Breakage and growth towards a stable aerobic granule size during the treatment of wastewater

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

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Author(s)

  • Marieska Verawaty
  • Stephan Tait
  • Maite Pijuan
  • Zhiguo Yuan
  • Philip L. Bond

Detail(s)

Original languageEnglish
Pages (from-to)5338-5349
Journal / PublicationWater Research
Volume47
Issue number14
Publication statusPublished - 5 Sept 2013
Externally publishedYes

Abstract

To better understand granule growth and breakage processes in aerobic granular sludge systems, the particle size of aerobic granules was tracked over 50 days of wastewater treatment within four sequencing batch reactors fed with abattoir wastewater. These experiments tested a novel hypothesis stating that granules equilibrate to a certain stable granule size (the critical size) which is determined by the influence of process conditions on the relative rates of granule growth and granule breakage or attrition. For granules that are larger than the critical size, granule breakage and attrition outweighs granule growth, and causes an overall reduction in granule size. For granules at the critical size, the overall growth and size reduction processes are balanced, and granule size is stable. For granules that are smaller than the critical size, granule growth outweighs granule breakage and attrition, and causes an overall increase in granule size. The experimental reactors were seeded with mature granules that were either small, medium, or large sized, these having respective median granule sizes of 425μm, 900μm and 1125μm. An additional reactor was seeded with a mixture of the sized granules to represent the original source of the granular sludge. The experimental results were analysed together with results of a previous granule formation study that used mixed seeding of granules and floccular sludge. The analysis supported the critical size hypothesis and showed that granules in the reactors did equilibrate towards a common critical size of around 600-800μm. Accordingly, it is expected that aerobic granular reactors at steady-state operation are likely to have granule size distributions around a characteristic critical size. Additionally, the results support that maintaining a quantity of granules above a particular size is important for granule formation during start-up and for process stability of aerobic granule systems. Hence, biomass washout needs to be carefully managed to optimize granule formation during the reactor start-up. © 2013 Elsevier Ltd.

Research Area(s)

  • Aerobic granules, Breakage, Critical granule size, Growth, Wastewater treatment

Bibliographic Note

Publication details (e.g. title, author(s), publication statuses and dates) are captured on an “AS IS” and “AS AVAILABLE” basis at the time of record harvesting from the data source. Suggestions for further amendments or supplementary information can be sent to lbscholars@cityu.edu.hk.

Citation Format(s)

Breakage and growth towards a stable aerobic granule size during the treatment of wastewater. / Verawaty, Marieska; Tait, Stephan; Pijuan, Maite et al.
In: Water Research, Vol. 47, No. 14, 05.09.2013, p. 5338-5349.

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review