Kansas Water Treatment Study Guide Class 2 Quiz

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Chlorination can increase the tastes and odors from phenolic compounds.

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.

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.

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.

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.

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

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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