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

Verawaty, Marieska (2013) Breakage and growth towards a stable aerobic granule size during the treatment of wastewater. Water Research. ISSN 00431354, 18792448

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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 ex�periments 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 425 mm, 900 mm and 1125 mm. 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 600e800 mm. Accordingly, it is ex�pected 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 for�mation 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.

Item Type:	Article
Subjects:	Q Science > QR Microbiology > QR1-502 Microbiology
Divisions:	08-Faculty of Mathematics and Natural Science > 46201-Biology (S1)
Depositing User:	Dr. Marieska Verawaty
Date Deposited:	13 Apr 2023 06:41
Last Modified:	02 May 2023 07:04
URI:	http://repository.unsri.ac.id/id/eprint/96236

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