Investigation into struvite solubility, growth and dissolution kinetics in the context of phosphorus recovery from wastewater
Notice bibliographique
Résumé
The present research was conducted to investigate the mechanisms controlling formation, dissolution and decomposition of the mineral, struvite (MgNH₄PO₄•6H₂O) in the context of phosphorus recovery from wastewater. Solubility, thermodynamics, kinetics and thermal decomposition of struvite were studied in laboratory and wastewater treatment environments to gain knowledge to optimize the phosphorus recovery process from wastewater through struvite crystallization. The thermodynamic solubility products (Ksp) of struvite were determined by extrapolating measured solubility product values to zero ionic strength, with -log Ksp of 13.36(±0.07) at 25⁰C, using an appropriate activity coefficient model. A representative temperature compensation factor (a = 0.0198⁰C-¹) has been derived for electrical conductivity (EC) correction, and a relationship between ionic strength (I) and EC has been developed for anaerobic digester supernatant/centrate samples from five different wastewater treatment plants in western Canada. The metastable region, where nucleation is negligible, for struvite precipitation was explored in this study. This region was used in a kinetics study to suppress nucleation of struvite during growth experiments in a bench-scale fluidized bed reactor (FBR). A linear growth rate model has been tested and proposed, which was found to be effective for struvite growth determination in FBRs. The dissolution processes of struvite were investigated in a batch reactor system using two different theoretical models. The experimental values of struvite dissolution were found to fit well with both models. In a mixed flow-through reactor system, the dissolution rates for struvite pellets were found to increase with the hydrogen ion concentration in the acidic pH, while the rate of dissolution in the alkaline pH was found to increase due to hydroxyl-promoted dissolution. The thermal decomposition study of struvite showed that the simultaneous loss of both ammonia and water molecules from the struvite structure occurred gradually as a function of temperature, rather than as a distinct step. A pilot-scale struvite recovery FBR developed at The University of British Columbia (UBC) was operated, using the knowledge gained from the thermodynamics and kinetics experiments. The pilot-scale FBR was found to be effective in recovering phosphate from anaerobic digester centrate in the form of a nearly pure struvite.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».