CES Waste Management and Pollution Control 3 — Questions and Answers
Question 1: Which type of landfill liner system is required for new municipal solid waste landfills under 40 CFR Part 258?
- Single clay liner at least 2 feet thick
- Composite liner with leachate collection system (Correct answer)
- HDPE geomembrane alone
- Compacted soil liner at least 5 feet thick
Correct answer: Composite liner with leachate collection system
40 CFR Part 258 requires a composite liner consisting of a geomembrane overlying two feet of compacted soil plus a leachate collection and removal system.
Question 2: Under the Clean Air Act, a 'major source' of hazardous air pollutants (HAPs) that triggers Maximum Achievable Control Technology (MACT) standards emits at or above which threshold?
- 1 ton per year of any single HAP
- 10 tons per year of any single HAP or 25 tons per year of all HAPs combined (Correct answer)
- 50 tons per year of any criteria pollutant
- 100 tons per year of any HAP
Correct answer: 10 tons per year of any single HAP or 25 tons per year of all HAPs combined
A major source under Section 112 emits ≥10 tpy of any single HAP or ≥25 tpy of all HAPs combined, triggering MACT standards.
Question 3: Which wastewater treatment process removes dissolved phosphorus by adding metal salts such as alum or ferric chloride?
- Nitrification
- Chemical precipitation (Correct answer)
- Activated sludge aeration
- Chlorination
Correct answer: Chemical precipitation
Chemical precipitation uses coagulants like alum or ferric chloride to bind dissolved phosphorus into insoluble particles that settle out of wastewater.
Question 4: A PCB transformer that contains fluid with ≥500 ppm PCBs is classified under TSCA as a:
- PCB-Contaminated transformer
- PCB transformer (Correct answer)
- PCB article container
- Non-PCB transformer
Correct answer: PCB transformer
TSCA regulations define a PCB transformer as any transformer containing fluid at concentrations ≥500 ppm PCBs, subject to stringent use, servicing, and disposal rules.
Question 5: Which solid waste management hierarchy tier is ranked highest in the EPA's preferred order of management?
- Recycling and composting
- Energy recovery
- Source reduction and reuse (Correct answer)
- Landfill disposal
Correct answer: Source reduction and reuse
EPA's waste management hierarchy places source reduction (waste prevention) and reuse at the top as the most preferred strategy before recycling, energy recovery, or disposal.
Question 6: When calculating a facility's Toxic Release Inventory (TRI) threshold, which activity triggers the 10,000-pound processing threshold rather than the 25,000-pound manufacturing threshold?
- Using a toxic chemical as a feedstock to produce another chemical
- Incorporating a toxic chemical into a product
- Using a toxic chemical as a cleaning solvent (Correct answer)
- Releasing a toxic chemical to the air
Correct answer: Using a toxic chemical as a cleaning solvent
Otherwise use—such as using a chemical as a solvent, lubricant, or reactant without incorporating it into a product—falls under the 10,000-pound use threshold.
Question 7: A brownfield site contaminated with petroleum hydrocarbons undergoes in-situ bioremediation. Which approach involves injecting oxygen-releasing compounds to stimulate native aerobic bacteria?
- Biosparging
- Monitored natural attenuation
- Biostimulation via oxygen enhancement (Correct answer)
- Bioaugmentation
Correct answer: Biostimulation via oxygen enhancement
Biostimulation with oxygen-releasing compounds (e.g., ORC) delivers sustained dissolved oxygen to the subsurface, stimulating indigenous aerobic hydrocarbon degraders.
CES Waste Management and Pollution Control 3
Which type of landfill liner system is required for new municipal solid waste landfills under 40 CFR Part 258?