Editing Sewage sludge (section)

=== 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" />