Download Class 'C' Water Exam: Comprehensive Q&A for Water Treatment Professionals and more Exams Water and Wastewater Engineering in PDF only on Docsity!
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Class "C" Water Exam 165 complete
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A common chemical used in the disenfection of a small water supply is- - ANSWER Calcium Hypochlorite
A physical connection between a potable water supply and a house well would be- - ANSWER A Cross Connection
The amount of Chlorine in mg/L that is used by reacting with iron, organics, or bacteria is called? - ANSWER Demand
All of the following are Physical characteristics of Chlorine gas- - ANSWER Greenish Yellow color
Heavier than air
Pungent, Penetrating odor
Corrosive
Which of the following would be considered a part of a hypo-chlorinator system? - ANSWER Solution feed pump
According to state requirements, all public water supply wells should be provided with a raised concrete sealing block, screened vents and- - ANSWER Flow measuring device
The drawdown of a water well is determined by- - ANSWER The difference in static and pumping levels
The pH of water indicates- - ANSWER If it is more acidic or base
The pH of water is expressed by a scale of numbers ranging from- - ANSWER 0-
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Water that is considered neutral is expressed on the pH scale at- - ANSWER 7.
Which of the following is a required step in collecting a routine distribution sample for bacteriological testing? - ANSWER Use of an approved, sterile container
Sand filtration will remove which of the following from surface water? - ANSWER Turbidity
Activated Carbon is used in a Surface Water Plant primarily for? - ANSWER Taste and Odor control
Which of the following chemical(s) are commonly used as coagulants in surface water treatment? - ANSWER Alum and Ferric Chloride
Ground storage tanks are required to be provided with which of the following? - ANSWER Screened Vents
An approved locking roof hatch
An overflow pipe with hinged flap device
Annual inspection and maintenance as needed
An elevated storage tank should be protected against corrosion by- - ANSWER Painting
Cathodic protection
Water stabilization
A public water supply system should maintain residual pressure of 20 psi and a minimum normal operating pressure of- - ANSWER 35 psi
Before a new or repaired water line is placed into service, it must be properly disinfected by providing a chlorine dosage of _____ and proper detention time. - ANSWER 50 mg/L
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_____ is the natural exchange of water between the earth and air. - ANSWER Hydrological Cycle
If and when a health hazard contamination event occurs in a public water system, the operator must contact the state regulatory authority within ___ hours by telephone. - ANSWER 24 hours
Potable water is that of- - ANSWER Maintained at adequate pressure
Pathogen free
Contains a chlorine residual
Excessive nitrates in drinking water can cause a condition that affects infants under the age of 6 months. This condition is known as- - ANSWER Blue babies
In surface water treatment the process of causing the fine particles in the water to join together to form larger heavier particles that settle in a clarifier is called- - ANSWER Coagulation
The test commonly used to determine the chemical dosage for the surface water plant is the ___ test. - ANSWER Jar test
Suspended solids are the solids portion that- - ANSWER Can be filtered with additional treatment
Cause mud balls and filter plugging
A public water system is required to take samples of water for bacteriological analysis. The organism that is used as an indicator is called- - ANSWER Coliform
Chlorine dosage is demand plus desired ___ - ANSWER Residual
A storage vessel that is the same diameter from the ground to the top and is more than 20 feet but less than 85 feet is called a- - ANSWER Stand pipe
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Potable water must be stored at an elevation at least 80.85 feet above the highest known connection to provide the minimum operating pressure of- - ANSWER 35 psi
A water tank that uses compressed air over water to provide pressure is called a- - ANSWER Hydro pneumatic tank
According to the lead and copper rule, pipe and fittings may not contain more than ___ lead or solder and flux may not contain more than 0.2% lead. - ANSWER 8.0%
When testing for chlorine residual DPD is used as an indicator, when DPD is added to water containing chlorine what color does the sample turn? - ANSWER Red
The most common valve(s) used for isolating a water leak is the ___ valve. - ANSWER Gate valve
In the distribution system when a valve or hydrant is opened or closed too fast it could result in a- - ANSWER Water hammer
The most commonly used pump in the distribution system is- - ANSWER Centrifugal
A Texas Class D Certified Operator can operate a public water system up to ___ connections. - ANSWER 250
All state of Texas Operator License's after issue are good for ___ years. - ANSWER 3 years
After analyzing monthly bacteriological samples the operator is notified that one testing point tested positive. The operator should- - ANSWER Collect another sample at the site that tested positive plus one within five connections upstream and one within five connections downstream and re-submit
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The process of adding enough chlorine to a water supply to complete all reactions with reducing compounds, ammonia, and organic materials so that some free chlorine is left is called- - ANSWER Breakpoint chlorination
The primary reason(s) for main line failures in the distribution system is- - ANSWER Internal and external corrosion
Improper backfill and lack of proper bedding
Check valves on the discharge side of a pump are used to- - ANSWER Prevent water from flowing back through the pump when the pump is off
___ and ___acids are by products of drinking water chlorination. - ANSWER Trihalomethanes and Haloacetic
There are ___ major underground aquifiers in Texas - ANSWER 8
The most common type of filter in a surface plant today is ___and is designed to treat and flow at- - ANSWER Rapid sand and designed to flow 2 gpm/ft
The maximum safe withdrawal rate of chlorine for a 150 pound cylinder is- - ANSWER 40 lbs. per 24 hours
When diluting a strong acid, always add ___ to ___ rather than the reverse. - ANSWER Acid/Base
The normal oxygen content of the atmosphere is ___ % - ANSWER 20.
Any atmosphere that is less than ___ % oxygen should not be entered without an approved self- contained breathing apparatus. - ANSWER 19.
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When chlorine gas is added to water, what compounds are formed? - ANSWER Hydrochloric acid
Hypochlorous acid
The most important federal law that impacts the water utility industry is? - ANSWER The Safe Drinking Water Act of 1974
An example of a non-community water system would be? - ANSWER RV Park
Hotel/Motel
Service Station
The EPA requires community water systems to provide customers with an annual? - ANSWER Consumer Confidence Report
When designing systems engineers use a rule of thumb of ___ gallons per person per day when more accurate data not available. - ANSWER 130 gallons
TCEQ requires community water systems to have a minimum production capacity of ___ per connection at peak demand. - ANSWER 0.6 gpm
The most important treatment in water is? - ANSWER Disinfection
Potable water means the water is- - ANSWER Safe for human consumption
Free of disease causing organisms
Has a chlorine residual
TCEQ requires notification from the operator if changes to the public water system occur such as- - ANSWER Change in water source, Water quality, or Health hazards
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In an excavation if a ladder is used as a means of exit, it must extend ___ feet above the ground and be secured and within ___ feet laterally of anyone in the excavation. - ANSWER 3 feet above and 25 feet laterally
A groundwater system that serves in excess of 1,000 connections must have at least ___ operator(s) with ___ license to meet minimum state requirements for public water systems. - ANSWER 2 operators with "C" license
It is desirable for the ph of treated water to be above ___ , otherwise ___conditions will exist. - ANSWER 7.0 and Corrosive
Fluorides are naturally occurring in some groundwater. Fluorides in drinking water should not exceed ___ mg/L - ANSWER 4.0 mg/L
Red water or red stains may be caused by ___ levels in the water. - ANSWER Iron
When chemicals are used at a water treatment plant, a ___day supply should be kept on hand at all times to comply with the state standards. - ANSWER 30
The presence of iron in water is most commonly treated by- - ANSWER Aeration
A common chemical oxidizer is- - ANSWER Potassium permanganate
If ground water is to be treated for several problems, the first process should be- - ANSWER Aeration
Excess fluoride in water may be removed by- - ANSWER Activated alumina
Trihalomethanes are formed by the reaction of ___. - ANSWER Free available chlorine
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TCEQ requires a water system to have disinfection equipment capable of providing at least ___ % greater capacity than the highest expected dosage at any time. - ANSWER 50 %
The rotometer on a gas chlorinator indicates the number of ___ of chlorine fed during a ___ period. - ANSWER Pounds/24hr
Using a ton cylinder or container, the maximum withdrawal rate should not exceed- - ANSWER 400 lbs.
A pinging sound or rocks bouncing sound coming from the pump typically indicates the pump is ___. - ANSWER Cavitating
A submersible pump and motor will be- - ANSWER Suspended by pipe, placed near the bottom of the well
The distance from the water level in the well to the centerline of the pump is- - ANSWER Static suction head
The distance from the water level in the well to the water level in a storage tank is- - ANSWER Total static head
The loss of energy which results from the movement of water through pipes and fittings is- - ANSWER Friction
If a water lubricated vertical turbine pump is started with dry bearings- - ANSWER The bearings will be damaged
Routinely measuring the static level and pumping level can- - ANSWER Detect problems with the pump, well screen, and or water level
The recommended capacities for ground storage is based on providing ___ to ___ hours of supply at ___ gallons per connection. - ANSWER 4 to 6 hours at 200 gallons per connection
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(Pressure reducing valve)
Artesian wells are- - ANSWER Naturally occurring and free flowing wells
Federal and State laws mandate bacteriological analyses of the water supply. The samples must be obtained at least every- - ANSWER Month
The rate of speed at which water moves is- - ANSWER Velocity
The unit of measure for water pressure is- - ANSWER PSI
The purpose of a thrust block is- - ANSWER Prevent movement at pipe joints
The four common classes of working pressure in water main pipes are- - ANSWER 100/150/200/
AWWA recommends that a 5/8 X 3/4 service meter must be tested every ___ years or ___ gallons of water registered. - ANSWER 5 to 10 years or 1,500,000 gallons
When pressure testing a water main, the test pressure should be- - ANSWER 1 1/2 times as great as the normal operating pressure
Repairing water main leaks should be repaired within ___. - ANSWER 24 hours
Scale build up and pots and pans is caused by- - ANSWER Hard water
An operator installing a corporation stop would be placing this device at- - ANSWER On the main line and the service line is attached
The term pathogenic refers to- - ANSWER Disease causing
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Calcium Hypochlorite (HTH) is corrosive and may be flammable in the presence of ___ or ___. - ANSWER Petroleum or Organic
You come upon an unconscious person who is unresponsive. The most important thing to check first is- - ANSWER The persons airway
Pathogens (disease causing organisms) can be transmitted through water, blood, or by breathing, the most obvious routes for entry into the body are- - ANSWER Mouth and any moist openings
The letters SCBA on a cabinet would indicate to the operator- - ANSWER Self contained breathing apparatus
Bacteria, viruses, parasites, and fungus are- - ANSWER Water-borne pathogenic organisms
Depending on weather conditions and moisture in the air an electrical arc may jump from ___ for 110 volts to ___for 440 volts - ANSWER Meer inches for 110 volt to 6 feet for 440
All warning signs in temporary traffic control zones shall have- - ANSWER Black letters on orange background
Chemical testing of surface water sources is required every- - ANSWER 1 year
Common surface water coagulants are- - ANSWER Aluminum sulfate
Ferric sulfate
Ferric chloride
The current MCL for Trihalomethanes (THM's) is- - ANSWER 0.8 mg/L
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If a sample for total alkalinity turns pink when phenolphthalein indicator is added, the ph of the sample is- - ANSWER 8.3 or above
Taste and odor compounds may be oxidized by- - ANSWER Adding activated alumina
Reverse osmosis
During photosynthesis algae produce ___that aids in the water treatment - ANSWER Oxygen
When someone asks about NTU they are- - ANSWER Asking about reporting units for turbidity
The five basic aerator designs used in water treatment are- - ANSWER Spray, Cascade, Packed Tower, Diffused, Air, and Mechanical
The second step of flocculation is particle- - ANSWER Destabilization
Proper backwash of a filter leaved the filter media- - ANSWER Clean and level
A rule of thumb for sludge blanket thickness in solids contact, sludge blanket, and upflow clarifier is ___the sidewall depth. - ANSWER 1/
Decayed natural organics most common in water are ___ acids. - ANSWER Humid and Fulvic
After disinfection and flushing of a super chlorinated new lines and service but prior to placing the line into service, bacteriological samples are required. The current standard is __________ sample for every __________ feet of line. - ANSWER One sample for every 1000 feet of line
Proper backwashing of a sand filter is accomplished when the filter media expands by ________ % - ANSWER 30% to 50%
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For cross connection control the TCEQ preferred method is- - ANSWER Physical air gap
One microorganism in water that is resistant to chlorine is- - ANSWER Cryptosporidium
All of the following are common types of water meters except- - ANSWER Positive displacement
Multi jet
Compound
Propeller
(Inverted parshall flume)
A "Boil Water" notice can be triggered by all the following except- - ANSWER Low distribution pressure
Water outages
Repeated unacceptable BAC-T samples
Failure to maintain good C12 residual
(The mayor has concerns about water quality)
