Solid and Hazardous Waste practice questions

Answer: D) 25–30 to 1

• AIncorrect. That's too nitrogen-rich.
• BIncorrect. That's far too nitrogen-rich.
• CIncorrect. That's far too carbon-rich.
• DCorrect. Too much carbon slows it; too much nitrogen releases ammonia.

Answer: D) Ignitability, corrosivity, reactivity and toxicity

40 CFR 261.21–261.24 define the four hazardous waste characteristics: ignitability, corrosivity, reactivity and toxicity. A waste that exhibits any one of them is a characteristic hazardous waste even if it is not listed.

• AIncorrect. Infectiousness is not a RCRA hazardous waste characteristic. The fourth characteristic is reactivity (§261.23), and medical/infectious waste is handled under other programs.
• BIncorrect. Persistence is not a Subpart C characteristic. The fourth characteristic is toxicity, which is measured with the TCLP extract against regulatory levels (§261.24).
• CIncorrect. Radioactivity is not a RCRA characteristic, since source, special nuclear and byproduct material are excluded from RCRA. Also, the regulatory term is ignitability, not flammability, and reactivity is missing from this set.
• DCorrect. Subpart C defines ignitability (D001, e.g., liquid flash point < 60 °C), corrosivity (D002, aqueous pH ≤ 2 or ≥ 12.5), reactivity (D003) and toxicity (D004–D043, by TCLP).

Answer: C) A site within the 100-year floodplain next to a wetland

Under the Part 258 location restrictions, landfill sites in 100-year floodplains, wetlands, fault areas, seismic impact zones, unstable areas and near airport runways need special demonstrations, so they are usually avoided. Clay soils and good road access are favorable factors.

• AIncorrect. The airport restriction in §258.10 applies only within 10,000 ft of turbojet runways or 5,000 ft of piston-aircraft runways, plus a notice requirement within 5 miles. A site 15 miles away is outside these limits.
• BIncorrect. Low-permeability soils and a deep water table help contain leachate and protect groundwater, so they make a site more suitable.
• CCorrect. Part 258 restricts units in 100-year floodplains (risk of washout and loss of flood storage) and in wetlands. A site needs a difficult demonstration to locate there, so these areas are normally avoided.
• DIncorrect. Good all-weather road access is a desirable siting factor for hauling waste, not a restriction.

Answer: B) Cleanup of abandoned or uncontrolled hazardous waste sites

• AIncorrect. That's the Safe Drinking Water Act.
• BCorrect. RCRA governs active waste management.
• CIncorrect. That's the Clean Air Act.
• DIncorrect. That's the Clean Water Act.

Answer: B) Trichloroethylene in permeable unsaturated sandy soil

SVE draws air through unsaturated soil with a vacuum and removes contaminants that partition into the vapor phase. It works best for VOCs such as TCE in permeable vadose-zone soils.

• AIncorrect. Metals like lead and chromium are not volatile, so a vacuum cannot pull them out as vapor. Clay's low permeability also limits airflow.
• BCorrect. TCE is a volatile organic compound. SVE applies a vacuum to the vadose zone, and air moves easily through permeable sand, carrying the volatilized contaminant to extraction wells.
• CIncorrect. Nitrate is not volatile, and SVE treats the unsaturated zone, not dissolved contamination in saturated aquifers.
• DIncorrect. Highly chlorinated PCBs have very low volatility, and saturated fine-grained sediments do not let air flow through them for vapor extraction.

Answer: C) Sterilizes the waste with high-pressure steam

• AIncorrect. It sterilizes.
• BIncorrect. That's incineration.
• CCorrect. It inactivates pathogens.
• DIncorrect. It sterilizes.

Answer: A) Half methane and half carbon dioxide

• ACorrect. Trace gases make up the rest.
• BIncorrect. Hydrogen is minor.
• CIncorrect. That's air.
• DIncorrect. CO₂ is a major component.

Answer: A) Concentrating collected waste for transport to a processing facility or disposal site

A transfer station is where waste from collection vehicles is concentrated into larger loads for transport to a processing facility or land disposal site (40 CFR 243.101).

• ACorrect. Under 40 CFR 243.101, a transfer station is a site where solid wastes are concentrated for transport to a processing facility or land disposal site. Moving waste into larger loads cuts hauling costs.
• BIncorrect. This describes the working face of a sanitary landfill, which is a land disposal site, not a transfer station.
• CIncorrect. This describes a waste-to-energy (combustion) facility, which is a processing facility, not a transfer station.
• DIncorrect. This describes a composting facility, which processes organic waste rather than consolidating it for transport.

Answer: B) 2,000 m³

• AIncorrect. Divide mass by density.
• BCorrect. 1,000,000 kg ÷ 500 kg/m³.
• CIncorrect. Convert tonnes to kg.
• DIncorrect. Recheck the arithmetic.

Answer: D) Sort and process recyclables

• AIncorrect. That's a treatment plant.
• BIncorrect. That's waste-to-energy.
• CIncorrect. That's a landfill.
• DCorrect. Sorted materials are sold to markets.