WASTEWATER CLASS 4 EXAM VIRGINIA | FROM
PRACTICE TO PERFECTION | GUARANTEED
SUCCESS!
In an electrical circuit, the grounding wire is indicated by which color? - Answer: Green
According to the Ohms Law, which electrical unit measures pressure? - Answer: Volts
According to the Ohms Law, which electrical unit measures resistance? - Answer:
Ohms
According to the Ohms Law, which electrical unit measures current? - Answer: Amps
How do you convert cubic feet to gallons? - Answer: Multiply by 7.48
How do you convert gallons to pounds? - Answer: Multiply by 8.34
Calculate the SVI of your aeration basin when your 30-minute settleable sample is 360
mL/L and your average mixed liquor suspended solids concentration is 4000 mg/L. -
Answer: 90
Solution:
360 x 1,000
------------- = 90
4,000
What is the most widely used dechlorination agent in a conventional chlorine gas plant?
- Answer: Sulfur Dioxide
What is the most prominent concern in failing to remove grit from the wastewater? -
Answer: Excessive wear and damage on mechanical equipment
1
APPHIA - Crafted with Care and Precision for Academic Excellence.
, What is the chemical formula for Sulfuric Acid? - Answer: H2SO4
What is the ideal velocity in a grit channel, in feet per second? - Answer: 1 fps
Conventional pump packing should be: - Answer: Tightened down to a drip
In a primary clarifier, the expected performance for removing settleable solids is 90-95%
removal. What about the removal of suspended solids? - Answer: 50%
When preparing a sample for laboratory analysis that involves acid and water, how
should the sample be poured? - Answer: Always pour the acid into the water
You are tasked with recording a manual flow sample in an open channel. Where will you
position yourself, relative to the weir, to record the most accurate measure of flow? -
Answer: Behind the weir, 4 times the maximum head of the weir
Why must a positive displacement pump never be started against a closed discharge
valve? - Answer: Excessive pressure may damage the line, the pump, and the motor
A circular tank is 45 feet in diameter and has a depth of 10 feet. What is the detention
time in hours when the flow is 1.42 MGD? - Answer: 2 hours
Solution:
0.785 x 45 x 45 x 10 x 7.48 x 24
----------------------------------- = 2.038
1,420,000
What is the most common device for measuring flow in an open channel? - Answer: V-
notch weir, then ultrasonic flowmeter.
2
APPHIA - Crafted with Care and Precision for Academic Excellence.
PRACTICE TO PERFECTION | GUARANTEED
SUCCESS!
In an electrical circuit, the grounding wire is indicated by which color? - Answer: Green
According to the Ohms Law, which electrical unit measures pressure? - Answer: Volts
According to the Ohms Law, which electrical unit measures resistance? - Answer:
Ohms
According to the Ohms Law, which electrical unit measures current? - Answer: Amps
How do you convert cubic feet to gallons? - Answer: Multiply by 7.48
How do you convert gallons to pounds? - Answer: Multiply by 8.34
Calculate the SVI of your aeration basin when your 30-minute settleable sample is 360
mL/L and your average mixed liquor suspended solids concentration is 4000 mg/L. -
Answer: 90
Solution:
360 x 1,000
------------- = 90
4,000
What is the most widely used dechlorination agent in a conventional chlorine gas plant?
- Answer: Sulfur Dioxide
What is the most prominent concern in failing to remove grit from the wastewater? -
Answer: Excessive wear and damage on mechanical equipment
1
APPHIA - Crafted with Care and Precision for Academic Excellence.
, What is the chemical formula for Sulfuric Acid? - Answer: H2SO4
What is the ideal velocity in a grit channel, in feet per second? - Answer: 1 fps
Conventional pump packing should be: - Answer: Tightened down to a drip
In a primary clarifier, the expected performance for removing settleable solids is 90-95%
removal. What about the removal of suspended solids? - Answer: 50%
When preparing a sample for laboratory analysis that involves acid and water, how
should the sample be poured? - Answer: Always pour the acid into the water
You are tasked with recording a manual flow sample in an open channel. Where will you
position yourself, relative to the weir, to record the most accurate measure of flow? -
Answer: Behind the weir, 4 times the maximum head of the weir
Why must a positive displacement pump never be started against a closed discharge
valve? - Answer: Excessive pressure may damage the line, the pump, and the motor
A circular tank is 45 feet in diameter and has a depth of 10 feet. What is the detention
time in hours when the flow is 1.42 MGD? - Answer: 2 hours
Solution:
0.785 x 45 x 45 x 10 x 7.48 x 24
----------------------------------- = 2.038
1,420,000
What is the most common device for measuring flow in an open channel? - Answer: V-
notch weir, then ultrasonic flowmeter.
2
APPHIA - Crafted with Care and Precision for Academic Excellence.
