Influence of the recirculation rate on the performance of Anerobic Aerobic Fixed Bed Reactor (AAFBR)

The objective of this research was to evaluate the influence of the recirculation rate on nutrient removal and on the hydrodynamic behavior of a fixed-bed anaerobic-aerobic reactor, operated on a bench scale, in the treatment of sanitary effluent. Different recirculation ratios (0.5, 1.0 and 1.5) we...

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Bibliographic Details
Authors: Freitas, Daiane Cristina de, Trevizani, Jéssica Luiza Bueno, Rocha, Edna Batista, Carvalho, Karina Querne de, Passig, Fernando Hermes, Tozzi, Adriana Regina, Pedrozo, Carina
Format: article
Status:Published version
Publication Date:2025
Country:Brasil
Institution:Universidade Federal de Santa Maria (UFSM)
Repository:Revista Ciência e Natura (Online)
Language:English
OAI Identifier:oai:ojs.pkp.sfu.ca:article/91482
Online Access:https://periodicos.ufsm.br/cienciaenatura/article/view/91482
Access Level:Open access
Keyword:Combined reactor
Removal of nutrients
Reactor hydrodynamics
Reator combinado
Remoção de nutrientes
Hidrodinâmica de reatores
Description
Summary:The objective of this research was to evaluate the influence of the recirculation rate on nutrient removal and on the hydrodynamic behavior of a fixed-bed anaerobic-aerobic reactor, operated on a bench scale, in the treatment of sanitary effluent. Different recirculation ratios (0.5, 1.0 and 1.5) were tested with a constant air flow of 10 L min-1. During the operation period, the physicochemical parameters were analyzed. Hydrodynamic tests were also carried out using pulse stimulus-response tests with the eosin Y tracer, to evaluate the hydrodynamic behavior and investigate anomalies. The 50% recirculation ratio proved to be the condition with the highest removal efficiency for total solids (83%). The 100% recirculation ratio was the most efficient for TKN (97%) and Nammon (99%). For the recirculation ratio of 150%, the highest removal efficiency was for phosphorus (33%). As for hydrodynamic behavior, according to the correlation of the theoretical uniparametric models tested, it is possible to state that the recirculation ratios of 50%, 100% and 150% presented correlation coefficients that indicate complete mixing, with good hydraulic efficiency for recirculation. of 100%. By varying these factors, it was possible to verify the influence of the recirculation ratio on the removal of nitrogen and phosphorus, as well as on the hydrodynamic behavior of the reactor.