Test questions Flashcards
A watercourse that flows continuously at all times of the year is called
Perennial stream
During the night, algae causes the PH of the water to
Decrease
Which of the following contributes to the creation of algae blooms?
Increased nutrients
Which of the following is found mainly in groundwater sources and forms a precipitate when oxidized?
Iron
The riparian doctrine is sometimes called the
Rule of the reasonable sharing
If a water body has a high salinity and is warm, it will generally be
Low in dissolved oxygen
Reservoir turnover is?
Caused by the denser water at the surface sinking toward the bottom
What does the term surface runoff refer to?
Water the flows into the rivers after rainfall
Hikers, bicyclists, all-terrain vehicles, and automobiles can all ________ of watershed land adjacent to a reservoir
Increase the threat of erosion
What is the term for a water-bearing geologic zone composed of material deposited by flowing rivers?
Alluvial aquifer
What effect will algae in a reservoir have on dissolved oxygen (DO)?
Increase the DO during the day and lower the DO during the night
What effect does alkalinity have on the use of copper sulfate as an algicide?
Copper sulfate is more effective as alkalinity decreases
The amount of water in a water-bearing formation depends on the
Porosity of the formation
What is the main characteristic of raw water that enables blue-green algae to grow?
Presence of nutrients
A well screen must be installed for which of the following?
Unconsolidated materials
What is the recommended loading rate for copper sulfate for algae control at an alkalinity greater than 50 mg/L
5.4 lb of copper sulfate per acre of surface area
What is the primary origin of Coliform bacteria in water supplies?
Animal or human feces
Which of the following best defines the term specific capacity ?
Amount of water a well will produce for each foot of drawdown
The most common type of well used for public water supply systems is a
Drilled well
Which of the following terms is defined as the killing of inactivation of pathogenic organisms in water?
Disinfection
Free chlorine residual values are based on a contact time of at least
10 minutes
What is the typical strength of calcium hypochlorite, i.e, available chlorine range?
65 to 70%
Which of the following chemicals will raise pH?
Soda ash
As water temperatures increase, the disinfection action of chlorine will
Increase
What effect will caustic soda have on water?
Increase the pH of the water
In order to prevent freezing, what is the maximum chlorine usage per day from a 150-lb cylinder?
42 lbs
Which of the following chemicals is used to soften water through chemical precipitation?
Calcium hydroxide
Mudballs are clumps of
Filter media and other material
Coagulation occurs during the first
1 to 5 seconds
A filter should be backwashed when it has high
Head loss
Which of the following chemicals decreases corrosion rates?
CaCO3 (calcium carbonate)
What is the most important test used to indicate proper sedimentation?
Turbidity
Which of the following is considered an excellent zeta potential?
-1 to -4
Which membrane type from the processes listed below has the smallest pore spaces?
Reverse osmosis
Which of the following should be used by an operator to test for residual chlorine?
DPD (N, N-diethyl-p-phenylenediamine)
Which of the following is a major part of a turbidimeter?
Light source
Which of the following parameters is used to indicate the clarity of water?
Turbidity
pH is a measure of
Hydrogen ion concentration
After chlorination, the free chlorine residual includes
OCl- and HOCl
Alkalinity consists predominantly of which of the following?
Bicarbonate, carbonate, and hydroxide
What is the log removal or inactivation required for viruses?
4.0 log
The highest concentration of hypochlorous acid occurs at what pH?
5
Which of the following will most accurately measure 500 mL of solution?
500-mL volumetric flask
Which of the following fluoride compounds comes in solution form?
Fluorosilicic acid
Four-log removal is
99.99%
What is the chemical formula for bicarbonate?
HCO-3
The capability of a water or chemical solution to resist a change is pH is called
Buffering capacity
In Coliform analyses using the presence-absence test, a sample should be incubated for
24 and 48 hours at 35*C
The optimal fluoride concentration in drinking water is set in relation to the
Annual average maximum daily air temperature
The optimum dosage for a polymer can be determined by which of the following tests?
Jar
In the multiple-tube fermentation method, what is the sequence of growth media?
LTB, BGB, and EMB
Giardia cysts range in size from
8 to 20 microns
The quality of oxygen that can remain dissolved in water is related to
Temperature
What is apparent color?
Color in a sample before it is filtered
After initial full-service operation, grease-lubricated bearings should be regreased at what frequency?
3 to 6 months
Check valves are used to prevent
Water from flowing in two directions
If only two rings of packing are used in the stuffing box, the joints should be
Staggered
Which of the following is a primary function of couplings?
Compensate for alignment changes
What is the correct formula for determining watts?
Watts = Amps x Volts
Centrifugal, positive displacement, and turbine are all
Types of pumps
A hypochlorinator is used to
Feed a liquid chlorine solution into a water supply
Water hammer is most likely to be caused by
Closing the valve too fast
Positive displacement pumps should be operated when
Suction and discharge line valves are open
A 1-ton cylinder filled with chlorine weighs approximately
3,700 lbs
Pump seals can be classified as
Packing ring or mechanical
What is the most probable cause of a pinging sound coming from a pump
Cavitation
Which of the following best describes the discharge rate of a piston-type pump?
Precise volume for each stroke
What is the main purpose for priming
Replace air with water inside the pump
What is the purpose of a vacuum regulator
Stop flow of chlorine gas if leak develops
Mechanical seals are more appropriate for pumps operating under which of the following conditions?
High suction head
Which of the following valves is most suitable for a throttling application?
Pressure reducing
The component of a centrifugal pump sometimes installed on the end of the suction pipe in order to hold the priming is the
Foot valve
What is the term for the combined efficiency of a pump and motor that is obtained by multiplying the pump efficiency by the motor efficiency
Wire-to-water efficiency
Opening the discharge valve one full turn on a chlorine cylinder will
Permit maximum discharge
What is the following best defined the term C value?
Number that describes the smoothness of the interior of a pipe
Tubercles can form on which of the following types of pipe
Ductile iron
Which of the following is a primary indicator of bearing failure
Noise from pump
Mechanical seals need replacement when leakage occurs from which of the following
Around the shaft
Which of the following parts in centrifugal pump restricts flow between the impeller discharge and suction areas
Wear rings
Small gaseous chlorine leaks in and around a chlorinator can be detected by the use of commercial strength
Ammonia
Packing should be replaced when tightening no longer controls the leakage from the
Packing gland
Air gap separation is measured from the flood level rim of the receiving vessel to the potable water supply pipe. What is the minimum separation of a correctly installed air gap?
2 times diameter if the pipe but not less that 1 inch
Which of the following causes air binding?
Release of dissolved gases in saturated cold water when pressure decreases in filter beds
Solids-contact units are most unstable under which of the following conditions?
Rapid increase in temperature
The least amount of head loss in a pipeline would be the result of a fully open
Gate valve
During a routine inspection on a centrifugal pump, the operation notices that the bearings are excessively hot. Which of the following is the most likely caused?
Overlubercation
Electric demand is
Amount of power in watts required during a certain time interval
A chlorine evaporator maintains a water bath at
170-180* F
Chlorine ton containers at room temperature will deliver gas at a maximum rate of
400 pounds per day
At a pumping station equipped with a centrifugal pump, which of the following can cause the discharge pressure to suddenly increase and the discharge quantity to suddenly decrease?
Pump control valve malfunctioned
Which of the following diseases is capable of being transmitted by water?
Typhoid
When any piece of electrical equipment is being worked on, the circuit breaker should be
De-energized and locked out
If ammonia vapor is passed over a chlorine leak in a cylinder valve, the presence of the leak is indicated by a
White cloud
Which of the following directly impacts the treatment of drinking water?
Safe drinking water act
Corrosive water acting in a customers plumbing may cause which of the following metals to enter their drinking water?
Lead
Spontaneous combustion can occur when activated carbon is mixed with
Chlorine compounds
What is the only acceptable breathing device to wear while handling chlorine leaks?
Self-contained breathing apparatus
A foul, rotten-egg odor from an aeration treatment unit is an indication that the source water contains
Hydrogen sulfide
Of the following types of extinguishers, which should be used on electrical fires?
Carbon dioxide
Wear safety goggles when
Handling acid
The proper emergency repair kit for a ton chlorine cylinder is an
Emergency kit B
What is the only type of self-contained breathing apparatus that should be used at water plants?
Positive-pressure
The use of ammonia solution on a chlorine gas leak from the disinfection assembly may cause which of the following?
Dense white smoke
Which of the following substances pose an immediate health threat whenever standards are exceeded?
Coliform and nitrate
Ozone contactors must have a system to collect ozone off-gas because ozone is
Toxic
What is causative organism for cholera?
Vibrio
Which health effect category refers to an organic chemical that is a known carcinogen?
Category 1
One volume of liquid chlorine gas will expand, at room temperature and pressure, to occupy how many volumes of gas?
460 volumes
What is the odor detection limit of chlorine gas?
0.3 ppm
Which of the following is the most common water complaint?
Objectionable taste and/or odor
According to the Surface Water Treatment Rule, water systems serving a population greater than 500 persons must sample the filtered water for turbidity every
4 hours
For surface water systems without filtration, the Surface Water Treatment Rule requires public water systems to
Maintain a CxT value above the minimum value
Surface water systems must treat, at a minimum, for
Coliform bacteria and turbidity
What US agency establishes drinking water standards?
USEPA
How is a public water system defined ?
Must have at least 15 service connections or serve at least 25 individuals daily at least 60 days per year
According to the Interim Enhanced Surface Water Treatment Rule, a public water system serving a population of 10,000 or more must maintain the combined effluent turbidity of direct or conventional filtration in 95% of all the measurements taken each month at
_< 0.3 ntu
Because it is not possible to routinely test for the presence of specific microorganisms is drinking water, the US environmental Protection Agency requires, for surface water systems, the use of
Treatment techniques
What does the abbreviation DBP stand for?
Disinfection by-product
What is the maximum contaminant level goal for chloride?
250 mg/l
What is the maximum contaminant level for nitrate (as nitrogen) in drinking water ?
10 mg/l
Which of the following has both a primary and secondary standard?
Fluoride
What is the maximum contaminant level goal for known or suspected carcinogens?
Zero
Which of the following violations is considered the most serious?
Tier 1
What is the maximum contaminant level goal for lead
Zero mg/l
Records of chemical analyses should be kept for a minimum of
10 years
A water system collects 180 samples for Coliform testing. What is the maximum number of samples that may test positive so that they system stays in compliance?
9
The treatment technique required by the US Environmental Protection Agency and used by a surface water system must ensure a log removal for Giardia cysts of
3 log
What is the ratio of lime to copper sulfate for controlling algae growth on basin walls?
1 part lime to 1 part copper sulfate
Copper sulfate is used in surface water reservoirs to control
Algae
Which is the correct order (on the average) from the smallest to largest for the microorganisms below?
Viruses, bacteria, Giardia cysts
What is the usual strength of sodium hypochlorite, i.e, available chlorine?
5-15%
Trihalomethanes are usually associated with
Water with organics that has been chlorinated
Which of the following disinfectants has a long-lasting residual?
Chlorine dioxide
Which of the following substances will reduce the effectiveness of chlorine disinfection?
Turbidity
Which of the following forms of chlorine has no disinfecting capacity
Hydrochloride acid
Red water may be caused by iron concentrations above
0.3 mg/l
Which of the following best defined adsorption?
Adhesion of gas, liquid, or dissolved substance onto the surface or interface zone of another substance
Hard water scale is usually caused by
Calcium carbonate
About how many alkalinity is required for each milligram per liter of alum added to raw water?
0.5 mg/l
A water treatment plant’s flocculation-coagulation and sedimentation professes should be checked if which of the following changes?
Turbidity
Which of the following is an example of a weighting agent?
Bentonite clay
Algae can shorten filter runs by
Clogging the filters
Coagulation is a chemical and physical reaction that converts
Nonsettleable solids into settleable solids
Water corrosion in metal piping will increase if
Total dissolved solid are high and the pH is below 7.0
What is schmutzdecke?
Fine sand and sticky mat if suspended matter that forms on the surface of a sand filter.
What is a cathode?
Negative pole of an electrolytic cell or system
What metals are most likely to leach from household plumbing and cause a health hazard ?
Copper and lead
The flow rate over conventional sedimentation basins is commonly designed not to exceed
20,000 gpd/sq ft
If poorly formed floc is leaving the settling basin, which of the following should be done?
Increase the coagulant or add a coagulant aid
Slow sand filters are cleaned by
Scraping about 1in. of sand off the top
What is the most common filtration rate for slow sand filters?
0.05 gpm/sq ft
Which of the following so long filter runs tend to cause?
Slime growths
What type of corrosion in a water system is caused when two different metals come into contact with each other?
Galvanic corrosion
When should ammonia be added to the water when making disinfectant chloramines to improve disinfection?
After the chlorine is added
Alum and ferric sulfate may have poor coagulation due to
Low alkalinity in the water
The process of catholic protection can be used to reduce or prevent corrosion by protecting metal parts exposed to
Soil
Which of the following disinfectants is usually generated on-site?
Chlorine dioxide
If too much potassium permanganate is used to treat water
The water turns pink
Which of the following chemicals can be activated for use as a coagulant aid with alum?
Sodium silicate
In conventional coagulation, the average time to develop heavy floc particles is
30 minutes
Which of the following is a difference between conventional filters and greensand filters
Greensand filters remove iron and manganese by adsorption and oxidation
Under heavy loading, head loss on a manganese greensand filter quickly becomes excessive because
Greensand grains are smaller than silica sand
The filter medium in DE filters is
Diatomaceous earth
Which of the following is a required treatment technique for the control of lead?
Corrosion control
Bar screens are used to
Remove debris
Which of the following factors affects the settling rate of particles?
Particle size
Coagulation process rely on
The formation of large settleable particles
Which of the following substances is the most effective disinfection residual?
Hypochlorous acid
Which type of solution contains 1 gram equivalent weight of a reactant compound per liter of solution?
Normal solution
What term describes a measure of the capacity of water to neutralize strong acids?
Alkalinity
What piece of laboratory glassware is primarily used to mix chemicals and measures approximate volumes?
Beaker
What laboratory device sterilizes laboratory apparatus and microbial media by using pressurized steam?
Autoclave
Which of the following chemicals cause alkalinity in water ?
Calcium carbonate and calcium oxide
What should the sample volume be when testing for total coliform bacteria?
100 Ml
Primary drinking water standards require Giardia removal at
Three log (99.9%)
Recarbonation basins are used to stabilize water after
Softening
The least reactive metals are called
Catholic metals
What precipitate is formed in alum coagulation?
Aluminum hydroxide
Autocaving will sterilize
With steam at 121*C and 15 psi
What is the most common method used to determine if water is close to the equilibrium point?
Langelier index
Which of the following is used to determine compliance for total coliforms ?
Presence-absence method
What is the percent potassium (K) by weight in potassium permanganate (KMnO4)?
24.742%
Small and medium-size utilities are considered to have optimal corrosion control if they meet the lead and copper action levels for
Two consecutive sampling periods
What is pressure head caused by?
Water elevation
The flow of electrical current is measured in
Amperes
Unless water cooled, the operating temperature of a mechanical seal in a pump should never exceed
160* F (71*C)
What term describes the condition that exits when the source of the water supply is below the centerline of the pump?
Suction lift
One horsepower is equal to how many foot-pounds per minute?
33,000
What is the most common use today for a positive-displacement pump?
Chemical feed pump
What is the purpose of a bypass valve on a larger size gate valve?
Reduce pressure across both sides to ease opening and closing
A corrosion-resistant pipe is used to carry the chlorine gas solution from the chlorine injector to the point of application because the pH range of the solution is
2-4 standard units
If a filter is operated so that the pressure in the bed is less than atmospheric, this can lead to short filter runs due to an operating condition known as
Air binding
Lead contamination in drinking water will cause children to have
Altered mental and physical development
Special care should be taken when using dry alum and quicklime because if mixed together
Explosive hydrogen gas may be released
OSHA is an acronym for
Occupational safety and Health Administration
Air scrubbers are
Used to neutralize chlorine leaks
The device that chances AC to DC by allowing current flow in only one direction is the
Rectifier
When handling fluoride chemicals, personnel should wear a respirator or mask approved by
NIOSH
What information must be on a warning tag attached to a switch that has been locked out ?
Name of person who kicked out the switch
Which of the following is colorless, odorless, lighter then air, highly flammable, and sometimes called swamp gas?
Methane
Which of the following is colorless, odorless, found mainly in groundwater, and can cause cancer?
Radon
What is the major health risk of nitrates ?
Methemoglobinemia
Is it critical to have zero headspace in the sample container when collecting a sample for
Organic chemical contaminants
According to the Surface Water Treatment Rule requirements, systems serving less than how many people may take grab samples to monitor disinfectant residual ?
3,300
A household faucet must remain unused for how many hours before a first draw sample is collected for analyses of lead and copper ?
6 hours
Public water systems using surface water as a source must continuously monitor the disinfection residual entering the distribution system if serving more than
3,300 people
Under the National Secondary Drinking Water Regulations, what is the secondary maximum contaminant level for total dissolved solids?
500 mg/L
Records for bacteriological analyses should be kept for a minimum of
5 years
Which of the following is NOT an important factor in filter sand selection?
Color
What is the threshold odor number (TON) that will begin to draw complaints from customers?
5 (TON)
