Page 1 of 136
Georgia Wastewater Operator Class III Certification
Exam ACTUAL EXAM COMPLETE QUESTIONS AND
CORRECT ANSWERS LATEST UPDATE THIS YEAR
Summarized Exam Coverage
The Georgia Wastewater Operator Class III certification is an intermediate-level credential for biological
wastewater treatment system operators . To qualify, candidates must complete 40 hours of a Board-
approved basic wastewater operator course and have 3 months of on-the-job experience (high school
diploma/GED) . Candidates may take the exam before completing the experience requirement but
cannot apply for certification until experience is met .
The exam contains 100 questions covering :
Domain Key Topics
Preliminary Bar screens (manual, mechanical, fine), comminutors, grit removal (velocity-controlled channels,
Treatment vortex), flow equalization, pumping systems/lift stations
Primary Sedimentation, surface overflow rate (SOR), weir loading, sludge/scum removal, short-circuiting,
Treatment sludge blanket measurement
Aeration (diffused/mechanical), MLSS/MLVSS, SVI, F/M ratio, MCRT (sludge age), DO control,
Activated Sludge
RAS/WAS rates, process configurations (conventional, extended aeration, SBR, oxidation ditch),
(Secondary)
troubleshooting (filamentous bulking, foaming, pin floc, dispersed growth)
Fixed Film Trickling filters (rock/plastic media), RBCs (rotating biological contractors), dosing rates, organic
Treatment loading, fly control, distribution arm maintenance
Gravity thickening, DAF thickening, anaerobic digestion (biogas, methane, temperature control),
Sludge Treatment
aerobic digestion, belt filter presses, centrifuge dewatering, polymer conditioning
Chlorination/dechlorination, chlorine residual (total/free), SO₂ dechlorination, UV disinfection,
Disinfection
contact time, chlorinator safety (H-type vs. solution feed)
Laboratory & BOD₅ (5-day test), TSS, pH, alkalinity, DO probes, ammonia/nitrate testing, microscopic examinati
Process Control (filament identification), sludge judge, calibration
Maintenance & Centrifugal pump (open impeller for sludge), positive displacement, pump curves, packing/gland
Pumps adjustment, VFDs, lift station operation, diffuser cleaning, belt press maintenance
Safety & Confined space entry (testing, permit), H₂S/CH₄ monitoring, LOTO, SCBA, chlorine safety, NPDES
Regulations permit limits, SSO reporting (24 hours), toxicity (cyanide, heavy metals)
, Page 2 of 136
1. A Class III wastewater operator notices large solids like rags and sticks entering the plant. Which unit
process is specifically designed to remove these?
A) Grit chamber
B) Bar screen
C) Primary clarifier
D) Comminutor
Answer: B
Bar screens are installed at the plant headworks to intercept coarse solids like rags, sticks, and plastics
before they damage downstream equipment .
2. What is the primary separation mechanism in a vortex-type grit removal system?
A) Gravity settling in a quiescent zone
B) Centrifugal force generated by tangential flow
C) Air flotation of light particles
D) Magnetic attraction of ferrous materials
Answer: B
, Page 3 of 136
Vortex grit chambers utilize a rotating flow pattern that creates centrifugal force, forcing heavier grit
particles outward against the chamber wall for removal while lighter organics remain in suspension .
3. Why must a bar screen be cleaned regularly?
A) To increase the Biological Oxygen Demand of the influent
B) To prevent flow reduction and potential upstream overflows
C) To improve the efficiency of the UV disinfection system
D) To reduce the chlorine demand of the secondary effluent
Answer: B
A clogged bar screen restricts flow, causing wastewater to back up and potentially overflow at the
headworks or manholes, creating environmental and public health hazards .
4. A flow equalization basin is constructed to improve plant performance. What is its primary function?
A) To settle out heavy inorganic solids like sand and gravel
B) To dampen hydraulic and organic load peaks
C) To disinfect the flow before biological treatment
D) To grind large particles into smaller pieces
Answer: B
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Equalization basins buffer fluctuations in flow rate and organic strength, providing a constant, treatable
load to downstream biological units and preventing process upsets .
5. What parameter is most directly measured to control the output of blowers in an activated sludge
aeration basin?
A) Mixed Liquor Suspended Solids (MLSS)
B) Sludge Volume Index (SVI)
C) Dissolved Oxygen (DO) concentration
D) Food-to-Microorganism (F/M) ratio
Answer: C
*DO sensors in the aeration basin send real-time signals to blowers, automatically adjusting airflow to
maintain a target DO setpoint (typically 1.5-3.0 mg/L) for optimal microbial activity .*
6. What is the "mean cell residence time" (MCRT) commonly called?
A) Hydraulic Retention Time (HRT)
B) Sludge age
C) Detention time
D) Return sludge rate
Georgia Wastewater Operator Class III Certification
Exam ACTUAL EXAM COMPLETE QUESTIONS AND
CORRECT ANSWERS LATEST UPDATE THIS YEAR
Summarized Exam Coverage
The Georgia Wastewater Operator Class III certification is an intermediate-level credential for biological
wastewater treatment system operators . To qualify, candidates must complete 40 hours of a Board-
approved basic wastewater operator course and have 3 months of on-the-job experience (high school
diploma/GED) . Candidates may take the exam before completing the experience requirement but
cannot apply for certification until experience is met .
The exam contains 100 questions covering :
Domain Key Topics
Preliminary Bar screens (manual, mechanical, fine), comminutors, grit removal (velocity-controlled channels,
Treatment vortex), flow equalization, pumping systems/lift stations
Primary Sedimentation, surface overflow rate (SOR), weir loading, sludge/scum removal, short-circuiting,
Treatment sludge blanket measurement
Aeration (diffused/mechanical), MLSS/MLVSS, SVI, F/M ratio, MCRT (sludge age), DO control,
Activated Sludge
RAS/WAS rates, process configurations (conventional, extended aeration, SBR, oxidation ditch),
(Secondary)
troubleshooting (filamentous bulking, foaming, pin floc, dispersed growth)
Fixed Film Trickling filters (rock/plastic media), RBCs (rotating biological contractors), dosing rates, organic
Treatment loading, fly control, distribution arm maintenance
Gravity thickening, DAF thickening, anaerobic digestion (biogas, methane, temperature control),
Sludge Treatment
aerobic digestion, belt filter presses, centrifuge dewatering, polymer conditioning
Chlorination/dechlorination, chlorine residual (total/free), SO₂ dechlorination, UV disinfection,
Disinfection
contact time, chlorinator safety (H-type vs. solution feed)
Laboratory & BOD₅ (5-day test), TSS, pH, alkalinity, DO probes, ammonia/nitrate testing, microscopic examinati
Process Control (filament identification), sludge judge, calibration
Maintenance & Centrifugal pump (open impeller for sludge), positive displacement, pump curves, packing/gland
Pumps adjustment, VFDs, lift station operation, diffuser cleaning, belt press maintenance
Safety & Confined space entry (testing, permit), H₂S/CH₄ monitoring, LOTO, SCBA, chlorine safety, NPDES
Regulations permit limits, SSO reporting (24 hours), toxicity (cyanide, heavy metals)
, Page 2 of 136
1. A Class III wastewater operator notices large solids like rags and sticks entering the plant. Which unit
process is specifically designed to remove these?
A) Grit chamber
B) Bar screen
C) Primary clarifier
D) Comminutor
Answer: B
Bar screens are installed at the plant headworks to intercept coarse solids like rags, sticks, and plastics
before they damage downstream equipment .
2. What is the primary separation mechanism in a vortex-type grit removal system?
A) Gravity settling in a quiescent zone
B) Centrifugal force generated by tangential flow
C) Air flotation of light particles
D) Magnetic attraction of ferrous materials
Answer: B
, Page 3 of 136
Vortex grit chambers utilize a rotating flow pattern that creates centrifugal force, forcing heavier grit
particles outward against the chamber wall for removal while lighter organics remain in suspension .
3. Why must a bar screen be cleaned regularly?
A) To increase the Biological Oxygen Demand of the influent
B) To prevent flow reduction and potential upstream overflows
C) To improve the efficiency of the UV disinfection system
D) To reduce the chlorine demand of the secondary effluent
Answer: B
A clogged bar screen restricts flow, causing wastewater to back up and potentially overflow at the
headworks or manholes, creating environmental and public health hazards .
4. A flow equalization basin is constructed to improve plant performance. What is its primary function?
A) To settle out heavy inorganic solids like sand and gravel
B) To dampen hydraulic and organic load peaks
C) To disinfect the flow before biological treatment
D) To grind large particles into smaller pieces
Answer: B
, Page 4 of 136
Equalization basins buffer fluctuations in flow rate and organic strength, providing a constant, treatable
load to downstream biological units and preventing process upsets .
5. What parameter is most directly measured to control the output of blowers in an activated sludge
aeration basin?
A) Mixed Liquor Suspended Solids (MLSS)
B) Sludge Volume Index (SVI)
C) Dissolved Oxygen (DO) concentration
D) Food-to-Microorganism (F/M) ratio
Answer: C
*DO sensors in the aeration basin send real-time signals to blowers, automatically adjusting airflow to
maintain a target DO setpoint (typically 1.5-3.0 mg/L) for optimal microbial activity .*
6. What is the "mean cell residence time" (MCRT) commonly called?
A) Hydraulic Retention Time (HRT)
B) Sludge age
C) Detention time
D) Return sludge rate
