Water Treatment Plant Operation Volume 2 Chapter 16
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Questions and Answers
- 1.
All available water supplies can be classified according to mineral quality
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
Water supplies can indeed be classified according to mineral quality. This classification is based on the presence and concentration of minerals in the water. Different water sources can have varying levels of minerals such as calcium, magnesium, and iron. These minerals can affect the taste, odor, and overall quality of the water. Therefore, it is accurate to say that all available water supplies can be classified based on their mineral content.Rate this question:
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- 2.
Osmosis is the passage of a fluid from a weak solution into a more concentrated solution across a semipermeable membrane
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
Osmosis is a process where a fluid, such as water, moves from an area of lower concentration to an area of higher concentration through a semipermeable membrane. This movement occurs in order to equalize the concentration on both sides of the membrane. Therefore, the statement that osmosis is the passage of a fluid from a weak solution into a more concentrated solution across a semipermeable membrane is true.Rate this question:
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- 3.
The water permeable (a) and the mineral permeability (b) Constance a characteristics of the particular membrane that is used in the processing it received
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
The statement is true because the water permeability and mineral permeability are indeed characteristics of the specific membrane used in its processing. These characteristics determine the membrane's ability to allow water and minerals to pass through it.Rate this question:
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- 4.
The water flux increases is mineral count content of the feed increases because the osmotic pressure contribution increases with increasing mineral content
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
The water flux does not increase as the mineral count content of the feed increases. In fact, the opposite is true. The osmotic pressure contribution decreases with increasing mineral content, leading to a decrease in water flux. Therefore, the statement is false.Rate this question:
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- 5.
Under ideal condition for a reverse osmosis unit (pure feed water and no fouling of the membrane surface), there is no change in water flocks with time
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
Under ideal conditions for a reverse osmosis unit, where the feed water is pure and there is no fouling of the membrane surface, there should be no change in water flocks with time. This means that the reverse osmosis process is effectively removing impurities and maintaining a consistent quality of water.Rate this question:
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- 6.
With a reverse osmosis unit, divalent ions, such as calcium and sulfate, are better rejected than monovalent ions such as sodium and chloride
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
Reverse osmosis is a process that uses a semi-permeable membrane to remove impurities from water. In this process, water is forced through the membrane, leaving behind contaminants. Divalent ions, such as calcium and sulfate, have a higher charge and larger size compared to monovalent ions like sodium and chloride. Due to their larger size and higher charge, divalent ions are less likely to pass through the membrane, making them better rejected by the reverse osmosis unit. Therefore, the statement that divalent ions are better rejected than monovalent ions in a reverse osmosis unit is true.Rate this question:
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- 7.
In the reverse osmosis operation as the temperature of the water increases, flux decreases
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
In reverse osmosis, as the temperature of the water increases, the flux actually increases. This is because higher temperatures increase the kinetic energy of the water molecules, causing them to move more rapidly. As a result, there is a higher rate of diffusion through the membrane, leading to an increase in flux. Therefore, the statement that the flux decreases with increasing temperature is incorrect.Rate this question:
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- 8.
Water is transmitted through the membrane and a much more rapid rates than minerals
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
Water is transmitted through the membrane at a much more rapid rate than minerals. This means that water molecules can easily pass through the membrane, while minerals may have difficulty doing so. This is because the membrane is selectively permeable, allowing for the passage of water molecules but restricting the movement of larger molecules such as minerals. As a result, water can be transported across the membrane more quickly compared to minerals, making the statement true.Rate this question:
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- 9.
Reverse osmosis modules provide a large surface area for the attachment and growth of bacterial slams and molds
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
Reverse osmosis modules have a large surface area due to their membrane structure. This surface area allows for the attachment and growth of bacterial slams and molds. Bacterial slams and molds can accumulate on the membrane, leading to fouling and decreased efficiency of the reverse osmosis system. Therefore, the statement is true.Rate this question:
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- 10.
When operating an electrodialysis unit, any process problems discovered must be acted upon immediately
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
When operating an electrodialysis unit, any process problems discovered must be acted upon immediately. This is because electrodialysis is a continuous process that relies on the proper functioning of various components, such as the membranes and electrodes. If any problems are left unaddressed, they can negatively impact the efficiency and effectiveness of the unit, leading to poor separation performance and potential damage to the equipment. Therefore, immediate action is necessary to ensure the smooth operation of the electrodialysis unit.Rate this question:
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- 11.
What is the term flux used to describe
- A.
The feasibility of the membrane to remove salinity
- B.
The flexibility of the semipermeable membrane
- C.
The fluctuations in flow through the semipermeable membrane
- D.
The rate of water flow to miss any permeable membrane
Correct Answer
D. The rate of water flow to miss any permeable membraneExplanation
The term flux is used to describe the rate of water flow through a permeable membrane. It refers to the amount of water that passes through the membrane per unit of time.Rate this question:
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- 12.
What could be the cause of a decrease in flux in a reverse osmosis unit
- A.
Membrane compaction
- B.
Membrane expansion
- C.
Membrane maintenance
- D.
Membrane temperature differential
Correct Answer
A. Membrane compactionExplanation
Membrane compaction could be the cause of a decrease in flux in a reverse osmosis unit. Compaction refers to the squeezing of the membrane which can lead to reduced pore size and increased resistance to water flow. This can result in a decrease in the amount of water that can pass through the membrane, leading to a decrease in flux.Rate this question:
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- 13.
What is the purpose of demineralization
- A.
To Deionize water
- B.
To determine water hardness
- C.
To recover and recycle minerals
- D.
To separate minerals from water
Correct Answer
D. To separate minerals from waterExplanation
The purpose of demineralization is to separate minerals from water. This process involves removing minerals such as calcium, magnesium, and iron, which can cause scaling and other issues in various industrial applications. Demineralization is commonly used in industries such as power plants, chemical processing, and water treatment to ensure the purity of water and prevent mineral buildup in equipment and pipes.Rate this question:
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- 14.
How is recovery defined demineralization process
- A.
The amount of minerals recovered for products sale
- B.
The percentage of feed flow that is recovered as product water
- C.
The percentage of feed salinity that is recovered as reject
- D.
The return of the membrane to original performance levels
Correct Answer
B. The percentage of feed flow that is recovered as product waterExplanation
Recovery in the demineralization process is defined as the percentage of feed flow that is recovered as product water. This means that it measures the amount of water that is successfully treated and converted into usable product water, compared to the total amount of feed water that enters the process. A higher recovery rate indicates a more efficient demineralization process, as it means a larger percentage of the feed water is being converted into usable product water.Rate this question:
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- 15.
Why is acid added as a pretreatment step before demineralization and using cellulose acetate membranes
- A.
To control corrosiveness
- B.
To increase hydrolysis
- C.
To reduce compaction
- D.
To slow hydrolysis
Correct Answer
D. To slow hydrolysisExplanation
Acid is added as a pretreatment step before demineralization and using cellulose acetate membranes to slow down the process of hydrolysis. Hydrolysis is a chemical reaction that occurs when water breaks down the chemical bonds in a substance. By slowing down hydrolysis, the acid helps to preserve the integrity of the cellulose acetate membranes and prevent them from breaking down too quickly. This ensures that the membranes can effectively separate the minerals from the water during the demineralization process.Rate this question:
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- 16.
What is concentrated polarization
- A.
A buildup of retained particles on the membrane surface due to be watering of the feed closest to the membrane
- B.
A concentration of minerals and the reject or recovery water
- C.
In mixing of water stew neutralize (polarize) the ionic content of the water
- D.
A polarization of minerals and the reject or recovery water
Correct Answer
A. A buildup of retained particles on the membrane surface due to be watering of the feed closest to the membraneExplanation
Concentrated polarization refers to a buildup of retained particles on the surface of a membrane. This occurs when the feed closest to the membrane contains a high concentration of particles, causing them to accumulate and create a layer on the membrane surface. This buildup can negatively affect the performance and efficiency of the membrane, leading to reduced filtration and potentially clogging the membrane.Rate this question:
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- 17.
What is the most common serious problem resulting from concentration polarization
- A.
Compaction of the membrane
- B.
Increasing tendency of precipitation of sparingly soluble salts and deposition of particle matter on the membrane surface
- C.
Leakage of salts and particulate matter through the membrane
- D.
Reduction and maintenance requirements
Correct Answer
B. Increasing tendency of precipitation of sparingly soluble salts and deposition of particle matter on the membrane surfaceExplanation
The most common serious problem resulting from concentration polarization is the increasing tendency of precipitation of sparingly soluble salts and deposition of particle matter on the membrane surface. This occurs when the concentration of solutes near the membrane surface becomes too high, leading to the formation of solid precipitates and the deposition of particles on the membrane. This can reduce the efficiency of the membrane and hinder its performance. Compaction of the membrane, leakage of salts and particulate matter, and reduction and maintenance requirements are not directly related to concentration polarization.Rate this question:
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- 18.
Provisions should be made for flushing reverse osmosis units under what conditions
- A.
When consumers complain of flavor and older problems
- B.
When iron bacteria cause rust or orange and water problems
- C.
When necessary to comply with a lead and copper rule
- D.
When treating seawater brackish water with high organic content
Correct Answer
D. When treating seawater brackish water with high organic contentExplanation
When treating seawater brackish water with high organic content, provisions should be made for flushing reverse osmosis units. This is because seawater and brackish water often contain high levels of organic matter, which can lead to fouling and clogging of the reverse osmosis membranes. Flushing the units helps to remove any accumulated organic material and maintain the efficiency of the system.Rate this question:
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- 19.
Which scale inhibitor is most frequently used to prevent the coding of the reverse osmosis membrane
- A.
None ionic polymer
- B.
Soda ash
- C.
Sodium hexametaphosphate
- D.
Sulfuric acid
Correct Answer
C. Sodium hexametaphosphateExplanation
Sodium hexametaphosphate is the most frequently used scale inhibitor to prevent the clogging of the reverse osmosis membrane. It is a chemical compound that helps to prevent the formation of scale or deposits on the membrane surface, which can reduce its efficiency and lifespan. Sodium hexametaphosphate works by binding to the calcium and magnesium ions in the water, preventing them from forming scale. This helps to maintain the performance and longevity of the reverse osmosis membrane.Rate this question:
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- 20.
What is the most common problem in Electrodialysis (ED) operation
- A.
Compacting of the membrane due to lack of washing
- B.
Corroding the membrane by an acidic solutions
- C.
Scaling or fouling of the membrane by both organic and inorganic materials
- D.
Tearing of the membrane by abrasive materials tearing of the membrane by abrasive materials
Correct Answer
C. Scaling or fouling of the membrane by both organic and inorganic materialsExplanation
Scaling or fouling of the membrane by both organic and inorganic materials is the most common problem in Electrodialysis (ED) operation. This occurs when the membrane becomes coated or clogged with deposits, which can be made up of various substances such as minerals, salts, or organic compounds. Scaling or fouling reduces the efficiency of the ED process and can lead to decreased performance and increased maintenance requirements. It is important to regularly clean and maintain the membrane to prevent scaling or fouling and ensure optimal operation of the ED system.Rate this question:
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- 21.
Which factors are contributing to The increased salinity of many rivers and lakes
- A.
Agricultural runoff
- B.
Coagulation/flocculation
- C.
Filtration
- D.
Moisture condensation
- E.
Waste discharge
Correct Answer(s)
A. Agricultural runoff
E. Waste dischargeExplanation
The increased salinity of many rivers and lakes can be attributed to agricultural runoff and waste discharge. Agricultural runoff occurs when excess fertilizers and pesticides are washed into nearby water bodies, increasing the salinity levels. Waste discharge from industries and households also contributes to the salinity as it introduces pollutants and chemicals into the water. These factors disrupt the natural balance of the water bodies and lead to an increase in salinity levels.Rate this question:
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- 22.
What are the advantages of thin-film composite membranes when comparing with cellulose acetate membranes
- A.
Higher costs
- B.
Higher rejection And flux rate
- C.
Lower salt passage rate increase after three years
- D.
Subject to biological attack
- E.
Subject to hydrolysis or compaction
Correct Answer(s)
B. Higher rejection And flux rate
C. Lower salt passage rate increase after three yearsExplanation
Thin-film composite membranes have several advantages over cellulose acetate membranes. Firstly, they have a higher rejection rate, meaning they can effectively remove more impurities and contaminants from the water. Additionally, thin-film composite membranes have a higher flux rate, which means they can process water at a faster rate. Moreover, these membranes have a lower salt passage rate increase after three years of use, indicating that they maintain their performance and efficiency over a longer period of time. However, it is important to note that thin-film composite membranes are also subject to biological attack and hydrolysis or compaction, which can affect their durability and lifespan.Rate this question:
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- 23.
The mineral(salt) flux (mineral passage)Through a membrane depends on which factors
- A.
Concentration gradient across the membrane
- B.
Mineral permeability constant
- C.
Osmotic pressure differential across the membrane
- D.
Pressure differential applied across the membrane
- E.
Water permeability constant
Correct Answer(s)
A. Concentration gradient across the membrane
B. Mineral permeability constantExplanation
The correct answer is concentration gradient across the membrane and mineral permeability constant. The concentration gradient refers to the difference in concentration of the mineral on either side of the membrane. This gradient drives the movement of the mineral through the membrane. The mineral permeability constant refers to the ability of the mineral to pass through the membrane. If the mineral has a high permeability constant, it will pass through the membrane more easily. Therefore, the flux of the mineral through the membrane depends on both the concentration gradient and the mineral permeability constant.Rate this question:
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- 24.
Which impurities can be deposited or the grow on the membrane surface of a reverse osmosis unit
- A.
Alkalinity
- B.
Bacteria
- C.
Dissolved in organics
- D.
Dissolved organics
- E.
Suspended solids
Correct Answer(s)
B. Bacteria
C. Dissolved in organics
D. Dissolved organics
E. Suspended solidsExplanation
The impurities that can be deposited or grow on the membrane surface of a reverse osmosis unit include bacteria, dissolved in organics, dissolved organics, and suspended solids. These impurities can accumulate on the membrane over time, leading to fouling and reduced efficiency of the reverse osmosis process. Regular cleaning and maintenance of the membrane are necessary to prevent the buildup of these impurities and ensure the optimal performance of the reverse osmosis unit.Rate this question:
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- 25.
Where should something about be located on reverse osmosis
- A.
On the concentrate line
- B.
On the feed line
- C.
On the permeate line
- D.
On the permeated line of the pressure vessel
- E.
On the work bench of each lap technician
Correct Answer(s)
A. On the concentrate line
B. On the feed line
C. On the permeate line
D. On the permeated line of the pressure vessel -
- 26.
In a reverse osmosis unit, operators should be able to collect samples during which modes of operation
- A.
Analyzing
- B.
Cleaning
- C.
Flushing
- D.
Rinsing
- E.
Servicing
Correct Answer(s)
B. Cleaning
C. Flushing
D. Rinsing
E. ServicingExplanation
In a reverse osmosis unit, operators should be able to collect samples during the cleaning, flushing, rinsing, and servicing modes of operation. These modes involve different processes that are necessary for maintaining the efficiency and functionality of the unit. During cleaning, any accumulated contaminants or particles are removed from the system. Flushing helps to remove any remaining cleaning agents or residues. Rinsing ensures that the system is thoroughly cleaned and prepared for operation. Lastly, servicing involves maintenance activities such as replacing filters or conducting repairs. Collecting samples during these modes allows operators to monitor the effectiveness of the processes and ensure the quality of the water produced.Rate this question:
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- 27.
Which types of commercial available membrane configurations have been reverse osmosis operating plants
- A.
Breakthrough
- B.
Empty bed
- C.
Hollow fine fiber
- D.
Spiral wound
- E.
Tubular
Correct Answer(s)
C. Hollow fine fiber
D. Spiral wound
E. TubularExplanation
The correct answer is Hollow fine fiber, Spiral wound, Tubular. These are the types of commercial available membrane configurations that have been used in reverse osmosis operating plants. Hollow fine fiber membranes consist of small, hollow fibers that allow water to pass through while retaining impurities. Spiral wound membranes are made up of flat sheets wound around a central tube, creating a spiral structure. Tubular membranes are cylindrical in shape and allow water to flow through the center while retaining contaminants on the outside. These configurations are commonly used in reverse osmosis plants for water purification.Rate this question:
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- 28.
What are the common causes of reverse osmosis membrane damage
- A.
Membrane compacting
- B.
Membrane fouling
- C.
Membrane hydrolysis due to bacterial degradation
- D.
Membrane hydrolysis do the pH outside operating limits
- E.
Membrane hydrolysis due to temperature outside operating limits
Correct Answer(s)
A. Membrane compacting
B. Membrane fouling
C. Membrane hydrolysis due to bacterial degradation
D. Membrane hydrolysis do the pH outside operating limits
E. Membrane hydrolysis due to temperature outside operating limitsExplanation
The common causes of reverse osmosis membrane damage include membrane compacting, membrane fouling, membrane hydrolysis due to bacterial degradation, membrane hydrolysis due to pH outside operating limits, and membrane hydrolysis due to temperature outside operating limits. These factors can lead to a decrease in the efficiency and effectiveness of the membrane, resulting in damage and reduced performance.Rate this question:
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- 29.
What aspects of demineralization plants require proper handling to ensure the safety and protection of personal
- A.
Chemicals
- B.
Electrical
- C.
Hydraulic
- D.
Lifting
- E.
Slip and falls
Correct Answer(s)
A. Chemicals
B. Electrical
C. HydraulicExplanation
Demineralization plants involve the use of various chemicals, electrical equipment, and hydraulic systems. These aspects require proper handling to ensure the safety and protection of personnel. Improper handling of chemicals can lead to accidents or exposure to harmful substances. Electrical equipment should be handled with caution to prevent electrical shocks or fires. Hydraulic systems should be operated properly to prevent leaks or malfunctions that can cause accidents. Overall, proper handling of these aspects is crucial to maintaining a safe working environment in demineralization plants.Rate this question:
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- 30.
What are the advantages of demineralization by electro dialysis (E D) process
- A.
Efficient removal of most organic constituents
- B.
Removal of all TDS
- C.
Waste Brine contains only salts removed
- D.
Well developed technology, including equipment and membranes
- E.
Zero energy requirements
Correct Answer(s)
B. Removal of all TDS
C. Waste Brine contains only salts removed
D. Well developed technology, including equipment and membranesExplanation
The advantages of demineralization by electro dialysis (E D) process include the efficient removal of most organic constituents, removal of all total dissolved solids (TDS), waste brine containing only salts that have been removed, a well-developed technology with available equipment and membranes, and zero energy requirements. This process is effective in removing both organic and inorganic impurities from water, resulting in high-quality demineralized water. The waste brine produced during the process only contains the salts that have been removed, making it easier to handle and dispose of. The technology and equipment used in electro dialysis have been well-established and refined, ensuring reliable and efficient operation. Additionally, the process requires no external energy input, making it cost-effective and environmentally friendly.Rate this question:
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- 31.
Which ions are found in seawater Or brackish water in appreciable quantities
- A.
Arsenic
- B.
Chloride
- C.
Magnesium
- D.
Sodium
- E.
Sulfate
Correct Answer(s)
B. Chloride
C. Magnesium
D. Sodium
E. SulfateExplanation
Seawater and brackish water contain appreciable quantities of chloride, magnesium, sodium, and sulfate ions. These ions are commonly found in seawater due to various natural processes. Chloride ions come from the dissolution of salts in the water, while magnesium and sulfate ions originate from the weathering of rocks and minerals. Sodium ions are present due to the weathering of rocks and the input from rivers and other water sources. These ions are essential for the survival of marine organisms and play a crucial role in maintaining the balance of the marine ecosystem.Rate this question:
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- 32.
Electro dialysis free treatment is required to remove its materials
- A.
Chloride
- B.
Chlorine residual
- C.
Iron
- D.
Manganese
- E.
Sodium
Correct Answer(s)
B. Chlorine residual
C. Iron
D. ManganeseExplanation
Electro dialysis is a process that uses an electric field to separate ions and molecules from a solution. In this case, the free treatment is required to remove the materials of chlorine residual, iron, and manganese. Chlorine residual refers to the remaining chlorine in water after disinfection, which needs to be removed to make the water safe for consumption. Iron and manganese are common contaminants found in water sources and can cause discoloration and unpleasant taste. Therefore, electro dialysis is necessary to remove these materials and ensure the water is clean and safe.Rate this question:
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- 33.
What are the benefits of using plastic pipe with electro dialysis units
- A.
Ability to recycle Unused materials
- B.
Ease of construction
- C.
Ease of waste materials
- D.
Hire assistance to corrosion and saline environment
- E.
Lower cost (compared to stainless steel)
Correct Answer(s)
B. Ease of construction
D. Hire assistance to corrosion and saline environment
E. Lower cost (compared to stainless steel)Explanation
Plastic pipes offer several benefits when used with electro dialysis units. Firstly, they are easy to construct, making installation and maintenance simpler and more efficient. Additionally, plastic pipes are resistant to corrosion and can withstand saline environments, ensuring their durability and longevity. Lastly, plastic pipes are generally more cost-effective compared to stainless steel pipes, making them a cost-efficient choice for electro dialysis units.Rate this question:
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- 34.
Which items are important considerations regarding electrical dialysis feed water quality
- A.
Bacteriological quality
- B.
Biological quality
- C.
Iron
- D.
PH
- E.
Silica
Correct Answer(s)
A. Bacteriological quality
B. Biological quality
C. Iron
E. SilicaExplanation
The important considerations regarding electrical dialysis feed water quality include bacteriological quality, biological quality, iron, and silica. Bacteriological quality refers to the presence of bacteria or microorganisms in the water, which can contaminate the dialysis process. Biological quality is also important as it includes the presence of viruses and other pathogens that can affect the safety of the dialysis treatment. Iron can cause scaling and damage to the dialysis equipment, while silica can also cause scaling and affect the performance of the dialysis process. Therefore, monitoring and maintaining these factors are crucial for ensuring the quality of the dialysis feed water.Rate this question:
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- 35.
Which operation and maintenance items should be performed daily on electro-dialysis units
- A.
Check the pressure drop across the cartridge filter
- B.
Fill out the lock sheet
- C.
Inspect stacks for excess external leakage
- D.
Verify that electrodes are bumping and flowing properly
- E.
Voltage probe the membrane stacks
Correct Answer(s)
A. Check the pressure drop across the cartridge filter
B. Fill out the lock sheet
C. Inspect stacks for excess external leakage
D. Verify that electrodes are bumping and flowing properlyExplanation
The daily operation and maintenance items that should be performed on electro-dialysis units include checking the pressure drop across the cartridge filter to ensure it is functioning properly, filling out the lock sheet to document any maintenance activities, inspecting stacks for excess external leakage to prevent any potential issues, and verifying that electrodes are bumping and flowing properly to ensure efficient operation. Voltage probing the membrane stacks is not mentioned as a daily maintenance task in this context.Rate this question:
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