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Insights into the Anaerobic Hydrolysis Process for Extracting Embedded EPS and Metals from Activated Sludge

The amount of sewage sludge generated from wastewater treatment plants globally is unavoidably increasing. In recent years, significant attention has been paid to the biorefinery concept based on the conversion of waste streams to high-value products, material, and energy by microorganisms. However,...

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Autores principales: Tonanzi, Barbara, Gallipoli, Agata, Gianico, Andrea, Annesini, Maria Cristina, Braguglia, Camilla Maria
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8703515/
https://www.ncbi.nlm.nih.gov/pubmed/34946124
http://dx.doi.org/10.3390/microorganisms9122523
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author Tonanzi, Barbara
Gallipoli, Agata
Gianico, Andrea
Annesini, Maria Cristina
Braguglia, Camilla Maria
author_facet Tonanzi, Barbara
Gallipoli, Agata
Gianico, Andrea
Annesini, Maria Cristina
Braguglia, Camilla Maria
author_sort Tonanzi, Barbara
collection PubMed
description The amount of sewage sludge generated from wastewater treatment plants globally is unavoidably increasing. In recent years, significant attention has been paid to the biorefinery concept based on the conversion of waste streams to high-value products, material, and energy by microorganisms. However, one of the most significant challenges in the field is the possibility of controlling the microorganisms’ pathways in the anaerobic environment. This study investigated two different anaerobic fermentation tests carried out with real waste activated sludge at high organic loading rate (10 g COD L(−1)d(−1)) and short hydraulic retention time (HRT) to comprehensively understand whether this configuration enhances extracellular polymeric substance (EPS) and metal solubilisation. The quantity of EPS recovered increased over time, while the chemical oxygen demand to EPS ratio remained in the range 1.31–1.45. Slightly acidic conditions and sludge floc disintegration promoted EPS matrix disruption and release, combined with the solubilisation of organically bound toxic metals, such as As, Be, Cu, Ni, V, and Zn, thereby increasing the overall metal removal efficiency due to the action of hydrolytic microorganisms. Bacteroidetes, Firmicutes, and Chloroflexi were the most abundant phyla observed, indicating that the short HRT imposed on the systems favoured the hydrolytic and acidogenic activity of these taxa.
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spelling pubmed-87035152021-12-25 Insights into the Anaerobic Hydrolysis Process for Extracting Embedded EPS and Metals from Activated Sludge Tonanzi, Barbara Gallipoli, Agata Gianico, Andrea Annesini, Maria Cristina Braguglia, Camilla Maria Microorganisms Article The amount of sewage sludge generated from wastewater treatment plants globally is unavoidably increasing. In recent years, significant attention has been paid to the biorefinery concept based on the conversion of waste streams to high-value products, material, and energy by microorganisms. However, one of the most significant challenges in the field is the possibility of controlling the microorganisms’ pathways in the anaerobic environment. This study investigated two different anaerobic fermentation tests carried out with real waste activated sludge at high organic loading rate (10 g COD L(−1)d(−1)) and short hydraulic retention time (HRT) to comprehensively understand whether this configuration enhances extracellular polymeric substance (EPS) and metal solubilisation. The quantity of EPS recovered increased over time, while the chemical oxygen demand to EPS ratio remained in the range 1.31–1.45. Slightly acidic conditions and sludge floc disintegration promoted EPS matrix disruption and release, combined with the solubilisation of organically bound toxic metals, such as As, Be, Cu, Ni, V, and Zn, thereby increasing the overall metal removal efficiency due to the action of hydrolytic microorganisms. Bacteroidetes, Firmicutes, and Chloroflexi were the most abundant phyla observed, indicating that the short HRT imposed on the systems favoured the hydrolytic and acidogenic activity of these taxa. MDPI 2021-12-06 /pmc/articles/PMC8703515/ /pubmed/34946124 http://dx.doi.org/10.3390/microorganisms9122523 Text en © 2021 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
Tonanzi, Barbara
Gallipoli, Agata
Gianico, Andrea
Annesini, Maria Cristina
Braguglia, Camilla Maria
Insights into the Anaerobic Hydrolysis Process for Extracting Embedded EPS and Metals from Activated Sludge
title Insights into the Anaerobic Hydrolysis Process for Extracting Embedded EPS and Metals from Activated Sludge
title_full Insights into the Anaerobic Hydrolysis Process for Extracting Embedded EPS and Metals from Activated Sludge
title_fullStr Insights into the Anaerobic Hydrolysis Process for Extracting Embedded EPS and Metals from Activated Sludge
title_full_unstemmed Insights into the Anaerobic Hydrolysis Process for Extracting Embedded EPS and Metals from Activated Sludge
title_short Insights into the Anaerobic Hydrolysis Process for Extracting Embedded EPS and Metals from Activated Sludge
title_sort insights into the anaerobic hydrolysis process for extracting embedded eps and metals from activated sludge
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8703515/
https://www.ncbi.nlm.nih.gov/pubmed/34946124
http://dx.doi.org/10.3390/microorganisms9122523
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