The effectiveness of divalent cation addition for highly saline activated sludge cultures: Influence of monovalent/divalent ratio and specific cations
<p>Saline wastewaters are prevalent in various industries and pose challenges to stable biological treatment. Increasing monovalent cation concentrations are commonly reported to deteriorate treatment and settling performance, while divalent cations can enhance flocculation and settling. Howev...
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2021
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| author | Raghavendran Sivasubramanian (16931775) |
| author2 | Guang-hao Chen (16931778) Hamish Robert Mackey (16931781) |
| author2_role | author author |
| author_facet | Raghavendran Sivasubramanian (16931775) Guang-hao Chen (16931778) Hamish Robert Mackey (16931781) |
| author_role | author |
| dc.creator.none.fl_str_mv | Raghavendran Sivasubramanian (16931775) Guang-hao Chen (16931778) Hamish Robert Mackey (16931781) |
| dc.date.none.fl_str_mv | 2021-07-01T00:00:00Z |
| dc.identifier.none.fl_str_mv | 10.1016/j.chemosphere.2021.129864 |
| dc.relation.none.fl_str_mv | https://figshare.com/articles/journal_contribution/The_effectiveness_of_divalent_cation_addition_for_highly_saline_activated_sludge_cultures_Influence_of_monovalent_divalent_ratio_and_specific_cations/24083172 |
| dc.rights.none.fl_str_mv | CC BY 4.0 info:eu-repo/semantics/openAccess |
| dc.subject.none.fl_str_mv | Engineering Chemical engineering Environmental engineering Environmental sciences Pollution and contamination Calcium Magnesium Potassium Salinity Flocculation Biological wastewater treatment |
| dc.title.none.fl_str_mv | The effectiveness of divalent cation addition for highly saline activated sludge cultures: Influence of monovalent/divalent ratio and specific cations |
| dc.type.none.fl_str_mv | Text Journal contribution info:eu-repo/semantics/publishedVersion text contribution to journal |
| description | <p>Saline wastewaters are prevalent in various industries and pose challenges to stable biological treatment. Increasing monovalent cation concentrations are commonly reported to deteriorate treatment and settling performance, while divalent cations can enhance flocculation and settling. However, many previous studies were performed at relatively low salinities and reports conflict on whether concentrations of monovalent cations, divalent cations, or their ratio (M/D) are most critical. This study investigates whether addition of divalent cations shows the same benefits at high salinity (~40 g NaCl.L<sup>-1</sup> ) and whether divalent ion concentration or M/D is a better predictor of enhancement. Nine sequencing batch reactors were operated at 0.8 M NaCl or KCl monovalent salt concentration, and the concentration of divalent cations (Ca<sup>2+</sup> and Mg<sup>2+</sup>) was varied. M/D was found to be the critical factor that consistently influenced sludge characteristics. It was particularly important in describing hydrophobicity, sludge volume index (SVI) and specific oxygen uptake rate (SOUR), with r<sub>partial </sub>of 0.879, 0.971 and 0.966 respectively in models that had an r<sup>2</sup><sub>adj</sub> greater than 0.93. Lower M/D also increased biomass concentrations and reduced extracellular polysaccharides, the latter which in turn correlated strongly with many shape and surface charge measures. The specific monovalent salt (Na<sup>+</sup> or K<sup>+</sup>) influenced treatment performance, biomass concentrations, hydrophobicity, SOUR, extracellular protein and SVI. The specific divalent cation was only important in describing SVI, where Mg<sup>2+</sup> was beneficial. Overall, this study shows that addition of divalent cations can greatly benefit high salinity activated sludge systems by improving the sludge structure, settling and organic removal.</p> <h2>Other Information</h2> <p>Published in: Chemosphere<br> License: <a href="http://creativecommons.org/licenses/by/4.0/" target="_blank">http://creativecommons.org/licenses/by/4.0/</a><br> See article on publisher's website: <a href="https://dx.doi.org/10.1016/j.chemosphere.2021.129864" target="_blank">https://dx.doi.org/10.1016/j.chemosphere.2021.129864</a></p> |
| eu_rights_str_mv | openAccess |
| id | Manara2_39b874537040c186d36c64dc85544039 |
| identifier_str_mv | 10.1016/j.chemosphere.2021.129864 |
| network_acronym_str | Manara2 |
| network_name_str | Manara2 |
| oai_identifier_str | oai:figshare.com:article/24083172 |
| publishDate | 2021 |
| repository.mail.fl_str_mv | |
| repository.name.fl_str_mv | |
| repository_id_str | |
| rights_invalid_str_mv | CC BY 4.0 |
| spelling | The effectiveness of divalent cation addition for highly saline activated sludge cultures: Influence of monovalent/divalent ratio and specific cationsRaghavendran Sivasubramanian (16931775)Guang-hao Chen (16931778)Hamish Robert Mackey (16931781)EngineeringChemical engineeringEnvironmental engineeringEnvironmental sciencesPollution and contaminationCalciumMagnesiumPotassiumSalinityFlocculationBiological wastewater treatment<p>Saline wastewaters are prevalent in various industries and pose challenges to stable biological treatment. Increasing monovalent cation concentrations are commonly reported to deteriorate treatment and settling performance, while divalent cations can enhance flocculation and settling. However, many previous studies were performed at relatively low salinities and reports conflict on whether concentrations of monovalent cations, divalent cations, or their ratio (M/D) are most critical. This study investigates whether addition of divalent cations shows the same benefits at high salinity (~40 g NaCl.L<sup>-1</sup> ) and whether divalent ion concentration or M/D is a better predictor of enhancement. Nine sequencing batch reactors were operated at 0.8 M NaCl or KCl monovalent salt concentration, and the concentration of divalent cations (Ca<sup>2+</sup> and Mg<sup>2+</sup>) was varied. M/D was found to be the critical factor that consistently influenced sludge characteristics. It was particularly important in describing hydrophobicity, sludge volume index (SVI) and specific oxygen uptake rate (SOUR), with r<sub>partial </sub>of 0.879, 0.971 and 0.966 respectively in models that had an r<sup>2</sup><sub>adj</sub> greater than 0.93. Lower M/D also increased biomass concentrations and reduced extracellular polysaccharides, the latter which in turn correlated strongly with many shape and surface charge measures. The specific monovalent salt (Na<sup>+</sup> or K<sup>+</sup>) influenced treatment performance, biomass concentrations, hydrophobicity, SOUR, extracellular protein and SVI. The specific divalent cation was only important in describing SVI, where Mg<sup>2+</sup> was beneficial. Overall, this study shows that addition of divalent cations can greatly benefit high salinity activated sludge systems by improving the sludge structure, settling and organic removal.</p> <h2>Other Information</h2> <p>Published in: Chemosphere<br> License: <a href="http://creativecommons.org/licenses/by/4.0/" target="_blank">http://creativecommons.org/licenses/by/4.0/</a><br> See article on publisher's website: <a href="https://dx.doi.org/10.1016/j.chemosphere.2021.129864" target="_blank">https://dx.doi.org/10.1016/j.chemosphere.2021.129864</a></p>2021-07-01T00:00:00ZTextJournal contributioninfo:eu-repo/semantics/publishedVersiontextcontribution to journal10.1016/j.chemosphere.2021.129864https://figshare.com/articles/journal_contribution/The_effectiveness_of_divalent_cation_addition_for_highly_saline_activated_sludge_cultures_Influence_of_monovalent_divalent_ratio_and_specific_cations/24083172CC BY 4.0info:eu-repo/semantics/openAccessoai:figshare.com:article/240831722021-07-01T00:00:00Z |
| spellingShingle | The effectiveness of divalent cation addition for highly saline activated sludge cultures: Influence of monovalent/divalent ratio and specific cations Raghavendran Sivasubramanian (16931775) Engineering Chemical engineering Environmental engineering Environmental sciences Pollution and contamination Calcium Magnesium Potassium Salinity Flocculation Biological wastewater treatment |
| status_str | publishedVersion |
| title | The effectiveness of divalent cation addition for highly saline activated sludge cultures: Influence of monovalent/divalent ratio and specific cations |
| title_full | The effectiveness of divalent cation addition for highly saline activated sludge cultures: Influence of monovalent/divalent ratio and specific cations |
| title_fullStr | The effectiveness of divalent cation addition for highly saline activated sludge cultures: Influence of monovalent/divalent ratio and specific cations |
| title_full_unstemmed | The effectiveness of divalent cation addition for highly saline activated sludge cultures: Influence of monovalent/divalent ratio and specific cations |
| title_short | The effectiveness of divalent cation addition for highly saline activated sludge cultures: Influence of monovalent/divalent ratio and specific cations |
| title_sort | The effectiveness of divalent cation addition for highly saline activated sludge cultures: Influence of monovalent/divalent ratio and specific cations |
| topic | Engineering Chemical engineering Environmental engineering Environmental sciences Pollution and contamination Calcium Magnesium Potassium Salinity Flocculation Biological wastewater treatment |