Chapter 16 Review (Part 1)

Solid Waste

Unwanted or unused materials produced by people.

Why are humans unique in waste production?

We create waste that other organisms can’t reuse.

What is waste in a system?

Outputs that aren’t useful or consumed.

What are the 2 inputs in a human system?

• Natural Resources

• Manufactured materials

What are the 2 outputs in a human system?

• Goods

• Waste

How is natural waste different from human waste?

Natural waste is reused by other organisms while human waste isn’t.

Throw-away society

A society that uses products briefly and then discards them.

When did the throw-away society grow in the US?

After World War 2.

What 3 factors caused the increase in waste post World War 2?

• Industrialization

• Wealth

• Consumer culture

Planned Obsolescence

Intentionally designing products to break or become outdated quickly.

Municipal Solid Waste (MSW)

Trash from homes, businesses, and institutions.

What percent of Municipal Solid Waste come from homes?

60%

What percent of Municipal Solid Waste come from businesses and institutions?

40%

How has Municipal Solid Waste changed over time in the US?

It increased a lot, then it leveled off recently.

How much waste is generated per person in the US, on a daily average?

2 kgs per day.

Why did waste increase?

Population growth → more consumption.

How does US waste compare globally?

Its much higher than developing countries.

How much waste per person is in developing countries?

Its lower per person but increasing overall.

What are 2 reasons why developing countries produce more waste?

• Population Growth

• Manufacturing goods for other countries

Waste Stream

How waste flows from its point of origin to its final destination.

What are the 3 endpoints of the waste stream?

• Recycling

• Landfill

• Incineration

When is a product entered into the waste stream?

When its discarded or no longer useful.

What item makes up the largest percentage of Municipal Solid Waste? How much (in percent)?

Paper → 27%

What is the percentage of Organic Waste in Municipal Solid Waste?

28%

What is the percentage of Plastic in Municipal Solid Waste?

13%

How much Municipal Solid Waste is recycled, in percent?

35%

What is the main effect of recycling paper?

It decreases a lot in landfill waste.

What makes up a larger portion of leftover waste after paper gets recycled?

Food and plastic waste.

Why are plastics harder to recycle?

It uses complex materials that can only be processed by a limited number of recycling systems.

Durable goods

Items that last for a long time.

Nondurable Goods

Items disposed after use, like paper or packaging.

Compostable Goods

Organic materials that decompose.

What is the largest waste category by use?

Containers and packaging.

E-waste

Discarded electronic devices.

Why is e-waste dangerous?

It contains toxic metals like lead and mercury.

What happens to toxic metals in landfills?

It can leak into groundwater.

Why is e-waste hard to recycle?

Its expensive and hard to dismantle.

Where is most US e-waste sent?

Asia.

Why is e-waste a major problem?

It uses unsafe recycling methods.

Who is affected by poor e-waste recycling?

Workers, children, and the environment.

What is the most concerning waste type by impact?

E-waste

What is a major challenge in waste management?

Its difficult to reduce waste and improve recycling methods.

What are the “3 Rs'”?

Reduce, Reuse, Recycle.

Rank the 3 Rs from highest to lowest in how effective it is in keeping waste away from landfills.

1. Reduce (Best)

2. Reuse

3. Recycle (Worst)

Composting

Turning organic waste into nutrient-rich soil.

Reduce

Use fewer materials to create less waste.

Why is reduce the best option?

It prevents waste before it exists.

Source Reduction

Cutting waste during product design or manufacturing?

Material substitution

Replacing harmful materials with better ones.

Break-even point

The number of times you need to use a reusable item before it becomes better than being disposed.

Reuse

Using items again instead of disposing it.

What is the main benefit of reusing things?

It extends how long an item can be used.

Does reuse always have zero-costs?

It sometimes uses energy, but not as much.

Recycling

Turning waste into raw materials to make new products.

Why is recycling less ideal then reducing or reusing items?

It uses energy for collecting, cleaning, and processing items.

Closed-loop recycling

Recycling a product into the same product as it was before.

Open-loop recycling

Recycling an item into a different product.

Zero-sort recycling

Mixing all recyclables together and sorting them later.

Why is recycling sometimes difficult?

Its costly and uses more energy.

How much of Municipal Solid Waste is recycled in the US, in percentage?

33.3%

Why do manufacturers like recycled materials?

It saves energy and reduces pollution.

Why is composting important?

It keeps organic waste out of landfills and reduces methane emissions.

What problem occurs when organic waste is in landfills?

It decomposes without oxygen and produces methane.

What 3 things does compost improve?

• Soil quality

• Nutrients

• Water retention

What 4 materials can be composted?

• Food scraps

• Yard waste

• Paper fibers

• Manure

What 2 things should not be composted?

• Meat

• Dairy

What is the ideal carbon-nitrogen ratio?

30:1

“Brown” materials

Dry, carbon rich materials like leaves and dried grass.

“Green” materials

Wet, nitrogen-rich materials like fresh plants.

Why is turning compost important?

It adds oxygen that keeps decomposition aerobic.

What happens if a compost lacks oxygen?

It produces methane and bad odors.

How do cities compost waste?

They pile organic material in rows and turn it regularly.

What helps kill harmful bacteria in compost?

Heat produced by microbes.

Worm composting

Using worms to break down food waste.

Can composting be done indoors?

Yes.

What are the 3 downsides of composting?

• Takes time

• Uses space

• Can attract pests if done poorly.