Texas Class C Surface Water Exam Review Questions and Answers, Exams of Water and Wastewater Engineering

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A disease that cannot be contracted by drinking contaminated water is: - - - correct answer ✅Malaria A non-permit confined space by OSHA standards means a confined space that: - - - correct answer ✅Does not contain or have the potential to contain any hazard capable of causing death When used in connection with the Safe Drinking Water Act, the term "MCL" means: - - - correct answer ✅Maximum Contaminant Level Examples of non-community water systems include: - - - correct answer ✅Highway rest areas The TCEQ requires that results be recorded and submitted daily for surface water supplies for: - - - correct answer ✅Disinfectant residuals, turbidity, total solids, pH, alkalinity

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tracking and maintaining an operator's training records is ultimately the responsibility of the: - - - correct answer ✅Operator An employee without a breathing apparatus is in a room where chlorine gas suddenly begins leaking. What should the employee do first? - - - correct answer ✅Keep mouth closed, keep head as high as possible, and quickly walk out of the room, holding their breath if possible Before changing a gas chlorine cylinder in a room, the first step should be: - - - correct answer ✅Start the exhaust vent fan Waterworks operator's holding grade c certificates are required to renew their certificates every three years and to: - - - correct answer ✅Inform the TCEQ of any address changes In order to insure that the water produced meets TCEQ standards, each surface water treatment plant must have a surface water operator on duty at all times when the plant is in operation or the plant must be provided with: - - - correct answer ✅Continuous turbidity and disinfectant residual

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monitors, automatic alarm systems, and an automatic shutdown system The major responsibility of a certified waterworks operator is to: - -

correct answer ✅Insure that a safe and adequate supply of drinking water is delivered to the customer's tap According to the TCEQ, a public water system is defined as any water system that provides piped water for human consumption to at least (a) service connections on a year-round basis or regularly serves (b) individuals daily at least_(c)_ days out of the year. - - - correct answer ✅(a) 15; (b) 25; (c) 60 Most of the surface water in Texas comes from: - - - correct answer ✅Precipitation that falls within the state The most important factor in preventing accidents is: - - - correct answer ✅The attitude of the employee Organics in surface water will combine with halogens to form: - - - correct answer ✅Trihalomethanes

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According to the average annual water budget for Texas, the majority of surface water leaves the state by: - - - correct answer ✅Evaporation and transpiration The term water stabilization refers to: - - - correct answer ✅pH adjustment Which pH measurements would indicate that water is basic: (6.0; 6.9; 7.0; 8.3) - - - correct answer ✅8. The Safe Water Drinking Act has set water quality standards for which category? - - - correct answer ✅Physical and chemical, radiological, and bacteriological When a coagulant reacts with finely divided and suspended material in raw water, a: - - - correct answer ✅Floc is formed

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The Rules and Regulations for Public Water Systems require straight flow rectangular sedimentation basins to be designed to provide a detention time of at least: - - - correct answer ✅6 hours Which of the following statements regarding sedimentation process is true: - - - correct answer ✅The 4 traditional zones of a rectangular sedimentation basin are the inlet zone, settling zone, outlet zone, and the sludge zone Tastes and odors caused by decaying vegetation can often be removed in the treatment process by the use of: - - - correct answer ✅Activated carbon What chemical is used for softening water? - - - correct answer ✅Lime (Soda Ash) The process of coagulation includes: - - - correct answer ✅A chemical reaction, a physical reaction, an agglomeration reaction, and neutralization of charged particles

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If sludge is allowed to remain too long on the bottom of a sedimentation basin, a problem could develop with: - - - correct answer ✅Taste and odor problems, reduction of detention time in the basin, resuspension of solids, and creation of septic conditions Coagulation is affected by: - - - correct answer ✅Turbidity, pH, and temperature In raw water reservoirs, the most common effect of aeration is: - - - correct answer ✅Removal of taste and odors Sedimentation is improved by: - - - correct answer ✅Uniform, horizontal, low velocity flow across the basin The most important water quality change in filter effluent is: - - - correct answer ✅Turbidity Soda ash is used in water treatment processes to: - - - correct answer ✅Adjust pH

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A sand filter will not remove: - - - correct answer ✅Dissolved oxygen The occurrence of mud balls in beds of filters may be prevented by:

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correct answer ✅Proper sedimentation The loss-of-head through a sand filter bed is influenced by: - - - correct answer ✅Sand particle size, filtration rate, water temperature, and the concentration of dissolved gas The term floc refers to: - - - correct answer ✅The flecks of coagulant containing trapped suspended matter The maximum flow rate through a sand filter should be: - - - correct answer ✅2-4 GPM per square foot Baffles are used to prevent short-circuiting in: - - - correct answer ✅Sedimentation basins

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Filter underdrains or bottoms serve several important purposes including: - - - correct answer ✅Deliver the backwash water uniformly underneath the filter media Jar tests are used to determine the: - - - correct answer ✅Correct chemical dosage The Rules and Regulations for Public Water Systems states that minimum pressures in all water distribution systems must not be less than 20 psi and that normal operating pressures must not be less than: - - - correct answer ✅35 psi The State Board of Insurance recommended capacity for ground storage includes: - - - correct answer ✅4-6 hour supply, 130 gallons per capita, 200 gallons per connection An altitude valve is used to: - - - correct answer ✅Control the water elevation in an elevated storage tank

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Two pressure gauges at the foot of two storage tanks are at the same elevation. The water levels in the two tanks are the same, but tank X holds, 1,000,000 gallons of water and tank Y holds 500, gallons. The gauge on tank X will have a reading of: - - - correct answer ✅The same as that of tank Y The capacity of a centrifugal pump will be decreased by: - - - correct answer ✅Insufficient suction head A standpipe: - - - correct answer ✅Has a diameter less than it's height The most effective method of cross connection control is: - - - correct answer ✅A physical air gap If using the combined available chlorine residual (CACR) method of disinfections: - - - correct answer ✅When water temperature decreases, the CACR must be increased in order to maintain proper chlorine residuals

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After installation or repair of a water line, it should be treated with:

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correct answer ✅50 mg/L of chlorine for 24 hours Calcium hypochlorite: - - - correct answer ✅is 60%-70% chlorine Chlorine gas: - - - correct answer ✅Is highly toxic and can be fatal; is corrosive in damp surroundings The Rules and Regulations for Public Water Systems states that distributions systems must maintain a chlorine residual of: - - - correct answer ✅0.2 mg/L of free chlorine or 0.5 mg/L of chloramines in the far reaches of the distribution system Ozone (O3) is: - - - correct answer ✅Toxic to humans When a section of water main is replaced, any organic material allowed to remain inside the pipe will: - - -

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correct answer ✅Increase chlorine demand, and decrease chlorine residual A water storage tank must be disinfected with a dosage of 50 mg/L. The tank is 36 feet in diameter and 20 feet high. The amount of 65% calcium hypochlorite needed is: Formula: MGD x 8.34 x mg/L = lbs - - - correct answer ✅97 lbs. (rounding) The chlorine demand on water from the plant is 3 mg/L. The operator treats 400,000 gallons of water with 20 lbs of chlorine gas. Under these conditions, the chlorine residual will be: Formula: MGD x 8.34 x mg/L = lbs - - - correct answer ✅3 mg/L (rounding) A chlorinator setting is 35 lbs/day. If the flow being chlorinated is 1.15 MGD, the chlorine dosage is: Formula: MGD x 8.34 x mg/L = lbs - - - correct answer ✅3.65 mg/L (rounding)

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When collecting a distribution sample for bacteriological testing, the person collecting the sample should allow water to run ___ before filling the sample bottle. - - - correct answer ✅As long as necessary to permit clearing of the service line The volume of a cylinder with a radius of 5 ft. and a height of 8 ft. is ____ ft^3. (3.14 x r^2 x H) - - - correct answer ✅628 ft^ The volume of a 100 ft. diameter tank that is 12 ft. deep is ___ ft^3.

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correct answer ✅94,200 ft^ A chemical commonly used to raise pH is: - - - correct answer ✅Lime (Soda ash) Black stains on plumbing fixtures might be attributed to what? - - - correct answer ✅Manganese

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One kilogram equals ___ grams - - - correct answer ✅ 1000 The indicator organisms used to determine contamination of drinking water are: - - - correct answer ✅Coliform groups The packing around the shaft of a centrifugal pump should be: - - - correct answer ✅Tightened just enough to allow an occasional drop of liquid to escape The chemical symbol of iron is: - - - correct answer ✅Fe One pound of pressure will raise water ___ ft. - - - correct answer ✅2.31 ft. Static head is defined as the: - - - correct answer ✅Pressure due to depth or elevation of water

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What is the volume of a settling tank 100 ft. long, 25 ft. wide, and 8 ft. deep? - - - correct answer ✅20,000 ft^ What is used to detect chlorine leaks? - - - correct answer ✅10% solution of ammonia hydroxide (ammonia) The pressure gauge reading at the base of a tank filled to a depth of 1 ft. is ___ psi - - - correct answer ✅0.433 psi The multiple-tube fermentation test consists of three distinct tests. These tests, in the order performed, are: - - - correct answer ✅Presumptive, confirmed, and completed tests Chlorine gas is more or less dense than air? - - - correct answer ✅More dense than air Polyphosphates may be used in water treatment to retard corrosion and: - - - correct answer ✅Calcium scale

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Calcium hypochlorite is formulated as a: - - - correct answer ✅Powder Chlorine leaks in metal containers tend to become: - - - correct answer ✅Larger Determining the pH of water is one of the important tests of water quality. The results of the pH test indicate the: - - - correct answer ✅Hydrogen ion activity Alkalinity is a direct measure of water's capability to resists changes in: - - - correct answer ✅pH (acidity) Leakage form a packing gland should be approximately: - - - correct answer ✅One drop per second A chlorine cylinder valve is thought to be leaking. If ammonia vapor is passed near the valve, the presence of a leak would be indicated by: - - - correct answer ✅White smoke

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If a fire hydrant requires a nozzle pressure of 100 psi, what head of water must be used to supply it? - - - correct answer ✅231 ft. Which type of pipe is most likely to be damaged by corrosion? - - - correct answer ✅Steel Carbon dioxide in water will do what to the pH? - - - correct answer ✅Lower the pH A pneumatic ejector lifts water from low points to higher levels. The device used to achieve this is a(n)? - - - correct answer ✅Air compressor Pressure is commonly measured in: - - - correct answer ✅Pounds per square in (psi) Mechanical seals are being installed in pumps because: - - - correct answer ✅Packing requires an undesirable leakage that seals eliminate

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Which of the following items must be placed when connecting a new chlorine cylinder? (Air and water regulator; fiber washer; needle valve and seat; pressure regulator) - - - correct answer ✅Fiber washer A major cause of pump and motor shaft coupling wear is a: - - - correct answer ✅Misalignment between pumps and motor flanges Filters in a water treatment process are primarily for removing or reducing what? - - - correct answer ✅Turbidity A water treatment plant receives an average flow of 261 gallons per minute. What is the daily flow of the plant? - - - correct answer ✅0.38 MGD (rounded) The free chlorine residual in water is the amount of: - - - correct answer ✅Uncombined chlorine that remains in the water after chlorine has been applied and allowed to react The chemical name for muriatic acid is what? - - - correct answer ✅Hydrochloric acid

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A chlorine residual in water can be determined by using the reagent: - - - correct answer ✅DPD - diethyl-p-pheylenediamine The most important use of chlorine in water treatment is what? - - - correct answer ✅Disinfectant What is the approximate volume in gallons occupied by 15,000 ft^ of water? - - - correct answer ✅112,200 gallons The difference between the amount of chlorine added to water and the amount of residual chlorine at the end of a specified contact time is called what? - - - correct answer ✅Chlorine Demand Water that requires a large amount of soap to produce an acceptable lather is said to be what? - - - correct answer ✅Hard

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A pump may be damaged if it is started with the discharge valve closed, and the pump is a(n): - - - correct answer ✅Positive displacement pump Prepared water sample bottles used for collecting samples for bacteriological examination contain sodium thiosulfate crystals. It is important not to rinse out the sample bottle because the sodium thiosulfate does what? - - - correct answer ✅Neutralizes any chlorine present in the sample Velocity of flow in water mains is usually expressed in terms of: - - - correct answer ✅Feet per second A pH reading of 6.0 in raw water indicates the sample is what? - - - correct answer ✅Acidic The temperature of water in a stream is 10 C. What is the equivalent temperature in F? - - - correct answer ✅50 F A grab sample represents the quality of the water when? - - - correct answer ✅Only when the sample was taken

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The pH scale runs from ___ to ___ - - - correct answer ✅0- Five gallons of water weighs ___ lbs - - - correct answer ✅41.7 lbs What is the approximate weight, in pounds, of 50,000 gallons of water? - - - correct answer ✅417,000 lbs The flow in 35,000 gallons per day. What is that in MGD? - - - correct answer ✅0.035 MGD The most important factor affecting the useful life of piping is the ability of that piping to resist what? - - - correct answer ✅Moisture of any kind A pH value of 7.0 is considered to be what? - - - correct answer ✅Neutral

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The discharge pressure gauge on a pump reads 15 psi. This is equivalent to ___ ft. of head - - - correct answer ✅35 ft Chlorine is very corrosive when combined with what? - - - correct answer ✅Moisture of any kind What is the surface area of a clarifier 40 ft. in diameter? - - - correct answer ✅1256 ft^2 Chloramines are formed by the addition of chlorine and what other chemical? - - - correct answer ✅Ammonia The purpose of a rotameter is to meter the flow of what? - - - correct answer ✅Chlorine gas (or any gas for that matter) A valve that joins a customer's service to the water main is called the ____ - - - correct answer ✅Corporation cock

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When compared to a 1-million gallon reservoir at the same elevation, how much pressure in the mains will a 100,000 gallon reservoir develop? (assume equal elevation for both) - - - correct answer ✅The same pressure What information must be on a warning tag attached to a switch that has been locked out? - - - correct answer ✅Signature of person who locked out the switch and who is the only person authorized to remove the tag Which one of the following types of meters has no moving parts? (propeller; proportional; rotameter; venturimeter) - - - correct answer ✅Venturimeter The component of a centrifugal pump that is sometimes installed on the end of the suction pipe to hold the priming is known as what? - - - correct answer ✅A foot valve Coagulation and sedimentation alone cannot remove all of the turbidity and suspended matter in raw water. The final step in the removal of suspended matter in water is what? - - - correct answer ✅Filtration

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What does water weight in terms of lbs/gallon? - - - correct answer ✅8.34 lbs/gal The chemical symbol for sodium is: - - - correct answer ✅Na The purpose for fluoridation of municipal water supplies is to help prevent what? - - - correct answer ✅Dental decay Chlorine valves are opened and closed with what? - - - correct answer ✅Valve wrenches provided with a cylinder or 1-ton container by the manufacturer What does one cubic foot of water weigh? - - - correct answer ✅62.4 lbs When opening and closing valves in high pressure lines, the valves should be opened and closed how? - - - correct answer ✅Slowly

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A hypochlorinator is used to feed ___ into a water supply - - - correct answer ✅Hypochlorite solution One cubic foot of water contains ___ gallons - - - correct answer ✅7.48 gallons One of the purposes of water storage tanks is to ____ - - - correct answer ✅Supply water at peak demands Mud, silt, clay, and other suspended matter in water that cause it to appear murky are called what? - - - correct answer ✅Turbidity If the pressure gauge at the bottom of a 200 ft. standpipe reads 68 psi, what is the static head in feet? - - - correct answer ✅157 ft The volume of a sample should depend on what? - - - correct answer ✅What tests the sample will be used for

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What does a pump need when the gland follower is pulled all the way down? - - - correct answer ✅A new packing Sodium hypochlorite is a compound that can be purchased in liquid solution and be used for what? - - - correct answer ✅Disinfection Gas chlorinators, when operated at high rates, can result in what? -

correct answer ✅Ice formation on the chlorine cylinder When a single water sample is reported as safe, this may be interpreted to mean what? - - - correct answer ✅That the water supply was safe at the sample point, at the time of the sampling In loading or unloading 150 lb chlorine cylinders, hand trucks should be used that are equipped with what? - - - correct answer ✅A retaining or safety chain