The selective role of nitrite in the PAO/GAO competition

Carlota Tayà, Vijay Kumar Garlapati, Albert Guisasola, Juan A. Baeza

Research output: Contribution to journalArticleResearchpeer-review

53 Citations (Scopus)


Proliferation of Glycogen Accumulating Organisms (GAOs) accounts as one of the major bottlenecks in biological phosphorus removal systems. GAO outcompeting polyphosphate accumulating organisms (PAOs) results in lower P-removal. Thus, finding optimal conditions that favour PAO in front of GAO is a current focus of research. This work shows how nitrite can provide a novel strategy for PAO enrichment. A propionate-fed GAO-enriched biomass (70% Defluviicoccus I, 18% Defluviicoccus II and 10% PAO) was subjected more than 50. d under anaerobic-anoxic conditions with nitrite as electron acceptor. These operational conditions led to a PAO-enriched sludge (85%) where GAO were washed out of the system (<10%), demonstrating the validity of the new approach for PAO enrichment. In addition, the presented suppression of Defluviicocus GAO with nitrite represents an add-on benefit to the nitrite-based systems since the proliferation of non-desirable GAO can be easily ruled out and added to the other benefits (i.e. lower aeration and COD requirements). © 2013 Elsevier Ltd.
Original languageEnglish
Pages (from-to)612-618
Issue number4
Publication statusPublished - 1 Oct 2013


  • Enhanced biological phosphorus removal (EBPR)
  • Glycogen Accumulating Organisms (GAOs)
  • Nitrite
  • Polyphosphate accumulating organisms (PAOs)
  • Selection


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