A plant-wide aqueous phase chemistry module describing pH variations and ion speciation/pairing in wastewater treatment process models
Article
Article Title | A plant-wide aqueous phase chemistry module describing pH variations and ion speciation/pairing in wastewater treatment process models |
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ERA Journal ID | 4694 |
Article Category | Article |
Authors | Flores-Alsina, Xavier (Author), Kazadi Mbamba, Christian (Author), Solon, Kimberley (Author), Vrecko, Darko (Author), Tait, Stephan (Author), Batstone, Damien J. (Author), Jeppsson, Ulf (Author) and Gernaey, Krist V. (Author) |
Journal Title | Water Research |
Journal Citation | 85, pp. 255-265 |
Number of Pages | 11 |
Year | 2015 |
Place of Publication | United Kingdom |
ISSN | 0043-1354 |
1879-2448 | |
Digital Object Identifier (DOI) | https://doi.org/10.1016/j.watres.2015.07.014 |
Web Address (URL) | https://www.sciencedirect.com/science/article/pii/S0043135415301160?via%3Dihub#! |
Abstract | There is a growing interest within the Wastewater Treatment Plant (WWTP) modelling community to correctly describe physico–chemical processes after many years of mainly focusing on biokinetics. Indeed, future modelling needs, such as a plant-wide phosphorus (P) description, require a major, but unavoidable, additional degree of complexity when representing cationic/anionic behaviour in Activated Sludge (AS)/Anaerobic Digestion (AD) systems. In this paper, a plant-wide aqueous phase chemistry module describing pH variations plus ion speciation/pairing is presented and interfaced with industry standard models. The module accounts for extensive consideration of non-ideality, including ion activities instead of molar concentrations and complex ion pairing. The general equilibria are formulated as a set of Differential Algebraic Equations (DAEs) instead of Ordinary Differential Equations (ODEs) in order to reduce the overall stiffness of the system, thereby enhancing simulation speed. Additionally, a multi-dimensional version of the Newton–Raphson algorithm is applied to handle the existing multiple algebraic inter-dependencies. The latter is reinforced with the Simulated Annealing method to increase the robustness of the solver making the system not so dependant of the initial conditions. Simulation results show pH predictions when describing Biological Nutrient Removal (BNR) by the activated sludge models (ASM) 1, 2d and 3 comparing the performance of a nitrogen removal (WWTP1) and a combined nitrogen and phosphorus removal (WWTP2) treatment plant configuration under different anaerobic/anoxic/aerobic conditions. The same framework is implemented in the Benchmark Simulation Model No. 2 (BSM2) version of the Anaerobic Digestion Model No. 1 (ADM1) (WWTP3) as well, predicting pH values at different cationic/anionic loads. In this way, the general applicability/flexibility of the proposed approach is demonstrated, by implementing the aqueous phase chemistry module in some of the most frequently used WWTP process simulation models. Finally, it is shown how traditional wastewater modelling studies can be complemented with a rigorous description of aqueous phase and ion chemistry (pH, speciation, complexation). |
Keywords | activity correction, ionic strength, ionic behaviour, dynamic pH prediction, multi-dimensional Newton Raphson, simulated annealing, physico–chemical modelling, water chemistry |
ANZSRC Field of Research 2020 | 401102. Environmentally sustainable engineering |
Public Notes | Files associated with this item cannot be displayed due to copyright restrictions. |
Byline Affiliations | Technical University of Denmark, Denmark |
University of Queensland | |
Lund University, Sweden | |
Jozef Stefan Institute, Slovenia | |
Institution of Origin | University of Southern Queensland |
https://research.usq.edu.au/item/q5316/a-plant-wide-aqueous-phase-chemistry-module-describing-ph-variations-and-ion-speciation-pairing-in-wastewater-treatment-process-models
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