New Mexico Water Operator Level 4 Practice Exam

These questions are part of the practice quiz. Start practicing

• Total dissolved solids (TDS) are defined as?
• In a conventional surface-water treatment process, which stage is responsible for destabilizing particles to prepare for aggregation?
• For calculating friction loss in a pipe, which factor is not required?
• The waterborne disease hardest to kill with chlorine is which?
• A near 1000 ft long ___ inch diameter PVC pipeline is to be installed in a rocky area. A 24 inch wide trench was excavated to a depth of 4 ft. How many cubic yards of bedding sand will be required to provide sand encasement around the pipe for a total depth of 24 inches, assuming 12 inches of bedding is to be replaced below the pipe?
• Why is it important to care when making rubber to glass connections in the laboratory?
• Mud balls observed in a sand filter after backwashing indicate which condition?
• Which of the following is an important component of cathodic protection?
• In cross-connection control, what is the minimum distance for an air gap between the fill pipe and the receiving tank rim when using an air gap?
• A detention time of 5 hours is within the usual 2-4 hour range.
• In the event of a security breach involving a storage tank hatch, which action is appropriate while awaiting confirmation?
• Which statement best defines air gap separation in a piping system?
• What determines the type of respiratory protection required for a specific tank?
• What is the purpose of an air relief valve on a pump?
• What does the presence of fecal coliform or non-coliform bacteria in a water sample indicate?
• What are essential elements of a water system emergency response plan?
• In the chlorine residual equation, which term describes the chlorine that is consumed by substances in water?
• How would a Level 4 operator participate in improving system reliability and resilience through asset management?
• What is the function of the headworks in a treatment plant and what components are typically included?
• In distribution system analysis, the energy grade line is used to compare with pipe elevations to determine which outcomes?
• Which statement best describes the OSHA Hazard Communication Standard's requirement for warnings and labels?
• How does increasing water age influence disinfection byproduct formation and microbial safety, and which management strategies help reduce water age?
• What percentage of the total workforce is on the dayshift if 5 of 8 employees are dayshift?
• Which of the following causes black stain on the plumbing fixtures?
• The Marble test is used to determine the stability of which component in water? (Variant wording)
• Which chemicals are usually most effective in removing odors and tastes due to inorganic matter in a water supply?
• Filters often indicate backwashing is needed. Which cue best signals this need?
• When using a non-exchange softening media such as Zeolite, what are these media commonly called?
• Why are Level 4 operators commonly required for supervisory roles, and what capabilities do they bring?
• Under US EPA Safe Drinking Water Act regulations, what is the basis for the number of monthly samples you must collect for BAC-T test?
• Which backflow prevention device would normally be used on the feed water line directly to a low-pressure boiler that uses chemical treatment of the feed water?
• How should a preventive maintenance program be integrated into daily operations for a water system?
• What effect will the addition of chlorine gas have on the pH of the water?
• Why is pH control important in water treatment beyond disinfection?
• Name several disinfectants used in drinking water treatment and summarize one pro/cons for each.
• Which aspect is essential for an effective flushing program in a distribution system?
• List typical regulatory compliance responsibilities that a Level 4 operator oversees.
• What is the correct interval for refresher training on SCBA equipment?
• An operator discovers that a log has been cut from the hatch of a distribution system storage tank. Until the incident is confirmed, this security breach should be treated as what?
• How often must a fluoride concentration be tested by operators who are fluoridating the public water supply?
• Under the US EPA Safe Drinking Water Act regulations, the monthly BAC-T sampling frequency is based on which factor?
• Differentiate between primary disinfection and secondary disinfection in water treatment.
• What are the essential components of an incident command structure in water system emergency management?
• Gravel packing is used to?
• Which arrangement is used to protect potable water lines used for priming non-potable water pumps on sewage pumps?
• Which form of chlorine is typically used for primary disinfection in drinking water treatment?
• Coliform bacteria must be tested for in accordance with the NMED drinking water regulations. What are coliform bacteria?
• Which of the following best describes organic contaminants such as herbicides and insecticides?
• An air line 200 ft long is installed in a well for determining water level. With air pumped and the pressure gauge stabilized at 36 psi, what is the water level in feet?
• Jar testing for coagulation produced an optimum coagulant dosage of 42.8 mg/L at a plant treating 2.0 MGD; with alum costing $200 per ton. What is the chemical cost for a 30-day period?
• What is the purpose of a flushing program for the distribution system?
• In a gravel well, what is the expected effect of screen encrustation?
• What is the purpose of mixing or baffling in storage tanks, and how does it affect residual distribution?
• What is the length of each sedimentation tank?
• Chlorine residual equals which of the following?
• In a ton cylinder, which valve provides access to the gas at the top?
• What information is typically collected and recorded during a flushing program?
• What is the acceptable accuracy range for small residential water meters?
• Under NM drinking water regulations, how many total coliform compliance samples must be collected per month by a community water system?
• The two sedimentation tanks at a surface water treatment plant are each 40' x 90' long and 10'6" deep; one tank is out of service and the plant is treating 2.37 MGD. What is the detention time in the sedimentation stage, in hours?
• HTH is which compound?
• In a water treatment plant using coagulation, sedimentation, and filtration, which chlorine application point minimizes THM formation?
• Which factor is associated with higher formation of disinfection byproducts in drinking water?
• How many pounds of HTH 70% available chlorine will be necessary to disinfect a water storage tank stand pipe 40 feet high and 18 feet in diameter using a 15 mg/L dosage?
• Where is backflow prevention typically required?
• Who prepares the exposure control plan required by OSHA blood-borne pathogen standards?
• What should you do to avoid faulty pH meter calibrations?
• Which process can be used to determine iron problems without removing the iron from the water?
• What is the primary reason for maintaining a disinfectant residual in the distribution system?
• What is the primary purpose of flocculation in surface-water treatment?
• To what extent should Level 4 operators coordinate activities to improve reliability and resilience in asset management?
• The Marble test is used to determine the stability of which component in water?
• Which condition is necessary for a vacuum-type chlorination system to operate properly?
• In the situation described in the preceding questions, how many BACT compliance samples must be collected by the Anywhere water system in June?
• Calculate the average detention time in days for a rectangular basin 90 ft long, 40 ft wide, and 15 ft deep with a flow rate of 2 MGD.
• What is the MCL for Arsenic in mg/l?
• If a sedimentation basin has a detention time of 3 hours, is this within the usual range of 2-4 hours?
• In a rapid gravity filtration test, the filter is 14x14 feet. The influent valve is closed and the water level drops 6 inches in 56 seconds. What is the filtration rate in GPM?
• Ozone as a disinfectant has which of the following characteristics?
• What is the primary purpose of adding coagulants in water treatment?
• A ground storage tank disinfection scenario requires adding chlorine gas so that the final concentration will be 15 mg/L when the tank is full. If the tank is 27 feet in diameter and 22'6" high from the bottom to overflow, approximately how many pounds of chlorine gas are needed?
• Granulated Activated Carbon (GAC) is primarily used to remove which type of compounds?
• Amperometric methods in water analysis are used to measure chlorine residual.
• What indicators prompt a distribution system flushing program?
• If finished water chlorine residual is 45 mg/L, what should an operator do first?
• Friction loss in pipelines is a function of which factors?
• If an employee repeatedly disregards safety requirements, which management action is appropriate?
• Which technique can be used for taste and color problems, in a water supply?
• When the vacuum on the chlorinator system is too low, where should you look for the problem?
• What is the Lead and Copper Rule and why are alkalinity and pH important for corrosion control?
• A solid contact basin combines which processes?
• In performing a jar test, which factor is least important?
• Amperometric methods in water analysis are used to measure which parameter?
• Which parameter is typically considered when evaluating disinfectant choice for a drinking-water distribution system?
• Which indicator is most directly used to determine when to initiate cleaning or backwashing in a membrane system?
• To determine friction loss, you need to know what?
• Approximately how many gallons are in one sedimentation tank?
• What is a pressure reducing valve (PRV) and what issues might indicate a malfunction?
• In the US EPA surface water rule, CT is defined as the product of disinfectant concentration and contact time.
• Filtration objective?
• What is the difference between return sludge and waste sludge in a clarifier?
• What is the width of each sedimentation tank?
• You are the operator of a community water system located in anywhere New Mexico, anywhere is required to collect a minimum of three compliance samples per month for a Total Coliform analysis. In April one of Anywhere's water system samples reported as Total Coliform positive all repeat samples collected, were reported Total Coliform negative. During May the anywhere water system reported a routine sample as total Coliform positive. One of the May repeat. Samples reported as fecal chloroform positive. Which of the following statements is correct?
• Under New Mexico drinking water regulations, how often must groundwater systems be sampled for inorganic contaminants such as selenium, mercury, and cyanide?
• Which term describes the amount of water a well will produce for each foot of drawdown?
• For a feed water line to a boiler with chemical treatment, which backflow prevention device is typically used?
• The acronym BACT stands for Best Available Control Technology.
• For HCH, which of the following ranges represents available chlorine content?
• A water system serving 14,000 people with conventional treatment requires which level of operator in charge under NM regulations?
• What does the term GAC refer to in water treatment?
• Which type of pump can be used with a well, regardless of the depth of the well?
• Which of the following substances combines with Magnesium to give a laxative affect to the water ?
• Compare the effects of alum and ferric chloride as coagulants with respect to pH change and sludge production.
• What action level and indicators are involved in bacteriological testing under the Safe Drinking Water Act, and what happens if coliforms are detected?
• Taste and odor problems in finished water are primarily traced to algae in what location?
• What is the correct sequence of steps a Level 4 operator would take to respond to a boil-water advisory?
• What is the purpose of an air line in well measurement?
• If the chlorination injector is not drawing solution effectively, which component should be checked first?
• Describe a typical chemical feed system layout and list safety considerations for handling treatment chemicals.
• How can a groundwater source be screened for surface water intrusion and what treatments might be applied if intrusion is detected?
• How many pounds of sand will be trapped per million gallons of water produced when pumping sand at 3 ppm by weight and installing a small trap?
• What is the function of a clearwell in a water treatment facility?
• Approximately how long is the PVC pipeline mentioned in the bedding sand calculation?
• Which term best describes chemicals used to prevent metal ions from interfering with water quality by binding them?
• Which of the following is the main cause of taste and odor problems in treatment surface water?
• In a 10 MGD conventional water treatment plant, continuous raw water pH monitoring shows pH rising during daylight hours and dropping during the night. What condition is indicated by this pattern?
• What is the minimum residual needed to kill viruses?
• What are common causes of taste and odor in finished water and typical mitigation strategies?
• Under NM drinking water regulations, what is the maximum number of hours allowed between collecting a distribution system sample and analysis for total coliforms?
• Why is thorough recordkeeping required for operator certification and system operation?
• Out of eight employees, five work the dayshift. What percentage of the total employees work the dayshift?
• A 12-inch pipe carrying 1200 GPM feeds into a 6-inch pipe. If the velocity in the 12-inch pipe is 3.4 ft/s, what is the velocity in the 6-inch pipe?
• HCH is typically what percentage of available chlorine?
• Which of the following is NOT typically a factor in choosing between chlorine and chloramine in a distribution system?
• What are the primary products formed when chlorine reacts with water?
• Surface water intake structures should be designed to draw water from which depths?
• Which action best supports maintaining safe distribution with respect to disinfectant residuals?
• How often must a surface water system be sampled for inorganic chemical contaminants, such as chromium, cyanide, fluoride and mercury?
• Which statement best describes how pH affects disinfection efficacy and corrosion propensity in water mains?
• What is the typical available chlorine percentage for HCH?
• Is positive or negative pressure needed to run a chlorinator?
• Height from bottom to overflow for the tank is 22'6". What is that height in inches?
• What is a venturi meter and how is it used to measure flow in water systems?
• Chlorination of water containing natural organic matter can lead to the formation of THMs. Which practice helps minimize THM formation?
• Why is corrosion control important in a distribution system, and what are common methods to achieve it?
• What is a sludge blanket in a clarifier, and why must it be managed?
• Mud balls observed after backwashing in a sand filtration system indicate which condition? (Variant wording)
• The generally accepted maximum filtration rate for a single-media rapid sand filter is approximately what?
• When insufficient chlorine is used for disinfection, the total chlorine residual may be made up of combined chlorine residual, causing taste and odor problems. What causes this problem?
• What does SCADA stand for and what is its role in water operations?
• Which statement best describes a primary objective of asset management in a water system?
• What is the depth of the sedimentation tank described in the plant layout?
• Distinguish between hardness and alkalinity and explain how each influences scale and corrosion.
• What is the Hazen-Williams equation used for and what variables does it involve?
• Which statement differentiates free chlorine from chloramines?
• A 10-inch water main 2,640 ft long is disinfected by applying 60 mg/L of chlorine and allowing it to stand 24 hours. Approximately how many pounds of dry hypochlorite 65% chlorine are needed?
• In the Hench scale test, the proper Polyphosphate dose is the lowest dose that delays noticeable discoloration for a period of how many days?
• What is the face area of each sedimentation tank (length times width)?
• Phosphate compounds such as sodium polyphosphate are inhibitors used to tie up forming ions. What is another name for these inhibitors?
• What do you get from the bottom valve of a ton cylinder, and the top valve?
• Which symptom would most strongly suggest a pressure-reducing valve is malfunctioning?
• One of your employees refuses to observe safety requirements. What should you do?
• Which of the following best describes the strategies commonly used to control taste and odor in drinking water?
• What is the primary purpose of the OSHA hazard communication standard?
• Disinfection objective?
• Which statement best describes the role of aeration in water treatment for taste and odor control?
• Which statement correctly defines chlorine residual in water treatment?
• Sedimentation stage objective in conventional treatment?
• Which range represents the virus inactivation residual requirement?
• What is the primary purpose of a finished water clear well in a conventional treatment plant?
• What is the purpose of an aeration step in water treatment, and in what scenarios is it used?
• Which statement about UV disinfection is true?
• The generally accepted maximum filtration rate for a single-media rapid sand filter is approximately what? (Variant wording)
• How is a regulatory-required disinfectant residual monitored and what actions are taken if readings indicate inadequate residuals?
• What is the usual detention time range in a sedimentation basin?
• Which kinds of chemicals are organic contaminants?
• Refresher training on proper use of SCBA equipment should be conducted on what frequency?
• The concept of degree of hazard is used to determine which type of backflow prevention devices should be used in a given situation. Which device must be used to protect a cross connection involving sewer-connected waste?
• What is the purpose of a rapid mix in coagulation and what parameters are typically controlled there?
• How does organic matter in water influence chlorine demand?
• Which disease requires higher levels of disinfection than the others?
• Explain the concept of head loss and why it matters in network design.
• What factors influence choosing chlorine versus chloramine as a disinfectant in a drinking-water distribution system?
• Define hydraulic grade line and explain how it is used in water distribution analysis.
• When an air gap is used, what is the minimum gap between the bottom of the fill pipe and the floor level rim of the receiving tank?
• Why is inhibited acid used to clean lime scale in a well screen?
• Why are iron and manganese found in higher concentrations in the deeper portions of water reservoirs?
• What information is key to determine that a well screen may be sand bridged?
• If the underdrains at a treatment plant are not functioning, which treatment unit is most likely affected?
• Backwashing in a rapid-sand filtration system reverses flow to clean the media. Which cues indicate backwashing is needed?
• A reduction in specific capacity indicates what outcome for the operation?
• How often should a cross-connection survey be conducted and what is its purpose?
• In the described sedimentation setup, how many tanks are currently in service?
• What causes a cone of depression?
• What is cross-connection control and why is it critical for drinking-water safety?
• Which factor best describes meter accuracy in residential water measurement?
• What is a water loss audit and why is it essential for utility management?
• A water main break reduces pressure in a section of the distribution system. Which is a possible consequence?
• Which of the following pumps is suitable for wells regardless of depth?
• Which of the following best defines nonrevenue water?
• Why is sample integrity critical for bacteriological testing and name two common sampling pitfalls.
• What is membrane fouling and what are common indicators that require cleaning or maintenance?
• How does pressure management affect water system reliability, and what typical causes of pressure loss should operators monitor?
• Which statement best describes a reason to monitor transmembrane pressure in a membrane system?
• What actions are taken if disinfectant residuals fall too low?
• How do you clean a well screen clogged with lime scale?
• What is the diameter of the tank used in the chlorine mass calculation?