東華大學圖書館 |

Wastewater Reclamation and Potable Reuse with Novel Processes: Membrane Performance and System Integration.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Wastewater Reclamation and Potable Reuse with Novel Processes: Membrane Performance and System Integration./
作者:	Morrow, Christopher P.
出版者:	Ann Arbor : ProQuest Dissertations & Theses, : 2018,
面頁冊數:	121 p.
附註:	Source: Dissertations Abstracts International, Volume: 81-09, Section: B.
Contained By:	Dissertations Abstracts International81-09B.
標題:	Environmental engineering. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=27812285
ISBN:	9781658403177

Wastewater Reclamation and Potable Reuse with Novel Processes: Membrane Performance and System Integration.
Morrow, Christopher P.

Wastewater Reclamation and Potable Reuse with Novel Processes: Membrane Performance and System Integration. - Ann Arbor : ProQuest Dissertations & Theses, 2018 - 121 p.

Source: Dissertations Abstracts International, Volume: 81-09, Section: B.

Thesis (Ph.D.)--University of Southern California, 2018.

This item must not be sold to any third party vendors.

Urban reliance on imported water and increasing water supply variability due to climate change have intensified efforts to increase the resiliency of water supplies on a global scale. For reuse applications, membrane bioreactors (MBRs) with microfiltration (MF) or ultrafiltration (UF) membranes submerged in a biological reactor have emerged as an efficient wastewater treatment process to provide high-quality filtrate to a subsequent reverse osmosis (RO) process followed by advanced oxidation. More recently, osmotic membrane bioreactors (OMBRs) with forward osmosis (FO) membranes submerged in the bioreactor are being investigated as low-fouling alternatives to conventional MBRs. If the opportunity exists to reconcentrate the FO draw solution with waste-heat driven membrane distillation (MD), then the OMBR-MD system can provide high quality product water with a low electrical energy requirement.In an aerobic OMBR-MD system, wastewater is fed into a bioreactor that is aerated to supply oxygen to the biomass and scour the membrane. Through osmosis, water diffuses from the bioreactor, across a semi-permeable FO membrane, into the draw solution. The FO membrane acts as a barrier to solute transport and provides high rejection of contaminants in the wastewater stream. The diluted draw solution is sent to MD for reconcentration and generation of product water.Compared to the MF or UF process in a conventional MBR, the FO process in the OMBR offers the advantage of much higher rejection (semi-permeable membrane versus microporous membrane) at lower hydraulic pressure. The FO membrane inside the bioreactor also has much less fouling propensity than MF/UF membranes, and thus, requires less scouring and much less frequent backwashing. When comparing an integrated OMBR-MD system with a conventional MBR-RO system, the higher rejection of the FO membranes also results in lower fouling propensity for the downstream process (RO or MD). When comparing FO draw solution recovery using RO or MD, both processes can utilize waste heat to reduce the required energy input; however, MD utilizes waste heat directly with a heat exchanger, whereas RO requires additional equipment (e.g., a pump, boiler, and turbine) to convert waste heat to electrical energy, resulting in a larger footprint. Furthermore, the electrical energy requirement for RO would increase as feed solution salinity increases whereas MD is only minimally affected by feed solution salinity.MF and UF membranes in MBRs pass dissolved solids while FO membranes in OMBRs generally do not. However, a key concern with OMBRs is elevated bioreactor salinity caused by retention of dissolved solutes from the influent wastewater and diffusion of draw solutes from the FO draw solution into the bioreactor by a phenomenon known as reverse salt flux (RSF). RSF is a critical concern of osmotic processes because it diminishes the salinity gradient, thus reducing the osmotic driving force for water flux; in the case of OMBRs, RSF also increases bioreactor salinity. High bioreactor salinity can affect microbial processes, for example decreasing the activity of nitrogen-removing bacteria. Ammonia-oxidizing bacteria, which are responsible for ammonia removal via nitrification, are particularly sensitive to salinity and sharp decreases in nitrification efficiency have been reported for bioreactors with salinities ranging from 2-15 g/L NaCl.The hydrodynamics and mixing that influence RSF and membrane fouling in OMBRs is highly influenced by FO module configuration. In the submerged configuration, the draw solution is circulated through the interior of the membrane module while the feed solution has no direct crossflow. Air bubbles can be used as a fouling control strategy with air scour of the membrane surface reducing membrane fouling. In the sidestream configuration, the membrane module is external to the bioreactor and the feed and draw solutions flow tangentially across the membrane surfaces. High crossflow velocities can be used as a fouling control strategy with hydraulic scour of the membrane surface reducing membrane fouling. Large ranges of steady-state salinities have been reported for both submerged (4.1-12.6 g/L NaCl) and sidestream (4.0-33.5 g/L NaCl) OMBR configurations. Despite the different salinities reported for each configuration, the role of membrane module configuration on RSF and bioreactor salinity is not well characterized.In addition to system-dependent parameters such as membrane module configuration, membrane-dependent parameters (e.g., water permeability (A), solute permeability (B), and the structural parameter (S)) are used as inputs to predict membrane performance. Several recent pilot-scale FO studies have reported a hydraulic pressure drop that occurs across larger membrane modules that is not observed with smaller, bench-scale testing systems. Thus, when FO processes are scaled-up, FO membrane performance will depend on a combination of osmotic pressure and hydraulic pressure. While osmotic pressure is unlikely to affect FO membrane structure and transport properties, hydraulic pressure may cause FO membrane compaction, changing membrane performance. Therefore, understanding compaction with FO membranes and how this affects membrane performance are also key aspects for designing novel FO membrane materials.Because FO is an osmosis-driven process, FO membrane fouling is less severe and more reversible than fouling in pressure-driven membrane processes (i.e., nanofiltration (NF) and RO). However, like pressure-driven membrane processes, FO membrane fouling can significantly hinder water flux. For RO and NF membranes, only initial foulant deposition is dependent on membrane properties and water flux is eventually restricted to the limiting flux, which has been shown to be membrane-independent. The limiting flux concept may also be applicable in FO, however, due to phenomenon unique to FO (e.g., internal concentration polarization and RSF), FO membrane fouling is more complex than membrane fouling in RO and NF. Thus, identification of membrane properties that influence performance under fouling conditions is key for improving performance in wastewater reuse systems where membrane fouling is expected to occur.

ISBN: 9781658403177Subjects--Topical Terms:

548583
Environmental engineering.
Subjects--Index Terms:

Wastewater reclamation

Wastewater Reclamation and Potable Reuse with Novel Processes: Membrane Performance and System Integration.
LDR:07428nmm a2200337 4500 001 2273102
005 20201105110342.5
008 220629s2018 ||||||||||||||||| ||eng d
020 $a 9781658403177
035 $a (MiAaPQ)AAI27812285
035 $a (MiAaPQ)US_Calif_50541
035 $a AAI27812285
040 $a MiAaPQ $c MiAaPQ
100 1 $a Morrow, Christopher P. $3 3550533
245 1 0 $a Wastewater Reclamation and Potable Reuse with Novel Processes: Membrane Performance and System Integration.
260 1 $a Ann Arbor : $b ProQuest Dissertations & Theses, $c 2018
300 $a 121 p.
500 $a Source: Dissertations Abstracts International, Volume: 81-09, Section: B.
500 $a Advisor: Chuildress, Amy Elizabeth.
502 $a Thesis (Ph.D.)--University of Southern California, 2018.
506 $a This item must not be sold to any third party vendors.
520 $a Urban reliance on imported water and increasing water supply variability due to climate change have intensified efforts to increase the resiliency of water supplies on a global scale. For reuse applications, membrane bioreactors (MBRs) with microfiltration (MF) or ultrafiltration (UF) membranes submerged in a biological reactor have emerged as an efficient wastewater treatment process to provide high-quality filtrate to a subsequent reverse osmosis (RO) process followed by advanced oxidation. More recently, osmotic membrane bioreactors (OMBRs) with forward osmosis (FO) membranes submerged in the bioreactor are being investigated as low-fouling alternatives to conventional MBRs. If the opportunity exists to reconcentrate the FO draw solution with waste-heat driven membrane distillation (MD), then the OMBR-MD system can provide high quality product water with a low electrical energy requirement.In an aerobic OMBR-MD system, wastewater is fed into a bioreactor that is aerated to supply oxygen to the biomass and scour the membrane. Through osmosis, water diffuses from the bioreactor, across a semi-permeable FO membrane, into the draw solution. The FO membrane acts as a barrier to solute transport and provides high rejection of contaminants in the wastewater stream. The diluted draw solution is sent to MD for reconcentration and generation of product water.Compared to the MF or UF process in a conventional MBR, the FO process in the OMBR offers the advantage of much higher rejection (semi-permeable membrane versus microporous membrane) at lower hydraulic pressure. The FO membrane inside the bioreactor also has much less fouling propensity than MF/UF membranes, and thus, requires less scouring and much less frequent backwashing. When comparing an integrated OMBR-MD system with a conventional MBR-RO system, the higher rejection of the FO membranes also results in lower fouling propensity for the downstream process (RO or MD). When comparing FO draw solution recovery using RO or MD, both processes can utilize waste heat to reduce the required energy input; however, MD utilizes waste heat directly with a heat exchanger, whereas RO requires additional equipment (e.g., a pump, boiler, and turbine) to convert waste heat to electrical energy, resulting in a larger footprint. Furthermore, the electrical energy requirement for RO would increase as feed solution salinity increases whereas MD is only minimally affected by feed solution salinity.MF and UF membranes in MBRs pass dissolved solids while FO membranes in OMBRs generally do not. However, a key concern with OMBRs is elevated bioreactor salinity caused by retention of dissolved solutes from the influent wastewater and diffusion of draw solutes from the FO draw solution into the bioreactor by a phenomenon known as reverse salt flux (RSF). RSF is a critical concern of osmotic processes because it diminishes the salinity gradient, thus reducing the osmotic driving force for water flux; in the case of OMBRs, RSF also increases bioreactor salinity. High bioreactor salinity can affect microbial processes, for example decreasing the activity of nitrogen-removing bacteria. Ammonia-oxidizing bacteria, which are responsible for ammonia removal via nitrification, are particularly sensitive to salinity and sharp decreases in nitrification efficiency have been reported for bioreactors with salinities ranging from 2-15 g/L NaCl.The hydrodynamics and mixing that influence RSF and membrane fouling in OMBRs is highly influenced by FO module configuration. In the submerged configuration, the draw solution is circulated through the interior of the membrane module while the feed solution has no direct crossflow. Air bubbles can be used as a fouling control strategy with air scour of the membrane surface reducing membrane fouling. In the sidestream configuration, the membrane module is external to the bioreactor and the feed and draw solutions flow tangentially across the membrane surfaces. High crossflow velocities can be used as a fouling control strategy with hydraulic scour of the membrane surface reducing membrane fouling. Large ranges of steady-state salinities have been reported for both submerged (4.1-12.6 g/L NaCl) and sidestream (4.0-33.5 g/L NaCl) OMBR configurations. Despite the different salinities reported for each configuration, the role of membrane module configuration on RSF and bioreactor salinity is not well characterized.In addition to system-dependent parameters such as membrane module configuration, membrane-dependent parameters (e.g., water permeability (A), solute permeability (B), and the structural parameter (S)) are used as inputs to predict membrane performance. Several recent pilot-scale FO studies have reported a hydraulic pressure drop that occurs across larger membrane modules that is not observed with smaller, bench-scale testing systems. Thus, when FO processes are scaled-up, FO membrane performance will depend on a combination of osmotic pressure and hydraulic pressure. While osmotic pressure is unlikely to affect FO membrane structure and transport properties, hydraulic pressure may cause FO membrane compaction, changing membrane performance. Therefore, understanding compaction with FO membranes and how this affects membrane performance are also key aspects for designing novel FO membrane materials.Because FO is an osmosis-driven process, FO membrane fouling is less severe and more reversible than fouling in pressure-driven membrane processes (i.e., nanofiltration (NF) and RO). However, like pressure-driven membrane processes, FO membrane fouling can significantly hinder water flux. For RO and NF membranes, only initial foulant deposition is dependent on membrane properties and water flux is eventually restricted to the limiting flux, which has been shown to be membrane-independent. The limiting flux concept may also be applicable in FO, however, due to phenomenon unique to FO (e.g., internal concentration polarization and RSF), FO membrane fouling is more complex than membrane fouling in RO and NF. Thus, identification of membrane properties that influence performance under fouling conditions is key for improving performance in wastewater reuse systems where membrane fouling is expected to occur.
590 $a School code: 0208.
650 4 $a Environmental engineering. $3 548583
653 $a Wastewater reclamation
653 $a Potable reuse
653 $a Water supply variability
690 $a 0775
710 2 $a University of Southern California. $3 700129
773 0 $t Dissertations Abstracts International $g 81-09B.
790 $a 0208
791 $a Ph.D.
792 $a 2018
793 $a English
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=27812285