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UBC Theses and Dissertations
Optimization of VFA production in an atad reactor with respect to aeration rates and removal of phosphorus, incorporating a magnesium ammonium phosphate (map) crystallizer from the atad supernatant Sharma, Abyartha
Abstract
Previous researchers have demonstrated that a mixture of primary and secondary sludge provides increased production of VFA in ATAD. Experiments were carried out at the UBC pilot plant, in two phases, using a 35/65 mixture of primary/secondary sludge, to determine the optimum aeration rate with respect to production/generation of VFA, and to investigate the removal of phosphorus by forced formation of struvite in an upflow crystallizer. The source sludge for the research was obtained from an on-site modified UCT process, and mixed in the correct ratios prior to feeding on an hourly basis to the 125-L tanks. The tanks, were configured in parallel and operated as individual first stage reactors, one of which was the control tank. During the first stage, the control tank was maintained at a constant aeration rate of 50 ml/min (as suggested by EPA). The aeration rate in the test tank was varied from 0 ml/min (nitrogen was supplied) to 100 ml/min, at increments of 25 ml/min. Throughout the entire experimental period, temperatures were in the thermophilic range, between 47°C and 58°C inside the tanks; feed solids were maintained around 1.4% TSS, and ORP was consistent between -300 mV and -450 mV. There was higher production of VFA at lower aeration rates, the highest occurring when 25 ml/min air was supplied. Analysis of nutrients confirmed that there was a high release of stored phosphorus and an increase in ammonia nitrogen. The ratio of VFA: PO₄-P was the highest when 25 ml/min air was supplied.
Item Metadata
Title |
Optimization of VFA production in an atad reactor with respect to aeration rates and removal of phosphorus, incorporating a magnesium ammonium phosphate (map) crystallizer from the atad supernatant
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
1999
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Description |
Previous researchers have demonstrated that a mixture of primary and secondary
sludge provides increased production of VFA in ATAD. Experiments were carried out at
the UBC pilot plant, in two phases, using a 35/65 mixture of primary/secondary sludge,
to determine the optimum aeration rate with respect to production/generation of VFA,
and to investigate the removal of phosphorus by forced formation of struvite in an upflow
crystallizer. The source sludge for the research was obtained from an on-site
modified UCT process, and mixed in the correct ratios prior to feeding on an hourly basis
to the 125-L tanks. The tanks, were configured in parallel and operated as individual first
stage reactors, one of which was the control tank.
During the first stage, the control tank was maintained at a constant aeration rate
of 50 ml/min (as suggested by EPA). The aeration rate in the test tank was varied from 0
ml/min (nitrogen was supplied) to 100 ml/min, at increments of 25 ml/min. Throughout
the entire experimental period, temperatures were in the thermophilic range, between
47°C and 58°C inside the tanks; feed solids were maintained around 1.4% TSS, and ORP
was consistent between -300 mV and -450 mV. There was higher production of VFA
at lower aeration rates, the highest occurring when 25 ml/min air was supplied. Analysis
of nutrients confirmed that there was a high release of stored phosphorus and an increase
in ammonia nitrogen. The ratio of VFA: PO₄-P was the highest when 25 ml/min air was
supplied.
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Extent |
6448368 bytes
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Genre | |
Type | |
File Format |
application/pdf
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Language |
eng
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Date Available |
2009-06-16
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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 |
10.14288/1.0050141
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Graduation Date |
1999-11
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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.