Environmental Engineering & Sustainability Flashcards

A municipality plans to install a landfill gas-to-energy system. Landfill gas typically consists of approximately what percentage of methane?

Answer: 45–60%

Landfill gas is typically composed of approximately 45–60% methane and 40–55% carbon dioxide, with trace amounts of other gases.

Which U.S. regulatory program requires large municipal separate storm sewer systems (MS4s) to obtain permits controlling stormwater runoff?

Answer: Clean Water Act Phase I and Phase II MS4 rules

EPA's Phase I (1990) and Phase II (1999) MS4 rules under the CWA NPDES program require municipalities to reduce pollutants in stormwater discharges.

In green infrastructure design, which practice is most effective at capturing and infiltrating stormwater at the source before it enters the storm drain system?

Answer: Bioretention cell (rain garden)

Bioretention cells infiltrate and filter stormwater at or near the point of rainfall, making them highly effective at source-level control.

A municipal engineer calculates the carbon footprint of a water distribution system. Which operational component typically contributes the most greenhouse gas emissions?

Answer: Energy use for pumping

Energy consumption for pumping water through distribution systems is the dominant source of GHG emissions in water utilities, often representing over 80% of total emissions.

Which environmental assessment tool is required for federal projects under the National Environmental Policy Act (NEPA) that may significantly affect the environment?

Answer: Environmental Impact Statement (EIS)

NEPA requires federal agencies to prepare an Environmental Impact Statement for major federal actions that significantly affect the quality of the human environment.

A city wants to reduce urban heat island effect. Which strategy provides the greatest long-term temperature reduction benefit?

Answer: Increasing urban tree canopy and green space coverage

Urban tree canopy provides the greatest long-term benefit through shading, evapotranspiration cooling, and stormwater management, reducing ambient temperatures by 2–8°C.

Under RCRA, a hazardous waste generator that produces between 100 and 1,000 kg of hazardous waste per month is classified as a:

Answer: Small Quantity Generator (SQG)

EPA classifies generators producing 100–1,000 kg/month of hazardous waste as Small Quantity Generators (SQGs), subject to intermediate regulatory requirements.