8.10 Waste Reduction Methods

The order matters because each step saves more than the next.

Reduce means not creating the waste in the first place: buying less, choosing products with less packaging, and making products last longer. It saves all the raw materials, energy and pollution of making the item.

Reuse means using an item again, as it is or for a new purpose: refillable water bottles, cloth bags, secondhand clothes, repairing instead of replacing. It saves the energy of making a new item, with little or no processing.

Recycling means breaking a used material down and making it into new products, such as melting aluminum cans to make new cans or pulping paper to make new paper. It saves raw materials and usually energy, but collecting, sorting, transporting and reprocessing still take energy and money.

• Pros: conserves raw materials, reduces mining and logging, recovers valuable and toxic metals from e-waste so they don't leach out of landfills, saves energy (recycling aluminum takes about 95 percent less energy than making it from bauxite ore), and keeps waste out of landfills.
• Cons: collection and sorting cost money; recycled-material prices rise and fall, so programs may lose money; contamination (food on containers, wrong items in the bin) can ruin whole batches; and many plastics can only be recycled into lower-quality products a few times, a process called downcycling.
• Bottom line: recycling helps, but it is less effective than reducing and reusing.

Composting lets microbes break down food scraps and yard waste with oxygen into a dark, crumbly material called humus or compost, which can be added to soil as a natural fertilizer that holds water and nutrients. A good compost pile mixes carbon-rich 'browns' (dry leaves, paper) with nitrogen-rich 'greens' (food scraps, grass clippings), stays moist, and is turned to let in air.

Composting keeps a large share of trash out of landfills, where it would otherwise produce methane. Downsides: piles can smell or attract pests if poorly managed, and it takes space and time.

Landfill gas capture collects methane from landfills through a network of pipes and burns it to make electricity or heat, instead of letting it escape as a greenhouse gas. Burning methane still makes CO₂, but CO₂ is a much weaker greenhouse gas than methane.

Waste-to-energy plants incinerate trash to make steam for electricity. This recovers energy and shrinks the volume of waste but has the air pollution and ash problems of incineration (topic 8.9).

Closed landfills can be capped and turned into parks, golf courses or restored habitat. New York City's former Fresh Kills Landfill on Staten Island, once one of the largest landfills in the world, is being converted into a large park, Freshkills Park, with grasslands and wetlands that support wildlife.