Wastewater Class 4 Exam Virginia
questions with complete verified detailed
solutions Latest Updated Version A+Guide
INTRODUCTION:
This document provides a complete set of Wastewater Class 4 exam
questions for Virginia, accompanied by detailed and verified
solutions. It covers key areas including wastewater treatment
processes, microbiology, hydraulics, chemistry, pumps, electrical
systems, sludge management, and operational adjustments. The
material is fully updated and structured to help students and
operators prepare for licensing exams with both theoretical and
calculation-based problems.
EXAM QUESTIONS AND ANSWERS:
Why is sodium hypochlorite sometimes added to the head of a
plant? --- correct answer ---To control odors.
What problems may arise from tightening the gland in a pump? ---
correct answer ---Excessive wear on shaft or shaft sleeve.
,A large number of amoebas would indicate what type of sludge? ---
correct answer ---Young sludge
A large number of rotifers would indicate what type of sludge? ---
correct answer ---Old sludge
Flagellates, Ciliates, and Rotifers are all part of what single-celled
group? --- correct answer ---Protozoa
Which microorganism is responsible for converting ammonia
nitrogen to nitrite? --- correct answer ---Nitrosomonas
Which microorganism is responsible for oxidizing nitrite into
nitrate? --- correct answer ---Nitrobacter
Among all the organisms in activated sludge, what percentage is
bacteria? --- correct answer ---95%
What does the Specific Oxygen Uptake Rate (SOUR) measure? ---
correct answer ---Amount of oxygen used by microorganisms to
consume one gram of food
,How many times greater is the reduction rate of aerobic bacteria
versus anaerobic bacteria? --- correct answer ---20 times - DOUBLE
CHECK THIS ANSWER - NOT SURE OF THIS
The casing surrounding the impeller on a pump is called the: ---
correct answer ---Volute
Valves should be closed slowly to prevent: --- correct answer ---
Water hammer
In an electrical circuit, a ___________ is used to reduce voltage
where needed. --- correct answer ---Transformer
What is the problem with over-lubricating a pump bearing? ---
correct answer ---It may cause overheating.
What is the surface loading rate of a rectangular tank with a length
of 26 ft and a width of 16 ft. The flow coming in is 1.3 MGD. ---
correct answer ---3,125 gallons per square feet
Solution:
26 x 16 = 416 square feet
1,300,000
, ---------- = 3,125
416
What is the hydraulic detention time of a rectangular tank with a
length of 26 ft, a width of 22 ft, and a height of 19 ft when the
influent flow is 1.3 MGD? --- correct answer ---1.5 hours
Solution:
26 x 22 x 19 x 7.48 x 24
-------------------------- = 1.50
1,300,000
How many minutes are in a day? --- correct answer ---1,440
If a math formula answer is normally in hours, but the question is
asking for minutes, multiply by 1440 instead of 24
Write out the entire Ohm's Law formula, including the units, and
the properties they measure. --- correct answer ---Amps (Current)
= Volts (Pressure) / Ohm's (Resistance)
Your plant is discharging 1.28 MGD at the outfall. The BOD
concentration in your discharge is 47 mg/L. What is the quantity of
questions with complete verified detailed
solutions Latest Updated Version A+Guide
INTRODUCTION:
This document provides a complete set of Wastewater Class 4 exam
questions for Virginia, accompanied by detailed and verified
solutions. It covers key areas including wastewater treatment
processes, microbiology, hydraulics, chemistry, pumps, electrical
systems, sludge management, and operational adjustments. The
material is fully updated and structured to help students and
operators prepare for licensing exams with both theoretical and
calculation-based problems.
EXAM QUESTIONS AND ANSWERS:
Why is sodium hypochlorite sometimes added to the head of a
plant? --- correct answer ---To control odors.
What problems may arise from tightening the gland in a pump? ---
correct answer ---Excessive wear on shaft or shaft sleeve.
,A large number of amoebas would indicate what type of sludge? ---
correct answer ---Young sludge
A large number of rotifers would indicate what type of sludge? ---
correct answer ---Old sludge
Flagellates, Ciliates, and Rotifers are all part of what single-celled
group? --- correct answer ---Protozoa
Which microorganism is responsible for converting ammonia
nitrogen to nitrite? --- correct answer ---Nitrosomonas
Which microorganism is responsible for oxidizing nitrite into
nitrate? --- correct answer ---Nitrobacter
Among all the organisms in activated sludge, what percentage is
bacteria? --- correct answer ---95%
What does the Specific Oxygen Uptake Rate (SOUR) measure? ---
correct answer ---Amount of oxygen used by microorganisms to
consume one gram of food
,How many times greater is the reduction rate of aerobic bacteria
versus anaerobic bacteria? --- correct answer ---20 times - DOUBLE
CHECK THIS ANSWER - NOT SURE OF THIS
The casing surrounding the impeller on a pump is called the: ---
correct answer ---Volute
Valves should be closed slowly to prevent: --- correct answer ---
Water hammer
In an electrical circuit, a ___________ is used to reduce voltage
where needed. --- correct answer ---Transformer
What is the problem with over-lubricating a pump bearing? ---
correct answer ---It may cause overheating.
What is the surface loading rate of a rectangular tank with a length
of 26 ft and a width of 16 ft. The flow coming in is 1.3 MGD. ---
correct answer ---3,125 gallons per square feet
Solution:
26 x 16 = 416 square feet
1,300,000
, ---------- = 3,125
416
What is the hydraulic detention time of a rectangular tank with a
length of 26 ft, a width of 22 ft, and a height of 19 ft when the
influent flow is 1.3 MGD? --- correct answer ---1.5 hours
Solution:
26 x 22 x 19 x 7.48 x 24
-------------------------- = 1.50
1,300,000
How many minutes are in a day? --- correct answer ---1,440
If a math formula answer is normally in hours, but the question is
asking for minutes, multiply by 1440 instead of 24
Write out the entire Ohm's Law formula, including the units, and
the properties they measure. --- correct answer ---Amps (Current)
= Volts (Pressure) / Ohm's (Resistance)
Your plant is discharging 1.28 MGD at the outfall. The BOD
concentration in your discharge is 47 mg/L. What is the quantity of
