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Aerobic membrane biological reactor treatment of recirculated mechanical newsprint whitewater at high temperatures Tardif, Olivier
Abstract
The membrane biological reactor (MBR) is a robust and stable biological treatment process which integrates biological oxidation with ultrafiltration for treating wastewaters. A lab scale MBR consisting of a 10 L aerobic reactor, a cross-flow tubular ultrafiltration unit (molecular weight cut-off = 75 kDaltons) and a progressive cavity pump was operated at temperatures ranging from 40 to 55°C, hydraulic retention times (HRT) of 2.8, 1.1 or 0.7 days, a solids retention time of 25 days and a transmembrane pressure of 79 kPa to treat a synthetic closed-mill mechanical newsprint Whitewater. The mixed-liquor volatile suspended solids concentration in the MBR varied with the operating conditions, ranging from 2 to 9 g/L. In another study, the effectiveness of the ultrafiltration component of the MBR alone was investigated. The synthetic Whitewater was ultrafiltered to a concentration factor of 37 using the ultrafiltration unit at a transmembrane pressure of 69 kPa and a cross-flow velocity of 1.7 m/s (same velocity as the MBR). These two treatment processes were assessed for the removal efficiency of total solids (TS), total dissolved solids (TDS), total chemical oxygen demand (TCOD), dissolved chemical oxygen demand (DCOD), dissolved organic carbon (DOC), colour, cationic demand, resin acids (RA) and fatty acids (FA). The MBR achieved similar removal efficiencies for all operating temperatures and hydraulic retention times. It was particularly effective at removing FA (100% removal), RA (average removal > 98%), TCOD (82% average removal), DCOD (78% average removal) and DOC (76% average removal). The reduction of the Whitewater cationic demand was good (64% average removal). The average removal efficiencies for TS (36%) and TDS (27%) were fair, while the MBR was ineffective at removing colour (-5% average removal). Ultrafiltration alone was not nearly as effective at removing the target contaminants from the synthetic Whitewater. The high removal efficiencies of RFA achieved with the MBR may be due to the fact that RFA have a tendency to be adsorbed by the biosolids, which are retained by the ultrafiltration membrane. This and other inherent advantages of the MBR suggest much potential for this process in treating recirculated Whitewater internally in pulp and paper mills.
Item Metadata
Title |
Aerobic membrane biological reactor treatment of recirculated mechanical newsprint whitewater at high temperatures
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
1996
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Description |
The membrane biological reactor (MBR) is a robust and stable biological treatment process
which integrates biological oxidation with ultrafiltration for treating wastewaters. A lab scale MBR
consisting of a 10 L aerobic reactor, a cross-flow tubular ultrafiltration unit (molecular weight cut-off =
75 kDaltons) and a progressive cavity pump was operated at temperatures ranging from 40 to 55°C,
hydraulic retention times (HRT) of 2.8, 1.1 or 0.7 days, a solids retention time of 25 days and a
transmembrane pressure of 79 kPa to treat a synthetic closed-mill mechanical newsprint Whitewater. The
mixed-liquor volatile suspended solids concentration in the MBR varied with the operating conditions,
ranging from 2 to 9 g/L. In another study, the effectiveness of the ultrafiltration component of the MBR
alone was investigated. The synthetic Whitewater was ultrafiltered to a concentration factor of 37 using
the ultrafiltration unit at a transmembrane pressure of 69 kPa and a cross-flow velocity of 1.7 m/s (same
velocity as the MBR). These two treatment processes were assessed for the removal efficiency of total
solids (TS), total dissolved solids (TDS), total chemical oxygen demand (TCOD), dissolved chemical
oxygen demand (DCOD), dissolved organic carbon (DOC), colour, cationic demand, resin acids (RA)
and fatty acids (FA).
The MBR achieved similar removal efficiencies for all operating temperatures and hydraulic
retention times. It was particularly effective at removing FA (100% removal), RA (average removal >
98%), TCOD (82% average removal), DCOD (78% average removal) and DOC (76% average removal).
The reduction of the Whitewater cationic demand was good (64% average removal). The average
removal efficiencies for TS (36%) and TDS (27%) were fair, while the MBR was ineffective at removing
colour (-5% average removal). Ultrafiltration alone was not nearly as effective at removing the target
contaminants from the synthetic Whitewater. The high removal efficiencies of RFA achieved with the
MBR may be due to the fact that RFA have a tendency to be adsorbed by the biosolids, which are
retained by the ultrafiltration membrane. This and other inherent advantages of the MBR suggest much
potential for this process in treating recirculated Whitewater internally in pulp and paper mills.
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Extent |
9608072 bytes
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Genre | |
Type | |
File Format |
application/pdf
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Language |
eng
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Date Available |
2009-02-17
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Provider |
Vancouver : University of British Columbia Library
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Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
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DOI |
10.14288/1.0050382
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Graduation Date |
1996-11
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Campus | |
Scholarly Level |
Graduate
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Aggregated Source Repository |
DSpace
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Item Media
Item Citations and Data
Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.