Removal of toxic metals from sewage sludge by EDTA in a closed-loop washing process

Morales Arteaga, Juan Francisco (avtor), Kaurin, Anela (avtor), Leštan, Domen (avtor)

Sewage sludge (SS) is a potential resource for P and other nutrients, but often contaminated with metals. SS containing Pb-102, Zn-968, Cu-267, Cr-101, Mn-222, and Fe-8374 mg kg$^{-1}$ was washed in a batch process for 1 h with a recycled washing solution containing 50 mmol L$^{-1}$ of recycled EDTA and 50 mmol L$^{-1}$ H$_2$SO$_4$, solid/liquid ratio 1/7 (w/V). After solid/liquid separation, the washed SS was further rinsed 3-times with cleansed recycled solutions. EDTA and process solutions were recycled/cleansed in a pH gradient of 12.5–2.0 imposed by addition of CaO and H$_2$SO$_4$ (the ReSoil® method). EDTA, recycled as ineffective Ca-EDTA, was activated by capturing Ca with H$_2$SO$_4$. The process was closed-looped, no wastewater was generated, solid waste was centrifuged away. 10 consecutive SS washing batches preserved the quality of the process solutions. Metals were mainly removed from the SS organic fraction, the average removal was Pb-35, Zn-59, Cu-60, Cr-19, Mn-25, and Fe-1%. Washing reduced the leachability of Cu and Cr from SS by 13.4 and 3.5 times, but increased the leachability of Pb, Zn, Mn, and Fe by 2.5, 3.8, 1.9, and 1.6 times, respectively. Metal concentrations in the leachates were below the limits stipulated as hazardous. The content of accessible P and K in washed SS decreased by 24 and 45%, and the total N decreased by 10%. Overall, the results prove the feasibility of the novel SS washing process.

• Jezik: Angleški jezik
• Ključne besede: potential toxic elements, toxic metals, soil washing, chelating agents, contaminated soil, EDTA, toxic emissions, phosphorus, sewage sludge
• Vrsta gradiva: Članek v reviji
• Tipologija: 1.01 - Izvirni znanstveni članek
• Organizacija: BF - Biotehniška fakulteta
• Status publikacije: Objavljeno
• Različica publikacije: Objavljena publikacija
• Leto izida: 2022
• Št. strani: 9 str.
• Številčenje: Vol. 307, pt. 2, art. 135917
• PID: 20.500.12556/RUL-140919
• UDK: 502.1
• ISSN pri članku: 0045-6535
• DOI: 10.1016/j.chemosphere.2022.135917
• COBISS.SI-ID: 122208003
• Datum objave v RUL: 21.09.2022

Gradivo je del revije

• Naslov: Chemosphere
• Skrajšan naslov: Chemosphere
• Založnik: Elsevier
• ISSN: 0045-6535
• COBISS.SI-ID: 25213696

Licence

• Licenca: CC BY 4.0, Creative Commons Priznanje avtorstva 4.0 Mednarodna
• Povezava: http://creativecommons.org/licenses/by/4.0/deed.sl
• Opis: To je standardna licenca Creative Commons, ki daje uporabnikom največ možnosti za nadaljnjo uporabo dela, pri čemer morajo navesti avtorja.

Sekundarni jezik

• Jezik: Slovenski jezik
• Ključne besede: toksične kovine, potencialno škodljivi elementi, EDTA, pranje tal, onesnaženost tal, remediacija tal

Projekti

• Financer: ARRS - Agencija za raziskovalno dejavnost Republike Slovenije
• Številka projekta: J7-2601
• Naslov: Metoda dekontaminacije aktivnih blat in njihovih produktov za njihovo trajnostno uporabo kot fosfatna gnojila

• Financer: ARRS - Agencija za raziskovalno dejavnost Republike Slovenije
• Številka projekta: P4-0085
• Naslov: Agroekosistemi