Wastewater Class 4 Exam Virginia |\ |\ |\ |\ |\
QUESTIONS WITH ANSWERS |\ |\
In an electrical circuit, the grounding wire is indicated by which
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
color? - CORRECT ANSWERS ✔✔Green
|\ |\ |\ |\
According to the Ohms Law, which electrical unit measures
|\ |\ |\ |\ |\ |\ |\ |\ |\
pressure? - CORRECT ANSWERS ✔✔Volts
|\ |\ |\ |\
According to the Ohms Law, which electrical unit measures
|\ |\ |\ |\ |\ |\ |\ |\ |\
resistance? - CORRECT ANSWERS ✔✔Ohms |\ |\ |\ |\
According to the Ohms Law, which electrical unit measures
|\ |\ |\ |\ |\ |\ |\ |\ |\
current? - CORRECT ANSWERS ✔✔Amps
|\ |\ |\ |\
How do you convert cubic feet to gallons? - CORRECT ANSWERS
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
✔✔Multiply by 7.48 |\ |\
How do you convert gallons to pounds? - CORRECT ANSWERS
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\
✔✔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. - CORRECT
|\ |\ |\ |\ |\ |\ |\ |\
ANSWERS ✔✔90 |\
,Solution:
360 x 1,000|\ |\
------------- = 90 |\ |\
|\ 4,000
What is the most widely used dechlorination agent in a
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\
conventional chlorine gas plant? - CORRECT ANSWERS ✔✔Sulfur |\ |\ |\ |\ |\ |\ |\ |\
Dioxide
What is the most prominent concern in failing to remove grit
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
from the wastewater? - CORRECT ANSWERS ✔✔Excessive wear
|\ |\ |\ |\ |\ |\ |\ |\
and damage on mechanical equipment
|\ |\ |\ |\
What is the chemical formula for Sulfuric Acid? - CORRECT
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\
ANSWERS ✔✔H2SO4 |\
What is the ideal velocity in a grit channel, in feet per second? -
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
CORRECT ANSWERS ✔✔1 fps |\ |\ |\
Conventional pump packing should be: - CORRECT ANSWERS |\ |\ |\ |\ |\ |\ |\ |\
✔✔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? - CORRECT ANSWERS ✔✔50% |\ |\ |\ |\ |\
, When preparing a sample for laboratory analysis that involves
|\ |\ |\ |\ |\ |\ |\ |\ |\
acid and water, how should the sample be poured? - CORRECT
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
ANSWERS ✔✔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? - CORRECT ANSWERS
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\
✔✔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? - CORRECT ANSWERS
|\ |\ |\ |\ |\ |\ |\ |\
✔✔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? -
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
CORRECT ANSWERS ✔✔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? - CORRECT ANSWERS ✔✔V-notch weir, then ultrasonic
|\ |\ |\ |\ |\ |\ |\ |\
flowmeter.
QUESTIONS WITH ANSWERS |\ |\
In an electrical circuit, the grounding wire is indicated by which
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
color? - CORRECT ANSWERS ✔✔Green
|\ |\ |\ |\
According to the Ohms Law, which electrical unit measures
|\ |\ |\ |\ |\ |\ |\ |\ |\
pressure? - CORRECT ANSWERS ✔✔Volts
|\ |\ |\ |\
According to the Ohms Law, which electrical unit measures
|\ |\ |\ |\ |\ |\ |\ |\ |\
resistance? - CORRECT ANSWERS ✔✔Ohms |\ |\ |\ |\
According to the Ohms Law, which electrical unit measures
|\ |\ |\ |\ |\ |\ |\ |\ |\
current? - CORRECT ANSWERS ✔✔Amps
|\ |\ |\ |\
How do you convert cubic feet to gallons? - CORRECT ANSWERS
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
✔✔Multiply by 7.48 |\ |\
How do you convert gallons to pounds? - CORRECT ANSWERS
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\
✔✔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. - CORRECT
|\ |\ |\ |\ |\ |\ |\ |\
ANSWERS ✔✔90 |\
,Solution:
360 x 1,000|\ |\
------------- = 90 |\ |\
|\ 4,000
What is the most widely used dechlorination agent in a
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\
conventional chlorine gas plant? - CORRECT ANSWERS ✔✔Sulfur |\ |\ |\ |\ |\ |\ |\ |\
Dioxide
What is the most prominent concern in failing to remove grit
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
from the wastewater? - CORRECT ANSWERS ✔✔Excessive wear
|\ |\ |\ |\ |\ |\ |\ |\
and damage on mechanical equipment
|\ |\ |\ |\
What is the chemical formula for Sulfuric Acid? - CORRECT
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\
ANSWERS ✔✔H2SO4 |\
What is the ideal velocity in a grit channel, in feet per second? -
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
CORRECT ANSWERS ✔✔1 fps |\ |\ |\
Conventional pump packing should be: - CORRECT ANSWERS |\ |\ |\ |\ |\ |\ |\ |\
✔✔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? - CORRECT ANSWERS ✔✔50% |\ |\ |\ |\ |\
, When preparing a sample for laboratory analysis that involves
|\ |\ |\ |\ |\ |\ |\ |\ |\
acid and water, how should the sample be poured? - CORRECT
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
ANSWERS ✔✔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? - CORRECT ANSWERS
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\
✔✔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? - CORRECT ANSWERS
|\ |\ |\ |\ |\ |\ |\ |\
✔✔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? -
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
CORRECT ANSWERS ✔✔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? - CORRECT ANSWERS ✔✔V-notch weir, then ultrasonic
|\ |\ |\ |\ |\ |\ |\ |\
flowmeter.
