Editing Sewage sludge (section)

== Disposal ==

===Landfill===
Sewage sludge deposition in landfills can circulate human-virulent species of ''[[Cryptosporidium]] and Giardia'' pathogens. [[Sonication]] and quicklime stabilization are most effective in inactivation of these pathogens; microwave energy disintegration and top-soil stabilization were less effective.<ref>{{Cite journal|last1=Graczyk|first1=Thaddeus K.|last2=Kacprzak|first2=Malgorzata|last3=Neczaj|first3=Ewa|last4=Tamang|first4=Leena|last5=Graczyk|first5=Halshka|last6=Lucy|first6=Frances E.|last7=Girouard|first7=Autumn S.|display-authors=3|date=2008-01-01|title=Occurrence of Cryptosporidium and Giardia in sewage sludge and solid waste landfill leachate and quantitative comparative analysis of sanitization treatments on pathogen inactivation|journal=Environmental Research|volume=106|issue=1|pages=27–33|doi=10.1016/j.envres.2007.05.005|pmid=17585898|bibcode=2008ER....106...27G|issn=0013-9351}}</ref>
A Texas county has launched a first-of-its-kind criminal investigation into waste management giant Synagro over PFAS-contaminated sewage sludge it is selling to Texas farmers as a cheap alternative to fertilizer.
<ref>{{Cite news |last=Perkins |first=Tom |date=2024-03-01 |title=Texas farmers claim company sold them PFAS-contaminated sludge that killed livestock |url=https://www.theguardian.com/environment/2024/mar/01/texas-farmers-pfas-killed-livestock |access-date=2024-11-21 |work=The Guardian |language=en-GB |issn=0261-3077}}</ref>  

As of 2023, 11% of sludge produced in the EU was disposed of in landfills.<ref name=":27">{{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> The EU is attempting to phase out the disposal of sludge in landfills.<ref name=":29">{{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>

===Ocean dumping===
It used to be common practice to dump sewage sludge into the ocean, however, this practice has stopped in many nations due to environmental concerns as well to domestic and international laws and treaties.<ref>{{Cite web|url=https://www.epa.gov/ocean-dumping/learn-about-ocean-dumping|title=Learn about Ocean Dumping|last=US EPA|first=OW|date=2015-07-10|website=US EPA|access-date=2019-11-12}}</ref> Ronald Reagan signed the law that prohibited ocean dumping as a means of disposal of sewage sludge in the US in 1988.<ref>{{Cite web|last=US EPA|first=OA|title=EPA History: Ocean Dumping Ban Act of 1988|url=https://archive.epa.gov/epa/aboutepa/epa-history-ocean-dumping-ban-act-1988.html|access-date=2022-01-12|website=archive.epa.gov|language=en}}</ref>

=== Incineration ===
Sludge can also be incinerated in [[sludge incineration]] plants which comes with its own set of environmental concerns (air pollution, disposal of the ash). [[Pyrolysis]] of the sludge to create [[syngas]] and potentially [[biochar]] is possible, as is combustion of biofuel produced from drying sewage sludge or [[incineration]] in a [[waste-to-energy]] facility for direct production of [[electricity]] and steam for [[district heating]] or industrial uses.

Thermal processes can greatly reduce the volume of the sludge, as well as achieve remediation of all or some of the biological concerns. Direct waste-to-energy incineration and complete combustion systems (such as the Gate 5 Energy System) will require multi-step cleaning of the exhaust gas, to ensure no hazardous substances are released. In addition, the ash produced by incineration or incomplete combustion processes (such as fluidized-bed dryers) may be difficult to use without subsequent treatment due to high heavy metal content; solutions to this include leaching of the ashes to remove heavy metals or in the case of ash produced in a complete-combustion process, or with biochar produced from a pyrolytic process, the heavy metals may be fixed in place and the ash material readily usable as a LEEDs preferred additive to concrete or asphalt.<ref name="USFA - SludgeAlternativeUses">{{cite journal|title= Sewage Sludge as Raw-Material in Asphalt Mixtures|year= 2013|last1= Ingunza|first1= Maria del Pilar Durante|last2= Júnior|first2= Olavo Francisco dos Santos|last3= Medeiros|first3= Sayonara Andrade|journal= Advanced Materials Research|volume= 664|pages= 638–643|editor-last1= Wu|editor-first1= Yun|editor-last2= Wu|editor-first2= Yijin|doi= 10.4028/www.scientific.net/AMR.664.638|s2cid= 137163083}}</ref>
Examples of other ways to use dried sewage sludge as an energy resource include the Gate 5 Energy System, an innovative process to power a steam turbine using heat from burning milled and dried sewage sludge, or combining dried sewage sludge with coal in [[coal-fired power station]]s. In both cases this allows for production of electricity with less carbon-dioxide emissions than conventional coal-fired power stations.<ref>{{cite journal |doi=10.1021/es052181g |title=Biosolids—A Fuel or a Waste? An Integrated Appraisal of Five Co-combustion Scenarios with Policy Analysis |year=2006 |last1=Cartmell |first1=Elise |last2=Gostelow |first2=Peter |last3=Riddell-Black |first3=Drusilla |last4=Simms |first4=Nigel |last5=Oakey |first5=John |last6=Morris |first6=Joe |last7=Jeffrey |first7=Paul |last8=Howsam |first8=Peter |last9=Pollard |first9=Simon J. |display-authors=3|journal=Environmental Science & Technology |volume=40 |issue=3 |pages=649–58 |pmid=16509299 |bibcode=2006EnST...40..649C |doi-access= }}</ref> 

As of 2023, 27% of sludge produced in the EU was incinerated.<ref name=":28">{{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>