Water Treatment Flashcards
In cooling towers, heavy metals, oxidizing chemicals, and non-oxidizing chemicals are used to:
Select one:
a. Inhibit corrosion
b. Inhibit biological fouling
c. Eliminate wood deterioration
d. Reduce scaling
b. Inhibit biological fouling
External deaeration:
Select one:
a. Removes dissolved gases from the water
b. Relies entirely on the addition of chemicals
c. Removes all dissolved gases and solids from the water
d. Only removes oxygen from the water
a. Removes dissolved gases from the water
Scaling is not as severe in cooling towers when compared to boilers because:
Select one:
a. Cooling towers evaporate less water
b. There are not as many dissolved solids in cooling tower water
c. Water temperatures are not as high in cooling towers as they are in boilers
d. Cooling tower water is constantly being aerated
c. Water temperatures are not as high in cooling towers as they are in boilers
To prevent scale formation, \_\_\_\_\_\_\_\_ is added to the boiler water. Select one: a. Zeolite b. Sodium chloride c. Amine d. Phosphate
d. Phosphate
In a galvanic corrosion cell, the metal that corrodes is the
Select one:
a. anode
b. cathode
c. noble metal
d. metal with the more positive electrochemical potential
a. anode
Water filters must be cleaned: Select one: a. If the water becomes hard b. When the dissolved solids are high c. By backwashing the filter media d. By chemically cleaning the filter media
c. By backwashing the filter media
Which of the following is an example of a dissolved solid? Select one: a. Magnesium sulphate b. Oxygen c. Sand d. Carbon dioxide
a. Magnesium sulphate
Materials which are generally larger than 2 micrometres and that are dispersed throughout the water, are called: Select one: a. Dissolved solids b. Colloidal particles c. Suspended matter d. Dissolved matter
c. Suspended matter
In cooling towers, sacrificial anodes work by
Select one:
a. plating the metal parts with non-corrosive metal ions.
b. neutralizing acidic compounds.
c. corroding, instead of the metal cooling tower parts
d. interfering with the formation of corrosive reaction products.
c. corroding, instead of the metal cooling tower parts
Suspended matter must be removed from feedwater to:
Select one:
a. Prevent overheating of the boiler metal
b. Prevent boiler waterside scale deposits
c. Reduce the alkalinity of the water
d. Eliminate the hardness of the water
Prevent overheating of the boiler metal
To minimize galvanic corrosion
Select one:
a. Use only noble metals.
b. A sacrificial anode may be installed to protect the cathodic materials.
c. If dissimilar metals are used, they must be directly connected to each other.
d. The electrochemical potential difference between any two connected materials must be greater than 0.15 V.
b. A sacrificial anode may be installed to protect the cathodic materials.
Galvanic corrosion depends on
Select one:
a. how fast the electrons flow through the electrolyte.
b. the difference in mass between the two inter-connecting metals.
c. the size of the sacrificial anode.
d. a difference in electrochemical potential between dissimilar metals.
d. a difference in electrochemical potential between dissimilar metals.
When only one specific type of metal is subject to corrosive attack, the corrosion process is called:
Select one:
a. cathodic corrosion
b. galvanic corrosion
c. selective leaching
d. anodic corrosion
c. selective leaching
Oxygen in condensate can cause:
Select one:
a. highly acidic water
b. low alkalinity
c. scale deposition
d. pitting corrosion
d. pitting corrosion
By definition, alum, when added to water to form floc in a clarifying system, is known as a: Select one: a. Curdler b. Congealant c. Coagulant d. Flocculant
d. Flocculant
The principal cause of steel corrosion in cooling towers is: Select one: a. Dissolved carbon dioxide b. High pH c. Dissolved oxygen d. Low pH
c. Dissolved oxygen
Where does the carbonic acid found in condensate come from?
Select one:
a. From the decomposition of dissolved carbonates and bicarbonates in the boiler water.
b. From inorganic compounds that enter through leaking heat exchangers.
c. From under-feeding oxygen scavengers to the boiler drum.
d. From the oxidation of carbon steel condensate piping.
a. From the decomposition of dissolved carbonates and bicarbonates in the boiler water.
Chillers must have _____________ to protect the evaporator coil from freezing damage.
Select one:
a. heaters
b. anti-freeze
c. frost plugs
d. freeze stats
d. freeze stats
In a steam plant, condensate treatment is necessary
Select one:
a. to provide clean, potable drinking water.
b. because condensate can contain impurities harmful to boilers and condensate return systems.
c. to provide ultra-pure boiler feedwater.
d. to aerate the condensate before it enters the deaerator.
b. because condensate can contain impurities harmful to boilers and condensate return systems.
Sludge conditioning in a boiler:
Select one:
a. Is controlled by the continuous blowdown
b. Prevents pollution from the blowdown water
c. Prevents precipitates from adhering to boiler surfaces
d. Is done to mix the sludge with the boiler water
c. Prevents precipitates from adhering to boiler surfaces
Direct measurement of condensate amine can be done using:
Select one:
a. a coupon rack
b. methyl purple and sulfuric acid
c. a chromatograph or a fluorometer
d. a commercially available iron analysis kit
c. a chromatograph or a fluorometer
When testing boiler water, a conductivity meter is used to measure:
Select one:
a. Total alkalinity
b. Hardness in parts per million or grains per gallon
c. Total suspended matter
d. Total dissolved solids
d. Total dissolved solids
What checks should be done yearly on heating or cooling systems that contain glycol?
Select one:
a. check for increasing pH and dissolved carbon dioxide
b. check toxicity and specific heat
c. check for viscosity and pour point
d. check for freeze point and inhibitor strength
d. check for freeze point and inhibitor strength
Condensate return line corrosion can be controlled by:
Select one:
a. Feeding sodium bicarbonate to the boiler
b. Adding sodium sulfite
c. Feeding amines
d. Adding polymers
c. Feeding amines
Phenolphthalein:
Select one:
a. Turns pink in the presence of hydroxide and carbonate alkalinity
b. Is fed to cast iron boilers
c. Prevents caustic embrittlement
d. Indicates the presence of dissolved oxygen
a. Turns pink in the presence of hydroxide and carbonate alkalinity
The wood used in cooling towers contains natural compounds called __________, that resist decay.
Select one:
a. celluloses
b. biocides
c. extractives
d. lignins
c. extractives
Coagulants, when added to water: Select one: a. Soften the water b. Will help remove fine particles c. Remove the dissolved solids d. Cause fine particles to float to the surface
b. Will help remove fine particles
During the “Rinse” stage when regenerating a sodium zeolite softener, the solution going to the sewer contains: Select one: a. Calcium sulphate b. Sulphates and bicarbonates c. Calcium and magnesium ions d. Sodium bicarbonates and sulphates
c. Calcium and magnesium ions
Sodium zeolite softeners:
Select one:
a. Remove all dissolved solids and suspended matter from the water
b. Remove calcium and magnesium ions from the water
c. Are regenerated with an acid solution
d. Remove all dissolved solids from the water
b. Remove calcium and magnesium ions from the water
Dezincification is a form of
Select one:
a. under-deposit corrosion
b. dielectric corrosion
c. selective leaching
d. stress corrosion cracking
c. selective leaching
Which of the following is NOT a cause of, or a factor in, closed loop system corrosion?
Select one:
a. low pH
b. galvanic action
c. dissolved oxygen
d. caustic gouging
d. caustic gouging
Caustic embrittlement of boiler metal is promoted by: Select one: a. Concentrations of sodium hydroxide b. Concentration of sodium chloride c. Overheating of boiler parts d. Concentration of sodium sulfite
a. Concentrations of sodium hydroxide
In cooling towers, structural wood is chemically attacked by a process called
Select one:
a. extractive leaching
b. delignification
c. cellulose deterioration
d. biological attack
b. delignification
Bicarbonates can be removed from boiler feedwater by:
Select one:
a. Filter tanks
b. A strainer in the feedwater line
c. Heating the water to just below its boiling point
d. Blowing off the boiler
c. Heating the water to just below its boiling point
Boiler water that is too alkaline will likely:
Select one:
a. Produce scale inside the boiler
b. Have a low pH
c. Cause foaming in the boiler
d. Cause grooving on a boiler’s waterside surfaces
c. Cause foaming in the boiler
Sodium phosphates:
Select one:
a. Produce a light, protective scale on the boiler heat transfer surfaces
b. Prevent scale formation
c. Absorb dissolved oxygen and prevent CO3 pitting
d. Prevent the formation of sludge
b. Prevent scale formation
In a zeolite water softener, the scale-forming salts are:
Select one:
a. Completely removed
b. Changed into non-scale forming sodium salts
c. Filtered out
d. Absorbed by the zeolite
b. Changed into non-scale forming sodium salts
What are dip slides used for?
Select one:
a. To prevent delignification of wooden components
b. To test for biological activity
c. To detect dissolved gases
d. To detect corrosion
b. To test for biological activity
Total alkalinity is measured:
Select one:
a. Using methyl purple indicator and sulfuric acid
b. Using potassium iodide-iodate and EDTA
c. To control the concentration of oxygen scavenger
d. Using phenolphthalein and sulfuric acid
a. Using methyl purple indicator and sulfuric acid
Boiler water with a pH of 6 is considered: Select one: a. Alkaline b. Basic c. Acidic d. Neutral
c. Acidic
A water sample taken from the service outlet of an ion-exchange softener shows 20 ppm hardness. The operator should:
Select one:
a. Add salt to the brine tank.
b. Rinse the softener.
c. Regenerate the softener.
d. Backwash the softener.
c. Regenerate the softener.
Total boiler water alkalinity is a measurement of dissolved:
Select one:
a. Carbonates, sulfates, and bicarbonates
b. Bicarbonates and chelants
c. Hydroxides, bicarbonates, and carbon dioxide
d. Hydroxides, carbonates, and bicarbonates
d. Hydroxides, carbonates, and bicarbonates
Chemicals are fed to a watertube boiler:
Select one:
a. With a small centrifugal pump
b. Into the top drum only
c. With a small positive displacement pump
d. With a hand pump
c. With a small positive displacement pump
Which of the following is a common test conducted on condensate?
Select one:
a. pH
b. sulfite residual
c. dissolved oxygen
d. dissolved carbon dioxide
a. pH
Filters are used: Select one: a. For external water treatment b. To remove dissolved solids c. To remove calcium bicarbonates d. For internal treatment
a. For external water treatment
The zeolite inside a water softener is used to:
Select one:
a. Regenerate the brine solution
b. Rinse the softened water
c. Exchange sodium ions for calcium and magnesium ions
d. Exchange calcium ions for magnesium ions
c. Exchange sodium ions for calcium and magnesium ions
Temporary hardness in feedwater is caused by: Select one: a. Sodium nitrate b. Magnesium bicarbonate c. Calcium carbonate d. Magnesium sulphate
b. Magnesium bicarbonate
The "total" or "methyl" alkalinity test indicates the alkalinity that is due to: Select one: a. Dissolved carbon dioxide b. Sodium Bicarbonate ions c. Hydroxide alkalinity d. All forms of alkalinity
d. All forms of alkalinity
Boiler water is treated in order to:
Select one:
a. prevent the water from becoming too alkaline
b. reduce the environmental impact of the blowoff effluent
c. remove suspended matter
d. prevent scale deposition and waterside corrosion
d. prevent scale deposition and waterside corrosion
To prevent scale deposition in cooling towers
Select one:
a. Keep the cycles of concentration above 10.
b. Reduce the rate of tower blowdown.
c. Keep scale-forming salts in solution, using crystal modification chemicals.
d. Keep the pH of the water high.
c. Keep scale-forming salts in solution, using crystal modification chemicals.
Chemicals used for condensate system treatment include ________ and _______ amines.
Select one:
a. aromatic and alkyl
b. softening and neutralizing
c. acidifying and alkalizing
d. neutralizing and filming
d. neutralizing and filming
Dissolved gases, such as oxygen and carbon dioxide, can be removed by a process known as: Select one: a. Deaeration b. Sedimentation c. Scrubbing d. Clarification
a. Deaeration
In condenser cooling water systems, sacrificial anodes work by
Select one:
a. corroding preferentially over components made of other metals.
b. interfering with the formation of corrosion products in a corrosion cell reaction.
c. neutralizing acidic compounds.
d. plating other metal parts with non-corrosive metal ions.
a. corroding preferentially over components made of other metals.
An acceptable pH value for boiler water is: Select one: a. 7.00 b. 6.95 c. 8.35 d. 10.50
d. 10.50
The main scale forming substance in cooling water towers is: Select one: a. Magnesium carbonate b. Sodium sulfite c. Calcium bicarbonate d. Sodium phosphate
c. Calcium bicarbonate
The normal loss of zeolite in a sodium zeolite softener is about \_\_\_\_\_\_\_ per year. Select one: a. 5% b. 3% c. 15% d. 10%
b. 3%
In feedwater, which of the following is an example of suspended matter? Select one: a. Sodium b. Sand c. Salt d. Calcium
b. Sand
A boiler has an M-alkalinity that is greater than the prescribed control range. What is the appropriate operator response?
Select one:
a. Increase the rate of sodium hydroxide feed.
b. Lower the boiler water level.
c. Increase the rate of continuous blowdown.
d. Reduce the frequency of bottom blowoff.
c. Increase the rate of continuous blowdown.
Which of these processes removes suspended matter from plugged filter beds? Select one: a. Regeneration b. Flushing c. Rinsing d. Backwashing
d. Backwashing
A conductivity meter is used to measure the: Select one: a. Alkalinity b. Electrolyte c. Hardness d. Total Dissolved Solids
d. Total Dissolved Solids
The component used to to prevent wasting steam through a deaerator vent is a: Select one: a. Cyclone separator b. Chevron drier c. Scrubber d. Vent condenser
d. Vent condenser
Sodium sulfite:
Select one:
a. Prevents the corrosion caused by oxygen in boiler water
b. Precipitates calcium and magnesium compounds
c. Prevents scale adhering to the tubes
d. Controls foaming
a. Prevents the corrosion caused by oxygen in boiler water
The dissolved solids in raw water: Select one: a. Cause pitting of boiler surfaces b. Cause grooving of piping surfaces c. Are organic matter d. Are usually removed by ion exchange
d. Are usually removed by ion exchange
When a boiler “primes”, it means that:
Select one:
a. The water has not been chemically treated
b. The boiler is being over fired
c. Water is being carried over with the steam
d. The steam vent is open, to allow it to fill
c. Water is being carried over with the steam
If boiler feedwater is neutral, its pH is: Select one: a. 0 b. 5 c. 7 d. 9
c. 7
The chemical used to regenerate the cation exchanger of a demineralizer is: Select one: a. Hydrochloric acid b. Caustic soda c. Sodium hydroxide d. Sulfuric acid
d. Sulfuric acid
If heating or cooling system water may come into contact with food products, ___________ is used to keep the water from freezing.
Select one:
a. ethylene glycol
b. methanol
c. octyl alcohol
d. propylene glycol
d. propylene glycol
The chemical used to regenerate the anion exchanger of a demineralizer is: Select one: a. Caustic soda b. Sulfuric acid c. Sodium chloride d. Hydrochloric acid
a. Caustic soda
The P-alkalinity is 220 ppm. The M-alkalinity is 240 ppm. What is the OH- alkalinity?
Select one:
a. 40 ppm
b. 0 ppm
c. 80 ppm
d. 200 ppm
d. 200 ppm
Filming amines protect against the harmful effects of:
Select one:
a. high condensate pH.
b. dissolved calcium and magnesium salts.
c. suspended solids and corrosion products.
d. dissolved carbon dioxide and oxygen.
d. dissolved carbon dioxide and oxygen.
Poorly functioning deaerators:
Select one:
a. may overheat the feedwater
b. permit scale forming compounds to enter the condensate system
c. should be compensated for by increasing the amine feed
d. increase the likelihood of grooving and pitting corrosion in condensate systems
d. increase the likelihood of grooving and pitting corrosion in condensate systems
How does one type of amine protect a condensate system?
Select one:
a. By scavenging oxygen from the condensate
b. By neutralizing carbonic acid
c. By neutralizing hydroxide alkalinity
d. By forming a protective film coating on scale forming solids
b. By neutralizing carbonic acid
Biological fouling in recirculating cooling water towers is caused by algae, \_\_\_\_\_ and bacteria growth. Select one: a. Flora b. Micro-organisms c. Fauna d. Fungi
d. Fungi
Sludge is usually removed from a boiler by:
Select one:
a. Filtering the water before it leaves the boiler
b. Vacuuming it from the bottom
c. Blowing off through the bottom blowoff connection
d. Blowing down through the continuous blowdown
c. Blowing off through the bottom blowoff connection
With internal treatment, chemicals are added to the boiler to
Select one:
a. precipitate dissolved solids
b. prevent dissolved solids from leaving the boiler
c. condition dissolved solids so they will not precipitate
d. treat dissolved solids so they will readily adhere to boiler surfaces
a. precipitate dissolved solids
Lime-soda softeners:
Select one:
a. Remove all dissolved solids from the water
b. Remove all dissolved solids and gases from the water
c. Remove lime from groundwater
d. Remove the scale forming dissolved solids
d. Remove the scale forming dissolved solids
Grooving and general thinning of the condensate return system is a result of:
Select one:
a. oxygen corrosion
b. carbonic acid corrosion
c. high alkalinity
d. scale build-up
b. carbonic acid corrosion
What is the consequence if condensate contains hardness?
Select one:
a. Corrosion by-products.
b. Reduced condensate line corrosion.
c. Boiler waterside scale deposition.
d. Pitting and grooving.
c. Boiler waterside scale deposition
A disadvantage of using glycol in heating or cooling systems instead of water is that
Select one:
a. all glycols are toxic
b. glycol has lower viscosity, so that fluid velocities increase.
c. more powerful pumps are required
d. glycol has a higher specific heat, so the systems run hotter
c. more powerful pumps are required
Ethylene glycol:
Select one:
a. Has a lower heat transfer efficiency in comparison to propylene glycol
b. Creates less friction losses in heating coils and piping, in comparison to hot water
c. Requires a smaller pump and less horsepower, in comparison to hot water
d. Has a lower heat transfer efficiency, in comparison to hot water
d. Has a lower heat transfer efficiency, in comparison to hot water
