Simultaneous aerobic stabilisation of sewage sludge and chelator-assisted removal of toxic metals in a closed-loop process

Fojkar, Barbara (avtor), Leštan, Domen (avtor)

Sewage sludge is a valuable source of phosphorus but contains toxic metals that hinder its use as fertilizer. We present a novel process that simultaneously stabilises sludge through post-aerobic digestion (12 days, pH 5.8–7.6, solid-to-liquid ratio 1:25 (dry w/v)) and removes toxic metals using ethylenediaminetetraacetate (EDTA, 10 mM). On average, 74.4% of EDTA was successfully recycled by alkalinization of process solution with quicklime (CaO) to pH 12.5 and reused in subsequent batches. Chelator losses were compensated by the addition of Na-EDTA. Toxic metals, along with excess Ca and Na, were effectively removed from the recycled process solution, enabling closed-loop operation without wastewater generation. During five consecutive batches, total solids in the sludge were reduced by an average of 23.2%, and 74, 61, 26, and 43% of Zn, Cu, Cr, and Pb, respectively, were removed. The leaching of residual toxic metals from the stabilised and decontaminated sludge was further reduced by 55–88% through the addition of zero-valent iron (3% dry w/w). The process also increased the phosphorus concentration in the sludge by 15% and improved its phytoavailability up to 1.8-fold

• Jezik: Angleški jezik
• Ključne besede: sewage sludge, phosphorous, toxic metals, EDTA, aerobic stabilization, closed process
• Vrsta gradiva: Članek v reviji
• Tipologija: 1.01 - Izvirni znanstveni članek
• Organizacija: BF - Biotehniška fakulteta
• Status publikacije: Objavljeno
• Različica publikacije: Objavljena publikacija
• Leto izida: 2025
• Št. strani: Str. 1-15
• Številčenje: Vol. 288, art. 124653
• PID: 20.500.12556/RUL-174623
• UDK: 628.3:502.175
• ISSN pri članku: 1879-2448
• DOI: 10.1016/j.watres.2025.124653
• COBISS.SI-ID: 251096579
• Datum objave v RUL: 07.10.2025

Gradivo je del revije

• Naslov: Water Research
• Založnik: Pergamon
• ISSN: 1879-2448
• COBISS.SI-ID: 23055365

Licence

• Licenca: CC BY-NC 4.0, Creative Commons Priznanje avtorstva-Nekomercialno 4.0 Mednarodna
• Povezava: http://creativecommons.org/licenses/by-nc/4.0/deed.sl
• Opis: Licenca Creative Commons, ki prepoveduje komercialno uporabo, vendar uporabniki ne rabijo upravljati materialnih avtorskih pravic na izpeljanih delih z enako licenco.

Sekundarni jezik

• Jezik: Slovenski jezik
• Ključne besede: blato komunalnih čistilnih naprav, fosfor, EDTA, aerobna stabilizacija, zaprti proces

Projekti

• Financer: ARIS - Javna agencija za znanstvenoraziskovalno in inovacijsko dejavnost Republike Slovenije
• Številka projekta: J7-50152
• Naslov: De-kontaminirano bio-oglje iz blat čistilnih naprav kot učinkovito gnojilo in sredstvo za izboljšanje tal

• Financer: ARIS - Javna agencija za znanstvenoraziskovalno in inovacijsko dejavnost Republike Slovenije
• Številka projekta: P4-0085
• Naslov: Agroekosistemi