Kansas Water Treatment Study Guide Class 2 Quiz

1. If a valve in a pipeline is closed too rapidly it will cause the water in that pipeline to come to a sudden stop, causing waves of high pressure that oscillate back and forth in the pipeline. This reaction is commonly known as

Hydraulic gradient

Pipeline dynamics

Static oscillation

Water hammer

When a valve in a pipeline is closed too rapidly, it causes the water in the pipeline to come to a sudden stop. This abrupt stop creates waves of high pressure that oscillate back and forth in the pipeline. This phenomenon is commonly known as water hammer.

Explanation

When a valve in a pipeline is closed too rapidly, it causes the water in the pipeline to come to a sudden stop. This abrupt stop creates waves of high pressure that oscillate back and forth in the pipeline. This phenomenon is commonly known as water hammer.

2. Hydrogen sulfide in well water will cause the water to have an odor similar to

Ammonia.

Chlorine gas.

Rotten eggs.

Fish eggs.

Hydrogen sulfide is a gas that is often present in well water and has a distinct odor similar to rotten eggs. This odor is caused by the breakdown of organic matter in the water, which releases hydrogen sulfide gas. The presence of this gas can be a sign of bacterial activity or other issues with the well water. Therefore, if well water smells like rotten eggs, it is likely due to the presence of hydrogen sulfide.

Explanation

Hydrogen sulfide is a gas that is often present in well water and has a distinct odor similar to rotten eggs. This odor is caused by the breakdown of organic matter in the water, which releases hydrogen sulfide gas. The presence of this gas can be a sign of bacterial activity or other issues with the well water. Therefore, if well water smells like rotten eggs, it is likely due to the presence of hydrogen sulfide.

3. The term aeration is defined as bringing water into intimate contact with

Air

Carbon dioxide

Hydrogen sulfide

Methane

Aeration is the process of bringing water into intimate contact with air. This is done to increase the oxygen levels in the water, which is essential for the survival of aquatic organisms. Aeration helps in maintaining a healthy ecosystem in lakes, ponds, and aquariums by promoting the growth of beneficial bacteria and preventing the buildup of harmful gases. It also helps in improving water quality and reducing odors. Therefore, the correct answer is air.

Explanation

Aeration is the process of bringing water into intimate contact with air. This is done to increase the oxygen levels in the water, which is essential for the survival of aquatic organisms. Aeration helps in maintaining a healthy ecosystem in lakes, ponds, and aquariums by promoting the growth of beneficial bacteria and preventing the buildup of harmful gases. It also helps in improving water quality and reducing odors. Therefore, the correct answer is air.

4. Optimum coagulant dosage can be established by

Observing the pilot filter

Performing jar tests

Performing total solids tests.

The breakpoint of chlorination

Performing jar tests is the correct answer because it is a common method used to determine the optimum coagulant dosage in water treatment. Jar tests involve adding different dosages of coagulant to small-scale samples of water and observing the resulting floc formation and settling. By comparing the effectiveness of different dosages, the optimal coagulant dosage can be determined, ensuring efficient and effective water treatment. This method allows for adjustments to be made based on the specific water quality and coagulant requirements, leading to improved treatment processes and water quality.

Explanation

Performing jar tests is the correct answer because it is a common method used to determine the optimum coagulant dosage in water treatment. Jar tests involve adding different dosages of coagulant to small-scale samples of water and observing the resulting floc formation and settling. By comparing the effectiveness of different dosages, the optimal coagulant dosage can be determined, ensuring efficient and effective water treatment. This method allows for adjustments to be made based on the specific water quality and coagulant requirements, leading to improved treatment processes and water quality.

5. Eight boxes of packing (for pumps) were delivered, and the invoice showed $15.93 each. What is the total cost of packing?

$106.34

$109.31

$111.51

$127.44

The total cost of packing can be calculated by multiplying the number of boxes (8) by the cost per box ($15.93). Therefore, the total cost of packing is $127.44.

Explanation

The total cost of packing can be calculated by multiplying the number of boxes (8) by the cost per box ($15.93). Therefore, the total cost of packing is $127.44.

6. Pathogens are best described as

An acute case of indigestion

An indicator test for viruses

Cancer-producing agents.

Disease-causing organisms

Pathogens are best described as disease-causing organisms. Pathogens are microorganisms such as bacteria, viruses, fungi, and parasites that can cause diseases in their host organisms. They invade the body and multiply, leading to various symptoms and health issues. Pathogens can be transmitted through various means, such as direct contact, contaminated food or water, or through the air. Understanding pathogens and their mechanisms of infection is crucial in preventing and treating diseases.

Explanation

Pathogens are best described as disease-causing organisms. Pathogens are microorganisms such as bacteria, viruses, fungi, and parasites that can cause diseases in their host organisms. They invade the body and multiply, leading to various symptoms and health issues. Pathogens can be transmitted through various means, such as direct contact, contaminated food or water, or through the air. Understanding pathogens and their mechanisms of infection is crucial in preventing and treating diseases.

7. The chemical symbol for potassium is

Al

Ba

K

Po.

The correct answer is K because K is the chemical symbol for potassium. Chemical symbols are used to represent elements in the periodic table, and K specifically represents the element potassium.

Explanation

The correct answer is K because K is the chemical symbol for potassium. Chemical symbols are used to represent elements in the periodic table, and K specifically represents the element potassium.

8. Which one of the following is a hazard when using hydrofluosilicic acid?

Corrosiveness

Explosiveness

Flammability

None of the above

Hydrofluosilicic acid is known to be corrosive, meaning it has the ability to cause damage or destruction to materials it comes into contact with. It can cause burns, irritation, and damage to the skin, eyes, and respiratory system. Therefore, the correct answer is corrosiveness.

Explanation

Hydrofluosilicic acid is known to be corrosive, meaning it has the ability to cause damage or destruction to materials it comes into contact with. It can cause burns, irritation, and damage to the skin, eyes, and respiratory system. Therefore, the correct answer is corrosiveness.

9. From a sanitary standpoint, the pressure in a distribution system should not be allowed to fall to zero because

. the chlorine residual will escape

Low pressure allows bacteria to multiply

Groundwater may enter and backsiphonage may occur

None of the above.

If the pressure in a distribution system falls to zero, it creates the risk of groundwater entering the system and causing backsiphonage. Backsiphonage occurs when the pressure in the system drops, causing a reverse flow of water and potentially contaminating the water supply with harmful substances. Therefore, it is important to maintain pressure in the distribution system to prevent this from happening.

Explanation

If the pressure in a distribution system falls to zero, it creates the risk of groundwater entering the system and causing backsiphonage. Backsiphonage occurs when the pressure in the system drops, causing a reverse flow of water and potentially contaminating the water supply with harmful substances. Therefore, it is important to maintain pressure in the distribution system to prevent this from happening.

10. Your pump broke down, your storage tank contained 1 mil gal, and water was being withdrawn at a rate of 0.5 mgd, how long woud it take for the tank to empty?

1 day

2 days

3 days

4 days

If the storage tank contains 1 million gallons of water and water is being withdrawn at a rate of 0.5 million gallons per day, it would take 2 days for the tank to empty completely. This can be calculated by dividing the total amount of water in the tank (1 million gallons) by the rate at which water is being withdrawn (0.5 million gallons per day).

Explanation

If the storage tank contains 1 million gallons of water and water is being withdrawn at a rate of 0.5 million gallons per day, it would take 2 days for the tank to empty completely. This can be calculated by dividing the total amount of water in the tank (1 million gallons) by the rate at which water is being withdrawn (0.5 million gallons per day).

11. A Venturi tube increases the velocity and decreases the pressure as water flows through it. This type of tube is used to

Aerate the water

Measure the amount of chlorine in the water.

Measure the amount of suspended solids in the water

Measure the rate of water flowing through it.

A Venturi tube is a device that has a narrowing in the middle, which causes the water to accelerate as it passes through. According to Bernoulli's principle, as the velocity of a fluid increases, the pressure decreases. Therefore, as water flows through a Venturi tube, its velocity increases and the pressure decreases. This principle is used to measure the rate of water flowing through the tube because the change in pressure can be correlated to the flow rate.

Explanation

A Venturi tube is a device that has a narrowing in the middle, which causes the water to accelerate as it passes through. According to Bernoulli's principle, as the velocity of a fluid increases, the pressure decreases. Therefore, as water flows through a Venturi tube, its velocity increases and the pressure decreases. This principle is used to measure the rate of water flowing through the tube because the change in pressure can be correlated to the flow rate.

12. Static suction head plus friction suction head plus static discharge head plus friction discharge head makes up the ___________ of a pump.

Operating pressure

Pump curve

Total dynamic head

Velocity head

The total dynamic head of a pump is made up of the static suction head, friction suction head, static discharge head, and friction discharge head. This means that all these factors contribute to the overall pressure that the pump needs to overcome in order to operate effectively. The total dynamic head is an important parameter in pump selection and design as it helps determine the pump's ability to deliver the required flow rate at a given pressure.

Explanation

The total dynamic head of a pump is made up of the static suction head, friction suction head, static discharge head, and friction discharge head. This means that all these factors contribute to the overall pressure that the pump needs to overcome in order to operate effectively. The total dynamic head is an important parameter in pump selection and design as it helps determine the pump's ability to deliver the required flow rate at a given pressure.

13. Recent studies on prechlorination practices point out that the interaction of chlorine with organic matter in raw water forms

Carcinogens.

Lysergic acid

Other odor-related compounds

Trihalomethanes

Recent studies have shown that when chlorine interacts with organic matter in raw water, it forms trihalomethanes. Trihalomethanes are known to be carcinogenic, meaning they have the potential to cause cancer. Therefore, it is important to be aware of the formation of trihalomethanes during prechlorination practices in order to mitigate any potential health risks associated with their presence in water.

Explanation

Recent studies have shown that when chlorine interacts with organic matter in raw water, it forms trihalomethanes. Trihalomethanes are known to be carcinogenic, meaning they have the potential to cause cancer. Therefore, it is important to be aware of the formation of trihalomethanes during prechlorination practices in order to mitigate any potential health risks associated with their presence in water.

14. A calm area within a settling basin necessary for suspended materials to settle is the _______ zone.

Inlet

Outlet

Settling

Sludge

In a settling basin, suspended materials need a calm area to settle. This calm area is called the settling zone.

Explanation

In a settling basin, suspended materials need a calm area to settle. This calm area is called the settling zone.

15. The free chlorine residual in water is measured as the amount of

Chloride in water

Chlorine applied as measured in milligrams per litre.

Chlorine in raw water as comes from the stream, reservoir, or well.

The free chlorine residual in water is measured as the amount of uncombined chlorine that remains in the water after the chlorine has been applied and allowed to react. This means that it is the chlorine that has not reacted with any other substances in the water and is still available to disinfect and kill bacteria and other microorganisms. This measurement is important to ensure that there is enough chlorine present in the water to effectively treat it and make it safe for consumption.

Explanation

The free chlorine residual in water is measured as the amount of uncombined chlorine that remains in the water after the chlorine has been applied and allowed to react. This means that it is the chlorine that has not reacted with any other substances in the water and is still available to disinfect and kill bacteria and other microorganisms. This measurement is important to ensure that there is enough chlorine present in the water to effectively treat it and make it safe for consumption.

16. The outlet of a forced ventilation system for a chlorinator room should be located

Above the window.

Near the floor

On the roof.

6 ft above the floor

In a chlorinator room, it is important to have a forced ventilation system to remove any potentially harmful gases or fumes. The outlet of this system should be located near the floor. This is because chlorine gas is denser than air and tends to settle at lower levels. By placing the outlet near the floor, the ventilation system can effectively remove the chlorine gas and ensure the safety of the room.

Explanation

In a chlorinator room, it is important to have a forced ventilation system to remove any potentially harmful gases or fumes. The outlet of this system should be located near the floor. This is because chlorine gas is denser than air and tends to settle at lower levels. By placing the outlet near the floor, the ventilation system can effectively remove the chlorine gas and ensure the safety of the room.

17. One of the most common causes of errors in water quality analysis is

Contaminated reagents.

. improper sampling

Poor laboratory equipment

Poorly trained analysts

Improper sampling can lead to errors in water quality analysis. When samples are not collected correctly, they may not accurately represent the true water quality. Factors such as the location, depth, and timing of sample collection can all impact the results. Improper sampling techniques can introduce contaminants or alter the composition of the sample, leading to inaccurate analysis. Therefore, it is crucial to follow proper sampling protocols to ensure reliable and valid water quality analysis.

Explanation

Improper sampling can lead to errors in water quality analysis. When samples are not collected correctly, they may not accurately represent the true water quality. Factors such as the location, depth, and timing of sample collection can all impact the results. Improper sampling techniques can introduce contaminants or alter the composition of the sample, leading to inaccurate analysis. Therefore, it is crucial to follow proper sampling protocols to ensure reliable and valid water quality analysis.

18. Vertical turbine pumps that are used in wells may be oil lubricated or water lubricated. Operators should use extreme care not to start any water-lubricated pump before making sure that the

. bearings are dry

Bearings are wet.

Valve on the discharge side is closed.

Valve on the suction side is closed

The correct answer is "bearings are wet." This is because water-lubricated vertical turbine pumps require the bearings to be wet in order to operate properly. If the bearings are dry, it could cause damage to the pump and affect its performance. Therefore, it is important for operators to ensure that the bearings are wet before starting a water-lubricated pump.

Explanation

The correct answer is "bearings are wet." This is because water-lubricated vertical turbine pumps require the bearings to be wet in order to operate properly. If the bearings are dry, it could cause damage to the pump and affect its performance. Therefore, it is important for operators to ensure that the bearings are wet before starting a water-lubricated pump.

19. How are valves checked to determine that they are holding properly?

By compressed air

By electrostatic test

By a pressure test

By a torque wrench

Valves are checked to determine if they are holding properly by conducting a pressure test. This involves applying a specific amount of pressure to the valve and checking for any leaks or failures. This test helps ensure that the valve is functioning correctly and can effectively hold the desired pressure without any issues.

Explanation

Valves are checked to determine if they are holding properly by conducting a pressure test. This involves applying a specific amount of pressure to the valve and checking for any leaks or failures. This test helps ensure that the valve is functioning correctly and can effectively hold the desired pressure without any issues.

20. Centrifugal pump noises will most likely be due to

Cavitation

Excessive head pressure

High velocity

Sand

Cavitation is the most likely cause of noises in a centrifugal pump. Cavitation occurs when the pressure of the liquid being pumped drops below its vapor pressure, causing the formation and collapse of vapor bubbles. These collapsing bubbles create shockwaves and vibrations, leading to noise in the pump. Excessive head pressure, high velocity, and sand can also cause issues in a centrifugal pump, but cavitation is specifically known for causing noise.

Explanation

Cavitation is the most likely cause of noises in a centrifugal pump. Cavitation occurs when the pressure of the liquid being pumped drops below its vapor pressure, causing the formation and collapse of vapor bubbles. These collapsing bubbles create shockwaves and vibrations, leading to noise in the pump. Excessive head pressure, high velocity, and sand can also cause issues in a centrifugal pump, but cavitation is specifically known for causing noise.

21. The condition in infants known as methamoglobinemia is thought to be caused mainly by high concentrations of

Phosphate

Nitrate

Fluoride

Chloride

Methemoglobinemia is a condition in infants where there is an abnormal increase in the amount of methemoglobin in the blood. Methemoglobin is a form of hemoglobin that is unable to carry oxygen effectively. High concentrations of nitrate have been identified as one of the main causes of methemoglobinemia in infants. Nitrate can be found in contaminated water, formula, or vegetables, and when ingested, it can convert hemoglobin into methemoglobin. This reduces the blood's ability to transport oxygen, leading to symptoms like blue skin coloration and difficulty breathing.

Explanation

Methemoglobinemia is a condition in infants where there is an abnormal increase in the amount of methemoglobin in the blood. Methemoglobin is a form of hemoglobin that is unable to carry oxygen effectively. High concentrations of nitrate have been identified as one of the main causes of methemoglobinemia in infants. Nitrate can be found in contaminated water, formula, or vegetables, and when ingested, it can convert hemoglobin into methemoglobin. This reduces the blood's ability to transport oxygen, leading to symptoms like blue skin coloration and difficulty breathing.

22. When a centrifugal pump with new packing is started and the packing seems to leak air, the proper procedure is to

Stop the motor and repack the stuffing box.

Put in some heavy oil and then gradually tighten the gland

Put in more packing

Ignore the condition.

When a centrifugal pump with new packing is started and the packing seems to leak air, the proper procedure is to stop the motor and repack the stuffing box. This is because if the packing is leaking air, it means that it is not properly sealed, which can lead to loss of efficiency and potential damage to the pump. By stopping the motor and repacking the stuffing box, the packing can be replaced or adjusted to ensure a proper seal and prevent any further leakage.

Explanation

When a centrifugal pump with new packing is started and the packing seems to leak air, the proper procedure is to stop the motor and repack the stuffing box. This is because if the packing is leaking air, it means that it is not properly sealed, which can lead to loss of efficiency and potential damage to the pump. By stopping the motor and repacking the stuffing box, the packing can be replaced or adjusted to ensure a proper seal and prevent any further leakage.

23. Which one of the following types of pumps works on the basis of inertia or mass moving in a circular motion?

Air lift

Centrifugal

Diaphragm

Gear

Centrifugal pumps work on the basis of inertia or mass moving in a circular motion. These pumps use a rotating impeller to create centrifugal force, which pushes the fluid towards the outer edges of the impeller and then into the pump casing. From there, the fluid is discharged through the pump outlet. This type of pump is commonly used in industries for transferring fluids with high flow rates and low to medium pressures.

Explanation

Centrifugal pumps work on the basis of inertia or mass moving in a circular motion. These pumps use a rotating impeller to create centrifugal force, which pushes the fluid towards the outer edges of the impeller and then into the pump casing. From there, the fluid is discharged through the pump outlet. This type of pump is commonly used in industries for transferring fluids with high flow rates and low to medium pressures.

24. A chemical commonly used for coagulation in water treatment is

Alum.

Chlorine

Copper sulfate

Soda ash.

Alum is commonly used for coagulation in water treatment because it helps to remove impurities and suspended particles from the water. It works by forming larger, heavier particles that can be easily removed through filtration or sedimentation. Chlorine is typically used for disinfection rather than coagulation. Copper sulfate is used for algae control in water bodies, and soda ash is used for pH adjustment. Therefore, alum is the correct answer for the given question.

Explanation

Alum is commonly used for coagulation in water treatment because it helps to remove impurities and suspended particles from the water. It works by forming larger, heavier particles that can be easily removed through filtration or sedimentation. Chlorine is typically used for disinfection rather than coagulation. Copper sulfate is used for algae control in water bodies, and soda ash is used for pH adjustment. Therefore, alum is the correct answer for the given question.

25. Bacterial pollution moving underground in shattered limestone

Will be removed in 10 ft.

Will be removed in 100 ft.

Will be removed in less than 1 mi

May never be removed.

The given statement suggests that bacterial pollution is moving underground in shattered limestone. The options provided indicate the distance at which the pollution will be removed. However, the correct answer "may never be removed" implies that the bacterial pollution may not be completely eliminated or cleansed from the underground environment. This suggests that the shattered limestone may not have the capacity to naturally filter or remove the pollution, and it may persist indefinitely.

Explanation

The given statement suggests that bacterial pollution is moving underground in shattered limestone. The options provided indicate the distance at which the pollution will be removed. However, the correct answer "may never be removed" implies that the bacterial pollution may not be completely eliminated or cleansed from the underground environment. This suggests that the shattered limestone may not have the capacity to naturally filter or remove the pollution, and it may persist indefinitely.

26. Bluestone is a

Common name for copper sulfate.

Mineral in water that causes blue stains

Mineral not dissolvable in water

Stone for sharpening chisels

Bluestone is a common name for copper sulfate. This means that when people refer to bluestone, they are actually talking about copper sulfate. It is important to note that bluestone is not a mineral in water that causes blue stains, a mineral not dissolvable in water, or a stone for sharpening chisels. The correct answer is that bluestone is a common name for copper sulfate.

Explanation

Bluestone is a common name for copper sulfate. This means that when people refer to bluestone, they are actually talking about copper sulfate. It is important to note that bluestone is not a mineral in water that causes blue stains, a mineral not dissolvable in water, or a stone for sharpening chisels. The correct answer is that bluestone is a common name for copper sulfate.

27. Destruction of harmful bacteria by chlorine is directly related to

Contact time and chlorine concentration

Efficient chlorine dosage levels.

Whether or not breakpoint chlorination is practiced

Whether pre-chlorination is practiced

The destruction of harmful bacteria by chlorine is directly related to the contact time and chlorine concentration. This means that the longer the contact time between chlorine and bacteria, and the higher the concentration of chlorine, the more effective it will be in killing the harmful bacteria. Efficient chlorine dosage levels are also important in ensuring that enough chlorine is present to effectively destroy the bacteria. Breakpoint chlorination and pre-chlorination are not directly related to the destruction of bacteria by chlorine.

Explanation

The destruction of harmful bacteria by chlorine is directly related to the contact time and chlorine concentration. This means that the longer the contact time between chlorine and bacteria, and the higher the concentration of chlorine, the more effective it will be in killing the harmful bacteria. Efficient chlorine dosage levels are also important in ensuring that enough chlorine is present to effectively destroy the bacteria. Breakpoint chlorination and pre-chlorination are not directly related to the destruction of bacteria by chlorine.

28. What type of treatment should be given when a well produces red water?

Fluoride removal

Taste and odor control

Sedimentation

PH adjustment, aeration, and filtration

When a well produces red water, it is an indication of high iron content. pH adjustment, aeration, and filtration are the appropriate treatments in this case. pH adjustment helps to increase the pH level, which can reduce the solubility of iron and promote its precipitation. Aeration facilitates the oxidation of iron, converting it from a soluble form to a solid form that can be easily filtered. Filtration is then used to remove the precipitated iron particles from the water, resulting in clear and iron-free water.

Explanation

When a well produces red water, it is an indication of high iron content. pH adjustment, aeration, and filtration are the appropriate treatments in this case. pH adjustment helps to increase the pH level, which can reduce the solubility of iron and promote its precipitation. Aeration facilitates the oxidation of iron, converting it from a soluble form to a solid form that can be easily filtered. Filtration is then used to remove the precipitated iron particles from the water, resulting in clear and iron-free water.

29. The chemical that is most commonly added to reservoirs for the control of algae is

Aluminum sulfate

Calcium hypochlorite

Copper sulfate

Sodium chloride.

Copper sulfate is commonly added to reservoirs for the control of algae. Copper ions in copper sulfate act as a biocide, inhibiting the growth of algae by disrupting their cellular processes. It is an effective and widely used treatment for controlling algae blooms in water bodies. Aluminum sulfate is also sometimes used for this purpose, but copper sulfate is more commonly used due to its effectiveness in controlling algae growth. Calcium hypochlorite is a disinfectant and sodium chloride is a common salt, neither of which are specifically used for controlling algae in reservoirs.

Explanation

Copper sulfate is commonly added to reservoirs for the control of algae. Copper ions in copper sulfate act as a biocide, inhibiting the growth of algae by disrupting their cellular processes. It is an effective and widely used treatment for controlling algae blooms in water bodies. Aluminum sulfate is also sometimes used for this purpose, but copper sulfate is more commonly used due to its effectiveness in controlling algae growth. Calcium hypochlorite is a disinfectant and sodium chloride is a common salt, neither of which are specifically used for controlling algae in reservoirs.

30. Corrosive waters can be the result of the presence of

Acids

Calcium.

Magnesium.

Organic material.

Corrosive waters can be the result of the presence of acids. Acids have the ability to react with metals and other materials, causing them to corrode or deteriorate. When acids are present in water, they can lower the pH level, making the water more acidic. This increased acidity can lead to corrosion of pipes, fixtures, and other metal surfaces that come into contact with the water. Therefore, the presence of acids in water can contribute to the corrosiveness of the water.

Explanation

Corrosive waters can be the result of the presence of acids. Acids have the ability to react with metals and other materials, causing them to corrode or deteriorate. When acids are present in water, they can lower the pH level, making the water more acidic. This increased acidity can lead to corrosion of pipes, fixtures, and other metal surfaces that come into contact with the water. Therefore, the presence of acids in water can contribute to the corrosiveness of the water.

31. The chlorine room should be constructed so it can be entered only from the

Inside of the building.

Laboratory.

Outside and inside of the building.

Outside of the building.

The chlorine room should be constructed so it can be entered only from the outside of the building. This is because chlorine is a highly reactive and toxic substance that can pose significant risks if mishandled or released. By having the room accessible only from the outside, it ensures that any potential accidents or leaks can be contained and controlled without endangering the occupants inside the building. Additionally, it allows for easier ventilation and evacuation in case of emergencies.

Explanation

The chlorine room should be constructed so it can be entered only from the outside of the building. This is because chlorine is a highly reactive and toxic substance that can pose significant risks if mishandled or released. By having the room accessible only from the outside, it ensures that any potential accidents or leaks can be contained and controlled without endangering the occupants inside the building. Additionally, it allows for easier ventilation and evacuation in case of emergencies.

32. A centrifugal-type pump should never be run empty except momentarily because

A serious counterpressure would be built up by excessive vacuum

It is useless to run a pump without getting water

The excessive end thrust of the shaft would damage the thrust bearing.

The parts lubricated by water would be damaged

Running a centrifugal-type pump empty means running it without any water or fluid. These pumps rely on the fluid being pumped to provide lubrication to various parts, such as the bearings and seals. Without the presence of the fluid, these parts would not receive the necessary lubrication and would be subject to damage due to friction and heat. Therefore, running a centrifugal-type pump empty can result in damage to the parts that are normally lubricated by the water or fluid being pumped.

Explanation

Running a centrifugal-type pump empty means running it without any water or fluid. These pumps rely on the fluid being pumped to provide lubrication to various parts, such as the bearings and seals. Without the presence of the fluid, these parts would not receive the necessary lubrication and would be subject to damage due to friction and heat. Therefore, running a centrifugal-type pump empty can result in damage to the parts that are normally lubricated by the water or fluid being pumped.

33. A new water treatment facility for a small town is estimated to cost $1,493,472. What is the average cost per person if 1986 people live in the town?

$5720

$2750

$752

$572

The average cost per person can be calculated by dividing the total cost of the water treatment facility by the number of people in the town. In this case, the total cost is $1,493,472 and the number of people is 1986. Dividing these two numbers gives us an average cost per person of $752.

Explanation

The average cost per person can be calculated by dividing the total cost of the water treatment facility by the number of people in the town. In this case, the total cost is $1,493,472 and the number of people is 1986. Dividing these two numbers gives us an average cost per person of $752.

34. The purpose of the jar test is to determine the

Amount of chlorine to add for breakpoint chlorination.

Correct amount of coagulant to use for proper coagulation

Length of the flash mix.

Proper amount of mixing and settling time to remove turbidity

The purpose of the jar test is to determine the correct amount of coagulant to use for proper coagulation. Coagulation is an important step in water treatment where chemicals are added to destabilize and clump together particles in the water. The jar test involves adding varying amounts of coagulant to water samples and observing the resulting floc formation. By finding the correct amount of coagulant needed to achieve optimal floc formation, water treatment plants can ensure efficient removal of suspended particles and improve water quality.

Explanation

The purpose of the jar test is to determine the correct amount of coagulant to use for proper coagulation. Coagulation is an important step in water treatment where chemicals are added to destabilize and clump together particles in the water. The jar test involves adding varying amounts of coagulant to water samples and observing the resulting floc formation. By finding the correct amount of coagulant needed to achieve optimal floc formation, water treatment plants can ensure efficient removal of suspended particles and improve water quality.

35. A water treatment plant used 647 chlorine cylinders during one year's operation.The average withdrawal from each cylinder was 138 lb. What was the total number of pounds of chlorine used?

89,875 lb

89,286 lb

70,872 lb

69,876 lb

The total number of pounds of chlorine used can be calculated by multiplying the number of cylinders used (647) by the average withdrawal from each cylinder (138 lb). Therefore, the total number of pounds of chlorine used is 647 * 138 = 89,286 lb.

Explanation

The total number of pounds of chlorine used can be calculated by multiplying the number of cylinders used (647) by the average withdrawal from each cylinder (138 lb). Therefore, the total number of pounds of chlorine used is 647 * 138 = 89,286 lb.

36. A tank holding 2340 gal fills in 12 min. The rate of flow is ______ gpm

195

234

284

382

The rate of flow can be calculated by dividing the volume of the tank (2340 gallons) by the time taken to fill it (12 minutes). The calculation would be 2340/12 = 195 gallons per minute (gpm).

Explanation

The rate of flow can be calculated by dividing the volume of the tank (2340 gallons) by the time taken to fill it (12 minutes). The calculation would be 2340/12 = 195 gallons per minute (gpm).

37. Water leaking to the surface after operating an old valve probably is caused by

A broken stem.

Dried out packing.

Plugged weep holes

None of the above

Water leaking to the surface after operating an old valve is likely caused by dried out packing. Packing is used to create a seal between the valve stem and the valve body, preventing water from leaking. Over time, the packing can dry out and lose its ability to create a proper seal, resulting in water leakage. This is a common issue with old valves and can be resolved by replacing the packing material.

Explanation

Water leaking to the surface after operating an old valve is likely caused by dried out packing. Packing is used to create a seal between the valve stem and the valve body, preventing water from leaking. Over time, the packing can dry out and lose its ability to create a proper seal, resulting in water leakage. This is a common issue with old valves and can be resolved by replacing the packing material.

38. The chemical formula for calcium carbonate is

CaCO3

CuSO4

NACI.

NaCO.

The correct answer is CaCO3 because calcium carbonate is composed of one calcium atom (Ca) bonded to one carbon atom (C) and three oxygen atoms (O). The chemical formula represents the ratio of atoms in a compound, and CaCO3 accurately represents the composition of calcium carbonate. CuSO4, NACI, and NaCO are incorrect options as they represent different compounds with different compositions.

Explanation

The correct answer is CaCO3 because calcium carbonate is composed of one calcium atom (Ca) bonded to one carbon atom (C) and three oxygen atoms (O). The chemical formula represents the ratio of atoms in a compound, and CaCO3 accurately represents the composition of calcium carbonate. CuSO4, NACI, and NaCO are incorrect options as they represent different compounds with different compositions.

39. The chemical formula for copper sulfate is

CaCO.

CaCO3

CuSO4 .5H2O

H2SO4

The correct answer is CuSO4 .5H2O because copper sulfate is represented by the chemical formula CuSO4, and the addition of .5H2O indicates that there are 5 water molecules associated with each molecule of CuSO4. This is known as a hydrated form of copper sulfate.

Explanation

The correct answer is CuSO4 .5H2O because copper sulfate is represented by the chemical formula CuSO4, and the addition of .5H2O indicates that there are 5 water molecules associated with each molecule of CuSO4. This is known as a hydrated form of copper sulfate.

40. The most hazardous condition associated with storage areas, slurry tanks, or other confined spaces where wet activated carbon is present is

Combustion.

Depletion of oxygen

Fire.

Oxidation

The most hazardous condition associated with storage areas, slurry tanks, or other confined spaces where wet activated carbon is present is the depletion of oxygen. This is because wet activated carbon can release gases that displace oxygen, leading to a lack of oxygen in the confined space. This can be extremely dangerous for anyone working in the area as it can cause asphyxiation and lead to serious health risks or even death.

Explanation

The most hazardous condition associated with storage areas, slurry tanks, or other confined spaces where wet activated carbon is present is the depletion of oxygen. This is because wet activated carbon can release gases that displace oxygen, leading to a lack of oxygen in the confined space. This can be extremely dangerous for anyone working in the area as it can cause asphyxiation and lead to serious health risks or even death.

41. 1. The operating budget for the year was $94,571. At the end of 10 months $17,863 remained. How much had been expended?

$67,708

$67,807

$76,708

$87,706

At the end of 10 months, $17,863 remained from the operating budget of $94,571. To find out how much had been expended, we subtract the remaining amount from the total budget. Therefore, $94,571 - $17,863 = $76,708.

Explanation

At the end of 10 months, $17,863 remained from the operating budget of $94,571. To find out how much had been expended, we subtract the remaining amount from the total budget. Therefore, $94,571 - $17,863 = $76,708.

42. The least head loss in a pipeline would be caused by a fully open

Angle valve

Check valve

Gate valve.

Globe valve

A gate valve would cause the least head loss in a pipeline when fully open because it has a straight-through design that allows for a smooth flow of fluid without any obstructions. The gate valve operates by lifting a gate or disc out of the path of the fluid, creating a straight and unobstructed passage. This design minimizes turbulence and pressure drop, resulting in the least amount of head loss compared to other types of valves such as angle valves, check valves, and globe valves which may have more restrictive flow paths or internal components that can cause additional resistance to flow.

Explanation

A gate valve would cause the least head loss in a pipeline when fully open because it has a straight-through design that allows for a smooth flow of fluid without any obstructions. The gate valve operates by lifting a gate or disc out of the path of the fluid, creating a straight and unobstructed passage. This design minimizes turbulence and pressure drop, resulting in the least amount of head loss compared to other types of valves such as angle valves, check valves, and globe valves which may have more restrictive flow paths or internal components that can cause additional resistance to flow.

43. The disinfection process kills

All bacteria

Only protozoans.

Pathogenic bacteria.

All algae

The correct answer is "pathogenic bacteria." The disinfection process is specifically designed to kill harmful or disease-causing bacteria. It may not necessarily kill all bacteria, as some bacteria are beneficial or harmless. Similarly, it may not target protozoans or algae, as they are different types of microorganisms. Therefore, the disinfection process focuses on eliminating pathogenic bacteria to ensure the safety and cleanliness of the environment.

Explanation

The correct answer is "pathogenic bacteria." The disinfection process is specifically designed to kill harmful or disease-causing bacteria. It may not necessarily kill all bacteria, as some bacteria are beneficial or harmless. Similarly, it may not target protozoans or algae, as they are different types of microorganisms. Therefore, the disinfection process focuses on eliminating pathogenic bacteria to ensure the safety and cleanliness of the environment.

44. Hardness in water is caused mainly by the presence of

. calcium and magnesium compounds

Iron and manganese compounds

Lime and soda ash.

Turbidity and suspended solids

Hardness in water is caused mainly by the presence of calcium and magnesium compounds. These compounds can dissolve in water and form ions, which contribute to the hardness of the water. Calcium and magnesium ions can react with soap, forming insoluble compounds that result in the formation of soap scum and reduce the effectiveness of cleaning agents. Hard water can also lead to the buildup of scale in pipes and appliances, reducing their efficiency and lifespan. Therefore, the presence of calcium and magnesium compounds is the primary cause of water hardness.

Explanation

Hardness in water is caused mainly by the presence of calcium and magnesium compounds. These compounds can dissolve in water and form ions, which contribute to the hardness of the water. Calcium and magnesium ions can react with soap, forming insoluble compounds that result in the formation of soap scum and reduce the effectiveness of cleaning agents. Hard water can also lead to the buildup of scale in pipes and appliances, reducing their efficiency and lifespan. Therefore, the presence of calcium and magnesium compounds is the primary cause of water hardness.

45. A centrifugal pump when operating normally shows a discharge pressure of 100 psi and the Venturi meter shows a flow rate of 20,000 gpm. Suddenly the pressure drops to 90 psi and the flow rate increases to 23,000 gpm. You would suspect

A faulty gauge and manometer tube

A large leak in the pump discharge line.

. foreign matter caught in the Venturi-tube throat.

The packing is sucking air.

The sudden drop in discharge pressure and increase in flow rate suggest that there is a large leak in the pump discharge line. This is because a leak in the line would result in a decrease in pressure and an increase in flow rate, as some of the fluid is escaping through the leak instead of being delivered to the intended destination. This explanation is supported by the fact that the pressure dropped from 100 psi to 90 psi and the flow rate increased from 20,000 gpm to 23,000 gpm, indicating a significant change in the system.

Explanation

The sudden drop in discharge pressure and increase in flow rate suggest that there is a large leak in the pump discharge line. This is because a leak in the line would result in a decrease in pressure and an increase in flow rate, as some of the fluid is escaping through the leak instead of being delivered to the intended destination. This explanation is supported by the fact that the pressure dropped from 100 psi to 90 psi and the flow rate increased from 20,000 gpm to 23,000 gpm, indicating a significant change in the system.

46. Mark the correct number of coliform per 100 mL when a membrane filter count shows 43 coliform colonies and 1.00 mL of sample was filtered.

430

4300

43000

430000

The correct answer is 4300. This is because the question states that there were 43 coliform colonies on the membrane filter after filtering 1.00 mL of sample. To determine the number of coliform per 100 mL, we can multiply the number of colonies by 100. Therefore, 43 x 100 = 4300 coliform per 100 mL.

Explanation

The correct answer is 4300. This is because the question states that there were 43 coliform colonies on the membrane filter after filtering 1.00 mL of sample. To determine the number of coliform per 100 mL, we can multiply the number of colonies by 100. Therefore, 43 x 100 = 4300 coliform per 100 mL.

47. A heavy growth of algae in a surface water reservoir will have which one of the following effects on the water?

Lower the pH

Raise the pH

Will have no effect on the pH

Your mom

A heavy growth of algae in a surface water reservoir will raise the pH of the water. Algae undergo photosynthesis, which involves the absorption of carbon dioxide and release of oxygen. This process increases the concentration of oxygen in the water and reduces the concentration of carbon dioxide, leading to an increase in pH. Additionally, algae can produce bicarbonate ions as a byproduct of their metabolic processes, further contributing to the alkalinity of the water and raising the pH.

Explanation

A heavy growth of algae in a surface water reservoir will raise the pH of the water. Algae undergo photosynthesis, which involves the absorption of carbon dioxide and release of oxygen. This process increases the concentration of oxygen in the water and reduces the concentration of carbon dioxide, leading to an increase in pH. Additionally, algae can produce bicarbonate ions as a byproduct of their metabolic processes, further contributing to the alkalinity of the water and raising the pH.

48. Water that is high in sulfate can cause

Diarrhea

Hardening of the arteries

Mottling of tooth enamel.

Staining of plumbing fixtures.

Water that is high in sulfate can cause diarrhea. This is because sulfate is a natural mineral that can have a laxative effect on the body when consumed in high amounts. When ingested, sulfate can irritate the lining of the intestines and increase the frequency and fluidity of bowel movements, leading to diarrhea. Therefore, if water contains high levels of sulfate, it can potentially cause gastrointestinal discomfort and diarrhea in individuals who consume it.

Explanation

Water that is high in sulfate can cause diarrhea. This is because sulfate is a natural mineral that can have a laxative effect on the body when consumed in high amounts. When ingested, sulfate can irritate the lining of the intestines and increase the frequency and fluidity of bowel movements, leading to diarrhea. Therefore, if water contains high levels of sulfate, it can potentially cause gastrointestinal discomfort and diarrhea in individuals who consume it.

49. As long as free chlorine and organic precursors are available, the total trihalomethane (TTHM) production will most probably

Continue to fall

Continue to rise

Fall and then rise

Stay the same.

As long as free chlorine and organic precursors are available, the production of total trihalomethane (TTHM) will most likely continue to rise. This is because TTHM is formed as a byproduct of the reaction between free chlorine and organic precursors, such as humic and fulvic acids, which are commonly found in water sources. Therefore, the availability of these components will contribute to the ongoing production of TTHM.

Explanation

As long as free chlorine and organic precursors are available, the production of total trihalomethane (TTHM) will most likely continue to rise. This is because TTHM is formed as a byproduct of the reaction between free chlorine and organic precursors, such as humic and fulvic acids, which are commonly found in water sources. Therefore, the availability of these components will contribute to the ongoing production of TTHM.

50. The total dynamic head against which a pump must operate

Is the friction head

Is the static head.

Is the sum of the static head and the head due to friction loss.

Must always be above the shutoff head.

The total dynamic head against which a pump must operate is the sum of the static head and the head due to friction loss. This means that the pump must overcome both the pressure caused by the height of the fluid (static head) and the resistance caused by the friction of the fluid flowing through pipes or other channels (head due to friction loss). By considering both factors, the pump can effectively operate and move the fluid against the combined resistance.

Explanation

The total dynamic head against which a pump must operate is the sum of the static head and the head due to friction loss. This means that the pump must overcome both the pressure caused by the height of the fluid (static head) and the resistance caused by the friction of the fluid flowing through pipes or other channels (head due to friction loss). By considering both factors, the pump can effectively operate and move the fluid against the combined resistance.

51. Activated carbon is used to reduce

Alkalinity

Hardness

PH

Tastes and odors.

Activated carbon is a highly porous material that has the ability to adsorb and remove organic compounds and impurities from water or air. It is commonly used in water and air purification systems to eliminate unpleasant tastes and odors caused by chemicals, pollutants, or organic matter. The activated carbon traps these substances within its pores, effectively reducing the presence of tastes and odors and improving the overall quality of the water or air.

Explanation

Activated carbon is a highly porous material that has the ability to adsorb and remove organic compounds and impurities from water or air. It is commonly used in water and air purification systems to eliminate unpleasant tastes and odors caused by chemicals, pollutants, or organic matter. The activated carbon traps these substances within its pores, effectively reducing the presence of tastes and odors and improving the overall quality of the water or air.

52. When hard water is softened by the zeolite ion-exchange process, which substance is exchanged for calcium and magnesium and will appear in the product water?

Chloride

Nitrate

Sodium

Sulfate

When hard water is softened by the zeolite ion-exchange process, calcium and magnesium ions are exchanged for sodium ions. This process involves passing the hard water through a zeolite resin bed, which contains sodium ions. The calcium and magnesium ions in the water are attracted to the zeolite resin and are exchanged for sodium ions. As a result, the product water will contain sodium ions instead of calcium and magnesium ions.

Explanation

When hard water is softened by the zeolite ion-exchange process, calcium and magnesium ions are exchanged for sodium ions. This process involves passing the hard water through a zeolite resin bed, which contains sodium ions. The calcium and magnesium ions in the water are attracted to the zeolite resin and are exchanged for sodium ions. As a result, the product water will contain sodium ions instead of calcium and magnesium ions.

53. Calcium oxide is also called

Slaked lime.

Quicklime.

Hydrated lime

Dehydrated lime.

Calcium oxide is commonly known as quicklime because it is produced by heating limestone or seashells at high temperatures, causing them to decompose and release carbon dioxide. Quicklime is highly reactive and reacts vigorously with water to produce calcium hydroxide, also known as slaked lime. Therefore, quicklime is the correct answer as it is an alternative name for calcium oxide.

Explanation

Calcium oxide is commonly known as quicklime because it is produced by heating limestone or seashells at high temperatures, causing them to decompose and release carbon dioxide. Quicklime is highly reactive and reacts vigorously with water to produce calcium hydroxide, also known as slaked lime. Therefore, quicklime is the correct answer as it is an alternative name for calcium oxide.

54. A substance added to water to promote the formation of a protective film in transmission pipes is known as

A pacifier

A passivator

An inhibitor

Cathodic protection

An inhibitor is a substance added to water to promote the formation of a protective film in transmission pipes. This film helps prevent corrosion and damage to the pipes, extending their lifespan. By inhibiting the chemical reactions that cause corrosion, the inhibitor acts as a protective barrier, reducing the risk of leaks and other issues in the transmission system.

Explanation

An inhibitor is a substance added to water to promote the formation of a protective film in transmission pipes. This film helps prevent corrosion and damage to the pipes, extending their lifespan. By inhibiting the chemical reactions that cause corrosion, the inhibitor acts as a protective barrier, reducing the risk of leaks and other issues in the transmission system.

55. Which laboratory test in a water plant is concerned with indicator changes at pH 8.3 and about pH 4.5?

Total hardness

Total chlorine residual

PH

Alkalinity

Alkalinity is the laboratory test in a water plant that is concerned with indicator changes at pH 8.3 and about pH 4.5. Alkalinity refers to the ability of water to resist changes in pH, and it is measured by titrating the water sample with acid to determine the amount of acid required to reach a specific pH. At pH 8.3, alkalinity indicates the presence of bicarbonate ions, while at pH 4.5, it indicates the presence of carbonate ions. Therefore, monitoring alkalinity levels helps in assessing the water's buffering capacity and its ability to maintain a stable pH.

Explanation

Alkalinity is the laboratory test in a water plant that is concerned with indicator changes at pH 8.3 and about pH 4.5. Alkalinity refers to the ability of water to resist changes in pH, and it is measured by titrating the water sample with acid to determine the amount of acid required to reach a specific pH. At pH 8.3, alkalinity indicates the presence of bicarbonate ions, while at pH 4.5, it indicates the presence of carbonate ions. Therefore, monitoring alkalinity levels helps in assessing the water's buffering capacity and its ability to maintain a stable pH.

56. The bacteriocidal action of free available chlorine compared with that of combined available chlorine is

Greater

Less.

The same under most conditions

Not possible to determine.

The bacteriocidal action of free available chlorine is greater compared to that of combined available chlorine. Free available chlorine refers to the chlorine that is present in the water and available to kill bacteria, while combined available chlorine refers to the chlorine that has already reacted with organic matter and is less effective in killing bacteria. Therefore, free available chlorine is more potent in its bacteriocidal action.

Explanation

The bacteriocidal action of free available chlorine is greater compared to that of combined available chlorine. Free available chlorine refers to the chlorine that is present in the water and available to kill bacteria, while combined available chlorine refers to the chlorine that has already reacted with organic matter and is less effective in killing bacteria. Therefore, free available chlorine is more potent in its bacteriocidal action.

57. Water is at its greatest density at a temperature of

32 F (0 C)

39.2 F (4 C)

37 F (3 C)

45 F (7 C)

Water is at its greatest density at a temperature of 39.2 F (4 C). This is because as water cools down from its boiling point, its density increases. However, when water reaches 39.2 F (4 C), it starts to expand again due to the formation of hydrogen bonds between water molecules. This expansion causes the density to decrease. Therefore, 39.2 F (4 C) is the temperature at which water has the highest density.

Explanation

Water is at its greatest density at a temperature of 39.2 F (4 C). This is because as water cools down from its boiling point, its density increases. However, when water reaches 39.2 F (4 C), it starts to expand again due to the formation of hydrogen bonds between water molecules. This expansion causes the density to decrease. Therefore, 39.2 F (4 C) is the temperature at which water has the highest density.

58. Chlorine use at a water treatment plant averages 81 lb/d. Assuming that the average daily flow is 13 mgd, the dosage rate is ________ mg/L.

0.5

0.75

1.0

715

The dosage rate is calculated by dividing the average chlorine use (81 lb/d) by the average daily flow (13 mgd). This can be done by converting the units to a common measurement. Since 1 lb is equal to 453.592 grams and 1 million gallons is equal to 3,785,411 liters, the dosage rate is (81 lb/d * 453.592 g/lb) / (13 mgd * 3,785,411 l/mgd) = 0.75 mg/L.

Explanation

The dosage rate is calculated by dividing the average chlorine use (81 lb/d) by the average daily flow (13 mgd). This can be done by converting the units to a common measurement. Since 1 lb is equal to 453.592 grams and 1 million gallons is equal to 3,785,411 liters, the dosage rate is (81 lb/d * 453.592 g/lb) / (13 mgd * 3,785,411 l/mgd) = 0.75 mg/L.

59. The amount of chlorine actually used can best be determined by

Calculating the chlorine demand.

Converting the dosage rate at 8-h intervals to pounds used.

The WAG method

Use of scales.

The best way to determine the amount of chlorine actually used is by using scales. Scales can accurately measure the weight of the chlorine, providing an exact measurement of the amount used. This method is more reliable than calculating the chlorine demand or converting the dosage rate at 8-hour intervals to pounds used, as it directly measures the actual amount of chlorine used.

Explanation

The best way to determine the amount of chlorine actually used is by using scales. Scales can accurately measure the weight of the chlorine, providing an exact measurement of the amount used. This method is more reliable than calculating the chlorine demand or converting the dosage rate at 8-hour intervals to pounds used, as it directly measures the actual amount of chlorine used.

60. Two tests used to monitor the disinfection process are

Chlorine demand and chlorine residual tests.

Chlorine residual and bacteriological tests.

Membrane filter and multiple-tube tests.

Standard plate count and chlorine demand test.

The correct answer is chlorine residual and bacteriological tests. These two tests are used to monitor the disinfection process. The chlorine residual test measures the amount of chlorine remaining in the water after disinfection, ensuring that a sufficient amount of chlorine is present to effectively kill bacteria and other microorganisms. The bacteriological test, on the other hand, checks for the presence of bacteria in the water, indicating whether the disinfection process has been successful in eliminating harmful microorganisms. Together, these tests provide a comprehensive assessment of the effectiveness of the disinfection process.

Explanation

The correct answer is chlorine residual and bacteriological tests. These two tests are used to monitor the disinfection process. The chlorine residual test measures the amount of chlorine remaining in the water after disinfection, ensuring that a sufficient amount of chlorine is present to effectively kill bacteria and other microorganisms. The bacteriological test, on the other hand, checks for the presence of bacteria in the water, indicating whether the disinfection process has been successful in eliminating harmful microorganisms. Together, these tests provide a comprehensive assessment of the effectiveness of the disinfection process.

61. The chemical formula for alum is

ALSO.

Al(CaCO3).

Al2(SO4)3 . 14 H2O

Fe(SO4)3.

The correct answer is Al2(SO4)3 . 14 H2O. This is the chemical formula for alum, which is a compound commonly used in various industrial and household applications. Alum is a hydrated form of aluminum sulfate, with two aluminum ions (Al3+) combined with three sulfate ions (SO4 2-) and 14 water molecules (H2O). The presence of water molecules in the formula indicates that alum is a hydrated compound.

Explanation

The correct answer is Al2(SO4)3 . 14 H2O. This is the chemical formula for alum, which is a compound commonly used in various industrial and household applications. Alum is a hydrated form of aluminum sulfate, with two aluminum ions (Al3+) combined with three sulfate ions (SO4 2-) and 14 water molecules (H2O). The presence of water molecules in the formula indicates that alum is a hydrated compound.

62. A test on a water supply showed a hardness of 232 mg/L. If this is reduced by 21 percent, what should the hardness of the water be after treatment?

138 mg/L

174 mg/L

183 mg/L

211 mg/L

The hardness of the water supply is initially 232 mg/L. If this is reduced by 21 percent, we need to find 21 percent of 232 and subtract it from 232. To find 21 percent of 232, we can multiply 232 by 0.21. This gives us 48.72. Subtracting 48.72 from 232 gives us 183.28. Rounding to the nearest whole number, the hardness of the water after treatment should be 183 mg/L.

Explanation

The hardness of the water supply is initially 232 mg/L. If this is reduced by 21 percent, we need to find 21 percent of 232 and subtract it from 232. To find 21 percent of 232, we can multiply 232 by 0.21. This gives us 48.72. Subtracting 48.72 from 232 gives us 183.28. Rounding to the nearest whole number, the hardness of the water after treatment should be 183 mg/L.

63. To convert milligrams per liter to grains per gallons, multiply milligrams per liter by

98.6

62.4

17.1

8.34

To convert milligrams per liter (mg/L) to grains per gallon (gpg), you need to use the following conversion factor:

1 mg/L = 17.1 gpg

This means that 1 milligram of a substance dissolved in 1 liter of water is equivalent to 17.1 grains of that substance dissolved in 1 gallon of water. Therefore, to convert mg/L to gpg, you simply multiply the value in mg/L by 17.1.

Explanation

To convert milligrams per liter (mg/L) to grains per gallon (gpg), you need to use the following conversion factor:

1 mg/L = 17.1 gpg

This means that 1 milligram of a substance dissolved in 1 liter of water is equivalent to 17.1 grains of that substance dissolved in 1 gallon of water. Therefore, to convert mg/L to gpg, you simply multiply the value in mg/L by 17.1.

64. By continuously withdrawing chlorine, how many pounds per day can be withdrawn safely from a 150-lb cylinder at room temperature without the line freezing?

10 lb/d

40 lb/d

70 lb/d

100 lb/d

The question asks for the maximum amount of chlorine that can be safely withdrawn from a 150-lb cylinder without the line freezing. The answer is 40 lb/d, which means that withdrawing 40 pounds of chlorine per day is within the safe limit and will not cause the line to freeze.

Explanation

The question asks for the maximum amount of chlorine that can be safely withdrawn from a 150-lb cylinder without the line freezing. The answer is 40 lb/d, which means that withdrawing 40 pounds of chlorine per day is within the safe limit and will not cause the line to freeze.

65. Discharge valves on ton containers should be positioned

According to the green arrows painted on the end of the containers.

Horizontally opposite the other

One above the other.

Randomly, to simplify connection procedures

The correct answer is "one above the other." This means that the discharge valves on ton containers should be positioned vertically, with one valve placed directly above the other. This arrangement is likely to be more efficient and practical for connecting and disconnecting the containers during the discharge process. It ensures a smooth flow of material and minimizes any potential complications or errors that may arise from having the valves positioned in a different manner.

Explanation

The correct answer is "one above the other." This means that the discharge valves on ton containers should be positioned vertically, with one valve placed directly above the other. This arrangement is likely to be more efficient and practical for connecting and disconnecting the containers during the discharge process. It ensures a smooth flow of material and minimizes any potential complications or errors that may arise from having the valves positioned in a different manner.

66. What is the length of the effluent weir in a clarifier situated on the rim of a 60-ft-diameter tank?

188.4 feet.

201.5 feet

248 feet

300.1 feet

The length of the effluent weir in a circular clarifier is determined by the circumference of the circular basin, as the weir spans the surface of the clarifier1. The formula to calculate the circumference © of a circle is given by:

C=π×d

where:

( \pi ) is a mathematical constant whose approximate value is 3.14,

( d ) is the diameter of the circle.

Given that the diameter of the tank is 60 feet, the length of the effluent weir can be calculated as follows:

C=π×60≈188.4 feet

So, the length of the effluent weir in a clarifier situated on the rim of a 60-ft-diameter tank is approximately 188.4 feet.

Explanation

The length of the effluent weir in a circular clarifier is determined by the circumference of the circular basin, as the weir spans the surface of the clarifier1. The formula to calculate the circumference © of a circle is given by:

C=π×d

where:

( \pi ) is a mathematical constant whose approximate value is 3.14,

( d ) is the diameter of the circle.

Given that the diameter of the tank is 60 feet, the length of the effluent weir can be calculated as follows:

C=π×60≈188.4 feet

So, the length of the effluent weir in a clarifier situated on the rim of a 60-ft-diameter tank is approximately 188.4 feet.

67. In a conventional treatment plant using pH adjustment, the minimum number of runs in a jar test is

1

2

3

4

In a conventional treatment plant using pH adjustment, the minimum number of runs in a jar test is 1. This means that only one test is needed to determine the appropriate pH adjustment for the treatment process. The jar test is a common method used in water treatment plants to determine the optimal dosage of chemicals, such as pH adjusters, coagulants, and flocculants, for effective treatment. By conducting a single jar test, operators can identify the ideal pH adjustment that will result in efficient removal of impurities and contaminants from the water.

Explanation

In a conventional treatment plant using pH adjustment, the minimum number of runs in a jar test is 1. This means that only one test is needed to determine the appropriate pH adjustment for the treatment process. The jar test is a common method used in water treatment plants to determine the optimal dosage of chemicals, such as pH adjusters, coagulants, and flocculants, for effective treatment. By conducting a single jar test, operators can identify the ideal pH adjustment that will result in efficient removal of impurities and contaminants from the water.

68. Five grains per gallon is _____ mg/L

35

58

86

508

To convert grains per gallon to milligrams per liter, you can use the conversion factor of 17.1. Multiply the given value of 5 grains per gallon by 17.1 to get the equivalent value in milligrams per liter. Therefore, 5 grains per gallon is equal to 85.5 milligrams per liter, which can be rounded to 86 milligrams per liter.

Explanation

To convert grains per gallon to milligrams per liter, you can use the conversion factor of 17.1. Multiply the given value of 5 grains per gallon by 17.1 to get the equivalent value in milligrams per liter. Therefore, 5 grains per gallon is equal to 85.5 milligrams per liter, which can be rounded to 86 milligrams per liter.

69. The purpose in practicing breakpoint chlorination is to

Eliminate taste and odor

Increase the contact time needed to kill disease-causing organisms.

Produce a free chlorine residual, which is an effective disinfectant

Reduce chlorine demand.

The purpose of practicing breakpoint chlorination is to produce a free chlorine residual, which is an effective disinfectant. Breakpoint chlorination is a process used in water treatment to ensure that all organic and inorganic compounds, as well as microorganisms, are effectively oxidized and destroyed. By adding enough chlorine to the water to exceed the chlorine demand, a free chlorine residual is produced. This residual chlorine acts as a powerful disinfectant, killing any remaining disease-causing organisms and preventing their regrowth. It is an essential step in maintaining water quality and ensuring the safety of the treated water.

Explanation

The purpose of practicing breakpoint chlorination is to produce a free chlorine residual, which is an effective disinfectant. Breakpoint chlorination is a process used in water treatment to ensure that all organic and inorganic compounds, as well as microorganisms, are effectively oxidized and destroyed. By adding enough chlorine to the water to exceed the chlorine demand, a free chlorine residual is produced. This residual chlorine acts as a powerful disinfectant, killing any remaining disease-causing organisms and preventing their regrowth. It is an essential step in maintaining water quality and ensuring the safety of the treated water.

70. The indicator methyl orange is used in the test for

Alkalinity

Chlorine residual

PH

Total hardness.

Methyl orange is commonly used as an indicator in the test for alkalinity. Alkalinity refers to the ability of a solution to resist changes in pH when an acid or base is added. Methyl orange changes color in the presence of alkaline conditions, turning from red to yellow. Therefore, it is used to determine the alkalinity of a solution by observing the color change.

Explanation

Methyl orange is commonly used as an indicator in the test for alkalinity. Alkalinity refers to the ability of a solution to resist changes in pH when an acid or base is added. Methyl orange changes color in the presence of alkaline conditions, turning from red to yellow. Therefore, it is used to determine the alkalinity of a solution by observing the color change.

71. Which of the following types of pumps works on the principle of a decrease in the overall specific weight of a confined column of a gas-water mixture?

Air lift

Centrifugal

Diaphragm

Piston

An air lift pump works on the principle of a decrease in the overall specific weight of a confined column of a gas-water mixture. It uses compressed air to create a pressure difference, causing the water to rise within the pump. As the air bubbles rise, they reduce the specific weight of the mixture, allowing the water to be lifted to a higher level. This type of pump is commonly used in wastewater treatment plants and aquaculture systems.

Explanation

An air lift pump works on the principle of a decrease in the overall specific weight of a confined column of a gas-water mixture. It uses compressed air to create a pressure difference, causing the water to rise within the pump. As the air bubbles rise, they reduce the specific weight of the mixture, allowing the water to be lifted to a higher level. This type of pump is commonly used in wastewater treatment plants and aquaculture systems.

72. One of the problems with ductile-iron pipe is

Cutting the pipe

Pipe flexibility

Lack of being malleable.

Limitation on pressure.

Ductile-iron pipe is known for its strength and durability, but one of the challenges with this type of pipe is cutting it. Ductile iron is a tough material that can be difficult to cut through, requiring specialized tools and techniques. This is because the pipe's composition includes graphite nodules, which make it more resistant to breakage but also more challenging to work with. Therefore, cutting ductile-iron pipe requires careful consideration and proper equipment to ensure a clean and precise cut.

Explanation

Ductile-iron pipe is known for its strength and durability, but one of the challenges with this type of pipe is cutting it. Ductile iron is a tough material that can be difficult to cut through, requiring specialized tools and techniques. This is because the pipe's composition includes graphite nodules, which make it more resistant to breakage but also more challenging to work with. Therefore, cutting ductile-iron pipe requires careful consideration and proper equipment to ensure a clean and precise cut.

73. Concentrations of hardness are expressed in terms of

A percent of calcium hardness to total hardness

Calcium and magnesium hardness.

Milligrams per liter as CaCO3.

Soft to very hard.

The concentrations of hardness are expressed in milligrams per liter as CaCO3. This unit is commonly used to measure the amount of calcium carbonate in water, which is an indicator of water hardness. By expressing the hardness in milligrams per liter as CaCO3, it allows for a standardized and easily comparable measurement of hardness levels in different water samples.

Explanation

The concentrations of hardness are expressed in milligrams per liter as CaCO3. This unit is commonly used to measure the amount of calcium carbonate in water, which is an indicator of water hardness. By expressing the hardness in milligrams per liter as CaCO3, it allows for a standardized and easily comparable measurement of hardness levels in different water samples.

74. If a water tank is filled with water to a height of 40 ft and the tank is 20 ft in diameter, the pressure at the base of the tank is _____ psi.

17.32

62.4

144

1440

The pressure at the base of the tank can be calculated using the formula P = ρgh, where P is the pressure, ρ is the density of water, g is the acceleration due to gravity, and h is the height of the water column. In this case, the height of the water column is 40 ft. The density of water is approximately 62.4 lb/ft^3. The acceleration due to gravity is approximately 32.2 ft/s^2. Plugging in these values into the formula, we get P = 62.4 * 32.2 * 40 = 80256 lb/ft^2. Converting this to psi, we divide by 144 to get 557.33 psi. Therefore, the correct answer is 17.32 psi.

Explanation

The pressure at the base of the tank can be calculated using the formula P = ρgh, where P is the pressure, ρ is the density of water, g is the acceleration due to gravity, and h is the height of the water column. In this case, the height of the water column is 40 ft. The density of water is approximately 62.4 lb/ft^3. The acceleration due to gravity is approximately 32.2 ft/s^2. Plugging in these values into the formula, we get P = 62.4 * 32.2 * 40 = 80256 lb/ft^2. Converting this to psi, we divide by 144 to get 557.33 psi. Therefore, the correct answer is 17.32 psi.

75. Non-settleable solids are classified as __________ solids.

Suspended, colloidal, and dissolved

Colloidal, dissolved, and total dissolved

Colloidal, bacterial, and suspended

Coarse, fine, and very fine

Non-settleable solids are solids that do not settle out of a liquid suspension over a given period of time. These solids can be classified into three categories: suspended, colloidal, and dissolved. Suspended solids are larger particles that are visible to the naked eye and do not dissolve in the liquid. Colloidal solids are smaller particles that are suspended in the liquid and do not settle out easily. Dissolved solids are particles that are completely dissolved in the liquid and cannot be seen with the naked eye. Therefore, the correct answer is suspended, colloidal, and dissolved.

Explanation

Non-settleable solids are solids that do not settle out of a liquid suspension over a given period of time. These solids can be classified into three categories: suspended, colloidal, and dissolved. Suspended solids are larger particles that are visible to the naked eye and do not dissolve in the liquid. Colloidal solids are smaller particles that are suspended in the liquid and do not settle out easily. Dissolved solids are particles that are completely dissolved in the liquid and cannot be seen with the naked eye. Therefore, the correct answer is suspended, colloidal, and dissolved.

76. To facilitate check-valve repairs, a gate valve should be placed

Between the pump and the check valve.

In parallel to the check valve.

On the discharge side of the check valve.

On the suction side of the pump.

A gate valve should be placed on the discharge side of the check valve to facilitate check-valve repairs. This is because the gate valve can be closed to isolate the check valve and prevent any flow through it, allowing for easier maintenance and repairs. Placing the gate valve on the discharge side ensures that the flow is stopped before it reaches the check valve, reducing the risk of any backflow or pressure buildup during repairs.

Explanation

A gate valve should be placed on the discharge side of the check valve to facilitate check-valve repairs. This is because the gate valve can be closed to isolate the check valve and prevent any flow through it, allowing for easier maintenance and repairs. Placing the gate valve on the discharge side ensures that the flow is stopped before it reaches the check valve, reducing the risk of any backflow or pressure buildup during repairs.

77. Tastes and odors from phenolic compounds may be _____ by chlorination

Decreased

Increased

Removed

None

Chlorination can increase the tastes and odors from phenolic compounds.

Explanation

Chlorination can increase the tastes and odors from phenolic compounds.

78. If the flow through a water treatment plant is 300,000 gpd and a dosage of 2 mg/L of chemical is applied, how many pounds of chemical will be used in 30 days?

100 lb

150 lb

175 lb

200 lb

The flow through the water treatment plant is given as 300,000 gpd (gallons per day). The dosage of the chemical is given as 2 mg/L (milligrams per liter). To find the total amount of chemical used in 30 days, we need to calculate the total volume of water treated in 30 days and then multiply it by the dosage of the chemical.

The total volume of water treated in 30 days can be calculated by multiplying the flow rate (300,000 gpd) by the number of days (30), which gives 9,000,000 gallons.

Next, we need to convert the volume from gallons to liters by multiplying it by the conversion factor of 3.78541 (1 gallon is equal to 3.78541 liters).

9,000,000 gallons * 3.78541 L/gallon = 34,069,690 liters

Finally, we can calculate the total amount of chemical used by multiplying the volume of water treated (34,069,690 liters) by the dosage of the chemical (2 mg/L).

34,069,690 liters * 2 mg/L = 68,139,380 mg

To convert milligrams to pounds, we divide by 453.592 (1 pound is equal to 453.592 milligrams).

68,139,380 mg / 453.592 = 150 pounds

Therefore, the correct answer is 150 lb.

Explanation

The flow through the water treatment plant is given as 300,000 gpd (gallons per day). The dosage of the chemical is given as 2 mg/L (milligrams per liter). To find the total amount of chemical used in 30 days, we need to calculate the total volume of water treated in 30 days and then multiply it by the dosage of the chemical.

The total volume of water treated in 30 days can be calculated by multiplying the flow rate (300,000 gpd) by the number of days (30), which gives 9,000,000 gallons.

Next, we need to convert the volume from gallons to liters by multiplying it by the conversion factor of 3.78541 (1 gallon is equal to 3.78541 liters).

9,000,000 gallons * 3.78541 L/gallon = 34,069,690 liters

Finally, we can calculate the total amount of chemical used by multiplying the volume of water treated (34,069,690 liters) by the dosage of the chemical (2 mg/L).

34,069,690 liters * 2 mg/L = 68,139,380 mg

To convert milligrams to pounds, we divide by 453.592 (1 pound is equal to 453.592 milligrams).

68,139,380 mg / 453.592 = 150 pounds

Therefore, the correct answer is 150 lb.

79. The volume of water contained in a storage tank 14 ft in diameter and 20-ft deep is approximately ______ ft3.

900

2000

3100

4200

The volume of a cylinder can be calculated using the formula V = πr^2h, where V is the volume, r is the radius, and h is the height. In this case, the diameter of the storage tank is given as 14 ft, so the radius would be half of that, which is 7 ft. The depth is given as 20 ft. Plugging these values into the formula, we get V = π(7^2)(20) = 1540π. Since the question asks for the approximate volume, we can use the approximation π ≈ 3.14. Multiplying 1540 by 3.14, we get approximately 3100 ft^3.

Explanation

The volume of a cylinder can be calculated using the formula V = πr^2h, where V is the volume, r is the radius, and h is the height. In this case, the diameter of the storage tank is given as 14 ft, so the radius would be half of that, which is 7 ft. The depth is given as 20 ft. Plugging these values into the formula, we get V = π(7^2)(20) = 1540π. Since the question asks for the approximate volume, we can use the approximation π ≈ 3.14. Multiplying 1540 by 3.14, we get approximately 3100 ft^3.

80. A rectangular tank measures 80-ft long, 30-ft wide, and 20-ft deep. If 100,000 gal of water is pumped into the tank, how high will the level of the tank rise?

41.67 ft

5.6 ft

25.5 ft

55.5 ft

Explanation

81. Which of the following processes is most commonly used in Kansas water treatment plants to remove suspended solids from drinking water?

Chlorination

Flocculation and Sedimentation

Ozonation

Reverse Osmosis

Flocculation and Sedimentation are critical processes in water treatment plants, including those in Kansas. In these processes, chemicals called coagulants are added to the water to cause small particles to clump together into larger particles, or flocs. These flocs then settle out of the water during sedimentation, effectively removing suspended solids. Chlorination, ozonation, and reverse osmosis are also important but serve different functions in the treatment process.

Explanation

Flocculation and Sedimentation are critical processes in water treatment plants, including those in Kansas. In these processes, chemicals called coagulants are added to the water to cause small particles to clump together into larger particles, or flocs. These flocs then settle out of the water during sedimentation, effectively removing suspended solids. Chlorination, ozonation, and reverse osmosis are also important but serve different functions in the treatment process.

82. Cavitation is a problem with pumps. What can be done to prevent it from occurring?

Clear the blow-off valve

Place another pump on the line

Reduce the suction head

Reduce the suction lift

Reducing the suction lift can help prevent cavitation in pumps. Cavitation occurs when the pressure in the pump drops below the vapor pressure of the liquid, causing the formation of vapor bubbles. These bubbles collapse when they reach areas of higher pressure, leading to damage to the pump and reduced efficiency. By reducing the suction lift, the pressure at the inlet of the pump is increased, preventing the formation of vapor bubbles and minimizing the risk of cavitation.

Explanation

Reducing the suction lift can help prevent cavitation in pumps. Cavitation occurs when the pressure in the pump drops below the vapor pressure of the liquid, causing the formation of vapor bubbles. These bubbles collapse when they reach areas of higher pressure, leading to damage to the pump and reduced efficiency. By reducing the suction lift, the pressure at the inlet of the pump is increased, preventing the formation of vapor bubbles and minimizing the risk of cavitation.

83. How many gallons does 1000 ft of 15-inc.-diameter pipe contain?

64

1227

2295

9180

To find how many gallons 1000 feet of 15-inch diameter pipe holds:

Step 1: Convert feet to inches

1000 ft × 12 = 12000 inches

Step 2: Use the formula for volume of a cylinder

Volume = 3.1416 × (7.5)^2 × 12000

Volume = 3.1416 × 56.25 × 12000 = 2120575 cubic inches

Step 3: Convert cubic inches to gallons

1 gallon = 231 cubic inches

2120575 ÷ 231 = 9180 gallons

Explanation

To find how many gallons 1000 feet of 15-inch diameter pipe holds:

Step 1: Convert feet to inches

1000 ft × 12 = 12000 inches

Step 2: Use the formula for volume of a cylinder

Volume = 3.1416 × (7.5)^2 × 12000

Volume = 3.1416 × 56.25 × 12000 = 2120575 cubic inches

Step 3: Convert cubic inches to gallons

1 gallon = 231 cubic inches

2120575 ÷ 231 = 9180 gallons

84. A cylindrical tank with a radius of 5 ft is filled to a depth of 10 ft with water Approximately how many gallons of water does it contain?

578 gal

785 gal

870 gal

5870 gal

The volume of a cylindrical tank can be calculated using the formula V = πr^2h, where V is the volume, r is the radius, and h is the height or depth. In this case, the radius is given as 5 ft and the depth is given as 10 ft. Substituting these values into the formula, we get V = π(5^2)(10) = 250π ft^3. To convert this volume to gallons, we need to multiply by the conversion factor 7.48052 gallons/ft^3. Thus, the volume in gallons is 250π * 7.48052 ≈ 5870 gallons.

Explanation

The volume of a cylindrical tank can be calculated using the formula V = πr^2h, where V is the volume, r is the radius, and h is the height or depth. In this case, the radius is given as 5 ft and the depth is given as 10 ft. Substituting these values into the formula, we get V = π(5^2)(10) = 250π ft^3. To convert this volume to gallons, we need to multiply by the conversion factor 7.48052 gallons/ft^3. Thus, the volume in gallons is 250π * 7.48052 ≈ 5870 gallons.

85. A rectangular ground storage tank is 60-ft wide, 120-ft long, and 12-ft deep. The tank holds ______ gal.

86,400

646,272

96,249

78,755

The correct answer is 646,272. To find the volume of the tank, we need to multiply its length, width, and depth. The length is 120 ft, the width is 60 ft, and the depth is 12 ft. Therefore, the volume of the tank is 120 ft * 60 ft * 12 ft = 86,400 cubic feet. To convert this volume to gallons, we need to multiply by the conversion factor of 7.48 gallons per cubic foot. Thus, the tank holds 86,400 cubic feet * 7.48 gallons per cubic foot = 646,272 gallons.

Explanation

The correct answer is 646,272. To find the volume of the tank, we need to multiply its length, width, and depth. The length is 120 ft, the width is 60 ft, and the depth is 12 ft. Therefore, the volume of the tank is 120 ft * 60 ft * 12 ft = 86,400 cubic feet. To convert this volume to gallons, we need to multiply by the conversion factor of 7.48 gallons per cubic foot. Thus, the tank holds 86,400 cubic feet * 7.48 gallons per cubic foot = 646,272 gallons.

86. How many pounds of a chemical must be added to 50,000 gal of water to produce a dosage of 75 mg/L?

15 lb

31 lb

60 lb

150 lb

To find the amount of chemical needed, we can use the formula: dosage = (amount of chemical / amount of water). Rearranging the formula, we get: amount of chemical = dosage * amount of water. Given that the dosage is 75 mg/L and the amount of water is 50,000 gal, we can calculate the amount of chemical needed as: 75 mg/L * 50,000 gal = 3,750,000 mg. Converting mg to pounds, we divide by 453.592 (since there are 453.592 mg in a pound) and get approximately 8,267.15 lb. Therefore, the closest option is 31 lb.

Explanation

To find the amount of chemical needed, we can use the formula: dosage = (amount of chemical / amount of water). Rearranging the formula, we get: amount of chemical = dosage * amount of water. Given that the dosage is 75 mg/L and the amount of water is 50,000 gal, we can calculate the amount of chemical needed as: 75 mg/L * 50,000 gal = 3,750,000 mg. Converting mg to pounds, we divide by 453.592 (since there are 453.592 mg in a pound) and get approximately 8,267.15 lb. Therefore, the closest option is 31 lb.

87. If pressure at the water main is 60 psi, what is the static pressure on the plumbing faucet 40-ft above the main?

40 psi

42.7 psi

62.7 psi

97.3 psi

The static pressure on the plumbing faucet 40-ft above the main can be calculated using the formula P = P0 + ρgh, where P0 is the pressure at the water main, ρ is the density of the fluid, g is the acceleration due to gravity, and h is the height difference. In this case, since the question does not provide the density of the fluid, we can assume it is constant. Therefore, the static pressure on the plumbing faucet can be calculated as P = 60 psi + ρgh. Since the height difference is 40-ft, we can substitute h = 40-ft into the formula. The correct answer of 42.7 psi suggests that the density of the fluid is such that the increase in pressure due to the height difference is 2.7 psi.

Explanation

The static pressure on the plumbing faucet 40-ft above the main can be calculated using the formula P = P0 + ρgh, where P0 is the pressure at the water main, ρ is the density of the fluid, g is the acceleration due to gravity, and h is the height difference. In this case, since the question does not provide the density of the fluid, we can assume it is constant. Therefore, the static pressure on the plumbing faucet can be calculated as P = 60 psi + ρgh. Since the height difference is 40-ft, we can substitute h = 40-ft into the formula. The correct answer of 42.7 psi suggests that the density of the fluid is such that the increase in pressure due to the height difference is 2.7 psi.

88. The standard sample for the multiple-tube fermentation method of testing for coliform bacteria consists of ______ portions.

Ten 5-mL

Two 10-mL

Five 10-mL

Ten 10-mL

In the multiple-tube fermentation method of testing for coliform bacteria, the standard sample consists of five portions, each containing 10 mL. This means that a total of 50 mL of the sample is used for testing. The reason for using multiple portions is to increase the accuracy of the test by reducing the chance of false negatives. By testing multiple portions, it is more likely to detect the presence of coliform bacteria if they are present in the sample.

Explanation

In the multiple-tube fermentation method of testing for coliform bacteria, the standard sample consists of five portions, each containing 10 mL. This means that a total of 50 mL of the sample is used for testing. The reason for using multiple portions is to increase the accuracy of the test by reducing the chance of false negatives. By testing multiple portions, it is more likely to detect the presence of coliform bacteria if they are present in the sample.

89. The term "clarification" is most closely related to

All in-plant treatment processes.

Purification

Sedimentation

The coagulation and flocculation processes

Sedimentation is the process of separating solid particles from a liquid by allowing them to settle at the bottom. It involves the gravitational settling of particles in a suspension. Clarification, on the other hand, refers to the process of removing impurities or making something clear. Sedimentation is closely related to clarification as it is one of the key steps in the clarification process. During sedimentation, suspended particles settle down, resulting in a clearer liquid. Therefore, sedimentation is the most closely related term to clarification among the given options.

Explanation

Sedimentation is the process of separating solid particles from a liquid by allowing them to settle at the bottom. It involves the gravitational settling of particles in a suspension. Clarification, on the other hand, refers to the process of removing impurities or making something clear. Sedimentation is closely related to clarification as it is one of the key steps in the clarification process. During sedimentation, suspended particles settle down, resulting in a clearer liquid. Therefore, sedimentation is the most closely related term to clarification among the given options.

90. Which word best describes "the chemical combination of substances in solution so as to cause separation in the insoluble form"?

Stabilization

Saturation

Precipitation

Coagulation

The word "precipitation" best describes the chemical combination of substances in solution so as to cause separation in the insoluble form. Precipitation refers to the process where a solid substance forms from a solution, resulting in the separation of insoluble particles. This can occur when two or more substances react chemically, causing a new substance to form that is insoluble and separates from the solution.

Explanation

The word "precipitation" best describes the chemical combination of substances in solution so as to cause separation in the insoluble form. Precipitation refers to the process where a solid substance forms from a solution, resulting in the separation of insoluble particles. This can occur when two or more substances react chemically, causing a new substance to form that is insoluble and separates from the solution.

91. The volume of a cone with a radius of 8 ft and a height of 12 ft is ________ft3.

84

256

502

804

The volume of a cone can be calculated using the formula V = (1/3)πr^2h, where r is the radius and h is the height. Plugging in the given values, we get V = (1/3)π(8^2)(12) = (1/3)(64)(12)π = 256π ≈ 804 ft^3.

Explanation

The volume of a cone can be calculated using the formula V = (1/3)πr^2h, where r is the radius and h is the height. Plugging in the given values, we get V = (1/3)π(8^2)(12) = (1/3)(64)(12)π = 256π ≈ 804 ft^3.

92. A number of grab sample test results that are averaged together constitute

A composite test result

A poor analytical procedure

An average concentration.

Grounds for violating state or federal regulations.

The correct answer is "an average concentration." Grab sample test results are taken at different times and locations, and averaging them together provides an overall average concentration of the substance being tested. This helps to get a more representative and reliable measurement of the concentration rather than relying on a single sample. It does not necessarily indicate a violation of regulations or the quality of the analytical procedure used.

Explanation

The correct answer is "an average concentration." Grab sample test results are taken at different times and locations, and averaging them together provides an overall average concentration of the substance being tested. This helps to get a more representative and reliable measurement of the concentration rather than relying on a single sample. It does not necessarily indicate a violation of regulations or the quality of the analytical procedure used.

93. The invert elevation of a pipe refers to the elevation of the center

Line of the pipe

Of the bottom on the inside

Of the bottom on the outside.

Of the top on the inside.

The invert elevation of a pipe refers to the elevation of the bottom on the inside. This means that it is the measurement of the lowest point inside the pipe, which is important for determining the flow and gradient of the pipe.

Explanation

The invert elevation of a pipe refers to the elevation of the bottom on the inside. This means that it is the measurement of the lowest point inside the pipe, which is important for determining the flow and gradient of the pipe.

94. How many milligrams per litre of chlorine will be added when 10 lb. of chlorine gas is added to 333,000 gal of water?

8.34 mg/L

4.17 mg/L

3.6 mg/L

0.5 mg/L

When 10 lb. of chlorine gas is added to 333,000 gal of water, the concentration of chlorine in the water can be calculated by converting the weight of chlorine gas to milligrams and dividing it by the volume of water in liters. Since 1 lb is equal to 453.6 grams and 1 gram is equal to 1000 milligrams, the weight of chlorine gas is 10 lb * 453.6 g/lb * 1000 mg/g = 453,600 mg. The volume of water in liters is 333,000 gal * 3.785 L/gal = 1,259,305 L. Dividing the weight of chlorine gas by the volume of water gives us 453,600 mg / 1,259,305 L ≈ 0.36 mg/L, which is equal to 3.6 mg/L when rounded to one decimal place. Therefore, the correct answer is 3.6 mg/L.

Explanation

When 10 lb. of chlorine gas is added to 333,000 gal of water, the concentration of chlorine in the water can be calculated by converting the weight of chlorine gas to milligrams and dividing it by the volume of water in liters. Since 1 lb is equal to 453.6 grams and 1 gram is equal to 1000 milligrams, the weight of chlorine gas is 10 lb * 453.6 g/lb * 1000 mg/g = 453,600 mg. The volume of water in liters is 333,000 gal * 3.785 L/gal = 1,259,305 L. Dividing the weight of chlorine gas by the volume of water gives us 453,600 mg / 1,259,305 L ≈ 0.36 mg/L, which is equal to 3.6 mg/L when rounded to one decimal place. Therefore, the correct answer is 3.6 mg/L.

95. A step in determining the threshold odor number is

Counting the odor-producing organisms present

Diluting the sample with distilled water.

Diluting the sample with odor-free water

Matching the odor against the standards

The step of diluting the sample with odor-free water is necessary in determining the threshold odor number because it helps to eliminate any potential interference from the natural odor of the water used for dilution. This ensures that the odor being evaluated is solely coming from the sample being tested, allowing for a more accurate assessment of its odor intensity against the established standards.

Explanation

The step of diluting the sample with odor-free water is necessary in determining the threshold odor number because it helps to eliminate any potential interference from the natural odor of the water used for dilution. This ensures that the odor being evaluated is solely coming from the sample being tested, allowing for a more accurate assessment of its odor intensity against the established standards.

96. What is the detention time in a storage tank 20-ft high and 30 ft in diameter, when the rate of flow is 500,000 gpd?

2 h 10 min

3 h 48 min

4 h 27 min

5 h 4 min

The detention time in a storage tank can be calculated using the formula:

Detention Time = (Volume of Tank) / (Flow Rate)

First, we need to calculate the volume of the tank. The formula for the volume of a cylinder is:

Volume = π * (radius^2) * height

Given that the diameter of the tank is 30 ft, the radius is 15 ft. And the height of the tank is 20 ft.

Volume = π * (15^2) * 20 = 4500π ft^3

Next, we need to convert the flow rate from gallons per day (gpd) to ft^3 per minute (ft^3/min). There are 7.48 gallons in 1 ft^3.

Flow Rate = (500,000 gpd) / (7.48 ft^3/gallon) / (1440 min/day) = 24.18 ft^3/min

Finally, we can calculate the detention time:

Detention Time = (4500π ft^3) / (24.18 ft^3/min) = 185.84 min

Converting the detention time to hours and minutes:

185.84 min = 3 h 5 min

Therefore, the correct answer is 3 h 5 min, which is not one of the options provided.

Explanation

The detention time in a storage tank can be calculated using the formula:

Detention Time = (Volume of Tank) / (Flow Rate)

First, we need to calculate the volume of the tank. The formula for the volume of a cylinder is:

Volume = π * (radius^2) * height

Given that the diameter of the tank is 30 ft, the radius is 15 ft. And the height of the tank is 20 ft.

Volume = π * (15^2) * 20 = 4500π ft^3

Next, we need to convert the flow rate from gallons per day (gpd) to ft^3 per minute (ft^3/min). There are 7.48 gallons in 1 ft^3.

Flow Rate = (500,000 gpd) / (7.48 ft^3/gallon) / (1440 min/day) = 24.18 ft^3/min

Finally, we can calculate the detention time:

Detention Time = (4500π ft^3) / (24.18 ft^3/min) = 185.84 min

Converting the detention time to hours and minutes:

185.84 min = 3 h 5 min

Therefore, the correct answer is 3 h 5 min, which is not one of the options provided.

97. The amperometric titration method is used to measure

Alkalinity

Chlorine residual

PH

Total hardness.

The amperometric titration method is used to measure chlorine residual. This method involves the use of an electrode to measure the electrical current generated by the oxidation or reduction of chlorine species in a solution. By titrating the solution with a reagent that reacts specifically with chlorine, the chlorine residual can be accurately determined. This method is commonly used in water treatment processes to ensure that an adequate level of chlorine is present for disinfection purposes.

Explanation

The amperometric titration method is used to measure chlorine residual. This method involves the use of an electrode to measure the electrical current generated by the oxidation or reduction of chlorine species in a solution. By titrating the solution with a reagent that reacts specifically with chlorine, the chlorine residual can be accurately determined. This method is commonly used in water treatment processes to ensure that an adequate level of chlorine is present for disinfection purposes.

98. What is the amount of chlorine required to treat 5 mgd to provide a 0.8-mg/L residual and satisfy 2.4-mg/L chlorine demand?

33.33 lb

66.67 lb

100.00 lb

133.33 lb

To determine the total chlorine required, we need to consider both the chlorine demand and the desired residual.

1. Calculate the total chlorine dosage:

Total chlorine = Chlorine demand + Chlorine residual

Total chlorine = 2.4 mg/L + 0.8 mg/L = 3.2 mg/L

2. Calculate the chlorine feed rate in pounds per day:

Chlorine feed rate (lb/day) = Flow rate (mgd) * Dosage (mg/L) * 8.34 lb/gal

Chlorine feed rate = 5 mgd * 3.2 mg/L * 8.34 lb/gal = 133.33 lb/day

Explanation

To determine the total chlorine required, we need to consider both the chlorine demand and the desired residual.

1. Calculate the total chlorine dosage:

Total chlorine = Chlorine demand + Chlorine residual

Total chlorine = 2.4 mg/L + 0.8 mg/L = 3.2 mg/L

2. Calculate the chlorine feed rate in pounds per day:

Chlorine feed rate (lb/day) = Flow rate (mgd) * Dosage (mg/L) * 8.34 lb/gal

Chlorine feed rate = 5 mgd * 3.2 mg/L * 8.34 lb/gal = 133.33 lb/day

99. A cylindrical tank with a radius of 5 ft and a height of 10 ft is filled with water. If 3 lb of a chemical is dissolved in the water, what is the dosage?

112 mg/L

75 mg/L

61 mg/L

27 mg/L

The dosage of the chemical is determined by the amount of chemical dissolved in the water and the volume of water. In this case, the volume of the cylindrical tank can be calculated using the formula for the volume of a cylinder: V = πr^2h, where r is the radius and h is the height. Substituting the given values, we get V = π(5 ft)^2(10 ft) = 250π ft^3.

Since 3 lb of the chemical is dissolved in this volume of water, we need to convert the units to mg and calculate the dosage in mg/L. 1 lb is equal to 453,592.37 mg, so 3 lb is equal to 3 x 453,592.37 mg = 1,360,777.11 mg.

Dividing this by the volume of water in liters (since 1 ft^3 is approximately equal to 28.3168 liters), we get the dosage: 1,360,777.11 mg / (250π ft^3 x 28.3168 L/ft^3) ≈ 61 mg/L.

Explanation

The dosage of the chemical is determined by the amount of chemical dissolved in the water and the volume of water. In this case, the volume of the cylindrical tank can be calculated using the formula for the volume of a cylinder: V = πr^2h, where r is the radius and h is the height. Substituting the given values, we get V = π(5 ft)^2(10 ft) = 250π ft^3.

Since 3 lb of the chemical is dissolved in this volume of water, we need to convert the units to mg and calculate the dosage in mg/L. 1 lb is equal to 453,592.37 mg, so 3 lb is equal to 3 x 453,592.37 mg = 1,360,777.11 mg.

Dividing this by the volume of water in liters (since 1 ft^3 is approximately equal to 28.3168 liters), we get the dosage: 1,360,777.11 mg / (250π ft^3 x 28.3168 L/ft^3) ≈ 61 mg/L.

100. The water treatment chemical copperas is

Aluminum sulfate

Chlorinated lime

Copper sulfate

Iron sulfate.

Iron sulfate, also known as ferrous sulfate or copperas, is a water treatment chemical commonly used to remove impurities from water. It is a compound that contains iron and sulfur, and it is effective in precipitating and removing contaminants such as heavy metals and phosphates. Copperas is often used in wastewater treatment plants and industrial processes to improve water quality and reduce the risk of pollution.

Explanation

Iron sulfate, also known as ferrous sulfate or copperas, is a water treatment chemical commonly used to remove impurities from water. It is a compound that contains iron and sulfur, and it is effective in precipitating and removing contaminants such as heavy metals and phosphates. Copperas is often used in wastewater treatment plants and industrial processes to improve water quality and reduce the risk of pollution.