Water operator “D”water Exam Questions and Complete Solutions.

Water operator “D”water Exam Questions and Complete Solutions What is the name of the State Agency responsible for enforcing the Safe Drinking Water Program in Texas? - Answer: Texas Commission on Environmental Quality (formally known as TNRCC) What minerals are associated with water hardness? - Answer: calcium and magnesium A public water system MUST at all times provide - - Answer: Adequate quantity of water Adequate water pressure Adequate Disinfection All of the Above A source of Groundwater would be - - Answer: Aquifer Fecal cooliform organisms sometimes found in water supplies are an indication - Answer: The Water supply is contaminated Harmful bacteria may be present Possible pathogenic organisms are in the water The water is unsuitable for drinking All the above A disease that May be spread by inadequately disinfected water is - - Answer: dysentery One method to determine the drawdown of a water well is - - Answer: An air line The pH of water indicates - - Answer: If it is more acid or base Assuming you collect more than one bacteriological sample monthly and your system receives notification from the lab that one of the samples taken in the distribution system comes back positive - your repeat sample(s) must be taken within________________________ hours (excluding weekends) and a total of_______________________repeat samples must be collected for each positive? - Answer: 24 hours & 3 repeat samples for each positive Water that is considered neutral is expressed on the pH scale at - - Answer: 7.0 Which of the following is a required step in collecting a routine distribution sample for bacteriological testing? - Answer: Use of an approved, sterile sample container Potable water means the water is - - Answer: Maintained at adequate pressure Pathogen free Contains a chlorine residual All the above Which of the following is an acceptable disinfection residual at the far reaches of the distribution system - - Answer: 0.2 mg/L free chlorine residual 0.5 mg/L chloramine residual for a surface water supply. 0.8 mg/L chloramine residual when using chloramine treatment 0.5 mg/L free chlorine residual for a groundwater supply All the above One gallon of water weighs - Answer: 8.34 pounds One foot of water inside a storage vessel will raise a pressure gauge at the bottom of the vessel by - - Answer: .433 lbs Common type(s) of pump(s) for use in water wells are - - Answer: Vertical Turbine Submersible and submersible _____________________________is the natural exchange of water between the earth and air - Answer: Hydrological Cycle 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. - Answer: 24 hours 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. - Answer: 0.8 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? - Answer: red The most common valve used for isolating a water leak is the___________ valve. - Answer: Gate valve In the distribution system when a valve or fire hydrant is opened or closed too fast it could result in a - - Answer: Water hammer The most commonly used pump in the distribution system is - - Answer: Centrifugal 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 - - Answer: Breakpoint chlorination The primary reason(s) for main line failures in the distribution system is - - Answer: Internal and external corrosion. Improper backfill and lack of proper bedding Check valves on the discharge side of a pump are used to- - Answer: Prevent water from flowing back through the pump when the pump is off 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 . - Answer: One sample for every 1,000 feet of line For Cross Connection Control the TCEQ's preferred method is - - Answer: Physical air gap One microorganism found in water that is resistant to chlorine iS- - Answer: Cryptosporidium Groundwater is generally well filtered and free of turbidity, color and organics, however it may be high in- - Answer: Hardness, Minerals & Inorganic's Livestock and septic tanks must be no closer than_______________to a public well. - Answer: 50 feet Feedlots, sewage treatment plants and landfills must be at least___________ feet from a public well. - Answer: 500 feet Red water or red stains may be caused by ___ levels in the water. - Answer: iron A pinging sound or rocks bouncing sound coming from the pump typically indicates the pump is ___. - Answer: cavitating In the distribution system where would a person expect to find a valve commonly referred to as a Corporation stop? - Answer: At the providers main line Your system is currently pumping 1.4 MGD and using 9.0 mg/L chlorine. The residual at the far end of the distribution system is 0.4 mg/L- what is the demand? - Answer: 8.6mg/L You are treating 21 MGD water how many gallons per minute is this? - Answer: 14,583 What is the approximate total volume in gallons of a circular tank, if it is 30 feet in diameter, and is 15 feet deep - Hint: pi XrXrXd X? - Answer: 79,300 In a groundwater system according to the well drillers report the hole was drilled 338 feet deep - the static level of water in the well is 108 feet - the pumping level is 171 feet. What is the drawdown? - Answer: 64 feet At the base of an elevated storage tank a pressure gauge reads 72 psi, how far above the gauge, is the water surface? - Answer: 166 How many pounds of 70% chlorine (HTH) will be needed to treat the same amount of water as 9.0 Ibs. of 100 % chlorine? - Answer: 12.85 The most important federal law that impacts the water utility industry is? - Answer: Safe Drinking Water Act of 1974 An example of a Non- Community Water System would be? - Answer: RV Park Hotel/Motel Service Station The EPA requires community water systems to provide customers with an annual? - Answer: Consumer confidence report A groundwater well is currently producing 820 gallons per minute. Convert 820 (gpm) to million gallons per day (mgd) - Answer: 1.18 In the distribution system where would a person expect to find a valve commonly referred to as a curb stop? - Answer: At the property line and immediately in front of the water meter Public water Systems in Texas are required to compile and maintain reports showing - - Answer: Pumpage and chemical used Date of dead-end flushing and storage tanks cleaned Microbiological tests and Chemical tests A Texas Class D Certified Operator can operate a public water system up to____________connections - Answer: 250 All state of Texas Operator License's after issue are good for years. - Answer: 3 years Waterlines should be installed no closer than____________________ feet to any sewer or other possible contaminate lines - Answer: 9 feet Calcium Hypochlorite (HTH) is used as a disinfectant in small systems, what percentage chlorine is this material typically? - Answer: 65-75% Flushing dead-end mains - current state regulations require that all public water systems flush dead-end mains to assure chlorine residual and water quality. What is the minimum flushing requirement? - Answer: once every month A physical connection between a potable water supply and a house well would be - - Answer: cross connection Excessive nitrates in drinking water can cause a condition that affects infants under the age of 6 months. This condition is known as - - Answer: blue babies A public water system is required to take samples of water for bacteriological analysis. The organism that is used as an indicator is called - - Answer: coliform Chlorine dosage is demand plus desired________________ - Answer: residual 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 - - Answer: Stand pipe A water tank that uses compressed air over water to provide pressure is called a - Answer: Hydro pneumatic tank Should a public water supply systems distribution system drop below 20 psi what is required of the operator? - Answer: Immediately correct the problem or cause of low pressure. Notify the Regional TCEQ Office and Issue a "Boil Water Notice" 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. - Answer: 50mg/L In a ground water system if the operator knows the "standing" water level in the well when the pump is off and he/she knows the water level in the well during "pumping" - he/she will be able to determine the______________of the well - Answer: Drawn down TCEQ requires community water systems to have a minimum production capacity of_____________ per connection at peak demand. - Answer: 0.6 gpm The mesh size is an important feature of a well screen because properly sized openings should - Answer: Reduce the amount of sand pumped A common chemical used in the disinfection of a small water supply is - Answer: calcium hypochlorite A public water supply system should maintain a system residual pressure of 20 psi and a minimum normal operating pressure of - - Answer: 35 psi The amount of Chlorine in mg/L that is used up by reacting with iron, organics, or bacteria is called? - Answer: demand The MOST important treatment in water is? - Answer: Disinfection Which of the following would be considered a part(s) of a hypo-chlorinator system? - Answer: Solution feed pump According to state requirements, all public water supply wells shall be provided with a raised concrete sealing block, screened vents and - - Answer: Flow measuring device