Ammonia nitrogen removal in step-feed rotating biological contactors

P. Saikaly, G. M. Ayoub*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


The effect of step-feed on biological ammonia nitrogen (NH3-N) removal in a rotating biological contactor (RBC) system consisting of two three-stage units (one control and one step-feed) treating synthetic wastewater was examined. The performance of the step-feed RBC was evaluated in comparison to a regularly fed RBC in terms of NH3-N removals and stage-dissolved oxygen (DO) conditions over a range of hydraulic and organic loading rates (HLR = 0.032 to 0. 125 m3 m-2. d-1 and OLR = 11.03 to 111.6 g COD m-2.d-1 ). The results indicate that the step-feed unit showed better removal efficiency (%) at high HLR and ORL than the regularly fed control unit. Increasing the HLR and the OLR resulted in a decrease in DO in all the stages of the two units. However, DO values in the step-feed system were higher than those recorded for the control system. In addition, O2 limiting conditions (DO < 2 mg l-1 ) and heavy growth of Beggiatoa were detected in stage 1 of the control unit at high loading rates.

Original languageEnglish (US)
Pages (from-to)177-191
Number of pages15
JournalWater, Air, and Soil Pollution
Issue number1-4
StatePublished - Nov 2003
Externally publishedYes


  • Ammonia-nitrogen
  • Hydraulic loading rate
  • Organic loading rate
  • Removal
  • Rotating biological contactor (RBC)
  • Step-feed

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Ecological Modeling
  • Water Science and Technology
  • Pollution


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