Strategies for mitigating challenges associated with trace organic compound removal by high-retention membrane bioreactors (HR-MBRs)
Abstract Due to the limitations of conventional ultrafiltration/microfiltration-based membrane bioreactors (UF/MF-MBRs) in removing trace organic compounds (TrOCs), the concept of high-retention membrane bioreactors (HR-MBRs) was introduced. Despite the benefits, HR-MBRs still suffer several drawbac...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Nature Portfolio
2024-03-01
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| Series: | npj Clean Water |
| Online Access: | https://doi.org/10.1038/s41545-024-00313-w |
| _version_ | 1797259561845915648 |
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| author | Oranso T. Mahlangu Thabo I. Nkambule Bhekie B. Mamba Faisal I. Hai |
| author_facet | Oranso T. Mahlangu Thabo I. Nkambule Bhekie B. Mamba Faisal I. Hai |
| author_sort | Oranso T. Mahlangu |
| collection | DOAJ |
| description | Abstract Due to the limitations of conventional ultrafiltration/microfiltration-based membrane bioreactors (UF/MF-MBRs) in removing trace organic compounds (TrOCs), the concept of high-retention membrane bioreactors (HR-MBRs) was introduced. Despite the benefits, HR-MBRs still suffer several drawbacks. Therefore, this paper critically reviews the effectiveness and feasibility of the proposed strategies to alleviate fouling, salinity build-up and incomplete biodegradation of TrOCs during wastewater treatment by HR-MBRs. The severity of each challenge is compared amongst the various configurations together with the associated capital and operational expenditure to determine the most cost-effective set-up. Guidance is provided on strategies and/or lessons that could be adopted from well-established processes used at municipal scale. Chemical cleaning as mitigation for fouling degrades membranes leading to poor TrOCs removal, while pre-treatment and membrane surface modification increase operational expenditure (OpEX). However, there are other environmentally-friendly pretreatment and cleaning options which hold great potential for future application. These options such as advanced oxidation processes (AOPs) are critically discussed in this work. Further, in-depth discussion is made on the pros and cons of the various approaches (such as frequent sludge withdrawal, intermittent UF/MF filtration and using organic salts) to alleviate salt build-up. Finally, incomplete biodegradation of rejected TrOCs in the bioreactor transfers problems of toxic pollutants from wastewater treatment to sludge management. Herein mitigation strategies including using stronger biological agents and coupling HR-MBRs with other techniques are debated. Despite the challenges, HR-MBRs are a promising solution for clean water production from TrOCs impaired wastewater. Therefore, more research is needed to improve the performance of HR-MBRs. |
| first_indexed | 2024-04-24T23:11:24Z |
| format | Article |
| id | doaj.art-44ed8a7d343b4321a6c260e4056b708f |
| institution | Directory Open Access Journal |
| issn | 2059-7037 |
| language | English |
| last_indexed | 2024-04-24T23:11:24Z |
| publishDate | 2024-03-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | npj Clean Water |
| spelling | doaj.art-44ed8a7d343b4321a6c260e4056b708f2024-03-17T12:12:47ZengNature Portfolionpj Clean Water2059-70372024-03-017113910.1038/s41545-024-00313-wStrategies for mitigating challenges associated with trace organic compound removal by high-retention membrane bioreactors (HR-MBRs)Oranso T. Mahlangu0Thabo I. Nkambule1Bhekie B. Mamba2Faisal I. Hai3Institute for Nanotechnology and Water Sustainability, College of Science, Engineering and Technology, University of South Africa, FloridaInstitute for Nanotechnology and Water Sustainability, College of Science, Engineering and Technology, University of South Africa, FloridaInstitute for Nanotechnology and Water Sustainability, College of Science, Engineering and Technology, University of South Africa, FloridaInstitute for Nanotechnology and Water Sustainability, College of Science, Engineering and Technology, University of South Africa, FloridaAbstract Due to the limitations of conventional ultrafiltration/microfiltration-based membrane bioreactors (UF/MF-MBRs) in removing trace organic compounds (TrOCs), the concept of high-retention membrane bioreactors (HR-MBRs) was introduced. Despite the benefits, HR-MBRs still suffer several drawbacks. Therefore, this paper critically reviews the effectiveness and feasibility of the proposed strategies to alleviate fouling, salinity build-up and incomplete biodegradation of TrOCs during wastewater treatment by HR-MBRs. The severity of each challenge is compared amongst the various configurations together with the associated capital and operational expenditure to determine the most cost-effective set-up. Guidance is provided on strategies and/or lessons that could be adopted from well-established processes used at municipal scale. Chemical cleaning as mitigation for fouling degrades membranes leading to poor TrOCs removal, while pre-treatment and membrane surface modification increase operational expenditure (OpEX). However, there are other environmentally-friendly pretreatment and cleaning options which hold great potential for future application. These options such as advanced oxidation processes (AOPs) are critically discussed in this work. Further, in-depth discussion is made on the pros and cons of the various approaches (such as frequent sludge withdrawal, intermittent UF/MF filtration and using organic salts) to alleviate salt build-up. Finally, incomplete biodegradation of rejected TrOCs in the bioreactor transfers problems of toxic pollutants from wastewater treatment to sludge management. Herein mitigation strategies including using stronger biological agents and coupling HR-MBRs with other techniques are debated. Despite the challenges, HR-MBRs are a promising solution for clean water production from TrOCs impaired wastewater. Therefore, more research is needed to improve the performance of HR-MBRs.https://doi.org/10.1038/s41545-024-00313-w |
| spellingShingle | Oranso T. Mahlangu Thabo I. Nkambule Bhekie B. Mamba Faisal I. Hai Strategies for mitigating challenges associated with trace organic compound removal by high-retention membrane bioreactors (HR-MBRs) npj Clean Water |
| title | Strategies for mitigating challenges associated with trace organic compound removal by high-retention membrane bioreactors (HR-MBRs) |
| title_full | Strategies for mitigating challenges associated with trace organic compound removal by high-retention membrane bioreactors (HR-MBRs) |
| title_fullStr | Strategies for mitigating challenges associated with trace organic compound removal by high-retention membrane bioreactors (HR-MBRs) |
| title_full_unstemmed | Strategies for mitigating challenges associated with trace organic compound removal by high-retention membrane bioreactors (HR-MBRs) |
| title_short | Strategies for mitigating challenges associated with trace organic compound removal by high-retention membrane bioreactors (HR-MBRs) |
| title_sort | strategies for mitigating challenges associated with trace organic compound removal by high retention membrane bioreactors hr mbrs |
| url | https://doi.org/10.1038/s41545-024-00313-w |
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