A novel nanofiltration based membrane bioreactor (NF-MBR) and reverse osmosis (RO) for water reclamation

In this study, a novel nanofiltration membrane bioreactor (NF-MBR) was developed and integrated with the reverse osmosis (RO) process for water reclamation. The underlying motivation of using NF-MBR as a pre-treatment to the RO process is to improve the RO feed quality and subsequently increase t...

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Main Author: Tay, Ming Feng
Other Authors: Chong Tzyy Haur
Format: Thesis-Doctor of Philosophy
Language:English
Published: Nanyang Technological University 2020
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Online Access:https://hdl.handle.net/10356/136655
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spelling sg-ntu-dr.10356-1366552020-10-28T08:40:30Z A novel nanofiltration based membrane bioreactor (NF-MBR) and reverse osmosis (RO) for water reclamation Tay, Ming Feng Chong Tzyy Haur School of Civil and Environmental Engineering Singapore Membrane Technology Centre thchong@ntu.edu.sg Engineering::Environmental engineering::Water treatment In this study, a novel nanofiltration membrane bioreactor (NF-MBR) was developed and integrated with the reverse osmosis (RO) process for water reclamation. The underlying motivation of using NF-MBR as a pre-treatment to the RO process is to improve the RO feed quality and subsequently increase the RO recovery ratio. The use of a glutaraldehyde (GA) crosslinked layer-by-layer polyelectrolyte low-pressure hollow fiber NF membrane has overcome the inherent issues of low permeate flux and membrane stability in the NF-MBR system. Higher organic removal was observed in the NF-MBR than the ultrafiltration MBR (UF-MBR) due to the extended retention time that allows the enhanced biodegradation of the retained organics in the bioreactor. In the NFMBR system applied in this study, the negative impact arisen from the salt accumulation was alleviated by allowing the passage of monovalent ions, particularly NaCl. The build-up of salts (i.e., Ca, Mg, PO4) is a function of SRT, hydraulic retention time (HRT) and membrane rejection. Despite the accumulation of salts, the NF-MBRs achieved excellent biodegradation efficiency, organic removal (>97%) and ammonia removal (>98%). The improved MBR permeate quality has led to ~3.7 times decrease in the RO fouling rates as compared to the UF-MBR+RO process. Further analysis indicated that the cake layer fouling that caused the cake-enhanced osmotic pressure (CEOP) effect contributed predominantly to the transmembrane pressure (TMP) increase in the NF-MBR. Our study substantiated that the NF-MBR+RO system is a feasible option for high recovery water reclamation by comparing the energy requirement for the NF-MBR+RO and UF-MBR+RO system. Doctor of Philosophy 2020-01-09T03:02:22Z 2020-01-09T03:02:22Z 2019 Thesis-Doctor of Philosophy Tay, M. F. (2019). A novel nanofiltration based membrane bioreactor (NF-MBR) and reverse osmosis (RO) for water reclamation. Doctoral thesis, Nanyang Technological University, Singapore. https://hdl.handle.net/10356/136655 10.32657/10356/136655 en This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License (CC BY-NC 4.0). application/pdf Nanyang Technological University
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic Engineering::Environmental engineering::Water treatment
spellingShingle Engineering::Environmental engineering::Water treatment
Tay, Ming Feng
A novel nanofiltration based membrane bioreactor (NF-MBR) and reverse osmosis (RO) for water reclamation
description In this study, a novel nanofiltration membrane bioreactor (NF-MBR) was developed and integrated with the reverse osmosis (RO) process for water reclamation. The underlying motivation of using NF-MBR as a pre-treatment to the RO process is to improve the RO feed quality and subsequently increase the RO recovery ratio. The use of a glutaraldehyde (GA) crosslinked layer-by-layer polyelectrolyte low-pressure hollow fiber NF membrane has overcome the inherent issues of low permeate flux and membrane stability in the NF-MBR system. Higher organic removal was observed in the NF-MBR than the ultrafiltration MBR (UF-MBR) due to the extended retention time that allows the enhanced biodegradation of the retained organics in the bioreactor. In the NFMBR system applied in this study, the negative impact arisen from the salt accumulation was alleviated by allowing the passage of monovalent ions, particularly NaCl. The build-up of salts (i.e., Ca, Mg, PO4) is a function of SRT, hydraulic retention time (HRT) and membrane rejection. Despite the accumulation of salts, the NF-MBRs achieved excellent biodegradation efficiency, organic removal (>97%) and ammonia removal (>98%). The improved MBR permeate quality has led to ~3.7 times decrease in the RO fouling rates as compared to the UF-MBR+RO process. Further analysis indicated that the cake layer fouling that caused the cake-enhanced osmotic pressure (CEOP) effect contributed predominantly to the transmembrane pressure (TMP) increase in the NF-MBR. Our study substantiated that the NF-MBR+RO system is a feasible option for high recovery water reclamation by comparing the energy requirement for the NF-MBR+RO and UF-MBR+RO system.
author2 Chong Tzyy Haur
author_facet Chong Tzyy Haur
Tay, Ming Feng
format Thesis-Doctor of Philosophy
author Tay, Ming Feng
author_sort Tay, Ming Feng
title A novel nanofiltration based membrane bioreactor (NF-MBR) and reverse osmosis (RO) for water reclamation
title_short A novel nanofiltration based membrane bioreactor (NF-MBR) and reverse osmosis (RO) for water reclamation
title_full A novel nanofiltration based membrane bioreactor (NF-MBR) and reverse osmosis (RO) for water reclamation
title_fullStr A novel nanofiltration based membrane bioreactor (NF-MBR) and reverse osmosis (RO) for water reclamation
title_full_unstemmed A novel nanofiltration based membrane bioreactor (NF-MBR) and reverse osmosis (RO) for water reclamation
title_sort novel nanofiltration based membrane bioreactor (nf-mbr) and reverse osmosis (ro) for water reclamation
publisher Nanyang Technological University
publishDate 2020
url https://hdl.handle.net/10356/136655
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