CPWM Cheat Sheet 2026

The 30 highest-yield CPWM facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. What is the typical methane concentration range found in landfill gas collected from a well-managed MSW landfill? → 35–60% methane by volume
2. In an LFG collection system, what does a negative wellhead pressure (vacuum) measurement indicate? → The blower system is actively drawing gas from the waste mass toward the collection system
3. What is the primary regulatory purpose of a gas collection and control system (GCCS) at a municipal solid waste landfill? → To capture and control LFG emissions to meet Clean Air Act requirements
4. At the top of the EPA waste management hierarchy is: → Source reduction and reuse
5. Which of the following is a primary goal of the EPA's Universal Waste Program? → To encourage the collection and recycling of certain common hazardous wastes
6. What is the BEST safety practice when a collection vehicle must back into a narrow alley? → Use a spotter wearing high‑visibility clothing to guide the driver.
7. Which metric is MOST commonly used to measure collection route efficiency? → Stops per vehicle‑day.
8. Life Cycle Assessment (LCA) evaluates impacts: → Across the entire product life cycle
9. What minimum destruction or removal efficiency must an enclosed combustion device achieve for NMOCs under EPA regulations for MSW landfill gas? → 98% destruction efficiency
10. What does 'digestate' refer to in anaerobic digestion of organic waste? → The solid/liquid residue remaining after digestion
11. Which financial instruments generated by LFG-to-energy projects can provide additional revenue through environmental commodity markets? → Renewable Energy Credits (RECs) and verified carbon offset credits
12. Which process involves heating organic material in the absence of oxygen to produce biochar and syngas? → Pyrolysis
13. In-vessel composting differs from windrow composting primarily because it: → Occurs inside an enclosed, controlled container
14. What minimum operating temperature must an enclosed combustion device maintain when treating landfill gas under EPA 40 CFR Part 60 Subpart Cf? → 1,500°F (815°C)
15. For efficient composting, the optimal carbon‑to‑nitrogen (C:N) ratio is approximately: → 25–30:1
16. What are the two primary components of landfill gas (LFG)? → Methane and carbon dioxide
17. Which of the following best describes 'renewable natural gas' (RNG) produced from a landfill? → LFG purified to pipeline-quality methane content for injection into the natural gas grid
18. Which routing objective is MOST important for municipal solid waste collection operations? → Minimize fuel consumption while completing all scheduled stops.
19. Which container design is BEST suited for automated side‑loader collection equipment? → 96‑gallon wheeled cart with ANSI lift bar
20. What is the primary purpose of turning a windrow compost pile? → To aerate the pile and redistribute heat
21. Stabilization/solidification of hazardous waste primarily aims to: → Reduce contaminant leachability
22. What is the PRIMARY purpose of a transfer station in the waste collection system? → Consolidate waste into larger vehicles for long‑distance transport.
23. Which element of a solid waste management plan typically identifies the quantities and types of waste generated within a service area? → Waste characterization or waste stream analysis
24. Which metric measures the proportion of material diverted from disposal? → Material recovery/diversion rate
25. Which U.S. law establishes cradle‑to‑grave management of hazardous waste? → Resource Conservation and Recovery Act (RCRA)
26. Deep‑well injection is generally permitted for which waste type? → Compatible non‑hazardous liquid waste
27. Using recycled glass cullet in new glass manufacturing primarily reduces: → Energy requirements in glass furnaces
28. Overloading a front‑loader collection truck MOST likely results in: → Accelerated wear on suspension and longer stopping distance.
29. Which of the following is a primary economic challenge for recycling programs, often causing financial instability for municipalities and MRFs? → Fluctuating market prices for recycled commodities.
30. After combustion in a mass‑burn waste‑to‑energy facility, the main solid residue requiring management is: → Bottom ash and fly ash