Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
684449 | Bioresource Technology | 2009 | 6 Pages |
Abstract
Sequencing batch reactors (SBRs) have several advantages, such as a lower footprint and a higher flexibility, compared to biofilm based reactors, such as rotating biological contactors. However, the critical parameters for a fast start-up of the nitrogen removal by oxygen-limited autotrophic nitrification/denitrification (OLAND) in a SBR are not available. In this study, a low critical minimum settling velocity (0.7 m hâ1) and a low volumetric exchange ratio (25%) were found to be essential to ensure a fast start-up, in contrast to a high critical minimum settling velocity (2 m hâ1) and a high volumetric exchange ratio (40%) which yielded no successful start-up. To prevent nitrite accumulation, two effective actions were found to restore the microbial activity balance between aerobic and anoxic ammonium-oxidizing bacteria (AerAOB and AnAOB). A daily biomass washout at a critical minimum settling velocity of 5 m hâ1 removed small aggregates rich in AerAOB activity, and the inclusion of an anoxic phase enhanced the AnAOB to convert the excess nitrite. This study showed that stable physicochemical conditions were needed to obtain a competitive nitrogen removal rate of 1.1 g N Lâ1 dâ1.
Related Topics
Physical Sciences and Engineering
Chemical Engineering
Process Chemistry and Technology
Authors
Haydée De Clippeleir, Siegfried E. Vlaeminck, Marta Carballa, Willy Verstraete,