Cheat sheet
NCEES PE Environmental Cheat Sheet
Water
- 24-36% of exam
- Water & Wastewater Treatment Disinfection CT & Baffling Drinking Water MCLs Biological Treatment & SRT
Solid and Hazardous Waste
- 14-21% of exam
- RCRA Waste Characteristics RCRA Generator Categories Landfill Design Waste Hierarchy
Sustainability
- 9-14% of exam
- Sustainability & LCA Embodied Carbon Circular Economy System Reliability
Air Quality
- 16-25% of exam
- Air Quality & NAAQS Air Pollution Control Gaussian Plume Title V Permits
Site Assessment and Remediation
- 16-25% of exam
- Site Assessment & Remediation Phase I & II ESA Remediation Technology Picker Risk Assessment
Environmental and Occupational Health
- 9-14% of exam
- OSHA & HAZWOPER Limits Confined Space Entry Noise Exposure HAZWOPER PPE Levels
Quick Facts
- Exam PE Environmental
- Body NCEES
- Format CBT, year-round
- Questions 80 questions
- Appointment 9 hours total
- Exam Time 8 hours
- Fee $400 to NCEES
- First-Time Pass 73% (Jan-Jun 2026)
- Repeat Pass 54% (Jan-Jun 2026)
- Passing Score Scaled, not published
- Reference Electronic handbook only
Baffling Factor Scale WA
- Unbaffled .1, poor .3, average .5, superior .7, plug 1.0
- 0.1: no baffles at all 0.5: average baffling design 0.7: superior baffling design 1.0: true plug flow
MCL vs MCLG WA
MCL
- Enforceable legal limit
- Feasible given treatment and cost
MCLG
- Non-enforceable health goal
- Zero for known carcinogens
- Enforceable vs aspirational
Water & Wastewater Treatment WA
- Coagulation Destabilizes colloidal particles
- Flocculation Aggregates into settleable floc
- Sedimentation Gravity settling in basin
- Filtration Typical rate 2-4 gpm/ft2
- Disinfection Inactivates pathogens via CT
- Jar Test Bench test picks coagulant dose
- DAF Air bubbles float out solids
Alkalinity vs Hardness WA
Alkalinity
- Acid-neutralizing capacity
- Driven by bicarbonate and carbonate
Hardness
- Dissolved calcium and magnesium
- Not the same as alkalinity
- Buffering vs mineral content
Disinfection CT & Baffling WA
- CT Concentration times contact time
- T10 Actual CT contact time
- Baffling Factor T10 over theoretical V/Q
- Unbaffled BF 0.1
- Poor BF 0.3
- Average BF 0.5
- Superior BF 0.7
- Plug Flow BF 1.0, ideal contact
Drinking Water MCLs WA
- Nitrate MCL 10 mg/L as N
- Arsenic MCL 0.010 mg/L
- TTHM MCL 0.080 mg/L
- Lead Action Level 0.015 mg/L, current rule
- LCRI Lead AL 0.010 mg/L, Nov 2027
- Copper Action Level 1.3 mg/L
- PFOA/PFOS MCL 4.0 ppt, due 2029
- LRAA Per-site running annual average
Biological Treatment & SRT WA
- BOD5 5-day oxygen demand test
- SRT Solids age in aeration basin
- HRT Tank volume over flow rate
- MLSS Mixed liquor suspended solids
- F/M Ratio Food to microorganism loading
- Yobs Observed yield, falls with SRT
- Nitrification Ammonia oxidized to nitrate
- Chlorine Feed MGD x dose x 8.34
Waste Hierarchy Order WA
- Reduce, then recycle, then recover energy, then dispose
- Reduce/reuse: most preferred Recycle/compost: second choice Energy recovery: combustion plus capture Landfill: least preferred
SQG vs LQG WA
SQG
- 100 to 1,000 kg/mo
- Fewer accumulation requirements
LQG
- 1,000+ kg/mo
- 90-day accumulation limit
- Monthly volume sets category
Waste Management Hierarchy WA
- Can eliminate the waste → Source reduction, reuse ( Most preferred option )
- Can't reduce, can divert → Recycling, composting ( Second choice )
- Can't divert the material → Energy recovery ( Combustion with recovery )
- No other option remains → Landfill disposal ( Least preferred option )
RCRA Waste Characteristics WA
- Ignitability D001 Flash point below 60°C
- Corrosivity D002 pH ≤2 or ≥12.5
- Reactivity D003 8 criteria, e.g. toxic gas
- Toxicity TCLP 40 CFR 261.24, D004-D043
- TCLP Benzene 0.5 mg/L (D018)
- TCLP Lead 5.0 mg/L (D008)
- TCLP DAF ~100x health-based drinking level
Generator Size Order WA
- VSQG under SQG under LQG, ranked by kg per month
- VSQG: 100 kg/mo or less SQG: 100 to 1,000 kg/mo LQG: 1,000+ kg/mo
DAF: Two Different Meanings WA
Dissolved Air Flotation
- Water and wastewater unit process
- Air bubbles float out solids
Dilution Attenuation Factor
- TCLP threshold derivation
- About 100x the health level
- Same acronym, different exam topics
RCRA Generator Categories WA
- VSQG 100 kg/mo hazardous waste max
- VSQG Acute 1 kg/mo acute waste max
- SQG 100 to 1,000 kg/mo
- LQG 1,000+ kg/mo hazardous waste
- LQG Acute Over 1 kg/mo acute waste
- Satellite Accumulation 55-gallon limit at generation point
- LQG Storage Time 90 days max on-site
Landfill Design (Subtitle D) WA
- Daily Cover 6 inches soil, each day
- Final Cover Infiltration 18 inches, tight as liner
- Final Cover Cap 1e-5 cm/s permeability, or less
- Erosion Layer 6 inches, supports vegetation
- Bathtub Effect Tight cover traps infiltrating water
- Composite Liner Beneath the waste cell
Sustainability & LCA SU
- LCA ISO 14040, four phases
- Goal & Scope LCA phase one
- LCI Inventory of inputs and outputs
- LCIA Translates flows into impacts
- Embodied Carbon Materials, transport, end-of-life emissions
- Operational Carbon Ongoing energy-use emissions
- Circular Economy Reuse and repair loops
- Reliability, Series Multiply each component's reliability
- Reliability, Parallel Fails only if all fail
SCR vs SNCR AI
SCR
- Catalyst present
- Lower flue-gas temperature
- Higher NOx removal
SNCR
- No catalyst used
- Hotter injection zone
- Lower removal, lower cost
- Catalyst raises removal and cost
Air Pollution Control Picker AI
- Fine particulate, high efficiency → Electrostatic Precipitator ( Charged collection plates )
- Dry dust, moderate gas temperature → Fabric Filter Baghouse ( Very high PM efficiency )
- Particulate plus gas removal → Venturi Scrubber ( Wet droplet capture )
- High NOx removal needed → SCR ( Catalyst, lower temperature )
- Lower cost, less removal → SNCR ( No catalyst, hotter zone )
- Elevated stack, need concentration → Gaussian Plume Model ( C falls as wind rises )
Air Quality & NAAQS AI
- NAAQS 6 criteria pollutants under CAA
- PM2.5 Annual 9.0 µg/m3 primary standard
- PM2.5 24-Hour 35 µg/m3 primary standard
- Attainment Area Meets the NAAQS
- Nonattainment Area Exceeds a NAAQS, needs SIP
- Title V Threshold 100 tpy; HAPs 10/25 tpy
- SIP State plan to reach attainment
- Gaussian Plume Peak drops as wind rises
ESA Sequence SI
- Phase I screens the site, Phase II confirms and samples
- Phase I: no sampling done Phase II: borings plus wells A REC triggers Phase II
Phase I vs Phase II ESA SI
Phase I
- Non-intrusive records review
- Finds RECs, no sampling
Phase II
- Intrusive borings and wells
- Confirms and characterizes contamination
- Screen first, then confirm
Remediation Technology Picker SI
- VOCs in vadose zone → Soil Vapor Extraction ( Vacuum volatilizes VOCs )
- VOCs below water table → Air Sparging ( Often paired with SVE )
- Dissolved plume containment → Pump-and-Treat ( Extract, treat, discharge )
- Need fast in-situ destruction → ISCO ( Permanganate, persulfate, or Fenton's )
- Slow-desorbing sorbed mass → Bioremediation ( Long operating timeline )
- Need REC screening only → Phase I ESA ( No sampling required )
- REC confirmed, need data → Phase II ESA ( Borings plus monitoring wells )
- Checking non-cancer risk → Hazard Quotient ( HQ at or below 1 )
Site Assessment & Remediation SI
- Phase I ESA Records review, finds RECs
- REC Recognized environmental condition
- Phase II ESA Borings, wells, lab analysis
- Hazard Quotient Intake over reference dose
- Cancer Risk Intake times slope factor
- Acceptable Risk Range 1e-6 to 1e-4 risk
- SVE Vacuum pulls VOCs from soil
- Air Sparging Injects air below water table
- Pump-and-Treat Extract, treat, then discharge
- ISCO Oxidants destroy contaminants in place
- CERCLA Superfund cleanup and liability law
- PRP Potentially responsible, strict liability
Hazard Quotient vs Cancer Risk SI
Hazard Quotient
- Intake over reference dose
- For non-carcinogens
- At or below 1 is fine
Cancer Risk
- Intake times slope factor
- For carcinogens
- 1e-6 to 1e-4 acceptable
- Ratio vs probability
SVE vs Air Sparging SI
SVE
- Vacuum, vadose zone
- Extracts vapor above water table
Air Sparging
- Injects air below water table
- Volatilizes dissolved-phase VOCs
- Above vs below the water table
PPE Levels A-D HE
- A = SCBA suit, B = air, C = APR, D = uniform
- Level A: max protection Level B: less skin, same air Level C: known contaminant, APR Level D: no hazard present
PEL vs TLV HE
OSHA PEL
- Legally enforceable limit
- Many date to the 1970s
ACGIH TLV
- Voluntary guideline only
- Updated more often, often lower
- Enforceable vs advisory
Confined Space Entry Test Order HE
- Entering a confined space → Test oxygen first ( 19.5% to 23.5% )
- Oxygen reading in range → Test flammability next ( Below 10% LFL )
- Flammability reading in range → Test toxics last ( Below the PEL )
- Noise TWA hits 85 dBA → Start hearing conservation ( Action level, not PEL )
- Noise TWA above 90 dBA → Exceeds the noise PEL ( Feasible controls required )
- Contaminant identity unknown → Wear Level B PPE ( Until air is characterized )
OSHA & HAZWOPER Limits HE
- OSHA PEL Legally enforceable exposure limit
- ACGIH TLV Voluntary, often stricter guideline
- Noise PEL 90 dBA, 8-hour TWA
- Noise Action Level 85 dBA triggers hearing program
- Exchange Rate 5 dB halves allowed time
- Benzene PEL 1 ppm, 8-hour TWA
- Benzene STEL 5 ppm over 15 minutes
- Benzene Action Level 0.5 ppm triggers monitoring
- Confined Space O2 19.5% to 23.5% acceptable
- Confined Space LFL Below 10% lower flammable limit
- HAZWOPER Level A Full encapsulating suit plus SCBA
- HAZWOPER Level D Uniform only, no hazard
Common Traps
TCLP vs Drinking Water MCL
- TCLP sets waste thresholds ≠ MCL sets drinking water limits
Stage 1 vs Stage 2 TTHM
- Stage 1 used one system RAA ≠ Stage 2 uses per-site LRAA
Action Level vs PEL
- Action level triggers monitoring ≠ PEL is the enforceable ceiling
NSPS vs NESHAP
- NSPS covers new-source criteria pollutants ≠ NESHAP under CAA 112 covers HAPs
Attainment vs Nonattainment
- Attainment area meets the NAAQS ≠ Nonattainment area exceeds a NAAQS
Sustainability vs Resilience
- Sustainability is long-term stewardship ≠ Resilience is disruption recovery
Series vs Parallel Reliability
- Series: each component lowers reliability ≠ Parallel: redundancy raises reliability
Last Minute
- 1. 80 questions in an 8-hour exam
- 2. $400 exam fee, paid to NCEES
- 3. Closed book: only NCEES's e-handbook allowed
- 4. No published passing score; it's scaled
- 5. Pass rate: 73% first-time, 54% repeat
- 6. Retake limit: 3 attempts per year
- 7. Water is biggest domain, 19-29 Qs
- 8. Sustainability domain is brand-new in 2026
- 9. T10 is real CT contact time
- 10. Test O2, then flammables, then toxics
- 11. Noise action level: 85 dBA TWA
- 12. TCLP limits run about 100x MCLs
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