Integrated chelator-based removal of toxic metals and aerobic digestion of sewage sludge

Fojkar, Barbara (author), Leštan, Domen (author)

The treatment of sewage sludge (SS) is one of the biggest challenges due to its large output and contamination with toxic metals (TMs). SS is also a potential resource for P, a strategic macronutrient in agriculture. The feasibility of integrated removal of TMs from SS by chelation and washing with ethylenediaminetetraacetate (EDTA) and SS solids reduction by aerobic digestion in bioreactors was investigated. In three consecutive SS treatment batches, an average of 70, 40 and 59% of Zn, Cu and Pb were removed. Cr was not chelated and remained in the SS. EDTA persisted during the aerobic digestion of SS and was efficiently recycled (82% on average) in the pH gradient 12.5 - 2 (ReSoil® method) and reused in the next batch. The reduction of SS solids (on average 18.4% in 6 days) was more efficient with EDTA than with the control treatment (7.4%). The integrated process also increased the concentration of plant-available P in the washed SS by an average of 1.6-fold compared to the control. EDTA induced fragmentation of SS. This resulted in a loss of SS dry matter (on average 26.1%) and total P (on average 24.6%). The novel integrated process efficiently removed TMs that chelate with EDTA, is scalable and should be compatible with current processes in wastewater treatment plants.

• Language: English
• Keywords: sewage sludge, toxic metals, phosphorus, ethylenediaminetetraacetate, aerobic digestion, ReSoil®
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: BF - Biotechnical Faculty
• Publication status: Published
• Publication version: Version of Record
• Year: 2025
• Number of pages: 9 str.
• Numbering: Vol. 495, art. 145047
• PID: 20.500.12556/RUL-167504
• UDC: 628.3:502.175
• ISSN on article: 0959-6526
• DOI: 10.1016/j.jclepro.2025.145047
• COBISS.SI-ID: 227243523
• Publication date in RUL: 25.02.2025

Record is a part of a journal

• Title: Journal of cleaner production
• Shortened title: J. clean. prod.
• Publisher: Elsevier
• ISSN: 0959-6526
• COBISS.SI-ID: 15470597

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: blato komunalnih čistilnih naprav, potencialno strupene kovine, toksične snovi, fosfor, aerobna obdelava, aerobna razgradnja, EDTA

Projects

• Funder: ARRS - Slovenian Research Agency
• Project number: J7-50152
• Name: Dekontaminirano biooglje iz blat čistilnih naprav kot učinkovito gnojilo in sredstvo za izboljšanje tal

• Funder: ARRS - Slovenian Research Agency
• Project number: P4-0085
• Name: Agroekosistemi