title: Influence of denitrification reactor retention time distribution (RTD) on dissolved oxygen control and nitrogen removal efficiency.
abstract: Low concentrations of dissolved oxygen (DO) are usually found in biological anoxic pre-denitrification reactors, causing a reduction in nitrogen removal efficiency. Therefore, the reduction of DO in such reactors is fundamental for achieving good nutrient removal. The article shows the results of an experimental study carried out to evaluate the effect of the anoxic reactor hydrodynamic model on both residual DO concentration and nitrogen removal efficiency. In particular, two hydrodynamic models were considered: the single completely mixed reactor and a series of four reactors that resemble plug-flow behaviour. The latter prove to be more effective in oxygen consumption, allowing a lower residual DO concentration than the former. The series of reactors also achieves better specific denitrification rates and higher denitrification efficiency. Moreover, the denitrification food to microrganism (F:M) ratio (F:MDEN) demonstrates a relevant synergic action in both controlling residual DO and improving the denitrification performance.
authors.affiliation: School of Industrial Engineering, University LIUC - Cattaneo, Corso Matteotti, 22, I-21053 Castellanza, Varese, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Raboni
authors.affiliation: Department of Civil Engineering and Computer Science Engineering, University of Rome 'Tor Vergata', Via Politecnico 1, I-00133 Roma, Italy.
authors.forename: Renato
authors.initials: R
authors.lastname: Gavasci
authors.affiliation: Department of Civil and Environmental Engineering, University of Roma La Sapienza, Via Eudossiana 18, I-00184 Rome, Italy E-mail: paolo.viotti@uniroma1.it.
authors.forename: Paolo
authors.initials: P
authors.lastname: Viotti
mesh_terms: D058440:Denitrification; D007700:Kinetics; D008962:Models, Theoretical; D009584:Nitrogen / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000295:instrumentation / Q000379:methods*
chemical_list: D009584:Nitrogen; D010100:Oxygen