Recycling involves processing used
materials (waste) into new products to prevent waste of potentially
useful materials, reduce the consumption of fresh raw materials, reduce
energy usage, reduce air pollution (from incineration) and water
pollution (from land filling) by reducing the need for "conventional"
waste disposal, and lower greenhouse gas emissions as compared to virgin
production. Recycling is a key component of modern waste reduction and
is the third component of the "Reduce, Reuse, Recycle" waste hierarchy.
Recyclable materials include many kinds
of glass, paper, metal, plastic, textiles, and electronics. Although
similar in effect, the composting or other reuse of biodegradable waste
– such as food or garden waste – is not typically considered recycling.
Materials to be recycled are either brought to a collection center or
picked up from the curbside, then sorted, cleaned, and reprocessed into
new materials bound for manufacturing.
In a strict sense, recycling of a
material would produce a fresh supply of the same material—for example,
used office paper would be converted into new office paper, or used
foamed polystyrene into new polystyrene. However, this is often
difficult or too expensive (compared with producing the same product
from raw materials or other sources), so "recycling" of many products or
materials involves their reuse in producing different materials (e.g.,
paperboard) instead. Another form of recycling is the salvage of certain
materials from complex products, either due to their intrinsic value
(e.g., lead from car batteries, or gold from computer components), or
due to their hazardous nature (e.g., removal and reuse of mercury from
various items). Critics dispute the net economic and environmental
benefits of recycling over its costs, and suggest that proponents of
recycling often make matters worse and suffer from confirmation bias.
Specifically, critics argue that the costs and energy used in collection
and transportation detract from (and outweigh) the costs and energy
saved in the production process; also that the jobs produced by the
recycling industry can be a poor trade for the jobs lost in logging,
mining, and other industries associated with virgin production; and that
materials such as paper pulp can only be recycled a few times before
material degradation prevents further recycling. Proponents of recycling
dispute each of these claims, and the validity of arguments from both
sides has led to enduring controversy.