Editing Recycling (section)

=== Sorting ===
[[File:Recycling Video.webm|thumb|Video of recycling sorting facility and processes]]

Once commingled recyclates are collected and delivered to a [[materials recovery facility]], the materials must be sorted. This is done in a series of stages, many of which involve automated processes, enabling a truckload of material to be fully sorted in less than an hour.<ref name="economisttruth" /> Some plants can now sort materials automatically; this is known as [[single-stream recycling]]. Automatic sorting may be aided by robotics and machine learning.<ref>{{Cite web|url=https://resource-recycling.com/recycling/2019/05/07/how-recycling-robots-have-spread-across-north-america/|title=How recycling robots have spread across North America|date=7 May 2019|website=Resource Recycling News|language=en-US|access-date=29 August 2019|archive-date=8 May 2019|archive-url=https://web.archive.org/web/20190508123102/https://resource-recycling.com/recycling/2019/05/07/how-recycling-robots-have-spread-across-north-america/|url-status=live}}</ref><ref>{{Cite web|url=https://www.therobotreport.com/amp-robotics-announces-largest-deployment-of-ai-guided-recycling-robots/|title=AMP Robotics announces largest deployment of AI-guided recycling robots|date=27 June 2019|website=The Robot Report|language=en-US|access-date=29 August 2019|archive-date=16 July 2019|archive-url=https://web.archive.org/web/20190716111353/https://www.therobotreport.com/amp-robotics-announces-largest-deployment-of-ai-guided-recycling-robots/|url-status=live}}</ref> In plants, a variety of materials is sorted including paper, different types of plastics, glass, metals, food scraps, and most types of [[Batteries (journal)|batteries]].<ref>{{cite web |last = None |first = None |title = Common Recyclable Materials |url = http://www.epa.gov/smm/wastewise/pubs/commonmats.pdf |publisher = United States Environmental Protection Agency |access-date = 2 February 2013 |date = 10 August 2015 |archive-date = 24 April 2013 |archive-url = https://web.archive.org/web/20130424084201/http://www.epa.gov/smm/wastewise/pubs/commonmats.pdf |url-status = live }}</ref> A 30% increase in recycling rates has been seen in areas with these plants.<ref>{{cite web |work=ScienceDaily |date=October 1, 2007 |url=https://www.sciencedaily.com/videos/2007/1002-recycling_without_sorting.htm |title=Recycling Without Sorting: Engineers Create Recycling Plant That Removes The Need To Sort |archive-url=https://web.archive.org/web/20080831095259/https://www.sciencedaily.com/videos/2007/1002-recycling_without_sorting.htm |archive-date=31 August 2008 }}</ref> In the US, there are over 300 materials recovery facilities.<ref>{{Cite web|url=https://resource-recycling.com/recycling/2018/10/01/sortation-by-the-numbers/|title=Sortation by the numbers|date=1 October 2018|website=Resource Recycling News|language=en-US|access-date=29 August 2019|archive-date=29 August 2019|archive-url=https://web.archive.org/web/20190829191919/https://resource-recycling.com/recycling/2018/10/01/sortation-by-the-numbers/|url-status=live}}</ref>

Initially, commingled recyclates are removed from the collection vehicle and placed on a conveyor belt spread out in a single layer. Large pieces of [[corrugated fiberboard]] and [[plastic bag]]s are removed by hand at this stage, as they can cause later machinery to jam.<ref name="economisttruth" />

[[File:Glass and plastic recycling 065 ubt.JPG|thumb|left|Early sorting of recyclable materials: glass and plastic bottles in [[Poland]].]]

Next, automated machinery such as disk screens and air classifiers separate the recyclates by weight, splitting lighter paper and plastic from heavier glass and metal. Cardboard is removed from mixed paper, and the most common types of plastic—[[Polyethylene terephthalate|PET]] (#1) and [[HDPE]] (#2)—are collected, so these materials can be diverted into the proper collection channels. This is usually done by hand; but in some sorting centers, [[Spectroscopy|spectroscopic]] scanners are used to differentiate between types of paper and plastic based on their absorbed wavelengths.<ref name="economisttruth" /> Plastics tend to be incompatible with each other due to differences in [[chemical composition]]; their [[polymer]] molecules repel each other, similar to oil and water.<ref>{{cite book |last1=Goodship |first1=Vannessa |title=Introduction to Plastics Recycling |date=2007 |publisher=iSmithers Rapra Publishing |isbn=978-1-84735-078-7 }}{{page needed|date=April 2021}}</ref>

Strong magnets are used to separate out [[ferrous metal]]s such as iron, steel and [[tin can]]s. [[Non-ferrous metal]]s are ejected by magnetic [[eddy current]]s: A rotating magnetic field [[electromagnetic induction|induces]] an electric current around aluminum cans, creating an eddy current inside the cans that is repulsed by a large [[magnetic field]], ejecting the cans from the stream.<ref name="economisttruth" />

[[File:Recycling Point - geograph.org.uk - 1382457.jpg|thumb|A recycling point in [[New Byth]], Scotland, with separate containers for paper, plastics, and differently colored glass]]

Finally, glass is sorted according to its color: brown, amber, green, or clear. It may be sorted either by hand,<ref name="economisttruth" /> or by a machine that uses colored filters to detect colors. Glass fragments smaller than {{convert|10|mm|in}} cannot be sorted automatically, and are mixed together as "glass fines".<ref>{{cite web |last = None |first = None |title = What Happens to My Recycling? |url = http://www.1coast.com.au/page8390/What-happens-to-my-recycling.aspx |publisher = 1coast.com.au |access-date = 21 July 2014 |url-status = dead |archive-url = https://web.archive.org/web/20140811010701/http://www.1coast.com.au/page8390/What-happens-to-my-recycling.aspx |archive-date = 11 August 2014 }}</ref>

In 2003, [[San Francisco]]'s Department of the Environment set a citywide goal of zero waste by 2020.<ref>{{cite web |title = Best Recycling Programs in the US & Around the World |url = http://www.cpmfg.com/2012/04/11/the-best-recycling-programs-in-the-us-around-the-world-infographic/ |publisher = cmfg.com |access-date = 1 February 2013 |archive-date = 12 May 2015 |archive-url = https://web.archive.org/web/20150512093851/http://www.cpmfg.com/2012/04/11/the-best-recycling-programs-in-the-us-around-the-world-infographic/ |url-status = dead }}</ref> San Francisco's refuse hauler, [[Recology]], operates an effective recyclables sorting facility that has helped the city reach a record-breaking landfill diversion rate of 80% as of 2021.<ref>{{cite web |url = http://www.sfenvironment.org/news/press-release/mayor-lee-announces-san-francisco-reaches-80-percent-landfill-waste-diversion-leads-all-cities-in-north-america |title = Mayor Lee Announces San Francisco Reaches 80 Percent Landfill Waste Diversion, Leads All Cities in North America |publisher = San Francisco Department of the Environment |date = 5 October 2012 |access-date = 9 June 2014 |archive-date = 24 June 2014 |archive-url = https://web.archive.org/web/20140624003706/http://www.sfenvironment.org/news/press-release/mayor-lee-announces-san-francisco-reaches-80-percent-landfill-waste-diversion-leads-all-cities-in-north-america |url-status = live }}</ref> Other American cities, including Los Angeles, have [https://www.ecowatch.com/best-cities-for-recycling-2652630134.html achieved similar rates].