Multi-scale individual-based model of microbial and byconversion dynamics in aerobic granular sludge

Joao B. Xavier, Merle K. De Kreuk, Cristian Picioreanu, Mark C.M. Van Loosdrecht

Research output: Contribution to journalArticlepeer-review

136 Scopus citations


Aerobic granular sludge is a novel compact biological wastewater treatment technology for integrated removal of COD (chemical oxygen demand), nitrogen, and phosphate charges. We present here a multiscale model of aerobic granular sludge sequencing batch reactors (GSBR) describing the complex dynamics of populations and nutrient removal. The macro scale describes bulk concentrations and effluent composition in six solutes (oxygen, acetate, ammonium, nitrite, nitrate, and phosphate). A finer scale, the scale of one granule (1.1 mm of diameter), describes the two-dimensional spatial arrangement of four bacterial groups-heterotrophs, ammonium oxidizers, nitrite oxidizers, and phosphate accumulating organisms (PAO) - using individual based modeling (IbM) with species-specific kinetic models. The model for PAO includes three internal storage compounds: polyhydroxyalkanoates (PHA), poly phosphate, and glycogen. Simulations of long-term reactor operation show how the microbial population and activity depends on the operating conditions. Short-term dynamics of solute bulk concentrations are also generated with results comparable to experimental data from lab scale reactors. Our results suggest that N-removal in GSBR occurs mostly via alternating nitrification/denitrification rather than simultaneous nitrification/denitrification, supporting an alternative strategy to improve N-removal in this promising wastewater treatment process. © 2007 American Chemical Society.
Original languageEnglish (US)
Pages (from-to)6410-6417
Number of pages8
JournalEnvironmental Science and Technology
Issue number18
StatePublished - Sep 15 2007
Externally publishedYes

Bibliographical note

Generated from Scopus record by KAUST IRTS on 2022-09-13

ASJC Scopus subject areas

  • Environmental Chemistry
  • General Chemistry


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