Editing Hazardous waste (section)

==Disposal ==
Historically, some hazardous wastes were disposed of in regular [[landfills]]. Hazardous wastes must often be stabilized and solidified in order to enter a landfill and must undergo different treatments in order to stabilize and dispose of them. Most flammable materials can be recycled into industrial fuel. Some materials with hazardous constituents can be recycled, such as lead acid batteries.  Many landfills require countermeasures against groundwater contamination. For example, a barrier has to be installed along the foundation of the landfill to contain the hazardous substances that may remain in the disposed waste.<ref>{{cite journal |last1=Malviya |first1=Rachana |last2=Chaudhary |first2=Rubina |year=2006 |title=Factors affecting hazardous waste solidification/Stabilization: A review |journal=Journal of Hazardous Materials |volume=137 |issue=1 |pages=267–276 |doi=10.1016/j.jhazmat.2006.01.065 |pmid=16530943}}</ref>

===Recycling===
Some hazardous wastes can be recycled into new products.<ref>{{Cite book |last1=Carysforth |first1=Carol |url=https://books.google.com/books?id=VitdgXrB7JcC&pg=PA131 |title=GCSE Applied Business for Edexcel: Double Award |last2=Neild |first2=Mike |date=2002 |publisher=Heinemann |isbn=9780435447205 |language=en}}</ref> Examples may include [[lead–acid battery|lead–acid batteries]] or [[electronic circuit board]]s. When [[heavy metals]] in these types of ashes go through the proper treatment, they could bind to other pollutants and convert them into easier-to-dispose solids, or they could be used as pavement filling. Such treatments reduce the level of threat of harmful chemicals, like [[Coal combustion products|fly]] and [[bottom ash]],<ref>{{Cite journal |last1=Zhao |first1=Xin-yue |last2=Yang |first2=Jin-yan |last3=Ning |first3=Ning |last4=Yang |first4=Zhi-shan |date=2022-06-01 |title=Chemical stabilization of heavy metals in municipal solid waste incineration fly ash: a review |url=https://doi.org/10.1007/s11356-022-19649-2 |journal=Environmental Science and Pollution Research |language=en |volume=29 |issue=27 |pages=40384–40402 |doi=10.1007/s11356-022-19649-2 |pmid=35338465 |bibcode=2022ESPR...2940384Z |s2cid=247683142 |issn=1614-7499}}</ref> while also recycling the safe product. 

=== Incineration ===
{{Main article|Incineration}}
Incinerators burn hazardous waste at high temperatures (1600°-2500°F, 870°-1400°C), greatly reducing its amount by decomposing it into [[ash]] and gases.<ref name=":2">{{Cite web |date=September 2012 |title=A Citizen's Guide to Incineration |url=https://www.epa.gov/sites/default/files/2015-04/documents/a_citizens_guide_to_incineration.pdf |access-date=2024-04-02 |website=United States Environmental Protection Agency}}</ref> Incineration works with many types of hazardous waste, including [[Soil contamination|contaminated soil]], [[sludge]], liquids, and gases. An incinerator can be built directly at a hazardous waste site, or more commonly, waste can be transported from a site to a permanent incineration facility.<ref name=":2" />

The ash and gases leftover from incineration can also be hazardous. Metals are not destroyed, and can either remain in the furnace or [[Phase transition|convert to gas]] and join the gas emissions. The ash needs to be stored in a hazardous waste landfill, although it takes less space than the original waste.<ref name=":2" /> Incineration releases gases such as [[carbon dioxide]], nitrogen oxides, ammonia, and volatile organic compounds.<ref>{{Cite web |date=March 5, 2014 |title=Emission From Waste Incineration |url=https://www.ipcc-nggip.iges.or.jp/public/gp/bgp/5_3_Waste_Incineration.pdf |access-date=April 2, 2024 |website=The Intergovernmental Panel on Climate Change}}</ref> Reactions in the furnace can also form [[hydrochloric acid]] gas and [[sulfur dioxide]]. To avoid releasing hazardous gases and solid waste [[Aerosol|suspended]] in those gases, modern incinerators are designed with systems to capture these emissions.<ref name=":1">{{Citation |last=Incineration |first=National Research Council (US) Committee on Health Effects of Waste |title=Incineration Processes and Environmental Releases |date=2000 |work=Waste Incineration & Public Health |url=https://www.ncbi.nlm.nih.gov/books/NBK233627/ |access-date=2024-04-02 |publisher=National Academies Press (US) |language=en}}</ref>

===Landfill===
Hazardous waste may be sequestered in a hazardous waste landfill or permanent disposal facility. "In terms of hazardous waste, a landfill is defined as a disposal facility or part of a facility where hazardous waste is placed or on land and which is not a pile, a land treatment facility, a surface impoundment, an underground [[injection well]], a salt dome formation, a salt bed formation, an underground mine, a cave, or a corrective action management unit (40 CFR 260.10)."<ref>{{Cite web |url=http://www.fedcenter.gov/assistance/facilitytour/landfills/hazwaste/ |title=Hazardous Waste Landfills |access-date=2008-11-25 |archive-date=2019-05-14 |archive-url=https://web.archive.org/web/20190514161525/https://www.fedcenter.gov/assistance/facilitytour/landfills/hazwaste/ |url-status=dead }}</ref><ref>[https://www.epa.gov/hw/land-disposal-restrictions-hazardous-waste Land Disposal Restrictions for Hazardous Waste]</ref>

=== Pyrolysis ===
Some hazardous waste types may be eliminated using [[pyrolysis]] in a high temperature not necessarily through electrical arc but starved of oxygen to avoid combustion.  However, when electrical arc is used to generate the required ultra heat (in excess of 3000 degree C temperature) all materials (waste) introduced into the process will melt into a molten slag and this technology is termed Plasma not pyrolysis. Plasma technology produces inert materials and when cooled solidifies into rock like material. These treatment methods are very expensive but may be preferable to high temperature incineration in some circumstances such as in the destruction of concentrated organic waste types, including PCBs, pesticides and other [[persistent organic pollutant]]s.<ref>{{Cite web |title=Scheduled Wastes - Plasma Arc Systems |url=http://www.environment.gov.au/settlements/publications/chemicals/scheduled-waste/swtt/plasma.html |url-status=dead |archive-url=https://web.archive.org/web/20091005153933/http://www.environment.gov.au/settlements/publications/chemicals/scheduled-waste/swtt/plasma.html#plascon |archive-date=2009-10-05 |access-date=2009-03-13}}</ref><ref>{{cite web |title=Microsoft PowerPoint - ESM of pesticide POPs part 3 |url=http://chm.pops.int/Portals/0/docs/Waste_Stockpiles/ESM%20of%20pesticide%20POPs%20part%203.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://chm.pops.int/Portals/0/docs/Waste_Stockpiles/ESM%20of%20pesticide%20POPs%20part%203.pdf |archive-date=2022-10-09 |url-status=live |access-date=2017-11-19}}</ref>