System Components
30%of exam
Maintenance + Rehab
25%of exam
Pump Stations
20%of exam
Safety + Compliance
15%of exam
Confined SpaceLOTOSSOCMOMEmergency Sequence
Math + Hydraulics
10%of exam
Flow UnitsVelocityVolumeHeadMath Picker
Quick Facts
- Exam
- Collection Operator
- Body
- WPI/state authority
- Questions
- 100 scored
- Pretest
- Up to 10
- Time
- 3 hours
- Pass
- 70%
- Math
- About 10%
- Credential
- Jurisdiction issued
Gravity vs Force Main
Gravity
- Slope driven
- Partly full
- Manhole access
Force main
- Pump driven
- Pressurized pipe
- Valve access
Slope or pump decides
Gravity Sewers
- Gravity main
- Downhill conveyance
- Lateral
- Building connection
- Interceptor
- Large collector
- Invert
- Pipe flowline
- Slope
- Drives velocity
- Sag
- Unwanted low spot
- Surcharge
- Pipe under pressure
Manhole vs Cleanout
Manhole
- Main access
- Worker entry
- Junction structure
Cleanout
- Small access
- Tool entry
- Usually lateral
Access size matters
Structures + Access
- Manhole
- Main access
- Cleanout
- Lateral access
- Drop manhole
- Controls elevation
- Channel
- Directs flow
- Bench
- Side platform
- Frame
- Supports cover
- Cover seal
- Blocks inflow
Pipe Defects
- Offset joint
- Misaligned pipe
- Crack
- Structural opening
- Fracture
- Broken wall
- Roots
- Joint intrusion
- Grease
- FOG deposit
- Debris
- Blockage material
- Crown corrosion
- H2S damage
I/I Clues
Fast peaks inflow; slow peaks infiltration.
FastInflowSlowInfiltration
Infiltration vs Inflow
Infiltration
- Groundwater entry
- Defects/joints
- Delayed wet response
Inflow
- Surface water entry
- Direct connections
- Fast rain response
Groundwater seeps; stormwater connects
Field Problem Picker
- Standing CCTV water→Grade repair(Sag)
- Roots at joints→Cut and repair(Defect)
- Restaurant stoppages→FOG control(Grease)
- Rainfall peak flow→I/I study(Wet weather)
- Smoke exits roof→Illegal inflow(Direct)
- Joint seepage→Grouting(Infiltration)
- Long cracked reach→CIPP(Lining)
- Collapsed segment→Excavate repair(Structural)
Cleaning Tools
- Jetting
- High-pressure water
- Rodding
- Mechanical cutting
- Bucket machine
- Heavy debris
- Pigging
- Force-main cleaning
- Vac truck
- Remove solids
- Root saw
- Cut roots
- Flushing
- Move deposits
CCTV vs Smoke Test
CCTV
- Inside view
- Pipe defects
- Condition coding
Smoke test
- Surface clues
- Inflow sources
- Illegal openings
Camera sees; smoke reveals
Inspection Tests
- CCTV
- Visual defects
- Smoke test
- Find inflow
- Dye test
- Trace connection
- Flow monitor
- Track peaks
- Lamp test
- Alignment check
- Manhole survey
- Surface defects
- Acoustic scan
- Screen blockages
Rehab Methods
- Point repair
- Fix short defect
- CIPP
- Lined pipe
- Sliplining
- Smaller inserted pipe
- Pipe bursting
- Replace in place
- Grouting
- Seal joints
- Manhole lining
- Protect structure
- Root control
- Slow regrowth
Pump Troubleshooting
Power, controls, pump, valves, force main.
PowerControlsPumpValvesMain
Lead vs Lag Pump
Lead
- Starts first
- Normal flow
- Alternates duty
Lag
- Starts second
- Peak flow
- Backup capacity
Level demand adds pumps
Station Alarm Picker
- High wet well→Restore pumping(Prevent SSO)
- Power failure→Generator(Backup)
- Pump short cycles→Check controls(Levels)
- Pump hums only→Check impeller(Clog)
- Reverse flow→Check valve(Backflow)
- No SCADA signal→Local inspection(Verify)
- Airlocked pump→Vent/prime(Air)
- Force-main break→Bypass/isolate(Contain)
Lift Station
- Wet well
- Stores influent
- Submersible pump
- Common wastewater pump
- Dry well
- Equipment room
- Lead pump
- Starts first
- Lag pump
- Adds capacity
- Float switch
- Level control
- Transducer
- Continuous level
Force Main
- Force main
- Pressurized discharge
- Check valve
- Stops backflow
- Plug valve
- Isolates flow
- Air release
- Vents gas
- Surge
- Pressure transient
- Bypass pump
- Temporary pumping
- Valve vault
- Access valves
SSO Sequence
Safe, stop, contain, recover, report.
SafeStopContainRecoverReport
SSO vs Backup
SSO
- System release
- Public/environment risk
- Reportable event
Backup
- Building impact
- Private property
- Cause investigation
Location changes response
Safety Response Picker
- Manhole entry→Test atmosphere(Before entry)
- Bad atmosphere→Ventilate(No entry)
- Servicing pump→LOTO(Zero energy)
- Open roadway→Traffic control(MUTCD)
- Overflow starts→Protect public(First)
- Flow nears drain→Contain flow(Block path)
- Chemical spill→Isolate area(Escalate)
- Entrant collapses→Non-entry rescue(Do not enter)
Safety Thresholds
- O2 low
- Below 19.5%
- O2 high
- Above 23.5%
- LEL hazard
- Above 10%
- H2S
- Toxic sewer gas
- Methane
- Flammable gas
- CO
- Toxic combustion gas
- Ventilation
- Fresh-air control
Confined Space Order
Test, ventilate, enter only when authorized.
TestVentilatePermitMonitor
Compliance Response
- SSO
- Untreated release
- NPDES
- Discharge permit
- CMOM
- Capacity management
- FOG
- Grease program
- Work order
- Maintenance record
- Chain-of-command
- Notification path
- Public notice
- Required warning
Math Formulas
- Area
- 0.785 x D2
- Flow
- Area x velocity
- Velocity
- Flow / area
- Volume
- Area x depth
- Detention
- Volume / flow
- Head
- Pressure x 2.31
- MGD
- Million gal/day
Common Traps
Treatment vs Collection
Convey wastewater ≠ Treat wastewater
Smell vs Meter
Meter proves safety ≠ Odor proves safety
Report vs Respond
Control source first ≠ Paperwork first
Switch vs LOTO
Verify zero energy ≠ Turn switch off
Sag vs Siphon
Unwanted belly ≠ Designed crossing
Pass vs Certification
Authority certifies ≠ Exam pass certifies
Last Minute
- 1.Gravity needs slope
- 2.Force mains need pumps
- 3.Manholes are access points
- 4.Infiltration = groundwater entry
- 5.Inflow = direct stormwater
- 6.Test atmosphere before entry
- 7.LOTO before pump service
- 8.High wet well prevents SSO
- 9.CCTV finds pipe defects
- 10.Q = area x velocity
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