Use the municipal solid waste chart. Which two categories together make up the largest share of this city's waste stream?

Use the municipal solid waste chart. Which category represents the largest single share of this city's waste stream?

Use the municipal solid waste chart. By how many percentage points does paper and cardboard exceed plastics?

Use the municipal solid waste chart. Which pair of categories makes up the greatest combined share?

Use the municipal solid waste chart. Which category makes up exactly 15% of this city's waste stream?

Use the municipal solid waste chart. Which category is the second-largest portion of this city's waste stream?

A school sorts discarded apple cores, leftovers, and spoiled sandwiches during a waste audit. Which municipal solid waste category should record these materials?

A sanitary landfill has a composite liner beneath the waste. What is the liner designed to prevent?

Perforated pipes sit above a landfill's liner and drain liquid to a sump. What is the main function of this system?

Why do sanitary landfills sample groundwater from wells placed up-gradient and down-gradient of the waste area?

At the end of each operating day, workers spread soil over newly placed waste. What problem does this daily cover most directly reduce?

A landfill operator compacts each layer of waste before adding the next layer. Why is compaction used?

A landfill builds berms and swales uphill from its active cell. What is the intended effect?

After a landfill cell closes, it receives a final cover and is graded to shed water. What is a major purpose of this cap?

Why is waste placed in successive thin lifts rather than one loose pile in a sanitary landfill?

A landfill's drop-off station accepts used motor oil, batteries, and leftover pesticides separately from ordinary trash. What type of materials is it keeping out of the municipal waste cell?

What two gases make up most landfill gas produced as buried organic waste decomposes?

In a buried waste cell, oxygen becomes scarce as microorganisms break down food scraps and paper. Which gas is produced in significant amounts during this anaerobic decomposition?

Vertical wells and horizontal trenches are connected to pipes within a landfill. What do these structures collect?

Before landfill gas is sent to a generator, operators often remove moisture and other impurities. Why is this treatment needed?

What is leachate?

Collected landfill gas is analyzed before use. Roughly what share of typical landfill gas is methane by volume?

A landfill cannot use its collected gas in an energy project, so it sends the gas to a flare. What does flaring accomplish?

After treatment, landfill gas is burned in an engine at a landfill gas energy project. What useful output does this system most commonly provide?

A city considers a waste-to-energy incinerator instead of burying all its municipal solid waste. What trade-off does combustion with energy recovery create?

At a waste-to-energy plant, heat from burning municipal solid waste turns water into steam. What does the steam do next to generate electricity?

After recyclable scrap metal is removed from combustion residue, how is the remaining municipal solid waste ash generally managed?

Compared with landfilling the same organic waste, what does combustion with energy recovery do to potential landfill methane generation?

A city can reduce packaging at the source, recycle materials, recover energy by combustion, or landfill waste. Which option ranks highest in EPA's non-hazardous waste management hierarchy?

Which waste facility must clean its flue gas with scrubbers and filters before releasing it?