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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| Format: | Article |
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MDPI AG
2021-12-01
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| Series: | Microorganisms |
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| Online Access: | https://www.mdpi.com/2076-2607/9/12/2523 |
| _version_ | 1797502330070892544 |
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| author | Barbara Tonanzi Agata Gallipoli Andrea Gianico Maria Cristina Annesini Camilla Maria Braguglia |
| author_facet | Barbara Tonanzi Agata Gallipoli Andrea Gianico Maria Cristina Annesini Camilla Maria Braguglia |
| author_sort | Barbara Tonanzi |
| collection | DOAJ |
| 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<sup>−1</sup>d<sup>−1</sup>) 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. <i>Bacteroidetes</i>, <i>Firmicutes</i>, and <i>Chloroflexi</i> were the most abundant phyla observed, indicating that the short HRT imposed on the systems favoured the hydrolytic and acidogenic activity of these taxa. |
| first_indexed | 2024-03-10T03:32:36Z |
| format | Article |
| id | doaj.art-b3d5ced63b9a440ebc0efb0dd4876673 |
| institution | Directory Open Access Journal |
| issn | 2076-2607 |
| language | English |
| last_indexed | 2024-03-10T03:32:36Z |
| publishDate | 2021-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Microorganisms |
| spelling | doaj.art-b3d5ced63b9a440ebc0efb0dd48766732023-11-23T09:39:15ZengMDPI AGMicroorganisms2076-26072021-12-01912252310.3390/microorganisms9122523Insights into the Anaerobic Hydrolysis Process for Extracting Embedded EPS and Metals from Activated SludgeBarbara Tonanzi0Agata Gallipoli1Andrea Gianico2Maria Cristina Annesini3Camilla Maria Braguglia4Water Research Institute, National Research Council of Italy, IRSA-CNR, Area della Ricerca RM1, Via Salaria km 29.300, Monterotondo, 00015 Roma, ItalyWater Research Institute, National Research Council of Italy, IRSA-CNR, Area della Ricerca RM1, Via Salaria km 29.300, Monterotondo, 00015 Roma, ItalyWater Research Institute, National Research Council of Italy, IRSA-CNR, Area della Ricerca RM1, Via Salaria km 29.300, Monterotondo, 00015 Roma, ItalyDipartimento di Ingegneria Chimica, Università degli Studi di Roma “La Sapienza”, 00184 Rome, ItalyWater Research Institute, National Research Council of Italy, IRSA-CNR, Area della Ricerca RM1, Via Salaria km 29.300, Monterotondo, 00015 Roma, ItalyThe 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<sup>−1</sup>d<sup>−1</sup>) 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. <i>Bacteroidetes</i>, <i>Firmicutes</i>, and <i>Chloroflexi</i> were the most abundant phyla observed, indicating that the short HRT imposed on the systems favoured the hydrolytic and acidogenic activity of these taxa.https://www.mdpi.com/2076-2607/9/12/2523anaerobic hydrolysisextracellular polymeric substanceswaste activated sludgetoxic metalshigh throughput 16S rRNA gene sequencingmicrobial communities |
| spellingShingle | Barbara Tonanzi Agata Gallipoli Andrea Gianico Maria Cristina Annesini Camilla Maria Braguglia Insights into the Anaerobic Hydrolysis Process for Extracting Embedded EPS and Metals from Activated Sludge Microorganisms anaerobic hydrolysis extracellular polymeric substances waste activated sludge toxic metals high throughput 16S rRNA gene sequencing microbial communities |
| 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 | anaerobic hydrolysis extracellular polymeric substances waste activated sludge toxic metals high throughput 16S rRNA gene sequencing microbial communities |
| url | https://www.mdpi.com/2076-2607/9/12/2523 |
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