Water License Part 2 Flashcards
The primary purpose of disinfecting water mains is to
1.create a chlorine taste and odor
2.sterilize the water main
3.kill disease causing organisms in the water
4.keep the inside of the main clean
kill disease causing organisms in the water
What is the most likely cause of decreasing drawdown and a constant static water level?
1.Cone of depression has changed
2.Well screen is worn
3.Aquifer is being pumped at a greater rate than recharge
4.Pump is losing efficiency
Pump is losing efficiency
AWWA recommends that 5/8 inch meters be tested every
15 years
3 years
5 years
10 years
10 years
To initially disinfect a pipeline, chlorine may be added to the water in a continuous flow, a slug, or
segmented
low dose
tablet
air injection
Tablet
What is the term for a framework of wood or metal installed to prevent the collapse of trench walls?
shoring
enforcement
sloping
support
Shoring
pH is a measure of
Dissolved solids
Water’s ability to neutralize acid
Conductivity
Hydrogen ions
Hydrogen ions
According to EPA regulations, the owner, or operator, of a public water system that fails to comply with applicable monitoring requirements must give notice to the public within
1.30 days of the violation by a public service announcement on local radio and television stations.
2.1 year of the violation by including a letter with the water bill.
3.1 week of the violation in a certified letter to each customer.
4.3 months of the violation, in a daily newspaper in the area served by the system.
3 months of the violation, in a daily newspaper in the area served by the system.
Which meter is the most accurate over a wide range of flows?
propeller
compound
proportional
turbine
Compound
The device used to monitor water flow to a consumer is a
rotometer
flow regulator
check valve
water meter
Water meter
Which valve is used to prevent a pipe from collapsing?
Gate valve
Ball valve
Vacuum relief valve
Needle valve
Vacuum relief valve
The relief valve is used to control or limit the pressure in a system or vessel which can build up by a process upset, instrument or equipment failure, or fire.
A confined aquifer containing groundwater under positive pressure is called
a flowing aquifer
a nubian aquifer
a geologic aquifer
an artesian aquifer
artesian aquifer
What is the motor horsepower (mhp) for a pump with the following parameters?
Motor efficiency: 87%
Total Head (TH): 107 ft
Pump efficiency: 79%
Flow: 2.54 mgd
69 mhp
79 mhp
29 mhp
87 mhp
69 mph
What agency establishes drinking water standards in the United States?
FDA
HHS
USGS
EPA
EPA
The Environmental Protection Agency (EPA) ensures safe drinking water for the public by setting standards for more than 160,000 public water systems throughout the United States. The EPA oversees states, local governments, and water suppliers to enforce the standards under the Safe Drinking Water Act.
The three main components of a centrifugal pump are
1.impeller, case, and shaft
2.bearing, housing, gasket
3.wear rings, lantern rings, and volute
4.shaft, wear rings, and power connection
impeller, case, and shaft
A 6 inch water line needs to be flushed. If the length of pipe to be flushed is 425 feet, how long will it take to flush the line at 35 gpm?
10 minutes
20 minutes
18 minutes
16 minutes
18 minutes
At what time of day is the water stored in the distribution system the oldest?
6:00 PM
12:00 AM
6:00 AM
12:00 PM
6 AM
Question 16 Explanation: Storage tanks are typically filled and emptied quickly during the day. As water usage declines during the evening hours tanks are filled and drained at a much slower rate. The age of the water in the system affects the water quality. As the water ages, the level of residual disinfectant decreases. At the same time, the level of disinfection byproducts (DBPs), such as trihalomethanes and haloacetic acids, may increase. Frequent water turnover in the system helps to ensure higher levels of residual disinfectant and lower levels of DBPs.
The hydrologic cycle is composed of all the following terms, except
precipitation
condensation
adsorption
evaporation
Adsorption
Which of the following is a measurement of the clarity of water?
pH
Turbidity
Chlorine residual
Hardness
Turbidity
What is the main purpose of a water storage facility?
1.To allow storage reserve during wet periods
2.To help maintain adequate pressures throughout the entire system
3.To meet needs for fire protection
4.To provide sufficient amount of water to average or equalize the daily demands plus provide minimum pressures to fight fires
To provide sufficient amount of water to average or equalize the daily demands plus provide minimum pressures to fight fires
PVC pipe can use tees, elbows, and other fittings from what other type of pipe?
ductile iron
copper
asbestos cement
concrete
Ductile Iron
Common method used to test water for chlorine residual
THM
VOC
DPD
HTH
DPD
The most common colorimetric method used today is called the DPD Colorimetric Method. In this method, N,N-diethyl-p-phenyldiamine (DPD) is the reagent added to the sample. Chlorine oxidizes this DPD to form a magenta colored compound known as Wurster Dye.
Methemoglobinemia, also known as Blue Baby Syndrome, is a serious medical condition caused by high levels of _______________ in drinking water.
Lead
Nitrate
Manganese
Nitrite
Nitrate
The MCL for Nitrate is 10 ppm.
Infants below the age of six months who drink water containing nitrate in excess of the MCL could become seriously ill and, if untreated, may die. Symptoms include shortness of breath and blue-baby syndrome.
High levels of Nitrate can be caused by runoff from fertilizer use; leaking septic tanks, sewage; erosion of natural deposits.
What is the best valve for limiting a water hammer?
Pinch
Needle
Pressure reducing
Pressure relief
Pressure relief
The amount of energy, in feet, that a pump supplies to the water is called
pump head
total head
pressure head
velocity head
Pump head
Which of the following is a measurement of head?
feet
absolute pressure
gauge pressure
foot-pounds
Feet
Head is expressed in units of height such as meters or feet.
There are four types of head used to calculate the total head in and out of a pump:
- Velocity head is due to the bulk motion of a fluid (kinetic energy).
- Elevation head is due to the fluid’s weight, the gravitational force acting on a column of fluid.
- Pressure head is due to the static pressure, the internal molecular motion of a fluid that exerts a force on its container.
- Resistance head (or friction head or Head Loss) is due to the frictional forces acting against a fluid’s motion by the container.
The amount water that can be raised vertically by a given pressure is called
pressure head
pump head
velocity head
total head
Pressure head
The primary reason for using dry barrel fire hydrants is to
allow easy maintenance of the hydrant
prevent water hammer
prevent rusting
prevent freezing in cold weather
Prevent freezing in cold weather
What is the recommended chlorine dosage when disinfecting a water main using tablets?
4 mg/L
10 mg/L
50 mg/L
25 mg/L
50 mg/L
According to the Center for Disease Control (CDC), what has caused the most waterborne disease outbreaks in the United States?
low chlorination
leaking backflow prevention equipment
corporate pollution
inadequate O&M of filtering systems
leaking backflow prevention equipment
The secondary standard for manganese recommends levels not exceed
0.02 mg/L
0.05 mg/L
0.03 mg/L
0.04 mg/L
0.05 mg/L
A waterborne disease that can be transferred to humans if proper disinfection is not provided is
measles
malaria
typhoid
gonorrhea
Typhoid
Why is excessive water pressure to residential homes objectionable?
1.Decreases the life of water heaters and other appliances using water
2.Causes foaming from faucets
3.Increases particulate matter reaching the customer
4.Causes erosion of the copper plumbing due to the high velocities, giving the water metallic taste
Decreases the life of water heaters and other appliances using water
What determines the required number of samples to be collected for systems monitoring lead and copper for the first time?
System size
Percentage of customers with old plumbing
Source water
Previous violations
Systems size
The height which a column of water will rise in a well is called?
Groundwater level
Potentiometric surface
Piezometric surface
Residual drawdown
Piezometric surface
What is the area of a trench that is 26.7 feet long and 4.1 feet wide?
122 sq ft
7 sq ft
109 sq ft
32 sq ft
109 sq ft
Multiply the length times the width
As the temperature of the water increases, the disinfecting action of chlorine is
not affected
likely to increase algae growth
less effective
more effective
More effective
Current meters are also known as
Venturi meters
Orifice meters
Insertion meters
Velocity meters
Velocity meters
What pump has an efficiency of 90 to 95% at very high pressure, close fitting impellers, and high maintenance costs?
Jet
Centrifugal
Mixed flow
Vertical turbine
Vertical turbine
What two chemicals cause hardness in water?
lead and copper
iron and manganese
calcium and magnesium
oxygen and hydrogen
Calcium and magnesium
Large full storage tanks are typically disinfected with a chlorine residual of
10 mg/L
25 mg/L
15 mg/L
50 mg/L
10 mg/L
How many gallons of paint are required to cover the outside perimeter and the top of a cylindrical tank that is 28-feet high and whose diameter is 14.5-feet? One gallon of paint covers 200 square feet of surface.
9 gallons
10 gallons
7 gallons
8 gallons
8 gallons
First calculate the area of the top of the tank using the formula Area = Pi x Radius² (a = π r²)
a = 3.14 (7.25)²
a = 165 sq ft
Next, determine the perimeter of the tank using the formula Circumference = 2 x pi x Radius (C=2πr):
P = 2(3.14) * 7.25
P = 45.53 ft
Next, calculate the area by multiplying the circumference and the height:
28 ft x 45.53 ft = 1,275 sq ft
Now, add the top of the tank area to the perimeter area to get the total surface area:
1,275 sq ft + 165 sq ft = 1,440 sq ft
Finally, divide the total surface area by 200 sq ft, the amount covered by one gallon:
1,440 sq ft / 200 sq ft = 7.2 gallons - You will need 8 gallons to paint the tank.
Baffling inside a storage facility may be needed to prevent “hot spots” and
- high chlorine residuals throughout the facility
2.long contact times with disinfectants
3.straight through flows
4.high temperatures throughout the storage facility
straight through flows
Where will you find a nutating disc in a water distribution system?
centrifugal pump
storage tank
fire hydrant
water meter
Water meter
Concrete thrust blocks are used to keep
joints from opening
valves from sinking
the pipe level
hydrants from being operated
Joints from opening
One of the major causes of pump and motor shaft coupling wear is
misalignment
a discharge pressure too high
worn seal
worn impeller
Misalignment
If two rings of packing are used in the stuffing box, how many degrees should the joints be staggered?
180-225 degrees
90-180 degrees
15-45 degrees
45-90 degrees
90-180 degrees
A type of joint used for ductile iron piping
Rubber gasket joint
Bell and spigot with rubber o-ring
Push-on joint
Expansion joint
Push on joint
Which class of fire involves sodium or magnesium?
Class B
Class C
Class A
Class D
Class D
Determine the number of gallons contained in a fully charged 6 inch water main that is 300 feet long.
6,341 gallons
440 gallons
63,415 gallons
1,450 gallons
440 gallons
The term drawdown, is best defined as
1.The distance from a well that the normal water level is affected by the cone of depression.
2.The water level in a well after a pump has operated for a period of time
3.A change in water elevation from normal level to pumping level
4.The distance from the ground to the pumping level
A change in water elevation from normal level to pumping level
