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

Juan Francisco Morales Arteaga (Avtor), Mojca Zupanc (Avtor), Matevž Dular (Avtor), Domen Leštan (Avtor), Anela Kaurin (Avtor)

Povzetek

Contamination with toxic metals prevents the use of sewage sludge (SS) as a soil fertilizer. Hydrodynamic cavitation, thermal microwaving, microwave-assisted alkaline, and acid hydrolysis coupled with ethylenediaminetetraacetate (EDTA) washing were tested as a method to remove toxic metals from SS. Acid hydrolysis coupled with EDTA washing was most effective and was used in a closed-loop process based on ReSoil technology. EDTA and process solutions were recycled at a pH gradient of 12.5–2, which was imposed by the addition of quicklime (CaO) and H2SO4. An average of 78%-Pb, 76%-Zn, 1%-Cu, and 17%-Cr were removed from SS in five consecutive batches. No wastewater was generated, only solid waste (40%). The EDTA lost in the process (42%) was resupplied in each batch. In a series of batches, the process solutions retained metal removal efficiency and quality. The treatment removed 70% and 23% of P and N, respectively, from SS and increased the leachability of Zn, Cu, Mn, and Fe in the washed SS by 11.7, 6.8, 1.4, and 5.2 times, respectively. Acid hydrolysis coupled with EDTA washing proved to be a technically feasible, closed-loop process but needs further development to reduce reagent, material, and nutrient loss and to reduce toxic emissions from the washed sludge.

Ključne besede

blato iz čistilnih naprav;strupene kovine;EDTA;čiščenje;mikrovalovna pečica;kavitacija;fosfor;sewage sludge;toxic metals;hydrolysis;microwaves;cavitation;phosphorus;

Podatki

Jezik:	Angleški jezik
Leto izida:	2023
Tipologija:	1.01 - Izvirni znanstveni članek
Organizacija:	UL BF - Biotehniška fakulteta
UDK:	502.1
COBISS:	140480003
ISSN:	1660-4601
Št. ogledov:	30
Št. prenosov:	5
Ocena:	0 (0 glasov)
Metapodatki:

Ostali podatki

Sekundarni jezik:	Slovenski jezik
Sekundarne ključne besede:	blato iz čistilnih naprav;strupene kovine;EDTA;čiščenje;mikrovalovna pečica;kavitacija;fosfor;
Vrsta dela (COBISS):	Članek v reviji
Strani:	13 str.
Letnik:	ǂVol. ǂ20
Zvezek:	ǂiss. ǂ3, art. 2544
Čas izdaje:	2023
DOI:	10.3390/ijerph20032544
ID:	17916532