Proliferation of glycogen accumulating organisms induced by Fe(III) dosing in a domestic wastewater treatment plant

A. Jobbágy, B. Literáthy, M. T. Wong, G. Tardy, W. T. Liu

Research output: Contribution to journalArticlepeer-review


To meet the effluent requirements given for the sensitive receiving body, the Southpest Wastewafer Treatment Plant of Budapest, Hungary uses a combined activated sludge-biofilter system with chemical precipitation for P removal. Causes of the proliferation of glycogen accumulating organisms (GAOs) observed in the unaerated/oxic activated sludge unit of this system were investigated both in full-scale and in lab-scale experiments combined with a detailed analysis of the microbial communities. Concentration profile measurements throughout the 8-stage activated sludge unit indicated anaerobic conditions in the first two unaerated reactors and low orthophosphate level (< 1 mg l-1) in all of the stages that could not be attributed to the influent quality, but to Fe (III)-dosing to the returned activated sludge. Microbiological analysis revealed the presence of GAOs from the GB group in the Gammaproteobacteria and occasionally tetrad-forming organisms from Actinobacteria, and the absence of Rhodocyclus-related polyphosphate accumulating organisms (PAOs) in the activated sludge samples. Comparative lab-scale studies carried out in two identically arranged UCT-systems with staged anoxic reactors also confirmed that Fe (III)-dosing may result in phosphorus deficiency of the microbial niche, leading to the suppression of growth and EBPR activity of PAOs and to the proliferation of GAOs.

Original languageEnglish (US)
Pages (from-to)101-109
Number of pages9
JournalWater Science and Technology
Issue number1
StatePublished - 2006
Externally publishedYes


  • Activated sludge
  • Chemical precipitation
  • Glycogen accumulating organisms
  • Phosphorus removal
  • Polyphosphate accumulating organisms

ASJC Scopus subject areas

  • Environmental Engineering
  • Water Science and Technology


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