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Membrane Aerated Biofilm Reactors – How longitudinal gradients influence nitrogen removal – A conceptual study

Acevedo Alonso, Vanessa and Lackner, Susanne (2019):
Membrane Aerated Biofilm Reactors – How longitudinal gradients influence nitrogen removal – A conceptual study.
In: Water Research, p. 115060, 166, ISSN 0043-1354,
[Online-Edition: http://www.sciencedirect.com/science/article/pii/S0043135419...],
[Article]

Abstract

Membrane-aerated biofilm reactors are becoming more important for nitrogen removal in the wastewater sector. One-dimensional (1D) models are widely used to study the performance of such systems; however, 1D models are not able to simulate the longitudinal gradients that exist in the reactor. Although there is experimental evidence that points to the existence of longitudinal gradients simple modeling approaches that consider these gradients are not yet developed. This study proposes a novel multi-compartment model that simulates the longitudinal substrate and oxygen gradients. It assesses the effects of temperature, biofilm thickness, number of compartments, and flow configuration (liquid and gas phase) on the modeling results. Additionally, it compares the capabilities of a traditional 1D model with those of the novel multi-compartment model. Our results show that a classical 1D model predicts a lower total dissolved nitrogen concentration (TDN) in the effluent in contrast to the predictions of the multi-compartment model. In the worst-case scenario, the TDN predicted by the traditional 1D model was three times lower than the prediction of the multi-compartment model. The results delivered by the models differ also in the axial gradients. The traditional 1D model, for example, predicted an oxygen concentration at the membrane surface of 0.4 mg-O2/l while the multi-compartment model predicted a concentration of 2.9 mg-O2/l. Finally, the results of this study show that the longitudinal oxygen gradient has an important effect on both, biomass distribution and effluent TDN, whereas the longitudinal substrate exclusively affected the effluent TDN.

Item Type: Article
Erschienen: 2019
Creators: Acevedo Alonso, Vanessa and Lackner, Susanne
Title: Membrane Aerated Biofilm Reactors – How longitudinal gradients influence nitrogen removal – A conceptual study
Language: German
Abstract:

Membrane-aerated biofilm reactors are becoming more important for nitrogen removal in the wastewater sector. One-dimensional (1D) models are widely used to study the performance of such systems; however, 1D models are not able to simulate the longitudinal gradients that exist in the reactor. Although there is experimental evidence that points to the existence of longitudinal gradients simple modeling approaches that consider these gradients are not yet developed. This study proposes a novel multi-compartment model that simulates the longitudinal substrate and oxygen gradients. It assesses the effects of temperature, biofilm thickness, number of compartments, and flow configuration (liquid and gas phase) on the modeling results. Additionally, it compares the capabilities of a traditional 1D model with those of the novel multi-compartment model. Our results show that a classical 1D model predicts a lower total dissolved nitrogen concentration (TDN) in the effluent in contrast to the predictions of the multi-compartment model. In the worst-case scenario, the TDN predicted by the traditional 1D model was three times lower than the prediction of the multi-compartment model. The results delivered by the models differ also in the axial gradients. The traditional 1D model, for example, predicted an oxygen concentration at the membrane surface of 0.4 mg-O2/l while the multi-compartment model predicted a concentration of 2.9 mg-O2/l. Finally, the results of this study show that the longitudinal oxygen gradient has an important effect on both, biomass distribution and effluent TDN, whereas the longitudinal substrate exclusively affected the effluent TDN.

Journal or Publication Title: Water Research
Volume: 166
Uncontrolled Keywords: Membrane aerated biofilm reactor Biofilm Nitrogen removal Oxygen gradient Substrate gradient Multi-compartment model
Divisions: 13 Department of Civil and Environmental Engineering Sciences
13 Department of Civil and Environmental Engineering Sciences > Institute IWAR
13 Department of Civil and Environmental Engineering Sciences > Institute IWAR > Wastewater Engineering
Date Deposited: 17 Oct 2019 07:06
Official URL: http://www.sciencedirect.com/science/article/pii/S0043135419...
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