Effect of decarbonation on alkaline reduction in two-phase UASB process

Methods for reducing the alkaline dosage in a two-phase UASB process were investigated. An alkaline simulation model was developed incorporating the recycle ratio of effluent, the mass transfer rate of carbon dioxide from the liquid to gas phase, and the dissociation of organic acids and carbonate....

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Bibliographic Details
Published in:Water science and technology 1996-09, Vol.34 (5-6), p.437-444
Main Authors: Nishimura, Sosuke, Yoda, Motoyuki
Format: Article
Language:eng ; jpn
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Summary:Methods for reducing the alkaline dosage in a two-phase UASB process were investigated. An alkaline simulation model was developed incorporating the recycle ratio of effluent, the mass transfer rate of carbon dioxide from the liquid to gas phase, and the dissociation of organic acids and carbonate. Model simulation showed that a considerable amount of alkaline was consumed needlessly in an attempt to neutralize bicarbonate generated in both the acidification phase and methanogenic phase. Decarbonation by bubbling air between the acidification section and UASB reactor was shown to be effective in reducing the amount of alkaline required for bicarbonate neutralization. Methanogenic bacteria in the system were not adversely affected by air bubbling during four months of continuous laboratory-scale operation.
ISSN:0273-1223
1996-9732
DOI:10.2166/wst.1996.0580