A systematic study of multiple minerals precipitation modelling in wastewater treatment

Kazadi Mbamba, Christian, Tait, Stephan, Flores-Alsina, Xavier and Batstone, Damien J. (2015) A systematic study of multiple minerals precipitation modelling in wastewater treatment. Water Research, 85 359-370. doi:10.1016/j.watres.2015.08.041

Author Kazadi Mbamba, Christian
Tait, Stephan
Flores-Alsina, Xavier
Batstone, Damien J.
Title A systematic study of multiple minerals precipitation modelling in wastewater treatment
Journal name Water Research   Check publisher's open access policy
ISSN 1879-2448
Publication date 2015-11-15
Year available 2015
Sub-type Article (original research)
DOI 10.1016/j.watres.2015.08.041
Open Access Status Not Open Access
Volume 85
Start page 359
End page 370
Total pages 12
Place of publication London, United Kingdom
Publisher IWA Publishing
Collection year 2016
Language eng
Formatted abstract
Mineral solids precipitation is important in wastewater treatment. However approaches to minerals precipitation modelling are varied, often empirical, and mostly focused on single precipitate classes. A common approach, applicable to multi-species precipitates, is needed to integrate into existing wastewater treatment models. The present study systematically tested a semi-mechanistic modelling approach, using various experimental platforms with multiple minerals precipitation. Experiments included dynamic titration with addition of sodium hydroxide to synthetic wastewater, and aeration to progressively increase pH and induce precipitation in real piggery digestate and sewage sludge digestate. The model approach consisted of an equilibrium part for aqueous phase reactions and a kinetic part for minerals precipitation. The model was fitted to dissolved calcium, magnesium, total inorganic carbon and phosphate. Results indicated that precipitation was dominated by the mineral struvite, forming together with varied and minor amounts of calcium phosphate and calcium carbonate. The model approach was noted to have the advantage of requiring a minimal number of fitted parameters, so the model was readily identifiable. Kinetic rate coefficients, which were statistically fitted, were generally in the range 0.35–11.6 h−1 with confidence intervals of 10–80% relative. Confidence regions for the kinetic rate coefficients were often asymmetric with model-data residuals increasing more gradually with larger coefficient values. This suggests that a large kinetic coefficient could be used when actual measured data is lacking for a particular precipitate-matrix combination. Correlation between the kinetic rate coefficients of different minerals was low, indicating that parameter values for individual minerals could be independently fitted (keeping all other model parameters constant). Implementation was therefore relatively flexible, and would be readily expandable to include other minerals.
Keyword Physico-chemical modelling
Parameter estimation
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2016 Collection
Advanced Water Management Centre Publications
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