CA Water Treatment Plant Operator Quiz Chapter 6

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  • 1/60 Questions

    A quick determination of filtration removal efficiency can be made by comparing filter influent and effluent turbidity levels with those of recent record.

    • True
    • False
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About This Quiz

Filtration
Water Treatment Plant Operation
Volume 1
Sixth Edition
Please let me know if there are any issues with the quiz such as typos, wrong answers, etc. .

CA Water Treatment Plant Operator Quiz Chapter 6 - Quiz

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  • 2. 

    Floc that is too large will cause the top portion of the filter bed to clog rapidly, thus leading to short filter runs.

    • True

    • False

    Correct Answer
    A. True
    Explanation
    If the floc in a filter is too large, it will quickly clog the top portion of the filter bed. This means that the filter will not be able to effectively remove particles and impurities from the water. As a result, the filter runs will be shorter because the filter bed will need to be cleaned or replaced more frequently. Therefore, the statement is true.

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  • 3. 

    Proper surface washing of filter beds should prevent mudball formation.

    • True

    • False

    Correct Answer
    A. True
    Explanation
    Proper surface washing of filter beds is effective in preventing mudball formation. This is because surface washing involves the use of high-pressure water or air to remove debris and sediment from the filter bed's surface. By regularly performing surface washing, any accumulated mud or dirt particles are dislodged and flushed out, preventing them from forming into mudballs. Therefore, it can be concluded that proper surface washing is an effective measure to prevent mudball formation in filter beds.

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  • 4. 

    Pressure filter media are fully enclosed and it is very difficult to assess he media condition by simple visual observation.

    • True

    • False

    Correct Answer
    A. True
    Explanation
    The statement explains that pressure filter media are fully enclosed, making it difficult to assess their condition through simple visual observation. This implies that one cannot determine the state of the media by just looking at it. Therefore, the answer "True" is correct.

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  • 5. 

    Particle counts and particle size distribution analyses present an informative picture of effluent quality produced during the filter ripening phase after a filter has been backwashed.

    • True

    • False

    Correct Answer
    A. True
    Explanation
    Particle counts and particle size distribution analyses provide valuable information about the quality of effluent produced during the filter ripening phase after a filter has been backwashed. These analyses can help determine the effectiveness of the backwashing process and the overall efficiency of the filter system. By measuring the number and size of particles in the effluent, operators can assess the level of filtration achieved and make any necessary adjustments to optimize performance. Therefore, the statement that particle counts and particle size distribution analyses present an informative picture of effluent quality during the filter ripening phase is true.

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  • 6. 

    If a turbidimeter is provided with an alarm feature, virtually instantaneous response to process failures can be achieved.

    • True

    • False

    Correct Answer
    A. True
    Explanation
    If a turbidimeter is equipped with an alarm feature, it means that it can detect any process failures or deviations from the desired turbidity levels in real-time. This allows for immediate notification and intervention, enabling quick corrective actions to be taken. Therefore, the statement that virtually instantaneous response to process failures can be achieved with a turbidimeter that has an alarm feature is true.

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  • 7. 

    Usually, when the backwash water coming up through the filter becomes clear, the media is clean.

    • True

    • False

    Correct Answer
    A. True
    Explanation
    When the backwash water coming up through the filter becomes clear, it indicates that the media in the filter is clean. This is because the backwash water is used to remove dirt, debris, and other impurities from the media. As the water passes through the filter and carries away these contaminants, it gradually becomes clear. Therefore, when the backwash water is clear, it signifies that the media has been effectively cleaned and is ready for further use.

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  • 8. 

    The relationship between turbidity breakthrough and limiting head loss is strongly affected by optimum chemical treatment.

    • True

    • False

    Correct Answer
    A. True
    Explanation
    The statement suggests that the relationship between turbidity breakthrough and limiting head loss is significantly influenced by the optimal use of chemical treatment. This implies that using the right chemicals in water treatment processes can effectively control and reduce turbidity breakthrough, which is the point at which the turbidity levels in water exceed the acceptable limit. Therefore, the statement is true as it highlights the importance of proper chemical treatment in managing turbidity breakthrough and limiting head loss.

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  • 9. 

    What is filter backwashing?

    • A buildup of head loss (pressure drop) across the filter media until it reaches some predetermined design limit

    • A crack or break in a filter bed allowing the passage of floc or particulate matter through a filter

    • A mass of solid particles that is made to flow like a liquid by injection of water

    • A process of reversing the flow of the water through the filter media to remove the entrapped solids

    Correct Answer
    A. A process of reversing the flow of the water through the filter media to remove the entrapped solids
    Explanation
    Filter backwashing is the process of reversing the flow of water through the filter media in order to remove the solids that have been trapped. By doing so, the entrapped solids are dislodged and flushed out of the filter, improving its efficiency and prolonging its lifespan. This technique is commonly used in various filtration systems, such as in swimming pools, water treatment plants, and industrial processes, to maintain the effectiveness of the filters and ensure clean and clear water output.

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  • 10. 

    What is the purpose of filtration?

    • The removal of iron and manganese from the water being treated

    • The removal of particulate impurities and floc from the water being treated

    • The removal of pathogens from the water being treated

    • The removal of tastes and odors from the water being treated

    Correct Answer
    A. The removal of particulate impurities and floc from the water being treated
    Explanation
    Filtration is the process of removing particulate impurities and floc from the water being treated. Particulate impurities can include dirt, sediment, and other solid particles that are suspended in the water. Floc refers to the clumps of particles that are formed during the coagulation and flocculation process. Filtration helps to remove these impurities and floc, resulting in cleaner and clearer water. This is an important step in water treatment to ensure that the water is safe and meets quality standards.

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  • 11. 

    Why is slow sand filtration popular for small systems?

    • Because of high quality source water

    • Because of low demands for water

    • Because of reliability and minimum operation and maintenance requirements

    • Because of the availability of slow sand

    Correct Answer
    A. Because of reliability and minimum operation and maintenance requirements
    Explanation
    Slow sand filtration is popular for small systems because it offers reliability and requires minimum operation and maintenance. This means that once the system is set up, it can consistently provide clean water without the need for constant monitoring or complex maintenance procedures. This makes it an attractive option for small systems that may not have the resources or personnel to dedicate to extensive upkeep. Additionally, slow sand is readily available, further contributing to its popularity.

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  • 12. 

    What is the filter production rate?

    • A measure of the amount of water that can be processed through an individual filter module in a given time period

    • A measure of the flow of water through a filter

    • A measure of the head loss through a filter

    • A measure of the velocity of water flowing down through a filter

    Correct Answer
    A. A measure of the amount of water that can be processed through an individual filter module in a given time period
    Explanation
    The filter production rate refers to the amount of water that can be processed through an individual filter module within a specific time period. This measurement indicates the efficiency and capacity of the filter to effectively remove impurities and contaminants from the water. It is a crucial parameter in determining the suitability and effectiveness of a filter system for a particular application or water treatment process.

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  • 13. 

    Typical functions operators will be expected to perform in the normal operation of the filtration process include which tasks?

    • Checking and adjusting process equipment (changing chemical feed rates)

    • Evaluating filter media condition (media loss, mudballs, cracking)

    • Evaluating water quality conditions (turbidity) and making appropriate process changes

    • Monitoring process performance

    • Visually inspecting facilities

    Correct Answer(s)
    A. Checking and adjusting process equipment (changing chemical feed rates)
    A. Evaluating filter media condition (media loss, mudballs, cracking)
    A. Evaluating water quality conditions (turbidity) and making appropriate process changes
    A. Monitoring process performance
    A. Visually inspecting facilities
    Explanation
    The typical functions that operators are expected to perform in the normal operation of the filtration process include checking and adjusting process equipment, such as changing chemical feed rates, evaluating the condition of the filter media for any signs of media loss, mudballs, or cracking, evaluating water quality conditions, specifically turbidity, and making appropriate process changes based on the evaluation, monitoring the performance of the filtration process, and visually inspecting the facilities to ensure everything is in proper working order.

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  • 14. 

    What is a particle counter?

    • A device which calibrates turbidimeters

    • A device which counts and measures the size of individual particles in water

    • A device which identifies the origin or source of particles

    • A device which measures turbidity

    Correct Answer
    A. A device which counts and measures the size of individual particles in water
    Explanation
    A particle counter is a device used to count and measure the size of individual particles in water. It is designed to provide accurate and precise measurements of the concentration and size distribution of particles present in a liquid sample. This information is important in various industries such as environmental monitoring, pharmaceutical manufacturing, and water treatment, as it helps to assess the quality and cleanliness of the water. By accurately counting and measuring the size of particles, a particle counter can provide valuable data for research, quality control, and regulatory compliance purposes.

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  • 15. 

    To demonstrate log removals of Giardia cysts and viruses, a water system may use particle counting as a substitute for Giardia cyst measurement.

    • True

    • False

    Correct Answer
    A. True
    Explanation
    Particle counting can be used as a substitute for Giardia cyst measurement in a water system to demonstrate log removals of Giardia cysts and viruses. This is because particle counting can provide an indication of the overall presence and removal of particles, including Giardia cysts and viruses, in the water system. By monitoring the particle count, the water system can assess the effectiveness of its treatment processes in removing these pathogens. Therefore, using particle counting as a substitute for Giardia cyst measurement can be a valid and practical approach in evaluating the log removals of these pathogens.

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  • 16. 

    Why should filter washing begin slowly?

    • To allow filter boils to develop uniformly

    • To ensure the loss of light of small-diameter filter media

    • To permit purging (removing) of any entrapped air from the filter media, and also to provide uniform expansion of the filter bed

    • To prevent damage from water hammer

    Correct Answer
    A. To permit purging (removing) of any entrapped air from the filter media, and also to provide uniform expansion of the filter bed
    Explanation
    Filter washing should begin slowly to allow for the purging of any entrapped air from the filter media. This is important to ensure that the filter bed expands uniformly and functions effectively. Starting the process too quickly could result in uneven expansion and potential damage to the filter.

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  • 17. 

    A filter is usually operated until just before clogging or breakthrough occurs.

    • True

    • False

    Correct Answer
    A. True
    Explanation
    A filter is designed to remove impurities from a substance. It is typically operated until it reaches the point just before clogging or breakthrough occurs. This means that the filter is used until it is almost filled with impurities or until it can no longer effectively remove impurities. At this point, the filter needs to be replaced or cleaned to maintain its efficiency. Therefore, the statement "A filter is usually operated until just before clogging or breakthrough occurs" is true.

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  • 18. 

    What is absorption?

    • The gathering of a gas, liquid, or dissolved substance on the surface or interface zone of another material

    • The sedimentation of particulates in very small spaces in a rock or granular material

    • The straining of particles through the pores in a filter

    • The taking in or soaking up of one substance into the body of another by molecular or chemical action

    Correct Answer
    A. The taking in or soaking up of one substance into the body of another by molecular or chemical action
    Explanation
    Absorption refers to the process of one substance being taken in or soaked up by another substance through molecular or chemical action. This can occur when a gas, liquid, or dissolved substance is gathered on the surface or interface zone of another material. It is different from sedimentation, which involves the settling of particles in small spaces, and straining, which involves the passage of particles through filter pores.

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  • 19. 

    Why are surface wash systems usually required for filtration systems?

    • In order to cleanse the filtered water before disinfection (chlorination)

    • In order to encourage mudball formation for subsequent removal

    • In order to produce optimum cleaning of the filter media during backwashing and to prevent mudballs

    • In order to reduce the volume of backwash water required

    Correct Answer
    A. In order to produce optimum cleaning of the filter media during backwashing and to prevent mudballs
    Explanation
    Surface wash systems are usually required for filtration systems in order to produce optimum cleaning of the filter media during backwashing and to prevent mudballs. During the filtration process, particles and debris can accumulate on the filter media, reducing its effectiveness. The surface wash system uses high-pressure water or air to agitate the filter media and dislodge any trapped particles, ensuring that the filter is cleaned thoroughly. By preventing mudballs from forming, the surface wash system helps maintain the efficiency of the filtration system and ensures that the filtered water is of high quality.

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  • 20. 

    A particle counter can tell the difference between a particle of clay and a microorganism (protozoan cysts or oocysts).

    • True

    • False

    Correct Answer
    A. False
    Explanation
    A particle counter cannot differentiate between a particle of clay and a microorganism such as protozoan cysts or oocysts. Particle counters primarily measure the size and number of particles in a given sample, but they cannot determine the composition or nature of the particles. Therefore, it is not true that a particle counter can tell the difference between a particle of clay and a microorganism.

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  • 21. 

    For waht reason must care be exercised in selecting the appropriate feed rate for a filter aid chemical

    • An adequate supply of the filter aid chemical may not be readily available

    • Extra safety precautions must be taken with higher filter aid chemical feed rates

    • Overdosing can cause a violation of the MCL

    • Overdosing can cause sealing of a filter media resulting in drastically shortened filter runs

    Correct Answer
    A. Overdosing can cause sealing of a filter media resulting in drastically shortened filter runs
    Explanation
    Care must be exercised in selecting the appropriate feed rate for a filter aid chemical because overdosing can cause sealing of the filter media, which can lead to drastically shortened filter runs. This means that the filter will not be able to operate efficiently for its intended lifespan, resulting in the need for more frequent maintenance and replacement of the filter media. This can be costly and time-consuming. Therefore, it is important to select the correct feed rate to avoid this issue and ensure optimal filter performance.

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  • 22. 

    In order to save money, energy, and water by maximizing production before backwashing, operators should run their filters until clogging or breakthrough occurs.

    • True

    • False

    Correct Answer
    A. False
    Explanation
    Running filters until clogging or breakthrough occurs would not save money, energy, or water. It would actually result in inefficiency and increased costs. It is more effective and economical to regularly clean and maintain filters to prevent clogging and breakthrough. This ensures optimal performance and prolongs the lifespan of the filters. Therefore, the statement is false.

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  • 23. 

    Which tasks are routine filtration process actions?

    • Checking the filter media condition

    • Checking the filtration process and backwash equipment condition

    • Inspecting the facilities

    • Making visual observations of the backwash operation

    • Operating the filters and backwash

    Correct Answer(s)
    A. Checking the filter media condition
    A. Checking the filtration process and backwash equipment condition
    A. Inspecting the facilities
    A. Making visual observations of the backwash operation
    A. Operating the filters and backwash
    Explanation
    The tasks mentioned in the answer are routine filtration process actions because they involve checking the condition of the filter media, filtration process, and backwash equipment. Additionally, inspecting the facilities and making visual observations of the backwash operation are also part of routine filtration process actions. Finally, operating the filters and backwash is another task that is commonly performed in the routine filtration process.

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  • 24. 

    How can filter baskwash problems be solved?

    • By adjusting backwash flow rates

    • By adjusting backwash surface wash duration

    • By adjusting backwash surface wash flow rates

    • By adjusting the duration of the backwash cycle

    • By adjusting the time sequence of the backwash cycle

    Correct Answer(s)
    A. By adjusting backwash flow rates
    A. By adjusting backwash surface wash duration
    A. By adjusting backwash surface wash flow rates
    A. By adjusting the duration of the backwash cycle
    A. By adjusting the time sequence of the backwash cycle
  • 25. 

    Operators can "bump" a filter to increase the length of the filter run and to avoid backwashing.

    • True

    • False

    Correct Answer
    A. False
    Explanation
    Operators cannot "bump" a filter to increase the length of the filter run and to avoid backwashing. This statement is false. Bumping refers to a technique where operators hit or tap the filter media to dislodge any trapped particles and improve the filter's performance. However, this method is not used to increase the length of the filter run or avoid backwashing. Backwashing is a necessary process to clean the filter media and remove accumulated dirt and debris.

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  • 26. 

    What should an operator do when there is an abrupt change in a critical water quality indicator?

    • Immediately contact the consumer (stakeholders)

    • Immediately enroll in an appropriate training course

    • Immediately notify the news media

    • Immediately review the performance of the filtration process

    • Immediately Immediately review the pretreatment process (coagulation, flocculation, and sedimentation)

    Correct Answer(s)
    A. Immediately review the performance of the filtration process
    A. Immediately Immediately review the pretreatment process (coagulation, flocculation, and sedimentation)
    Explanation
    When there is an abrupt change in a critical water quality indicator, the operator should immediately review the performance of the filtration process and the pretreatment process (coagulation, flocculation, and sedimentation). This is necessary to identify any issues or malfunctions in these processes that may have caused the change in water quality. By reviewing the filtration process and pretreatment process, the operator can assess if any adjustments or corrective actions are needed to maintain the desired water quality standards. This proactive approach helps ensure that the water treatment system is functioning properly and continues to provide safe and clean water to consumers.

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  • 27. 

    How does the rate-of-flow  filter control system work?

    • Each filter effluent control valve is connected to a flow-meter and, as the filter run continues and the media begins to clog, the control valve slowly opens to maintain a constant flow of water through the filter

    • The flow rate varies with head loss and each filter operates at the same, but variable, water surface level

    • The flow to each filter influent is split or divided to each weir and equal flow is automatically distributed to each filter

    • The influent flow to each filter is divided by a weir and the water surface level in each filter varies according to headloss, but the flow rate remains constant for each filter

    Correct Answer
    A. Each filter effluent control valve is connected to a flow-meter and, as the filter run continues and the media begins to clog, the control valve slowly opens to maintain a constant flow of water through the filter
    Explanation
    The correct answer explains how the rate-of-flow filter control system works. It states that each filter effluent control valve is connected to a flow-meter. As the filter run continues and the media begins to clog, the control valve slowly opens to maintain a constant flow of water through the filter. This means that as the filter gets clogged, the control valve adjusts to ensure that the flow rate of water remains consistent.

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  • 28. 

    What is the "ripening period" for a filter?

    • When applications of the floc build up on the material previously deposited on the media surface

    • When the floc buildup causes taste and odors

    • When the floc buildup on the filter media degrades

    • When the period of floc buildup reaches excessive headloss

    Correct Answer
    A. When applications of the floc build up on the material previously deposited on the media surface
    Explanation
    The "ripening period" for a filter refers to the point when applications of the floc (a combination of suspended particles and coagulated material) start to accumulate on the material that was previously deposited on the surface of the filter media. This buildup of floc can cause taste and odor issues in the filtered water. As the floc continues to accumulate, it eventually degrades the filter media and reaches a point of excessive headloss, which signifies the end of the ripening period.

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  • 29. 

    Why should operators avoid running their filters until clogging or breakthrough occurs?

    • Because clogging or breakthrough will increase filter maintenance requirements

    • Because clogging or breakthrough will require additional space for sludge disposal

    • Because clogging or breakthrough will require more backwash water

    • Because when breakthrough occurs, there will be an increase in filtered water turbidity

    Correct Answer
    A. Because when breakthrough occurs, there will be an increase in filtered water turbidity
    Explanation
    Operators should avoid running their filters until clogging or breakthrough occurs because when breakthrough occurs, there will be an increase in filtered water turbidity. This means that the water will become more cloudy or murky, indicating that the filter is no longer effectively removing impurities. Running the filters until this point can lead to decreased water quality and potentially harmful contaminants entering the system. It is important to monitor and maintain filters regularly to prevent clogging or breakthrough and ensure the production of clean and safe water.

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  • 30. 

    What is the best way to compare filter runs? By using the

    • Effluent turbidity levels

    • Length of the filtration cycle

    • Unit Filter Run Volume (UFRV) technigue

    • Volume of backwash water per cycle

    Correct Answer
    A. Unit Filter Run Volume (UFRV) technigue
    Explanation
    The best way to compare filter runs is by using the Unit Filter Run Volume (UFRV) technique. This technique allows for a standardized comparison of filter runs by measuring the volume of water filtered before the filter needs to be backwashed. By comparing the UFRV for different filter runs, one can determine the efficiency and effectiveness of the filtration system. This method takes into account the filtration cycle length, effluent turbidity levels, and volume of backwash water per cycle, providing a comprehensive assessment of the filter's performance.

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  • 31. 

    Under what filtration conditions is the addition of a polymer coagulant aid or chemical filter aid often beneficial?

    • At filtration rates when filtered water has high turbidity levels

    • At filtration rates when mudballs tend to form during backwash

    • At high filtration rates when iron and alum floc will shear in the pores of the filter and short filter runs will result because of turbidity breakthrough

    • At high filtration rates when there is insufficient water in the backwash water tank

    Correct Answer
    A. At high filtration rates when iron and alum floc will shear in the pores of the filter and short filter runs will result because of turbidity breakthrough
    Explanation
    Adding a polymer coagulant aid or chemical filter aid can be beneficial under high filtration rates when iron and alum floc will shear in the pores of the filter. This is because the addition of a coagulant aid or filter aid can help prevent the shearing of floc, which can lead to short filter runs and turbidity breakthrough. By using a coagulant aid or filter aid, the filtration process can be more efficient and effective in removing turbidity from the filtered water.

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  • 32. 

    The removal of mechanisms that apply to slow sand siltration are directly comparable to those used in rapid san filtration.

    • True

    • False

    Correct Answer
    A. False
    Explanation
    The statement is false because the removal mechanisms in slow sand filtration are not directly comparable to those used in rapid sand filtration. While both methods aim to remove impurities from water, slow sand filtration relies on biological processes such as microbial activity and sedimentation, while rapid sand filtration primarily relies on physical processes such as sedimentation and adsorption. Therefore, the mechanisms involved in these two filtration methods differ significantly.

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  • 33. 

    Turbidity readings provide an indication of the number or size of particles.

    • True

    • False

    Correct Answer
    A. False
    Explanation
    Turbidity readings do not provide an indication of the number or size of particles. Turbidity is a measure of the cloudiness or haziness of a liquid due to suspended particles. It does not provide specific information about the number or size of these particles. Therefore, the statement is false.

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  • 34. 

    What is the Unit Filter Run Volume (UFRV) in gallons per square foot if a plant filters 2.8 million gallons before backwashing is required and the filter surface area is 500 square feet?

    • 5,000 gal/sq ft

    • 5,600 gal/sq ft

    • 6,000 gal/sq ft

    • 6,200 gal/sq ft

    • 6,400 gal/sq ft

    Correct Answer
    A. 5,600 gal/sq ft
    Explanation
    The Unit Filter Run Volume (UFRV) is calculated by dividing the total volume filtered before backwashing by the filter surface area. In this case, the plant filters 2.8 million gallons (2,800,000) before backwashing is required, and the filter surface area is 500 square feet. Therefore, the UFRV is 2,800,000 gallons divided by 500 square feet, which equals 5,600 gallons per square foot.

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  • 35. 

    What is adsorption?

    • The gathering of a gas, liquid, or dissolved substance on the surface or interface zone of another material.

    • The sedimentation of particulates in very small spaces in a rock or granulated material

    • The straining of particles through the pores in a filter

    • The taking in or soaking up of one substance into the body of another by molecular or chemical action

    Correct Answer
    A. The gathering of a gas, liquid, or dissolved substance on the surface or interface zone of another material.
    Explanation
    Adsorption refers to the process in which a gas, liquid, or dissolved substance accumulates or gathers on the surface or interface zone of another material. This can occur due to attractive forces between the adsorbate (the substance being adsorbed) and the adsorbent (the material on which the adsorption occurs). Adsorption is different from absorption, which involves the penetration and diffusion of a substance into the bulk of another material.

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  • 36. 

    What is the percent of water filtered that is used for backwashing if a plant filters 1.8 million gallons and 28,000  gallons of filtered water is used for backwashing?

    • 1.11%

    • 1.22%

    • 1.30%

    • 1.39%

    • 1.56%

    Correct Answer
    A. 1.56%
    Explanation
    The percent of water filtered that is used for backwashing can be calculated by dividing the amount of water used for backwashing (28,000 gallons) by the total amount of water filtered (1.8 million gallons) and then multiplying by 100. In this case, the calculation would be (28,000/1,800,000) x 100 = 1.56%. Therefore, the correct answer is 1.56%.

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  • 37. 

    Which factors are desirable filter media characteristics?

    • Does not react with substances in the water (is inert and easy to clean up)

    • Free of impurities

    • Good hydraulic characteristics (is permeable)

    • Hard and durable

    • Insoluble in water

    Correct Answer(s)
    A. Does not react with substances in the water (is inert and easy to clean up)
    A. Free of impurities
    A. Good hydraulic characteristics (is permeable)
    A. Hard and durable
    A. Insoluble in water
    Explanation
    The desirable filter media characteristics include not reacting with substances in the water, being free of impurities, having good hydraulic characteristics (being permeable), being hard and durable, and being insoluble in water. These characteristics ensure that the filter media will effectively remove contaminants from the water without introducing any additional substances or impurities. Additionally, the media should have good hydraulic characteristics to allow water to flow through easily, and it should be hard and durable to withstand the filtration process. Being insoluble in water is important to prevent the media from breaking down or dissolving in the water.

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  • 38. 

    What are particulates?

    • Clumps of bacteria and particulate impurities that have come together and formed a cluster

    • Very small, finely divided solids (particles that do not dissolve) that remain dispersed in a liquid for a long time due to their small size and electrical charge

    • Very small open spaces in a rock or granular material

    • Very small solids suspend in water which can vary widely in size, shape, density, and electrical charge

    Correct Answer
    A. Very small solids suspend in water which can vary widely in size, shape, density, and electrical charge
    Explanation
    Particulates are very small solids that are suspended in water. They can vary in size, shape, density, and electrical charge. These particles do not dissolve in the water and remain dispersed for a long time due to their small size and electrical charge. They can come in various forms and can be made up of different materials.

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  • 39. 

    If the head of water on the filter media of a gravity filter is 3.5 feet, what is the pressure on the media surface in pounds per square inch (psi)?

    • 1.3 psi

    • 1.5 psi

    • 1.7 psi

    • 1.9 psi

    • 2.2 psi

    Correct Answer
    A. 1.5 psi
    Explanation
    The pressure on the media surface can be calculated using the formula: pressure (psi) = head (feet) / 2.31. Plugging in the given value of 3.5 feet, we get: 3.5 / 2.31 = 1.516 psi. Rounded to the nearest tenth, the answer is 1.5 psi.

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  • 40. 

    During a 24-hour period, a water treatment plant filters 1.4 million gallons. The surface area of the filters is 500 square feet. What is the filtration rate in gallons per minute per square foot?

    • 1.9 GPM/sq ft

    • 2.1 GPM/sq ft

    • 2.3 GPM/sq ft

    • 2.5 GPM/sq ft

    • 2.7 GPM/sq ft

    Correct Answer
    A. 1.9 GPM/sq ft
    Explanation
    The filtration rate can be calculated by dividing the total volume of water filtered in a given time period by the surface area of the filters. In this case, the filtration rate is calculated by dividing 1.4 million gallons by 24 hours, then dividing the result by 60 minutes, and finally dividing it by the surface area of 500 square feet. The calculation results in a filtration rate of 1.9 gallons per minute per square foot.

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  • 41. 

    What is the pressure in pounds per square foot on the bottom of a tank when the water depth is 16 feet?

    • 624 lbs/sq ft

    • 749 lbs/sq ft

    • 998 lbs/sq ft

    • 1,122 lbs/sq ft

    • 1,248 lbs/sq ft

    Correct Answer
    A. 998 lbs/sq ft
    Explanation
    The pressure at the bottom of a tank is determined by the weight of the water above it. The pressure increases with depth. The weight of the water is given by the formula weight = density x volume x acceleration due to gravity. Since the density of water is constant, the weight is directly proportional to the depth. Therefore, the pressure at the bottom of a tank at a depth of 16 feet is greater than the pressure at a depth of 12 feet. Among the given options, the closest value to the pressure at 16 feet is 998 lbs/sq ft.

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  • 42. 

    What is the best way to ensure high filtration efficiency?

    • Keep the filters clean by backwashing

    • Minimize the head loss through the filters

    • Perform the jar tests on a regular basis

    • Select an effluent turbidity goal (level) and stay below the target value

    Correct Answer
    A. Select an effluent turbidity goal (level) and stay below the target value
    Explanation
    To ensure high filtration efficiency, it is best to select an effluent turbidity goal and strive to keep the turbidity level below the set target value. This means maintaining a low level of suspended particles in the filtered water, which indicates effective filtration. By setting a specific goal and monitoring the turbidity regularly, any deviations can be addressed promptly to maintain optimal filtration efficiency.

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  • 43. 

    The high sensitivity of the particle counter makes which sampling tasks critical for proper operation?

    • Handling and delivery

    • Preservation and storage

    • Retrieval and delivery

    • Storage and retrieval

    Correct Answer
    A. Handling and delivery
    Explanation
    The high sensitivity of the particle counter requires careful handling and delivery to ensure proper operation. If the particles are not handled and delivered correctly, it can lead to contamination or damage to the counter, affecting its accuracy and performance. Therefore, proper handling and delivery are critical for maintaining the integrity and functionality of the particle counter.

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  • 44. 

    What is the upward force in pounds on the bottom of an  empty sedimentation basin caused by a groundwater depth of 8 feet above the tank bottom? The basin is 10 feet wide and 30 feet long.

    • 112,300 lbs

    • 122,000 lbs

    • 131,000 lbs

    • 149,800 lbs

    • 168,500 lbs

    Correct Answer
    A. 149,800 lbs
    Explanation
    The upward force on the bottom of the sedimentation basin is caused by the pressure exerted by the groundwater above it. This pressure is determined by the depth of the groundwater and the area of the bottom of the basin. In this case, the groundwater depth is given as 8 feet and the basin is 10 feet wide and 30 feet long. To calculate the upward force, we can use the formula: Force = Pressure x Area. The pressure is equal to the weight of the water above the bottom of the basin, which can be calculated as the product of the density of water (62.4 lbs/ft³), the depth of the groundwater (8 ft), and the acceleration due to gravity (32.2 ft/s²). The area of the bottom of the basin is 10 feet wide and 30 feet long. By substituting these values into the formula, we get: Force = (62.4 lbs/ft³) x (8 ft) x (32.2 ft/s²) x (10 ft) x (30 ft) = 149,800 lbs.

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  • 45. 

    When working around filtration equipment such as pumps and motors, which items are potential safety hazards?

    • Electrical equipment

    • Mechanical equipment

    • Open-surface filters

    • Pathogenic organisms

    • Valve and pump vaults, sumps, and filter galleries

    Correct Answer(s)
    A. Electrical equipment
    A. Mechanical equipment
    A. Open-surface filters
    A. Valve and pump vaults, sumps, and filter galleries
    Explanation
    When working around filtration equipment such as pumps and motors, several items can pose potential safety hazards. Electrical equipment can be hazardous due to the risk of electric shock or short circuits. Mechanical equipment can be dangerous if not properly maintained, as it can cause injuries or accidents. Open-surface filters can be hazardous as they may have sharp edges or contain harmful substances. Valve and pump vaults, sumps, and filter galleries can pose risks such as falling or getting trapped. Therefore, all of these items are potential safety hazards when working around filtration equipment.

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  • 46. 

    With lengthening filter run time, the percentage of large particles passing through the filter often decreases while small particles increase.

    • True

    • False

    Correct Answer
    A. False
    Explanation
    The statement suggests that as the filter run time increases, the percentage of large particles passing through the filter decreases while small particles increase. However, the correct answer is false. In reality, as the filter run time increases, the filter becomes clogged with particles, causing a decrease in its efficiency. This leads to an increase in the percentage of particles, both large and small, passing through the filter.

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  • 47. 

    Filter removal efficiency depends largely on which factors?

    • Effectiveness of the pretreatment process in conditioning the suspended solids for removal by sedimentation and filtration

    • Filter operation

    • Quality of the water being treated

    • Recordkeeping program

    • Weather conditions

    Correct Answer(s)
    A. Effectiveness of the pretreatment process in conditioning the suspended solids for removal by sedimentation and filtration
    A. Filter operation
    A. Quality of the water being treated
    Explanation
    The filter removal efficiency depends largely on the effectiveness of the pretreatment process in conditioning the suspended solids for removal by sedimentation and filtration, the filter operation, and the quality of the water being treated. These factors play a crucial role in determining how well the filter can remove the suspended solids and contaminants from the water. The pretreatment process prepares the solids for removal, while the filter operation ensures proper functioning of the filter. The quality of the water being treated also affects the efficiency of the filter, as different types and levels of contaminants require different filtration methods.

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  • 48. 

    After start-up of a backwash pump, operators should always check for which items?

    • Excessive noise

    • Excessive vibration

    • Leakage (water, lubricants)

    • Overheating

    • Volute flow

    Correct Answer(s)
    A. Excessive noise
    A. Excessive vibration
    A. Leakage (water, lubricants)
    A. Overheating
    Explanation
    After starting up a backwash pump, operators should always check for excessive noise, excessive vibration, leakage (water, lubricants), and overheating. This is important to ensure that the pump is functioning properly and to identify any potential issues or malfunctions. Excessive noise or vibration could indicate a problem with the pump's motor or impeller, while leakage could suggest a seal or gasket failure. Overheating may be a sign of motor or bearing issues, which need to be addressed promptly to prevent further damage. Regular checks of these items help to maintain the pump's efficiency and prevent costly repairs or downtime.

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  • 49. 

    Particle counts can be correlated with turbidity.

    • True

    • False

    Correct Answer
    A. False
    Explanation
    Particle counts cannot be directly correlated with turbidity. While both turbidity and particle counts are measures of water quality, they are not interchangeable. Turbidity measures the cloudiness or haziness of a liquid caused by suspended particles, while particle counts specifically measure the number of particles present in a given volume of liquid. Therefore, while turbidity can provide an indication of the presence of particles, it does not provide an accurate measure of the actual particle count.

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  • Current Version
  • Mar 22, 2023
    Quiz Edited by
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  • Dec 31, 2011
    Quiz Created by
    PaulMJr

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