Page 1 of 138
Texas Wastewater Collection System Operator
Class II Exam ACTUAL QUESTIONS AND
ANSWERS LATEST UPDATE THIS YEAR
Texas Wastewater Collection System Operator Class II Exam
POINT-FORM SUMMARIZED EXAM COVERAGE
• TCEQ jurisdiction: Texas Commission on Environmental Quality administers occupational
licensing for collection system operators
• Exam format: Computer-based testing (CBT); 3-hour time limit; minimum passing score 70%
• License requirements: High school diploma or GED, TCEQ-approved training course, exam
passage
• Class II operator role: Responsible for operating and maintaining complex collection systems,
managing system integrity, regulatory compliance, and emergency response
• Collection system purpose: Collect and transport wastewater from homes, businesses, and
industries to treatment facility
• Self-cleaning velocity: Minimum 2 feet per second to prevent solids deposition and blockages
• Gravity sewer design: Maintain 2–10 ft/s for self-cleansing while avoiding scouring damage
• Typical daily flow per person: Approximately 100 gallons per day
• Wastewater composition: Approximately 99.9% water and 0.1% solids
• Wastewater characteristics: Physical, chemical, bacteriological, and radiological categories
• Fresh sewage appearance: Gray color with slight odor; septic sewage is dark with pungent odor
• BOD (Biochemical Oxygen Demand): Measures strength of sewage (organic matter content)
• pH scale neutral point: pH 7.0
• Hydrogen sulfide (H₂S): Rotten egg odor; toxic and flammable; produced by anaerobic
decomposition
• H₂S corrosion mechanism: Gas rises, bacteria oxidize it to sulfuric acid, which corrodes concrete
pipe crowns and manholes
• Methane gas: Lighter than air, explosive, odorless; produced by anaerobic decomposition
• Pathogens: Disease-causing bacteria found in wastewater
• Wastewater diseases: Typhoid, paratyphoid, bacillary dysentery, cholera, polio, infectious
hepatitis
• Lift station function: Moves wastewater from lower to higher elevations using pumps when
gravity flow insufficient
• Pump types for raw wastewater: Non-clog centrifugal pumps (most common) designed with
large passages for solids handling
• Cavitation in pumps: Caused by insufficient suction head, leading to vapor bubble collapse,
rattling noise, and pressure drop
• Air-bound pump: Trapped air prevents water from being drawn into casing; pump operates but
delivers no flow
• Check valve function: Prevents backflow into pump when pump stops
• Bubbler system: Measures liquid level by sensing backpressure from air bubbling through tube
in wet well
• Wet well: Chamber where wastewater collects before pumping
, Page 2 of 138
• Submersible pumps advantage: Eliminate need for separate dry-well structure, reducing
construction costs and safety hazards
• Variable frequency drives (VFDs): Adjust pump speed to match flow demand for energy savings
and process control
• Force main: Pressurized pipe that carries wastewater from lift stations
• Air release valve: Removes trapped air from force mains to prevent flow restriction and surging
• Water hammer: Pressure surge in force main when pump starts or stops suddenly
• Manhole purpose: Provides access for inspection, maintenance, and flow measurement
• Manhole inspection frequency: At least annually
• Confined space requirements (OSHA 29 CFR 1910.146): Atmospheric testing (oxygen
19.5-23.5%), written entry permit, standby person, retrieval system
• Oxygen safe range for entry: 19.5% to 23.5% by volume
• PPE for confined space: Atmospheric monitor, retrieval harness, ventilation, appropriate
respirator
• Lockout/tagout (LOTO): Required before performing maintenance on energized electrical
equipment
• Sewer cleaning methods: High-pressure jetting (jet rodder), rodding, balling, flushing, poly pigs
• Jetting safety hazard: Blocked nozzle can cause hose to whip violently; risk of injury to operator
• Pig (poly pig): Cylindrical device inserted into force main, propelled by line pressure to clean
interior walls
• CCTV inspection: Visual assessment of pipe interior to identify cracks, joint offsets, root
intrusion, and debris
• Smoke testing: Identifies leaks, defects, and illegal stormwater connections by observing smoke
escape
• Dye testing: Traces water flow to identify cross-connections and sources of inflow
• Pipeline location tools: Pipe locators and metal detectors used before excavation to avoid
damaging utilities
• Infiltration: Groundwater entering sewer through cracks, defective joints, or deteriorated
manholes
• Inflow: Stormwater entering through direct connections (roof drains, downspouts, manhole
covers)
• I&I consequences: Increased flow, potential overflows, higher treatment costs
• Sanitary sewer overflow (SSO): Release of untreated sewage from collection system; must be
reported to TCEQ
• SSO most common cause: Blockages due to grease, roots, and debris
• FOG (Fats, Oils, Grease): Primary cause of sewer blockages; requires public education and source
control
• Root intrusion: Roots enter through pipe joints and cracks, seeking moisture; can cause
blockages and pipe damage
• Chemical root treatment: Root inhibitors (e.g., copper sulfate, metam sodium) control regrowth
• Grease accumulation management: Increased cleaning frequency plus investigation of
contributing sources
• Pipe materials resistant to root intrusion: PVC is most resistant; clay and concrete more
susceptible
• Combined sewers: Carry both sanitary sewage and stormwater; may cause CSOs during heavy
rain
, Page 3 of 138
• Manhole corrosion indicators: Crown deterioration from sulfuric acid, exposed aggregate,
softened concrete
• Protective coatings for manholes: Applied to concrete to prevent H₂S corrosion
• Trench safety: All trenches over 5 feet deep require shoring or protective system per OSHA
• Soil classification: Determines required slope for benching or shoring; must be done by
competent person
• Collection system mapping: Shows pipe locations, manholes, and infrastructure for maintenance
and emergency response
• Sewer System Evaluation Survey (SSES): Identifies I&I sources, defects, and capacity problems
• Preventive maintenance: Routine cleaning and inspection to prevent unexpected failures and
blockages
• Record keeping: Maintenance logs, inspection reports, and overflow documentation
• CMOM program: Capacity, Management, Operation, and Maintenance – addresses SSO
prevention under Clean Water Act
• Emergency response: First priority is personnel safety; second is containment to protect
environment
• Bypass pumping: Temporary pumping to maintain service while repairing sewer lines
• Trenchless rehabilitation: Cured-in-place pipe (CIPP) – inserts resin-saturated liner cured to form
new pipe inside old
• Hydro excavation: Uses pressurized water and vacuum to excavate; safer than mechanical
digging near utilities
• SCADA: Supervisory Control and Data Acquisition – remote monitoring and control of pumps,
levels, and alarms
• Ultrasonic flow meter: Measures flow velocity and depth to calculate wastewater flow rates
• Flow equalization basin: Stores excess flow during peak events; reduces downstream treatment
plant loading
• Force main leak detection: Most reliable method is flow isolation and pressure testing
• Pump cycling excessive: Frequent on/off cycles indicate pump oversized for inflow or floats set
too close together
• Wet well level rise during dry weather: Indicates possible water main break discharging into
sewer
• Texas Water Code: State law regulating pollution control in Texas
• TAC references: Chapter 217 (design criteria) and Chapter 30 (rules for wastewater systems)
Wastewater Characteristics & Collection System Purpose (Questions 1-35)
1. What is the primary purpose of a wastewater collection system?
A) Treat wastewater before discharge to surface waters
, Page 4 of 138
B) Disinfect effluent before releasing to the environment
C) Collect and transport wastewater from sources to a treatment facility
D) Store drinking water for distribution during emergencies
Answer: C
Rationale: The collection system's main function is to safely convey wastewater from homes,
businesses, and industries to a treatment plant, preventing environmental contamination .
2. Maintaining a minimum velocity of 2 feet per second in a wastewater collection system is primarily
intended to achieve what outcome?
A) Prevent excessive wear on pipe materials from scouring
B) Ensure adequate oxygen transfer for aerobic decomposition
C) Reduce the likelihood of solids deposition and subsequent blockages
D) Minimize the potential for hydrogen sulfide gas formation
Answer: C
Rationale: Maintaining a self-cleaning velocity of at least 2 fps prevents solids from settling out of the
wastewater, which would otherwise accumulate and cause blockages .
Texas Wastewater Collection System Operator
Class II Exam ACTUAL QUESTIONS AND
ANSWERS LATEST UPDATE THIS YEAR
Texas Wastewater Collection System Operator Class II Exam
POINT-FORM SUMMARIZED EXAM COVERAGE
• TCEQ jurisdiction: Texas Commission on Environmental Quality administers occupational
licensing for collection system operators
• Exam format: Computer-based testing (CBT); 3-hour time limit; minimum passing score 70%
• License requirements: High school diploma or GED, TCEQ-approved training course, exam
passage
• Class II operator role: Responsible for operating and maintaining complex collection systems,
managing system integrity, regulatory compliance, and emergency response
• Collection system purpose: Collect and transport wastewater from homes, businesses, and
industries to treatment facility
• Self-cleaning velocity: Minimum 2 feet per second to prevent solids deposition and blockages
• Gravity sewer design: Maintain 2–10 ft/s for self-cleansing while avoiding scouring damage
• Typical daily flow per person: Approximately 100 gallons per day
• Wastewater composition: Approximately 99.9% water and 0.1% solids
• Wastewater characteristics: Physical, chemical, bacteriological, and radiological categories
• Fresh sewage appearance: Gray color with slight odor; septic sewage is dark with pungent odor
• BOD (Biochemical Oxygen Demand): Measures strength of sewage (organic matter content)
• pH scale neutral point: pH 7.0
• Hydrogen sulfide (H₂S): Rotten egg odor; toxic and flammable; produced by anaerobic
decomposition
• H₂S corrosion mechanism: Gas rises, bacteria oxidize it to sulfuric acid, which corrodes concrete
pipe crowns and manholes
• Methane gas: Lighter than air, explosive, odorless; produced by anaerobic decomposition
• Pathogens: Disease-causing bacteria found in wastewater
• Wastewater diseases: Typhoid, paratyphoid, bacillary dysentery, cholera, polio, infectious
hepatitis
• Lift station function: Moves wastewater from lower to higher elevations using pumps when
gravity flow insufficient
• Pump types for raw wastewater: Non-clog centrifugal pumps (most common) designed with
large passages for solids handling
• Cavitation in pumps: Caused by insufficient suction head, leading to vapor bubble collapse,
rattling noise, and pressure drop
• Air-bound pump: Trapped air prevents water from being drawn into casing; pump operates but
delivers no flow
• Check valve function: Prevents backflow into pump when pump stops
• Bubbler system: Measures liquid level by sensing backpressure from air bubbling through tube
in wet well
• Wet well: Chamber where wastewater collects before pumping
, Page 2 of 138
• Submersible pumps advantage: Eliminate need for separate dry-well structure, reducing
construction costs and safety hazards
• Variable frequency drives (VFDs): Adjust pump speed to match flow demand for energy savings
and process control
• Force main: Pressurized pipe that carries wastewater from lift stations
• Air release valve: Removes trapped air from force mains to prevent flow restriction and surging
• Water hammer: Pressure surge in force main when pump starts or stops suddenly
• Manhole purpose: Provides access for inspection, maintenance, and flow measurement
• Manhole inspection frequency: At least annually
• Confined space requirements (OSHA 29 CFR 1910.146): Atmospheric testing (oxygen
19.5-23.5%), written entry permit, standby person, retrieval system
• Oxygen safe range for entry: 19.5% to 23.5% by volume
• PPE for confined space: Atmospheric monitor, retrieval harness, ventilation, appropriate
respirator
• Lockout/tagout (LOTO): Required before performing maintenance on energized electrical
equipment
• Sewer cleaning methods: High-pressure jetting (jet rodder), rodding, balling, flushing, poly pigs
• Jetting safety hazard: Blocked nozzle can cause hose to whip violently; risk of injury to operator
• Pig (poly pig): Cylindrical device inserted into force main, propelled by line pressure to clean
interior walls
• CCTV inspection: Visual assessment of pipe interior to identify cracks, joint offsets, root
intrusion, and debris
• Smoke testing: Identifies leaks, defects, and illegal stormwater connections by observing smoke
escape
• Dye testing: Traces water flow to identify cross-connections and sources of inflow
• Pipeline location tools: Pipe locators and metal detectors used before excavation to avoid
damaging utilities
• Infiltration: Groundwater entering sewer through cracks, defective joints, or deteriorated
manholes
• Inflow: Stormwater entering through direct connections (roof drains, downspouts, manhole
covers)
• I&I consequences: Increased flow, potential overflows, higher treatment costs
• Sanitary sewer overflow (SSO): Release of untreated sewage from collection system; must be
reported to TCEQ
• SSO most common cause: Blockages due to grease, roots, and debris
• FOG (Fats, Oils, Grease): Primary cause of sewer blockages; requires public education and source
control
• Root intrusion: Roots enter through pipe joints and cracks, seeking moisture; can cause
blockages and pipe damage
• Chemical root treatment: Root inhibitors (e.g., copper sulfate, metam sodium) control regrowth
• Grease accumulation management: Increased cleaning frequency plus investigation of
contributing sources
• Pipe materials resistant to root intrusion: PVC is most resistant; clay and concrete more
susceptible
• Combined sewers: Carry both sanitary sewage and stormwater; may cause CSOs during heavy
rain
, Page 3 of 138
• Manhole corrosion indicators: Crown deterioration from sulfuric acid, exposed aggregate,
softened concrete
• Protective coatings for manholes: Applied to concrete to prevent H₂S corrosion
• Trench safety: All trenches over 5 feet deep require shoring or protective system per OSHA
• Soil classification: Determines required slope for benching or shoring; must be done by
competent person
• Collection system mapping: Shows pipe locations, manholes, and infrastructure for maintenance
and emergency response
• Sewer System Evaluation Survey (SSES): Identifies I&I sources, defects, and capacity problems
• Preventive maintenance: Routine cleaning and inspection to prevent unexpected failures and
blockages
• Record keeping: Maintenance logs, inspection reports, and overflow documentation
• CMOM program: Capacity, Management, Operation, and Maintenance – addresses SSO
prevention under Clean Water Act
• Emergency response: First priority is personnel safety; second is containment to protect
environment
• Bypass pumping: Temporary pumping to maintain service while repairing sewer lines
• Trenchless rehabilitation: Cured-in-place pipe (CIPP) – inserts resin-saturated liner cured to form
new pipe inside old
• Hydro excavation: Uses pressurized water and vacuum to excavate; safer than mechanical
digging near utilities
• SCADA: Supervisory Control and Data Acquisition – remote monitoring and control of pumps,
levels, and alarms
• Ultrasonic flow meter: Measures flow velocity and depth to calculate wastewater flow rates
• Flow equalization basin: Stores excess flow during peak events; reduces downstream treatment
plant loading
• Force main leak detection: Most reliable method is flow isolation and pressure testing
• Pump cycling excessive: Frequent on/off cycles indicate pump oversized for inflow or floats set
too close together
• Wet well level rise during dry weather: Indicates possible water main break discharging into
sewer
• Texas Water Code: State law regulating pollution control in Texas
• TAC references: Chapter 217 (design criteria) and Chapter 30 (rules for wastewater systems)
Wastewater Characteristics & Collection System Purpose (Questions 1-35)
1. What is the primary purpose of a wastewater collection system?
A) Treat wastewater before discharge to surface waters
, Page 4 of 138
B) Disinfect effluent before releasing to the environment
C) Collect and transport wastewater from sources to a treatment facility
D) Store drinking water for distribution during emergencies
Answer: C
Rationale: The collection system's main function is to safely convey wastewater from homes,
businesses, and industries to a treatment plant, preventing environmental contamination .
2. Maintaining a minimum velocity of 2 feet per second in a wastewater collection system is primarily
intended to achieve what outcome?
A) Prevent excessive wear on pipe materials from scouring
B) Ensure adequate oxygen transfer for aerobic decomposition
C) Reduce the likelihood of solids deposition and subsequent blockages
D) Minimize the potential for hydrogen sulfide gas formation
Answer: C
Rationale: Maintaining a self-cleaning velocity of at least 2 fps prevents solids from settling out of the
wastewater, which would otherwise accumulate and cause blockages .
