9.2 Recycling, Composting and Reuse

Notes

Recycling processes used materials into new products. Composting turns food and yard waste into soil-enriching humus.

• Recycling saves energy and raw materials. Making aluminum from recycled cans uses about 95% less energy than making it from ore.
• Closed-loop recycling turns a product into the same product again (can to can). Downcycling makes a lower-quality product (plastic bottles into carpet fiber).
• Problems: contamination (food or wrong items in recycling), fluctuating markets, and the fact that many plastics are hard to recycle economically.
• Composting reduces landfill methane and returns nutrients to soil.
• Source reduction (buying less, avoiding packaging) is more effective than recycling. E-waste (old electronics) contains valuable metals and toxic substances (lead, mercury) and needs special handling.
• Example: a household composts food scraps, which turns waste into soil amendment and avoids methane from a landfill.