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Removal of Toxic Metals from Sewage Sludge by Acid Hydrolysis Coupled with EDTA Washing in a Closed-Loop Process

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....

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Autores principales: Morales Arteaga, Juan Francisco, Zupanc, Mojca, Dular, Matevž, Lestan, Domen, Kaurin, Anela
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9916202/
https://www.ncbi.nlm.nih.gov/pubmed/36767910
http://dx.doi.org/10.3390/ijerph20032544
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author Morales Arteaga, Juan Francisco
Zupanc, Mojca
Dular, Matevž
Lestan, Domen
Kaurin, Anela
author_facet Morales Arteaga, Juan Francisco
Zupanc, Mojca
Dular, Matevž
Lestan, Domen
Kaurin, Anela
author_sort Morales Arteaga, Juan Francisco
collection PubMed
description 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 H(2)SO(4). 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.
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spelling pubmed-99162022023-02-11 Removal of Toxic Metals from Sewage Sludge by Acid Hydrolysis Coupled with EDTA Washing in a Closed-Loop Process Morales Arteaga, Juan Francisco Zupanc, Mojca Dular, Matevž Lestan, Domen Kaurin, Anela Int J Environ Res Public Health Article 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 H(2)SO(4). 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. MDPI 2023-01-31 /pmc/articles/PMC9916202/ /pubmed/36767910 http://dx.doi.org/10.3390/ijerph20032544 Text en © 2023 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Morales Arteaga, Juan Francisco
Zupanc, Mojca
Dular, Matevž
Lestan, Domen
Kaurin, Anela
Removal of Toxic Metals from Sewage Sludge by Acid Hydrolysis Coupled with EDTA Washing in a Closed-Loop Process
title Removal of Toxic Metals from Sewage Sludge by Acid Hydrolysis Coupled with EDTA Washing in a Closed-Loop Process
title_full Removal of Toxic Metals from Sewage Sludge by Acid Hydrolysis Coupled with EDTA Washing in a Closed-Loop Process
title_fullStr Removal of Toxic Metals from Sewage Sludge by Acid Hydrolysis Coupled with EDTA Washing in a Closed-Loop Process
title_full_unstemmed Removal of Toxic Metals from Sewage Sludge by Acid Hydrolysis Coupled with EDTA Washing in a Closed-Loop Process
title_short Removal of Toxic Metals from Sewage Sludge by Acid Hydrolysis Coupled with EDTA Washing in a Closed-Loop Process
title_sort removal of toxic metals from sewage sludge by acid hydrolysis coupled with edta washing in a closed-loop process
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9916202/
https://www.ncbi.nlm.nih.gov/pubmed/36767910
http://dx.doi.org/10.3390/ijerph20032544
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