Editing Sewage sludge (section)

== Use ==

=== Land application ===
{{Main|Biosolids}}

[[Biosolids]] is a term widely used to denote the byproduct of domestic and commercial [[Sewage treatment|sewage and wastewater treatment]] that is to be used in agriculture. National regulations that dictate the practice of land application of treated sewage sludge differ widely and e.g. in the US there are widespread disputes about this practice.
[[File:Shovel excavator loading the sewage sludge (6305610332).jpg|alt=A yellow shovel excavator with a man visible at the wheel in the cab, is pushing a huge pile of sewage sludge which looks like very dark colored dirt, which is filling most of the bottom half of the image. This is taking place on a bare field, with light brown soil visible, whose color contrasts strongly with the dark sewage sludge. In the background, there is a green field, and a yellow field, and trees.  |thumb|A shovel excavator loading solid sewage sludge for land application.]]

Depending on their level of treatment and resultant pollutant content, biosolids can be used in regulated applications for non-food agriculture, food agriculture,<ref name="Cornell-Sludge">{{cite journal |last1=Harrison |first1=Ellen Z. |last2=Oakes |first2=Summer Rayne |author-link2=Summer Rayne Oakes |year=2003 |title=Investigation of alleged health incidents associated with land application of sewage sludges |journal=New Solutions |volume=12 |issue=4 |pages=387–408 |bibcode=2003NewSo..12..387H |doi=10.2190/0FJ0-T6HJ-08EM-HWW8 |pmid=17208785 |s2cid=26931475 |hdl-access=free |hdl=1813/5319}}</ref> or distribution for unlimited use. Treated biosolids can be produced in cake, granular, pellet, or liquid form and are spread over land before being incorporated into the soil or injected directly into the soil by specialist contractors. Such use was pioneered by the production of [[Milorganite]] in 1926.{{Citation needed|date=August 2022|reason="pioneered"? Citation needed, otherwise it's just a commercial plug. Pioneered as in the very first use of biosolids from sewage as a fertiliser in the whole world? That's highly unlikely...}}

Use of sewage sludge has shown an increase in level of soil available phosphorus and [[soil salinity]].<ref>{{cite journal |last1=Hosseinpur |first1=Alireza |last2=Pashamokhtari |first2=Hamed |year=2013 |title=The effects of incubation on phosphorus desorption properties, phosphorus availability, and salinity of biosolids-amended soils |journal=[[Environmental Earth Sciences]] |volume=69 |issue=3 |pages=899–908 |bibcode=2013EES....69..899H |doi=10.1007/s12665-012-1975-6 |s2cid=140537340}}</ref>

The findings of a 20-year field study of air, land, and water in Arizona, concluded that use of biosolids is sustainable and improves the soil and crops.<ref name="Artiola2006">{{cite web |last=Artiola |first=Janick F. |date=November 2006 |title=Biosolids land use in Arizona |url=http://cals.arizona.edu/pubs/consumer/az1426.pdf |archive-url=https://web.archive.org/web/20080309015544/http://cals.arizona.edu/pubs/consumer/az1426.pdf |archive-date=9 March 2008 |access-date=2 June 2017 |website=[[University of Arizona]]}}</ref> Other studies report that plants uptake large quantities of [[heavy metals]] and toxic pollutants that are retained by produce, which is then consumed by humans.<ref name="McBrideRichardsMJ2000">{{cite journal |last1=McBride |first1=Murray B. |last2=Richards |first2=Brian K. |last3=Steenhuis |first3=Tammo S. |last4=Spiers |first4=G. |date=May–June 2000 |title=Molybdenum Uptake by Forage Crops Grown on Sewage Sludge-Amended Soils in the Field and Greenhouse |url=http://soilandwater.bee.cornell.edu/publications/McBrideJEQ00.pdf |journal=[[Journal of Environmental Quality]] |volume=29 |issue=3 |pages=848–54 |bibcode=2000JEnvQ..29..848M |doi=10.2134/jeq2000.00472425002900030021x |access-date=2 June 2017}}</ref><ref name="KimMcBride2007">{{cite journal |last1=Kim |first1=Bojeong |last2=McBride |first2=Murray B. |last3=Richards |first3=Brian K. |last4=Steenhuis |first4=Tammo S. |year=2007 |title=The long-term effect of sludge application on Cu, Zn, and Mo behavior in soils and accumulation in soybean seeds |journal=Plant and Soil |volume=299 |issue=1–2 |pages=227–36 |doi=10.1007/s11104-007-9377-3 |bibcode=2007PlSoi.299..227K |s2cid=24692709}}</ref><ref name="McBrideCSSPA2005">{{cite journal |last1=McBride |first1=Murray B. |year=2005 |title=Molybdenum and Copper Uptake by Forage Grasses and Legumes Grown on a Metal-Contaminated Sludge Site |journal=Communications in Soil Science and Plant Analysis |volume=36 |issue=17–18 |pages=2489–501 |doi=10.1080/00103620500255840 |bibcode=2005CSSPA..36.2489M |s2cid=98655719}}</ref>

A PhD thesis studying the addition of sludge to neutralize soil acidity concluded that the practice was not recommended if large amounts are used because the sludge produces acids when it oxidizes.<ref>{{cite web |last=Bulegoa |first=Komunikazio |date=8 January 2009 |title=Adding high doses of sludge to neutralize soil acidity not advisable |url=http://www.basqueresearch.com/berria_irakurri.asp?Berri_Kod=2016&hizk=I |access-date=2 June 2017 |website=Basque Research}}</ref>

Studies have indicated that pharmaceuticals and personal care products, which often adsorb to sludge during wastewater treatment, can persist in agricultural soils following [[biosolid]] application.<ref name="Edwards_Pharmaceutical_2009">{{cite journal |last1=Edwards |first1=M. |last2=Topp |first2=E. |last3=Metcalfe |first3=CD. |last4=Li |first4=H. |last5=Gottschall |first5=N. |last6=Bolton |first6=P. |last7=Curnoe |first7=W. |last8=Payne |first8=M. |last9=Beck |first9=A. |last10=Kleywegt |first10=S. |last11=Lapen |first11=DR. |display-authors=3 |date=1 July 2009 |title=Pharmaceutical and personal care products in tile drainage following surface spreading and injection of dewatered municipal biosolids to an agricultural field |journal=[[Science of the Total Environment]] |volume=407 |issue=14 |pages=4220–30 |bibcode=2009ScTEn.407.4220E |doi=10.1016/j.scitotenv.2009.02.028 |pmid=19394680}}</ref> Some of these chemicals, including potential [[endocrine disruptor]] triclosan, can also travel through the soil column and leach into agricultural [[tile drainage]] at detectable levels.<ref name="Edwards_Pharmaceutical_2009" /><ref name="Xia_Triclocarban_2009">{{cite journal |last1=Xia |first1=Kang |last2=Hundal |first2=Lakhwinder S. |last3=Kumar |first3=Kuldip |last4=Armbrust |first4=Kevin |last5=Cox |first5=Albert E. |last6=Granato |first6=Thomas C. |display-authors=3 |year=2010 |title=Triclocarban, triclosan, polybrominated diphenyl ethers, and 4-nonylphenol in biosolids and in soil receiving 33-year biosolids application |journal=Environmental Toxicology and Chemistry |volume=29 |issue=3 |pages=597–605 |doi=10.1002/etc.66 |pmid=20821484 |s2cid=8455892 |doi-access=free}}</ref> Other studies, however, have shown that these chemicals remain adsorbed to surface soil particles, making them more susceptible to surface erosion than infiltration.<ref>{{cite journal |last1=Cha |first1=Jongmun |last2=Cupples |first2=Alison M. |year=2009 |title=Detection of the antimicrobials triclocarban and triclosan in agricultural soils following land application of municipal biosolids |journal=Water Research |volume=43 |issue=9 |pages=2522–30 |bibcode=2009WatRe..43.2522C |doi=10.1016/j.watres.2009.03.004 |pmid=19327812}}</ref><ref>{{cite journal |last1=Cha |first1=Jongmun |last2=Cupples |first2=Alison M. |year=2010 |title=Triclocarban and triclosan biodegradation at field concentrations and the resulting leaching potentials in three agricultural soils |journal=Chemosphere |volume=81 |issue=4 |pages=494–9 |bibcode=2010Chmsp..81..494C |doi=10.1016/j.chemosphere.2010.07.040 |pmid=20705327}}</ref> These studies are also mixed in their findings regarding the persistence of chemicals such as [[triclosan]], [[triclocarban]], and other pharmaceuticals. The impact of this persistence in soils is unknown, but the link to human and land animal health is likely tied to the capacity for plants to absorb and accumulate these chemicals in their consumed tissues. Studies of this kind are in early stages, but evidence of root uptake and translocation to leaves did occur for both triclosan and triclocarban in [[Glycine max|soybeans]].<ref>{{cite journal |last1=Wu |first1=Chenxi |last2=Spongberg |first2=Alison L. |last3=Witter |first3=Jason D. |last4=Fang |first4=Min |last5=Czajkowski |first5=Kevin P. |display-authors=3 |year=2010 |title=Uptake of Pharmaceutical and Personal Care Products by Soybean Plants from Soils Applied with Biosolids and Irrigated with Contaminated Water |journal=Environmental Science & Technology |volume=44 |issue=16 |pages=6157–61 |bibcode=2010EnST...44.6157W |doi=10.1021/es1011115 |pmid=20704212}}</ref> This effect was not present in [[zea mays|corn]] when tested in a different study.<ref name="Xia_Triclocarban_2009" />

A cautionary approach to land application of biosolids has been advocated by some for regions where soils have lower capacities for toxics absorption or due to the presence of unknowns in sewage biosolids.<ref>{{cite journal |last1=Harrison |first1=Ellen Z. |last2=McBride |first2=Murray B. |last3=Bouldin |first3=David R. |year=1999 |title=Land application of sewage sludges: An appraisal of the US regulations |journal=International Journal of Environment and Pollution |volume=11 |pages=1–36 |doi=10.1504/IJEP.1999.002247 |hdl-access=free |hdl=1813/5299}}</ref><ref name="HarrisonMcBride2009">{{Cite web |last1=Harrison |first1=Ellen Z |last2=McBride |first2=Murray |date=March 2009 |title=Case for Caution Revisited: Health and Environmental Impacts of Application of Sewage Sludges to Agricultural Land |url=http://cwmi.css.cornell.edu/case.pdf |access-date=16 January 2016 |publisher=Cornell Waste Management Institute}}</ref> In 2007 the Northeast Regional Multi-State Research Committee (NEC 1001) issued conservative guidelines tailored to the soils and conditions typical of the northeastern US.<ref name="BarkerHarrisonetal2007">{{cite web |last1=Barker |first1=Allen |last2=Harrison |first2=Ellen |last3=Hay |first3=Anthony |last4=Krogmann |first4=Uta |last5=McBride |first5=Murray |last6=McDowell |first6=William |last7=Richards |first7=Brian |last8=Steenhuis |first8=Tammo |last9=Stehouwer |first9=Richard |display-authors=3 |date=April 2007 |title=Guidelines for Application of Sewage Biosolids to Agricultural Lands in the Northeastern U.S. |url=https://ecommons.cornell.edu/bitstream/handle/1813/7934/NEGuidelinesE317.pdf?sequence=1&isAllowed=y |access-date=2 June 2017 |website=[[Cornell University]]}}</ref>

Use of sewage sludge is prohibited for produce to be labeled [[USDA-certified organic]].<ref>{{cite web |title=Understanding Organic Food Labels, Benefits, and Claims |url=http://www.helpguide.org/life/organic_foods_pesticides_gmo.htm |archive-url=https://web.archive.org/web/20120109004544/http://www.helpguide.org/life/organic_foods_pesticides_gmo.htm |archive-date=9 January 2012 |access-date=2 June 2017 |website=HelpGuide}}</ref> In 2014 the United States grocery chain [[Whole Foods Market|Whole Foods]] banned produce grown in sewage sludge.<ref>{{cite news |date=23 January 2014 |title=Whole Foods Draws A Line In The Sludge |url=http://www.foodrepublic.com/2014/01/23/whole-foods-draws-line-sludge |access-date=26 February 2017 |website=Food Republic}}</ref><ref>{{cite news |last=Barclay |first=Eliza |date=21 January 2014 |title=Whole Foods Bans Produce Grown With Sludge. But Who Wins? |url=https://www.npr.org/blogs/thesalt/2014/01/17/263370333/whole-foods-bans-produce-grown-with-sludge-but-who-wins |access-date=26 February 2017 |website=[[NPR]]}}</ref>

Treated sewage sludge has been used in the UK, Europe and China agriculturally for more than 80 years, though there is increasing pressure in some countries to stop the practice of land application due to farm land contamination<ref>{{cite web |last=Guangwei |first=He |date=7 July 2014 |title=In China's Heartland, A Toxic Trail Leads from Factories to Fields to Food |url=http://e360.yale.edu/features/chinas_toxic_trail_leads_from_factories_to_food |access-date=5 June 2017 |website=[[Yale School of Forestry & Environmental Studies|Yale Environment 360]]}}</ref> and negative public opinion.<ref>{{cite web |last=Reid |first=Andy |date=21 December 2015 |title=Sewage sludge prompts outrage |url=https://www.pressreader.com/usa/sun-sentinel-broward-edition/20151221/281487865308034 |access-date=5 June 2017 |website=[[PressReader]] |publisher=[[Sun-Sentinel|Sun Sentinel]]}}</ref><ref>{{cite web |last=Godfrey |first=Miles |date=7 August 2008 |title=Outrage as 'Poohaven' sewage plant is approved |url=http://www.theargus.co.uk/news/3576502.Outrage_as__Poohaven__sewage_plant_is_approved/ |access-date=5 June 2017 |website=[[The Argus (Brighton)|The Argus]]}}</ref><ref>{{cite web |last=Richardson |first=Jill |date=4 March 2010 |title=Outrage in San Francisco: City Gives Residents 'Organic' Compost Containing Toxic Sewage Sludge |url=http://www.alternet.org/health/145904/outrage_in_san_francisco:_city_gives_away_'organic'_compost_to_residents_containing_toxic_sewage_sludge/ |access-date=5 June 2017 |website=[[AlterNet]]}}</ref> In the 1990s, there was pressure in some European countries to ban the use of sewage sludge as a fertilizer. Switzerland, Sweden, Austria, and others introduced a ban. Still, the dominant method for disposal of sewage sludge in the EU is via application to agricultural lands.<ref name=":210">{{Citation |title=COMMISSION STAFF WORKING DOCUMENT EXECUTIVE SUMMARY OF THE EVALUATION Council Directive 86/278/EEC of 12 June 1986 on the protection of the environment, and in particular of the soil, when sewage sludge is used in agriculture |date=2023 |url=https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=SWD:2023:158:FIN&qid=1684830815132 |access-date=2024-10-18 |language=en}}</ref> As of 2023, 40% of sludge produced in the EU was used on agricultural land.<ref name=":211">{{Citation |title=COMMISSION STAFF WORKING DOCUMENT EXECUTIVE SUMMARY OF THE EVALUATION Council Directive 86/278/EEC of 12 June 1986 on the protection of the environment, and in particular of the soil, when sewage sludge is used in agriculture |date=2023 |url=https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=SWD:2023:158:FIN&qid=1684830815132 |access-date=2024-10-18 |language=en}}</ref> Since the 1960s there has been cooperative activity with industry to reduce the inputs of persistent substances from factories. This has been very successful and, for example, the content of [[cadmium]] in sewage sludge in major European cities is now only 1% of what it was in 1970.<ref>{{cite book |last=Zorpas |first=Antonis A. |title=Handbook of Natural Zeolites |publisher=Bentham Science |year=2012 |isbn=978-1-60805-446-6 |editor-last1=Inglezakis |editor-first1=Vassilis J. |page=289 |chapter=Contribution of Zeolites in Sewage Sludge Composting |editor-last2=Zorpas |editor-first2=Antonis A. |chapter-url=https://books.google.com/books?id=p88zmymzTMUC&q=the+content+of+cadmium+in+sewage+sludge+in+major+European+cities+is+now+only+1%25+of+what+it+was+in+1970&pg=PA289}}</ref>

=== Transformation into products ===
Sewage sludge is an agglomeration of concentrated wastes, and therefore it contains many potentially extractable and useable components.<ref name=":6">{{Cite journal |last1=Bagheri |first1=Marzieh |last2=Bauer |first2=Torben |last3=Burgman |first3=Linus Ekman |last4=Wetterlund |first4=Elisabeth |date=2023 |title=Fifty years of sewage sludge management research: Mapping researchers' motivations and concerns |url=https://linkinghub.elsevier.com/retrieve/pii/S0301479722019855 |journal=Journal of Environmental Management |volume=325 |issue=Pt A |pages=116412 |doi=10.1016/j.jenvman.2022.116412 |pmid=36274309 |bibcode=2023JEnvM.32516412B |issn=0301-4797}}</ref> These can include using sludge to produce energy, create carbon-based components, extract [[phosphorus]] and [[nitrogen]], or make bricks or other construction materials.<ref name=":6" />

Recycling of [[phosphate]] is regarded as especially important because the phosphate industry predicts that at the current rate of extraction the economic reserves will be exhausted in 100 or at most 250 years.<ref>{{cite book |author=<!--Staff writer(s); no by-line.--> |url=https://dl.sciencesocieties.org/publications/books/articles/agronomymonogra/phosphorusagric/frontmatter |title=Phosphorus: Agriculture and the Environment |publisher=[[American Society of Agronomy|ASA]], [[Soil Science Society of America|SSSA]], CSSA |year=2005 |isbn=978-0-89118-269-6 |editor-last1=Sims |editor-first1=J. Thomas |access-date=5 June 2017 |editor-last2=Sharpley |editor-first2=Andrew N.}}</ref> Phosphate can be recovered with minimal capital expenditure as technology currently exists, but municipalities have little political will to attempt nutrient extraction, instead opting for a "take all the other stuff" mentality.<ref>{{cite web |last=Morgenschweis |first=Christa |title=Phosphorus recovery with Pearl technology |url=http://grontmij.com/pearl |archive-url=https://web.archive.org/web/20160318134353/http://grontmij.com/pearl |archive-date=18 March 2016 |access-date=5 June 2017 |website=[[Grontmij]]}}</ref>{{unreliable source?|date= June 2017}}

One potential drawback of extracting products from sludge — as opposed to land application — is that only some of the sludge is used and the rest still needs disposal.<ref name=":6" /> It can also be very expensive to develop and use appropriate technologies for extracting resources.<ref name=":6" />