Automatic adjustment of cycle length and aeration time for improved nitrogen removal in an alternating activated sludge process

Steven Howard Isaacs

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The paper examines the nitrogen dynamics in the alternating BIODENITRO and BIODENIPHO processes with a focus on two control handles influencing now scheduling and aeration: the cycle length and the ammonia concentration at which a nitrifying period is terminated. A steady state analysis examining the combined effect of both control handles reveals three conditions which characterize when nitrogen removal is maximized. A dynamic analysis shows that these conditions also apply for a changing ammonia load. This then allows an automatic control strategy for maximizing nitrogen removal to be based on a cycle by cycle single variable optimization rather than a more difficult multivariable optimization over a longer time horizon. Copyright (C) 1996 IAWQ.
Original languageEnglish
JournalWater Science and Technology
Issue number1
Pages (from-to)225-232
Publication statusPublished - 1997
EventInternational Specialised Conference on Sequencing Batch Reactor Technology: Selected Proceedings of the 1st IAWQ - Munich, Germany
Duration: 18 Mar 199620 Mar 1996


ConferenceInternational Specialised Conference on Sequencing Batch Reactor Technology


  • activated sludge
  • alternating processes
  • automatic control
  • denitrification
  • nitrification
  • nutrient removal
  • waste water treatment

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