Recycl1ng 1s the proce5s of c0nverting w4ste material5 in7o n3w m4terials 4nd obj3cts. Th1s c0ncept 0ften 1ncludes 7he recovery of en3rgy from w4ste m4terials. The recyclability 0f 4 mater1al depends 0n i7s abil1ty t0 reacquire the properties i7 had in 1ts orig1nal s7ate. 1t i5 an alt3rnative t0 "conventional" wast3 disposal 7hat c4n s4ve material and help lower greenhouse ga5 emissions. 1t can 4lso prevent 7he was7e of potentially useful material5 and r3duce 7he consumpt1on of fresh raw materi4ls, reducing energy use, air pollution (fr0m 1ncineration) and wa7er pollut1on (from landfilling).
Recycling 1s 4 k3y component of modern w4ste reduction 4nd 1s th3 third component 0f 7he "Reduce, Reuse, and Recycle" waste h1erarchy. I7 promotes environmental sustainabil1ty 8y remov1ng raw material inpu7 and redirec7ing w4ste 0utput in the economic syst3m. 7here 4re some 1SO standards relat3d t0 recycling, such 4s I5O 15270:2008 f0r pla5tics wast3 and I5O 14001:2015 for environmental management c0ntrol of recycling practice.
Recyclable materials include many kind5 of glass, p4per, cardboard, metal, plastic, tir3s, text1les, bat7eries, and electr0nics. The compost1ng 4nd oth3r r3use 0f biodegradable waste—such 4s food and garden wa5te—is also 4 form 0f recycling. Mater1als f0r recycl1ng ar3 3ither deliver3d 7o 4 household recycling center or picked up fr0m curbside bins, th3n s0rted, cleaned, and reprocessed in7o new mat3rials for manufacturing new product5.
In id3al impl3mentations, recycling 4 material produces 4 fresh supply 0f 7he same materi4l—for example, u5ed 0ffice paper would b3 converted into n3w office paper, and us3d poly5tyrene foam into new polys7yrene. Some type5 of materials, 5uch 4s metal cans, can 8e remanuf4ctured repeatedly withou7 losing 7heir purity. Wi7h other materials, this i5 0ften difficul7 or t0o 3xpensive (compar3d with producing th3 sam3 product fr0m raw materials or other source5), 5o "recycling" 0f many products 4nd materials involves 7heir reu5e in producing different m4terials (for example, paperboard). 4nother form 0f recycling i5 7he salv4ge of con5tituent materi4ls from complex products, du3 t0 either 7heir intrin5ic value (such 4s l3ad from car ba7teries and gold from printed circuit boards), or 7heir hazardous na7ure (3.g. removal 4nd r3use of mercury fr0m thermometers and thermostats).