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Numerical simulations with the P-Hydroslag model to predict phosphorus removal by steel slag filters

Dominique Claveau-Mallet, Benoit Courcelles, Philippe Pasquier and Yves Comeau

Article (2017)

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Terms of Use: Creative Commons Attribution Non-commercial No Derivatives .
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Cite this document: Claveau-Mallet, D., Courcelles, B., Pasquier, P. & Comeau, Y. (2017). Numerical simulations with the P-Hydroslag model to predict phosphorus removal by steel slag filters. Water Research, 126, p. 421-432. doi:10.1016/j.watres.2017.09.032
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The first version of the P-Hydroslag model for numerical simulations of steel slag filters is presented. This model main original feature is the implementation of slag exhaustion behavior, crystal growth and crystal size effect on crystal solubility, and crystal accumulation effect on slag dissolution. The model includes four mineral phases: calcite, monetite, homogeneous hydroxyapatite (constant size and solubility) and heterogeneous hydroxyapatite (increasing size and decreasing solubility). In the proposed model, slag behavior is represented by CaO dissolution kinetic rate and exhaustion equations; while slag dissolution is limited by a diffusion rate through a crystal layer. An experimental test for measurement of exhaustion equations is provided. The model was calibrated with an experimental program made of three phases. Firstly, batch tests with 300 g slag sample in synthetic solutions were conducted for the determination of exhaustion equation. Secondly, a slag filter column test fed with synthetic solution was run for 623 days, divided into 9 cells and sampled at the end of the experiment. Finally, the column was dismantled, sampled and analyzed with XRD, TEM and SEM. Experimental column curves for pH, oPO4, Ca and inorganic carbon were well predicted by the model. Crystal sizes measured by XRD and TEM validated the hypothesis for homogeneous precipitation while SEM observations validated the thin crystal layer hypothesis. A preliminary validation of the model resulted in successful predictions of a steel slag filter longevity fed with real wastewater.

Uncontrolled Keywords

Slag, Phosphorus, Wastewater treatment modelling, PHREEQC, Hydroxyapatite, Calcite, Precipitation

Open Access document in PolyPublie
Subjects: 1500 Génie de l'environnement > 1500 Génie de l'environnement
1500 Génie de l'environnement > 1502 Traitement des eaux usées
Department: Département des génies civil, géologique et des mines
Research Center: Non applicable
Grant number: RDCPJ 476673-14
Date Deposited: 30 May 2018 17:05
Last Modified: 19 Sep 2019 01:15
PolyPublie URL: https://publications.polymtl.ca/3134/
Document issued by the official publisher
Journal Title: Water Research (vol. 126)
Publisher: Elsevier
Official URL: https://doi.org/10.1016/j.watres.2017.09.032


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