Water Treatment Class 3
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If a water supply exceeds a maximum contaminant level, whose responsibility is it to notify the consumer?
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EPA
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Laboratory
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State
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Water supplier
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Welcome to the Water Treatment Quiz for class 3! Water treatment is a vital process that ensures access to clean and safe water for various purposes. This quiz will test your knowledge about the fascinating world of water treatment and the techniques involved in purifying water.
Water treatment, but also gain a deeper understanding of the critical role it plays See morein public health and environmental sustainability. So, dive into the world of water treatment and see how well you know the processes that make our water clean, safe, and suitable for consumption! If you like this quiz, share it with your friends.
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- 2.
Treated water is always used for backwashing
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Because of its availability
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Because the use of untreated water is more costly.
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To avoid contamination of the filter bed.
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To lessen sludge disposal problems.
Correct Answer
A. To avoid contamination of the filter bed.Explanation
The correct answer is to avoid contamination of the filter bed. Using treated water for backwashing helps prevent any potential contamination of the filter bed, ensuring that the water being filtered remains clean and safe for use. Using untreated water could introduce impurities or contaminants into the filter bed, compromising its effectiveness in removing pollutants from the water. Therefore, using treated water is essential to maintain the integrity and efficiency of the filtration process.Rate this question:
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- 3.
Sedimentation is improved by
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A sludge blanket
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Reducing the detention period in the basin
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Short circuiting
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Uniform, horizontal, low-velocity flow across the basin.
Correct Answer
A. Uniform, horizontal, low-velocity flow across the basin.Explanation
Uniform, horizontal, low-velocity flow across the basin improves sedimentation because it allows for the settling of suspended particles in the water. When the flow is uniform and horizontal, it prevents the formation of dead zones or areas of high velocity, which can disrupt the settling process. Low velocity ensures that particles have enough time to settle, while a uniform and horizontal flow helps to evenly distribute the particles across the basin, increasing the efficiency of sedimentation.Rate this question:
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- 4.
If a fuse continues to blow, you should
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Inspect the affected equipment to determine the cause
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Provide a jumper in the box
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Replace it with a fuse of lower capacity.
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Replace it with a higher capacity fuse.
Correct Answer
A. Inspect the affected equipment to determine the causeExplanation
If a fuse continues to blow, it is important to inspect the affected equipment to determine the cause. This is because a blown fuse is often an indication of an underlying issue or fault in the equipment. By inspecting the equipment, one can identify any faulty components, loose connections, or other problems that may be causing the fuse to blow. Once the cause is determined, appropriate measures can be taken to rectify the issue and prevent further fuse blowouts. Replacing the fuse with a lower or higher capacity or providing a jumper in the box would not address the root cause of the problem and may lead to further damage or safety hazards.Rate this question:
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- 5.
Harvesting, dewatering, dredging, shading, and lining are all methods for controlling rooted aquatic plants
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Without much effort
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Physically
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Chemically.
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Biologically
Correct Answer
A. PhysicallyExplanation
Physically controlling rooted aquatic plants involves methods such as harvesting, dewatering, dredging, shading, and lining. These methods require physical intervention to remove or restrict the growth of aquatic plants. Harvesting involves manually cutting or removing the plants from the water. Dewatering involves reducing the water level to expose and dry out the plants. Dredging involves removing the plants by scooping or suctioning them from the water. Shading involves blocking sunlight to prevent plant growth. Lining involves placing physical barriers to restrict the spread of plants. These methods do not involve chemical or biological means of control.Rate this question:
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- 6.
Sedimentation can be improved by
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Lowering the water temperature after flocculation.
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Maintaining a uniform, horizontal, low-velocity flow across the basin
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Maintaining a uniform sludge blanket
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Reducing the detention time
Correct Answer
A. Maintaining a uniform, horizontal, low-velocity flow across the basinExplanation
Maintaining a uniform, horizontal, low-velocity flow across the basin can improve sedimentation. This is because it helps to prevent the re-suspension of settled particles, allowing them to settle and accumulate at the bottom of the basin more effectively. By ensuring a uniform flow, the particles are less likely to be disturbed and remain settled, resulting in improved sedimentation. Additionally, a low-velocity flow helps to minimize turbulence, which can also prevent the re-suspension of particles and promote better settling.Rate this question:
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- 7.
Objectives for a preventive maintenance program include
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Eliminate parts inventory
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Get organized to unstop overflowing manholes quickly
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Increase use of standby equipment.
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Reduce emergency repairs and maintenance.
Correct Answer
A. Reduce emergency repairs and maintenance.Explanation
The correct answer is "reduce emergency repairs and maintenance." This objective is important for a preventive maintenance program because it aims to minimize unexpected breakdowns and repairs, which can be costly and disruptive. By implementing regular maintenance procedures and inspections, potential issues can be identified and addressed before they escalate into emergencies, leading to a more efficient and cost-effective maintenance program.Rate this question:
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- 8.
An operator is caught in a room where chlorine gas is leaking. If the operator does not have a mask, what should the operator do?
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Keep mouth closed, keep head as high as possible, and quickly walk out of the room, holding breath if possible.
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Lay down on the floor and quickly crawl out of the room
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Pull shirt over mouth and face and quickly walk out of the room
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Walk out of the room quickly.
Correct Answer
A. Keep mouth closed, keep head as high as possible, and quickly walk out of the room, holding breath if possible.Explanation
The correct answer suggests that the operator should keep their mouth closed to avoid inhaling the chlorine gas, keep their head as high as possible to avoid the gas sinking to the ground, and quickly walk out of the room to minimize exposure. Holding their breath if possible can further reduce the risk of inhaling the gas. This combination of actions aims to protect the operator from the harmful effects of chlorine gas and ensure their safety.Rate this question:
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- 9.
Water may be aerated by several methods, almost all of which involve
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Covering the storage facilities
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Exposing a large surface area to the atmosphere
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Increasing the pressure
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Reducing its temperature
Correct Answer
A. Exposing a large surface area to the atmosphereExplanation
Exposing a large surface area to the atmosphere is a method of aerating water. When water is exposed to the atmosphere, it allows for the exchange of gases, particularly oxygen, between the air and water. This process helps to increase the dissolved oxygen levels in the water, which is essential for aquatic organisms to survive. By increasing the surface area of water in contact with the air, more oxygen can be absorbed, improving the overall quality and health of the water.Rate this question:
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- 10.
The most desirable place to feed activated carbon in a lime-soda ash softening plant is
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After lime feed.
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In the clearwell
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To raw water at earliest stage possible.
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With lime feed
Correct Answer
A. To raw water at earliest stage possible.Explanation
The most desirable place to feed activated carbon in a lime-soda ash softening plant is to the raw water at the earliest stage possible. This is because activated carbon is used to remove organic compounds, taste, and odor from the water. By adding it at the earliest stage, it ensures that these impurities are effectively removed before the water goes through the lime-soda ash softening process. Adding activated carbon after lime feed or in the clearwell may not be as effective in removing these impurities, leading to lower water quality.Rate this question:
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- 11.
Treatment plant operators should
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Obtain reports of school dental-health surveys to better determine whether local fluoridation is necessary or effective.
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Insist on oral fluoridation treatments if their community does not fluoridate.
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Have some knowledge of the health effects associated with fluoridation
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None of the above
Correct Answer
A. Have some knowledge of the health effects associated with fluoridationExplanation
Treatment plant operators should have some knowledge of the health effects associated with fluoridation. This knowledge is important in order to make informed decisions about whether or not local fluoridation is necessary or effective. By understanding the potential health benefits and risks of fluoridation, treatment plant operators can ensure that they are providing safe and effective water treatment for their community.Rate this question:
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- 12.
When operating a surface-water treatment plant, which of the following laboratory tests is of most significance for establishing chemical dosages for coagulating water?
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Calcium and magnesium
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PH and alkalinity
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Sulfates
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Total hardness
Correct Answer
A. pH and alkalinityExplanation
pH and alkalinity are the most significant laboratory tests for establishing chemical dosages for coagulating water in a surface-water treatment plant. pH determines the acidity or alkalinity of the water, which affects the efficiency of coagulation. Alkalinity measures the water's ability to resist changes in pH, indicating its buffering capacity. By analyzing pH and alkalinity levels, operators can determine the appropriate chemical dosages needed to achieve optimal coagulation and flocculation in the treatment process.Rate this question:
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- 13.
Fire fighting may cause low pressure in an area of a distribution system. The lowpressure might lead to
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Contamination of the system by backsiphonage
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Ice formation in the pipes
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Loss of chlorine residual
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Muddy water.
Correct Answer
A. Contamination of the system by backsiphonageExplanation
When fire fighting causes low pressure in a distribution system, it creates a potential for backsiphonage. Backsiphonage occurs when there is a sudden drop in pressure, causing water to flow backward from a contaminated source into the distribution system. This can lead to the contamination of the system, as the water from the contaminated source mixes with the clean water in the distribution system. Therefore, the low pressure caused by fire fighting can result in the system being contaminated by backsiphonage.Rate this question:
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- 14.
Sodium thiosulfate crystals are placed in bacteriological sample bottles to
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Hold pH at a constant value
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Kill any pathogens that may be present in the sample
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Neutralize any chlorine present in the sample
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Preserve the sample.
Correct Answer
A. Neutralize any chlorine present in the sampleExplanation
Sodium thiosulfate crystals are used to neutralize any chlorine present in the sample. Chlorine is commonly used as a disinfectant in water treatment, and if it is present in the bacteriological sample, it can interfere with the growth of bacteria. Sodium thiosulfate reacts with chlorine to form harmless chloride ions, effectively neutralizing its disinfectant properties. This allows the bacteria in the sample to grow and be preserved for further analysis.Rate this question:
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- 15.
The carrying capacity of water mains is often reduced by
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High pressure.
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Looping.
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Tuberculation
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Vacuum breakers.
Correct Answer
A. TuberculationExplanation
Tuberculation refers to the buildup of mineral deposits, such as rust and scale, on the inner walls of water mains. This accumulation can reduce the carrying capacity of the mains by narrowing the diameter and obstructing the flow of water. As a result, the water pressure decreases, and the overall efficiency of the water distribution system is compromised. Therefore, tuberculation is a common factor that reduces the carrying capacity of water mains.Rate this question:
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- 16.
Adsorption operates on the principle of
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Adhesion
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Chance collision
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Gravity
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Magnetic polarization
Correct Answer
A. AdhesionExplanation
Adsorption operates on the principle of adhesion, which refers to the attraction between molecules of different substances. In adsorption, molecules from a gas or liquid adhere to the surface of a solid material. This occurs because the attractive forces between the molecules of the gas or liquid and the solid surface are stronger than the cohesive forces between the molecules of the gas or liquid. As a result, the molecules adhere to the solid surface, forming a thin film or layer. Adhesion is the fundamental principle behind adsorption processes.Rate this question:
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- 17.
A water treatment plant produces 850,000 gpd. On one day 24,526 gal was used for backwashing the filters. What was the net production for this day?
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406,740 gal
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604,740 gal
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476,604 gal
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825,474 gal
Correct Answer
A. 825,474 galExplanation
The net production for the day can be calculated by subtracting the amount of water used for backwashing the filters from the total production. In this case, the total production is 850,000 gpd and the amount used for backwashing is 24,526 gal. Therefore, the net production for the day is 850,000 - 24,526 = 825,474 gal.Rate this question:
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- 18.
Hydrogen sulfide in water may be effectively controlled by
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Aeration.
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Filtration.
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Fluoridation
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Sedimentation.
Correct Answer
A. Aeration.Explanation
Hydrogen sulfide is a gas that can dissolve in water, causing an unpleasant odor and taste. Aeration is the process of introducing air into the water, which helps to oxidize and remove hydrogen sulfide. This is achieved by exposing the water to air, allowing the gas to escape and reducing its concentration. Filtration, fluoridation, and sedimentation are not effective methods for controlling hydrogen sulfide in water.Rate this question:
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- 19.
The efficiency of the aeration process is primarily determined by the
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Velocity of air flow.
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Surface contact between air and water
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Number of splash areas
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Mixing patterns.
Correct Answer
A. Surface contact between air and waterExplanation
The efficiency of the aeration process is primarily determined by the surface contact between air and water. This is because aeration involves introducing air into water to increase the oxygen levels. The more surface area of water that comes into contact with the air, the more oxygen can be transferred from the air to the water. This allows for better oxygenation of the water, which is essential for various biological and chemical processes. Therefore, maximizing the surface contact between air and water is crucial for improving the efficiency of the aeration process.Rate this question:
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- 20.
Automation of a water system would provide
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Constant pressure.
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Cross-connection control
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Prevention of corrosion
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Prevention of main breaks
Correct Answer
A. Constant pressure.Explanation
Automation of a water system would provide constant pressure by ensuring that the water supply is regulated and maintained at a consistent level. This eliminates the need for manual adjustments and allows for a steady flow of water throughout the system. Constant pressure is essential for various applications such as household use, irrigation, and industrial processes, as it ensures reliable and efficient operation. By automating the water system, fluctuations in pressure can be minimized, resulting in improved performance and customer satisfaction.Rate this question:
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- 21.
Practicing breakpoint chlorination involves chlorine addition until
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Taste and odor characteristics of a swimming pool have dissipated
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Combined chlorine residual reaches its highest point of disinfection
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Chloroorganics and chloramines have formed
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Chloroorganics and chloramines are destroyed and free available chlorine residual is formed.
Correct Answer
A. Chloroorganics and chloramines are destroyed and free available chlorine residual is formed.Explanation
Practicing breakpoint chlorination involves adding chlorine until chloroorganics and chloramines are destroyed and free available chlorine residual is formed. This process is necessary to ensure effective disinfection of the swimming pool. Chloroorganics and chloramines can cause unpleasant taste and odor in the pool, so it is important to eliminate them. By reaching the breakpoint, the chlorine is able to break down these compounds and create a residual of free available chlorine, which is crucial for maintaining a safe and clean swimming environment.Rate this question:
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- 22.
A portion of cast-iron pipe after five years of use shows a white-colored scale ½ -in. thick on the inside pipe walls. This means that
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The water has been corrosive
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The water is chemically unstable and is depositing calcium carbonate
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The C factor should increase due to the lining effect.
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Red water will soon become a problem
Correct Answer
A. The water is chemically unstable and is depositing calcium carbonateExplanation
The white-colored scale on the inside pipe walls indicates the deposition of calcium carbonate. This suggests that the water is chemically unstable and is causing the formation of this scale.Rate this question:
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- 23.
Effectiveness of the coagulation/flocculation process is best measured
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Against a coagulant performance curve.
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By titration to an end point.
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By visual observation.
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Using a nephelometric turbidimeter
Correct Answer
A. Using a nephelometric turbidimeterExplanation
The effectiveness of the coagulation/flocculation process is best measured using a nephelometric turbidimeter. This device measures the turbidity of a water sample by shining a light through it and detecting the amount of scattered light. Turbidity is a measure of the cloudiness or haziness of a liquid, and it is directly related to the effectiveness of the coagulation/flocculation process. By monitoring the turbidity over time, the coagulant performance curve can be established, which shows the relationship between the dosage of coagulant and the resulting turbidity. This curve helps determine the optimal dosage of coagulant for efficient water treatment.Rate this question:
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- 24.
"Black water" complaints are the result of
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Alum entering the distribution system.
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High threshold odor numbers in the treated water
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High trihalomethanes
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Powdered activated carbon entering the distribution system
Correct Answer
A. Powdered activated carbon entering the distribution systemExplanation
The presence of "black water" complaints can be attributed to powdered activated carbon entering the distribution system. This is because powdered activated carbon is commonly used in water treatment processes to remove organic compounds and improve water quality. However, if the carbon is not properly filtered or if there is a malfunction in the system, it can enter the distribution system and cause discoloration of the water, resulting in black water complaints from consumers.Rate this question:
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- 25.
If static pressure in a water system is too high, the remedy is to
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Install a booster pump
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Install pressure-reducing valves.throttle the suction valve on the well pump
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Throttle the suction valve on the well pump
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None of the above
Correct Answer
A. Install pressure-reducing valves.throttle the suction valve on the well pumpExplanation
If the static pressure in a water system is too high, the remedy is to install pressure-reducing valves and throttle the suction valve on the well pump. This combination of actions will help regulate and reduce the pressure within the system, ensuring that it does not exceed safe levels. Installing a booster pump would only further increase the pressure, which is not the desired solution in this case.Rate this question:
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- 26.
Both alum and ferric sulfate are affected by
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Alkalinity
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Filter media selection
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Other coagulants
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Sunlight.
Correct Answer
A. AlkalinityExplanation
Alum and ferric sulfate are both affected by alkalinity. Alkalinity refers to the ability of water to resist changes in pH. In the case of alum and ferric sulfate, alkalinity can impact their effectiveness as coagulants in water treatment. High alkalinity can reduce the efficiency of coagulation, leading to inadequate removal of suspended particles and contaminants. On the other hand, low alkalinity can result in excessive coagulant dosage and pH fluctuations. Therefore, understanding and controlling alkalinity levels is crucial for optimizing the coagulation process and ensuring efficient water treatment.Rate this question:
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- 27.
The amount of time a sample can be stored depends on
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The laboratory procedure being used
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The stability of the constituent to be tested and whether the sample can be preserved.
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The temperature
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Whether the sample contains raw or treated water.
Correct Answer
A. The stability of the constituent to be tested and whether the sample can be preserved.Explanation
The amount of time a sample can be stored depends on the stability of the constituent to be tested and whether the sample can be preserved. This means that if the constituent is stable and the sample can be preserved properly, it can be stored for a longer period of time. On the other hand, if the constituent is not stable or the sample cannot be preserved adequately, it may have a shorter storage time. Factors such as the laboratory procedure being used, temperature, and whether the sample contains raw or treated water may also have an impact on the storage time, but the primary determinant is the stability of the constituent and the preservation of the sample.Rate this question:
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- 28.
If a filter has been out of service and allowed to go dry, which filter control valveshould be used to refill it with water?
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Effluent valve
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Influent valve
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Rewash valve
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Backwash inlet valve
Correct Answer
A. Backwash inlet valveExplanation
When a filter has been out of service and allowed to go dry, the backwash inlet valve should be used to refill it with water. The backwash inlet valve is responsible for allowing water to enter the filter during the backwashing process, which helps to clean and remove any accumulated debris. In this case, since the filter has been out of service and needs to be refilled with water, the backwash inlet valve would be the appropriate choice to ensure water flow into the filter.Rate this question:
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- 29.
A condition that tends to increase the corrosiveness of water on metals is
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High dissolved oxygen content
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High fluoride concentration
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Low dissolved oxygen content
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Low total dissolved solids
Correct Answer
A. High dissolved oxygen contentExplanation
High dissolved oxygen content tends to increase the corrosiveness of water on metals because oxygen is a strong oxidizing agent. When oxygen dissolves in water, it can react with the metal surface, leading to the formation of metal oxides or hydroxides. These compounds can corrode the metal, causing it to deteriorate over time. Therefore, water with high dissolved oxygen content is more likely to accelerate the corrosion process on metals.Rate this question:
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- 30.
An important reason for analyzing raw-water samples for color is
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To improve customer relations.
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To comply with the Secondary Drinking Water Regulations
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Because the test data is a good baseline indicator for treatment plant efficiency.
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Because it may indicate high levels of organic compounds, which may produce trihalomethanes upon contact with chlorine.
Correct Answer
A. Because it may indicate high levels of organic compounds, which may produce trihalomethanes upon contact with chlorine.Explanation
Analyzing raw-water samples for color is important because it may indicate high levels of organic compounds, which may produce trihalomethanes upon contact with chlorine. Trihalomethanes are potentially harmful compounds that can form when chlorine reacts with organic matter in water. Therefore, monitoring the color of raw-water samples can serve as an early warning sign for the presence of organic compounds and help ensure the safety and quality of drinking water.Rate this question:
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- 31.
The removal of organic materials using activated carbon depends on
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Adsorption.
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Filtration
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Oxidation
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Recarbonation.
Correct Answer
A. Adsorption.Explanation
Activated carbon is known for its ability to adsorb organic materials. Adsorption is the process in which molecules from a fluid phase adhere to the surface of a solid. In the case of activated carbon, its large surface area and porous structure allow it to effectively trap and remove organic compounds through adsorption. Filtration, oxidation, and recarbonation are not directly related to the removal of organic materials using activated carbon.Rate this question:
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- 32.
All chlorine cylinders are required to contain at least one fusible metal safety device (plug) designed to melt at between _____ Degrees F
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98 - 105
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120 - 150
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158 - 165
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200 - 212
Correct Answer
A. 158 - 165Explanation
Chlorine cylinders are required to have a fusible metal safety device (plug) that is designed to melt at a specific temperature range. The correct answer is 158 - 165 degrees Fahrenheit. This means that the plug will melt if the temperature inside the cylinder reaches this range, allowing the pressure to be released and preventing the cylinder from exploding.Rate this question:
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- 33.
When using the multiple-tube fermentation test method and coliform organismsoccur in six out of ten of the 10-mL portions of a single standard sample, then
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Customers should be told to boil their water
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The system must collect a set of repeat samples within 24 h.
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The chlorine residual should be increased to 1.0 mg/L
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The water main should be flushed for 24 h.
Correct Answer
A. The system must collect a set of repeat samples within 24 h.Explanation
When coliform organisms occur in six out of ten of the 10-mL portions of a single standard sample using the multiple-tube fermentation test method, it indicates a potential contamination issue. In such cases, it is necessary for the system to collect a set of repeat samples within 24 hours. This is important to confirm the presence of coliform organisms and to assess the extent of the contamination. Collecting repeat samples helps ensure the accuracy of the test results and allows for appropriate actions to be taken to address the issue and protect the customers' health.Rate this question:
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- 34.
Polyelectrolytes are
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Coagulants
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Coagulant aids
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Used for hardness reduction
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Used for pH adjustment
Correct Answer
A. Coagulant aidsExplanation
Polyelectrolytes are substances that are used in water treatment processes to aid in the coagulation of suspended particles. They work by neutralizing the charges on the particles, allowing them to come together and form larger flocs that can be easily removed from the water. While coagulants are substances that directly cause the particles to come together, polyelectrolytes act as coagulant aids, enhancing the effectiveness of the coagulants. Therefore, the correct answer is "coagulant aids".Rate this question:
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- 35.
Fluoride chemicals, like many chemicals used in water treatment, constitute a variety of potential health hazards, but the hazard most common in handling and feeding dry fluoride compounds is
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Asphyxiation.
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Bodily contact.
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Ingestion.
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Inhalation.
Correct Answer
A. Inhalation.Explanation
Fluoride chemicals used in water treatment can pose various health hazards, but the most common hazard associated with handling and feeding dry fluoride compounds is inhalation. This means that the act of breathing in these chemicals can be dangerous. Inhalation of fluoride compounds can lead to respiratory issues and other adverse health effects.Rate this question:
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- 36.
With the coming of winter, the water temperature drops. A likely operational problem at a filtration plant with coagulation is
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Floc carryover from the sedimentation system
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High alkalinity
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High chlorine residual
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Odor.
Correct Answer
A. Floc carryover from the sedimentation systemExplanation
During winter, the water temperature drops, which can lead to a decrease in the efficiency of the coagulation process at a filtration plant. Coagulation is the process of adding chemicals to the water to form flocs, which help in the removal of impurities. If the water temperature drops too low, the flocs may not form properly or may break apart, resulting in floc carryover from the sedimentation system. This means that the flocs are not settling properly and are carried over into the filtered water, leading to reduced water quality.Rate this question:
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- 37.
When both chlorine and polyphosphate are added to a well, which should be fedfirst?
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Chlorine
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Polyphosphate
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Both added simultaneously
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Either may be added first
Correct Answer
A. PolyphosphateExplanation
Polyphosphate should be fed first because it helps to prevent the formation of scale and corrosion in the well. By adding polyphosphate first, it forms a protective layer on the surfaces of the well and pipes, which helps to inhibit the build-up of mineral deposits and reduces the risk of corrosion. Once the polyphosphate has been added, chlorine can then be added to disinfect the water and kill any bacteria or pathogens that may be present. This sequential addition ensures that both the prevention of scale and corrosion and the disinfection of the water are effectively achieved.Rate this question:
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- 38.
Coagulation usually
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Occurs in seconds
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Occurs in minutes
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Occurs in hours
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Depends on coagulant and mixing rates
Correct Answer
A. Occurs in secondsExplanation
Coagulation refers to the process of clumping together of particles in a liquid to form larger, heavier particles. This process typically happens very quickly, usually within seconds. The coagulant, which is a substance added to the liquid to facilitate coagulation, along with the mixing rates, play a role in determining the speed at which coagulation occurs. However, regardless of these factors, coagulation is generally a rapid process that happens within seconds.Rate this question:
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- 39.
If excessive media loss occurs consistently, one should
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Check the rate-of-flow controller for malfunctioning
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Discontinue using surface washers.
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Investigate all backwashing procedures
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Probe the filter bed.
Correct Answer
A. Investigate all backwashing proceduresExplanation
Excessive media loss refers to the loss of filter media during the backwashing process. Investigating all backwashing procedures is the correct answer because it suggests examining the entire process of backwashing to identify any potential issues or mistakes that may be causing the excessive media loss. This could include checking the duration, frequency, and intensity of backwashing, as well as ensuring that all steps and equipment involved in the process are functioning properly. By investigating all backwashing procedures, one can pinpoint and address the underlying cause of the excessive media loss.Rate this question:
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- 40.
What type of treatment should be given when a well produces red water?
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PH adjustment, aeration, and filtration
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Sedimentation
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Softening
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Taste and odor control
Correct Answer
A. pH adjustment, aeration, and filtrationExplanation
When a well produces red water, it indicates the presence of iron or manganese in the water. pH adjustment, aeration, and filtration are the appropriate treatments for this issue. pH adjustment helps to balance the acidity or alkalinity of the water, aeration allows the iron or manganese to oxidize and form solid particles that can be filtered out, and filtration removes the solid particles from the water. This treatment process helps to improve the quality and appearance of the water by addressing the cause of the red color.Rate this question:
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- 41.
Trihalomethanes are formed when
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The water contains organic chemicals
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The water contains large concentrations of inorganic chemicals
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The filters are backwashed
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Chlorine reacts with humic and fulvic acids in water
Correct Answer
A. Chlorine reacts with humic and fulvic acids in waterExplanation
Trihalomethanes are formed when chlorine reacts with humic and fulvic acids in water. Humic and fulvic acids are organic chemicals that are naturally present in water sources. When chlorine, which is often used as a disinfectant in water treatment, reacts with these organic acids, it forms trihalomethanes. Trihalomethanes are a group of chemical compounds that can be harmful to human health when consumed in large concentrations. Therefore, it is important to monitor and control the levels of trihalomethanes in drinking water.Rate this question:
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- 42.
Baffles are installed downstream of the basin inlet to
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Reduce velocity.
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Induce turbulence
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Collect settled water as it leaves the basin
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Channel the water
Correct Answer
A. Reduce velocity.Explanation
Baffles are installed downstream of the basin inlet to reduce velocity. Baffles are structures or devices that are placed in a fluid flow to disrupt the flow pattern and slow down the velocity of the fluid. By reducing the velocity, baffles help to prevent the water from flowing too quickly through the basin, allowing sediment and particles to settle out more effectively. This helps in the process of water treatment and improves the efficiency of the basin.Rate this question:
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- 43.
Ferric hydroxide is
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A strong solution for purging bacterial growths
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Common rust
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Formed at the cathode
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Used for dissolving tubercules
Correct Answer
A. Common rustExplanation
Ferric hydroxide is commonly known as rust. Rust is formed when iron or steel reacts with oxygen and moisture in the air. It is a reddish-brown substance that forms a flaky layer on the surface of metal objects. Rust is not a solution for purging bacterial growths, nor is it used for dissolving tubercules. Therefore, the correct answer is common rust.Rate this question:
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- 44.
The detention time usually required in a conventional straight-flow sedimentationbasin is _______ h.
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0.5 - 1
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2 - 6
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10 - 12
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24
Correct Answer
A. 2 - 6Explanation
The detention time required in a conventional straight-flow sedimentation basin is typically between 2 to 6 hours. This is because the sedimentation process involves allowing the water to flow slowly through the basin, allowing enough time for the suspended particles to settle at the bottom. A detention time of 2 to 6 hours ensures that there is sufficient time for the settling process to occur effectively, resulting in clearer water.Rate this question:
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- 45.
Anabaena can cause what undesirable characteristic in water?
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Color and decomposition
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Evaporation and contamination
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Hardness and "blue babies"
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Taste and odor
Correct Answer
A. Taste and odorExplanation
Anabaena is a type of cyanobacteria that can produce compounds called geosmin and methylisoborneol, which are responsible for causing unpleasant taste and odor in water. These compounds can give the water a musty or earthy smell and taste, making it undesirable for consumption.Rate this question:
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- 46.
The main purpose of flocculation is to
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Allow chemicals to mix thoroughly
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Bring together microfloc particles
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Filter out suspended particles
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Settle out suspended particles.
Correct Answer
A. Bring together microfloc particlesExplanation
Flocculation is a process used in water treatment where small particles in the water are brought together to form larger particles called microflocs. These microflocs are easier to remove from the water through sedimentation or filtration processes. The main purpose of flocculation is to bring together these microfloc particles, as it helps in the efficient removal of suspended particles from the water. By allowing the particles to aggregate and form larger flocs, they can be easily separated from the water, resulting in clearer and cleaner water.Rate this question:
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- 47.
The term volatile can best be defined as
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A precipitate
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Capable of being easily attacked
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Highly explosive
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Turning to vapor easily
Correct Answer
A. Turning to vapor easilyExplanation
The term volatile refers to substances or compounds that have a tendency to evaporate or turn into vapor easily at relatively low temperatures. This means that volatile substances have a high vapor pressure and can easily transition from a liquid or solid state to a gaseous state. Volatility is often associated with substances that have low boiling points and are easily vaporized, such as certain solvents or volatile organic compounds.Rate this question:
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- 48.
If maintaining pressure in a fluoride feed system is not necessary, backflow can best be prevented by
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Installing an atmospheric loop.
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Installing a vacuum breaker.
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Installing an antisiphoning device
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Providing an air gap.
Correct Answer
A. Providing an air gap.Explanation
An air gap is the best way to prevent backflow in a fluoride feed system when maintaining pressure is not necessary. An air gap is a physical separation between the water supply and the fluoride feed system, creating a vertical gap that prevents any possibility of backflow. This ensures that contaminated water cannot flow back into the main water supply, keeping it safe and free from any potential contamination. Installing an atmospheric loop, vacuum breaker, or antisiphoning device may provide some level of protection, but none are as effective as providing an air gap.Rate this question:
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- 49.
One method to detect short-circuiting problems is to
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Change coagulants and coagulant aids.
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Conduct tracer studies
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Increase detention time.
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Install perforated baffles
Correct Answer
A. Conduct tracer studiesExplanation
Conducting tracer studies is a method used to detect short-circuiting problems in a system. Tracer studies involve introducing a tracer substance into the system and monitoring its movement to identify any areas of the system where the flow is not uniform. By conducting tracer studies, any short-circuiting problems can be identified and addressed, allowing for more efficient and effective operation of the system.Rate this question:
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Current Version
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Oct 30, 2024Quiz Edited by
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Aug 04, 2015Quiz Created by
Brandon Gebhart
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