8.10 - Waste Reduction

Question 1

Reduce Reuse Recycle

Answer 1

• Reducing consumption is the most sustainable because it decreases natural resources harvesting and the energy inputs to creating, packaging, and shipping goods
• Reusing = the next most sustainable because it doesnt require additional energy to create a product
• Recycling = processing and converting solid waste material into new products
  - Least sustainable of the three Rs due to the amount of energy it requires to process and convert waste materials

Question 2

Recycling Pros and Cons

Answer 2

Pros:
- Reduces demand for new materials, especially metals and wood which cause habitat destruction & soil erosion when harvested
- Reduces energy required to ship raw materials and produce new products (fewer FF comb, less CC)
- Reduces landfill volume, conserving landfill space & reducing need for more landfills

Cons:
- Recycling is costly and still required significant energy
- Cities that offer recycling services need to process, sort, and sell collected materials; prices change rapidly, leading to “recycled” materials often being thrown away
- When citizens recycle items that shouldn’t be recycled (wrappers with food, styrofoam, etc.) it increases the cost for cities to sort & process)

Question 3

Composting

Answer 3

Org. matter (food scraps, paper, yard waste) being decomposed under controlled conditions
- Reduces landfill volume and produces rich organic matter that can enhance water holding capacity, nutrient levels of agricultural or garden soil
- Produces valuable product to sell (compost)
- Reduces the amount of methane released by anaerobic decomposition of organic matter in landfills
- Should be done w/proper mix of “browns” (Carbon) to “greens” (N) ~ 30:1
- Should also be aerated and mixed to optimize decomposition (bacteria need O2 for decomp.)

• Potential drawbacks include the foul smell that can be produced if not properly rotated & aerated and rodents or other pests that may be attracted

Question 4

E-Waste

Answer 4

Waste from electronics (phones, computers, etc.) that often contain heavy metals (lead, merc, cadmium)
- Can leach these toxic metals into soil & groundwater if disposed of in landfills or open dump
- Can be recycled and reused to create new electronics, but often sent to developing nations for recycling due to health hazards, more strict env. & worker protection laws in developing nations
- Can be dismantled and sold to countries that extract valuable metals (gold, silver, platinum) from motherboards
- Often burned or dumped due to less strict env. regulations or lack of enforcement in developing nations

Question 5

Waste to Energy

Answer 5

• Waste can be incinerated (burned) to reduce the volume & also generate electricity; most waste (paper, plastic, food) = hydrogen, carbon, and oxygen so it easily combusts at high temp.
• Same process as burning coal, NG, biomass
• Heat → water → steam → turbine → generator → ⚡
• Methane gas produced by decomposition in landfill can be collected with pipes & burned to generate electricity
• Heat → water → steam → turbine → generator → ⚡
• Reduces landfill volume
• Produces electricity without fracking or mining for FFs