The role of food/microorganism ratio in denitrification reactors: how it affects the sizing and operation of the denitrification process

  • Renato Gavasci Department of Civil Engineering and Computer Science Engineering. Università degli Studi di Roma Tor Vergata, Via Politecnico 1, 00133, Rome, Italy.
  • Francesco Lombardi Department of Civil Engineering and Computer Science Engineering. Università degli Studi di Roma Tor Vergata, Via Politecnico 1, 00133, Rome, Italy.
  • Massimo Raboni Department Hydraulics and Environmental Engineering. University of Pavia, Corso Str. Nuova, n° 65, 27100, Pavia, Italy.
DOI: https://doi.org/10.4136/ambi-agua.2656
Keywords: activated sludge, biological process, denitrification, nitrogen removal, sewage treatment.

Abstract

Two calculation models of the Specific Denitrification Rate (SDNR) are analyzed to highlight the sensitivity of this parameter to the Food:Microorganisms ratio in the denitrification reactor (F:MDEN). One of these models is empirical while the second was elaborated on a deterministic basis. Both models reveal a linear dependence of SDNR20°C on F:MDEN and in a first approximation they are comparable only in a narrow range of concentration of dissolved oxygen (DO) in denitrification, specifically DO=0.25-0.35 mg L-1. These values frequently occur in well designed and well operated sewage treatment plants. Outside this range, the role of F:MDEN must necessarily be examined in combination with DO because of the relevant influence of the latter on the efficiency of the denitrification process.


Published
26/01/2021
Issue
Vol. 16 No. 1 (2021)
Section
Papers

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