A common chemical oxidizer is aeration - Answer: If groundwater is to be treated for several problems, the first process should be activated alumina - Answer: Excess fluoride in water may be removed by free available chlorine - Answer: Trihalomethanes are formed by the reaction of ___________________ with organics 50% - Answer: TCEQ requires a water system to have disinfection equipment capable of proving at least ____ % greater capacity than the highest expected dosage at any time. pounds 24 hours - Answer: The rotometer ona gas chlorinator indicates the number of ____ of chlorine fed during a ____ period 16.3 - Answer: how many pounds of 70% chlorine (HTH) will be needed to treat the same amount of water as 9.0 lbs of 100% chlorine? 400 lbs - Answer: Using a ton cylinder or container, the maximum withdrawal rate should not exceed cavitating - Answer: A pinging sound or rocks bouncing sound coming from the pump typically indicates the pump is suspended by pipe placed near the bottom of the well - Answer: A submersible pump and motor will be static suction head - Answer: The distance from the water level in the well to the centerline of the pump is total static head - Answer: The distance from the water level in the well to the water level in the storage tank is friction - Answer: The loss of energy which results from the movement of water through pipes and fittings is the bearings will be damaged - Answer: If a water lubricated vertical turbine pump is started with dry bearings, detect problems with the pump, well screen, and water level - Answer: Routinely measuring the static level and pumping level can 4 to 6 hours at 200 gallons per connection - Answer: The recommended capacities for ground storage is based on providing ___ to ____ hours of supply at _____ gallons per connection 6 inch - Answer: Fire codes require water main sizes in residential areas to be at least __________ when fire hydrants are attached. 4 times - Answer: Flows in pipe depends greatly on pipe diameter. Doubling the pipe diameter increases the carrying capacity by ________ times if friction is not considered. 15% - Answer: Unaccounted for water loss should be less than ____% of water production corrosion - Answer: A critical factor affecting the useful life of service lines is the ability of the pipe material to resist internal and external _____. 5 years - Answer: The results of bacteriological analysis shall be kept on file and available for _____ years 171,066 - Answer: A well pumped for 45 days. The beginning meter reading was 7,456,400 and 45 days later the same meter reading was 15,154,400. What was the average flow in gallons per day? 33,000 feet lbs - Answer: One horsepower is equal to ________ feet pounds of force per minute. 972 gpm - Answer: A groundwater well is currently producing 1.4 MGD. Calculate and convert 1.4 MGD to GPM. 750 connections - Answer: Elevated storage is required for systems over ___ connections. 2500 connections - Answer: Pressure vessels (tanks) are not recommended for systems over ______ connections elevated storage tank - Answer: Altitude valves are used to control the level of water in a atmospheric vacuum breaker pressure vacuum breaker testable double check valved assemblies reduced pressure zone devices. - Answer: When an air gap is not prectical, other acceptable backflow prevention devices are acceptable (depending upon application). All of teh following devices are acceptable in certain circumstances 32 samples - Answer: If a new water main is installed and the total length of the new line is six miles. How many bacteriological samples must be taken? 7.48 gallons and 67.32 gallons - Answer: In a cubic foot of water there are ______ gallons. How many gallons are there in 9 cubic feet of water? 924 - Answer: You are instructed to install 3.5 miles of 6" water line. The pipe comes in 20 ft. lengths. How many joints of pipe will you have installed once the job is complete? 2152 gpm - Answer: A new subdivision is proposed for your community. The projected water use for the subdivision upon completion is 3.1 mgd. How many gallons per minute will that be? 12,910 lbs - Answer: You are the operator of a surface water treatment plant currently treating 4.3 mgd. The required dosage of alum is 12mg/L. How many pounds of Alum will you use in a month? naturally occurring and free flowing wells - Answer: Artesian wells are Month - Answer: Federal and state laws mandate bacteriological analyses of the water supply. These samples must be obtained at least every velocity - Answer: The rate of speed at which water moves is PSI - Answer: the unit of measure for water pressure is prevent movement at pipe joints - Answer: The purpose of a thrust block is 100/150/200/250 - Answer: The four common classes of working pressure in water main pipes are 288 - Answer: Volume equals length times width times height. Using this information if a container is 12 feet long, 4 feet wide, and 6 feet high - what is the volume of this container? 5 to 10 years or 1,500,000 gallons - Answer: AWWA recommends that a 5/8 times 3/4 service meter be tested every _____ years or ____ gallons of water registered. 1 1/2 times as great as the normal operating pressure - Answer: When pressure testing a water main, the pressure should be 24 hours - Answer: Reported water main leaks should be repaired within hard water - Answer: Scale build up in pots and pans is caused by sterile - Answer: The term pathogenic refers to petroleum or organics - Answer: Calcium hypochlorite (HTH) is corrosive and may be flammable in the presence of ____ or _____ the persons airway - Answer: You come upon an unconscious person who is unresponsive. The most important thing to check first is mouth and any moist openings - Answer: Pathogens (disease causing organisms) can be transmitted through water, blood, or by breathing. The most obvious routes for entry into the body are self contained breathing apparatus - Answer: The letters SCBA on a cabinet would indicate to the operator water borne pathogenic organisms - Answer: Bacteria, Viruses, parasites, and fungus are meer inches for 110 volt to 6 feet for 440 - Answer: Depending on weather conditions and moisture in the air an electrical arc may jump from ____ for 110 volts to ____ for 440 volts. black letters on orange background - Answer: All warning signs in temporary traffic control zones shall have 1 year - Answer: Chemical testing of surface water sources required every aluminum sulfate ferric sulfate ammonia nitrate - Answer: Common surface water coagulants are 0.8 mg.L - Answer: The current MCL fro trihalomethanes (THM) is plastic - Answer: To load liquid Alum into a chemical feeder, you should use hoses or piping of the correct coagulant dosage - Answer: The jar test is considered proper process control for a surface water plant and is used to determine 10.0 mg/L - Answer: The primary MCL for nitrate in drinking water is Epilimnion - Answer: When a lake or reservoir stratifies the best water quality is found in what zone? pH turbidity temperature filter backwash - Answer: What factors significantly affect the coagulation process low pH - Answer: A source water high in color coagulates better at a 90 days - Answer: TCEQ rules require that all turbidimeters be calibrated every floc is formed - Answer: When a traditional coagulant reacts with alkalinity in a raw water, what occurs? the measure of force preventing particles from joining involved in coagulation - Answer: Zeta potential is capping - Answer: Replacing approximately 6 inches of sand with 6 inches of anthracite coal is called ___________ a filter. 24 to 30 inches - Answer: The top of backwash troughs should be _____ inches above the top of the filter media. 8.3 or above - Answer: If a sample for total alkalinity turns pink when phenolphthalein indicator is added, the pH of the sample is adding activated alumina reverse osmosis - Answer: An appropriate method of removing excess fluoride from drinking water is chlorine ozone - Answer: Taste and odor compounds may be oxidized by oxygen - Answer: During photosynthesis algae produce ____ that aids in the water treatment. asking about reporting units for turbidity - Answer: When someone asks about NTU they are spray cascade packed tower diffused air and mechanical - Answer: The first basic aerator designs used in water treatment are destabilization - Answer: The second step of flocculation is particle clean and level - Answer: Proper backwash of a filter leaves the filter media 1/4 - Answer: A rule of thumb for sludge blanket thickness in solids contact, sludge blanket, and upflow clarifier is ____ the side wall depth. humic and fulvic - Answer: Decayed natural organics most common in water are ______ acids. reduce taste and odor in water - Answer: One purpose of using chloramines in water would be?? macrofiltration ultrafiltation nanofiltration reverse osmosis - Answer: Filtration options related to the membrane processes are enhance - Answer: Flocculant or coagulant aids ____ flocculation when coagulants alone are not effective. high / low - Answer: If coagulant dosage is too ______, floc formation continues past flocculation and into sedimentation. Likewise if the coagulant dosage is too ____, not enough floc will form to remove turbidity. giardia and cryptosporidium - Answer: Recycling is water recovery from spent backwash and sludge drainage. Recycling carries the risk of returning to the plant _____ and _____. trihalomethanes - Answer: Chlorine in the most common disinfectant used today and it reacts with certain source water organics and could form _____________. disinfection by products / trihalomethanes - Answer: Chloramines, chlorine dioxide, and ozone produce _____________________ but not ________________. generated on site and used immediately - Answer: Chlorine dioxide (ClO2) is a unstable disinfectant and must be monochloramine - Answer: Chlorine to ammonia ratios of 3:1 to 5:1 produce ________________. algae - Answer: __________________ is the most frequent cause of taste and odor problems in surface supplies. 3,170 minutes 52.8 hours - Answer: As an operator you know you have a ground storage tank 40 ft tall and 60 ft in diameter. You also know the tank is currently at 1/4 capacity and filling at the rate of 700 gpm. There is also a booster pump running emptying this same tabke at the rate of 500 gpm. If conditions remain the same - How long will it take in minutes or hours to fill this tank to full? 12.8 lbs - Answer: You are charged with the task of chlorinating 20,000 gallons of water in a new distribution line with a dosage of 50 mg/L using 65% HTH. How many pounds of HTH will you use?