Enhanced sludge solubilization and dewaterability by synergistic effects of nitrite and freezing
In this study, nitrite was added into sludge during freezing process to evaluate its role in waste activated sludge (WAS) solubilization and effect on sludge dewatering characteristics. The results showed that the introduction of 100 mg L−1 of nitrite could increase dissolved organic carbon (DOC) co...
| Main Authors: | , , , , |
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| Other Authors: | |
| Format: | Journal Article |
| Language: | English |
| Published: |
2018
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| Online Access: | https://hdl.handle.net/10356/87730 http://hdl.handle.net/10220/45478 |
| _version_ | 1811684983524294656 |
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| author | Sun, Faqian Xiao, Keke Zhu, Wenyu Withanage, Nipuna Zhou, Yan |
| author2 | Advanced Environmental Biotechnology Centre (AEBC) |
| author_facet | Advanced Environmental Biotechnology Centre (AEBC) Sun, Faqian Xiao, Keke Zhu, Wenyu Withanage, Nipuna Zhou, Yan |
| author_sort | Sun, Faqian |
| collection | NTU |
| description | In this study, nitrite was added into sludge during freezing process to evaluate its role in waste activated sludge (WAS) solubilization and effect on sludge dewatering characteristics. The results showed that the introduction of 100 mg L−1 of nitrite could increase dissolved organic carbon (DOC) concentration from 29.5 to 48.8 mg DOC g−1 VSS under freezing conditions. More DOC was released with the increase of nitrite concentration. Freezing temperature, or freezing speed, also played a role in sludge solubilization. It was found that some readily-biodegradable low molecular weight (LMW) compounds, e.g. LMW protein, LMW polysaccharide, LMW neutrals, building blocks and LMW acids, were mainly released during the freezing process with the presence of nitrite. Interestingly, nitrite could also improve the sludge filterability at the lower nitrite concentration as a result of the increased sludge particle size. However, electrolytes (sodium nitrite) addition effects may mask such enhancement when nitrite concentration was high (800 mg L−1). The rheological characteristics of sludge could be well modeled by Herchel-Bulkley model and the introduction of nitrite into freezing process further increased sludge flowability and decreased sludge viscosity. These results indicated that freezing with the presence of suitable concentration of nitrite could promote sludge solubilization and dewaterability. As such, good liquid and solid separation can be achieved with the recovery of liquid stream as carbon source. |
| first_indexed | 2024-10-01T04:37:18Z |
| format | Journal Article |
| id | ntu-10356/87730 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2024-10-01T04:37:18Z |
| publishDate | 2018 |
| record_format | dspace |
| spelling | ntu-10356/877302022-07-29T01:18:00Z Enhanced sludge solubilization and dewaterability by synergistic effects of nitrite and freezing Sun, Faqian Xiao, Keke Zhu, Wenyu Withanage, Nipuna Zhou, Yan Advanced Environmental Biotechnology Centre (AEBC) Nanyang Environment and Water Research Institute Waste Activated Sludge Freezing In this study, nitrite was added into sludge during freezing process to evaluate its role in waste activated sludge (WAS) solubilization and effect on sludge dewatering characteristics. The results showed that the introduction of 100 mg L−1 of nitrite could increase dissolved organic carbon (DOC) concentration from 29.5 to 48.8 mg DOC g−1 VSS under freezing conditions. More DOC was released with the increase of nitrite concentration. Freezing temperature, or freezing speed, also played a role in sludge solubilization. It was found that some readily-biodegradable low molecular weight (LMW) compounds, e.g. LMW protein, LMW polysaccharide, LMW neutrals, building blocks and LMW acids, were mainly released during the freezing process with the presence of nitrite. Interestingly, nitrite could also improve the sludge filterability at the lower nitrite concentration as a result of the increased sludge particle size. However, electrolytes (sodium nitrite) addition effects may mask such enhancement when nitrite concentration was high (800 mg L−1). The rheological characteristics of sludge could be well modeled by Herchel-Bulkley model and the introduction of nitrite into freezing process further increased sludge flowability and decreased sludge viscosity. These results indicated that freezing with the presence of suitable concentration of nitrite could promote sludge solubilization and dewaterability. As such, good liquid and solid separation can be achieved with the recovery of liquid stream as carbon source. Accepted version 2018-08-06T07:27:55Z 2019-12-06T16:48:08Z 2018-08-06T07:27:55Z 2019-12-06T16:48:08Z 2018 Journal Article Sun, F., Xiao, K., Zhu, W., Withanage, N., & Zhou, Y. (2018). Enhanced sludge solubilization and dewaterability by synergistic effects of nitrite and freezing. Water Research, 130, 208-214. 0043-1354 https://hdl.handle.net/10356/87730 http://hdl.handle.net/10220/45478 10.1016/j.watres.2017.11.066 en Water Research © 2017 Elsevier Ltd. This is the author created version of a work that has been peer reviewed and accepted for publication by Water Research, Elsevier Ltd. It incorporates referee’s comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is available at: [http://dx.doi.org/10.1016/j.watres.2017.11.066]. 30 p. application/pdf |
| spellingShingle | Waste Activated Sludge Freezing Sun, Faqian Xiao, Keke Zhu, Wenyu Withanage, Nipuna Zhou, Yan Enhanced sludge solubilization and dewaterability by synergistic effects of nitrite and freezing |
| title | Enhanced sludge solubilization and dewaterability by synergistic effects of nitrite and freezing |
| title_full | Enhanced sludge solubilization and dewaterability by synergistic effects of nitrite and freezing |
| title_fullStr | Enhanced sludge solubilization and dewaterability by synergistic effects of nitrite and freezing |
| title_full_unstemmed | Enhanced sludge solubilization and dewaterability by synergistic effects of nitrite and freezing |
| title_short | Enhanced sludge solubilization and dewaterability by synergistic effects of nitrite and freezing |
| title_sort | enhanced sludge solubilization and dewaterability by synergistic effects of nitrite and freezing |
| topic | Waste Activated Sludge Freezing |
| url | https://hdl.handle.net/10356/87730 http://hdl.handle.net/10220/45478 |
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