High temperature membrane bioreactor treating kraft evaporator condensate under steady and transient conditions
Notice bibliographique
Résumé
Research results from Bérubé (2000) have shown that the treatment of kraft evaporator condensate for reuse using a high temperature membrane bioreactor (MBR) is not only technically feasible, but can also be economically attractive. However, dynamics in daily operating conditions at kraft mills would result in non-steady state loadings to such a treatment system. Hence, the influence of transient operating conditions on an MBR system requires investigation before the system could be considered for full-scale plants. Two bench-scale, high temperature MBRs (called RI for Reactor 1 and R2 for Reactor 2) were operated under conditions proposed by Bérubé (2000) to examine system performance under steady state operation. The operating parameters selected were as follows - 38-day sludge retention time (SRT), 9-hr hydraulic retention time (HRT), and evaporator condensate that contained 1,200 mg methanol /L. During the steady state experiment, the MBRs exhibited stable removal of the main contaminants. Removal efficiencies of 95 % for methanol and 64 % for organic components expressed as total organic carbon (TOC) were observed. Observed growth yields as low as 0.037 for RI and 0.025 for R2 were found. Effects of methanol shock loadings, black liquor spills, and pulp mill shutdown on a high temperature MBR treating condensate were the focus of the present research project. The reactors were subjected to four shock loadings to investigate long-term effects, and one shock loading to identify short-term effects. Results showed that the high temperature MBRs were reasonably stable and able to achieve the same removal efficiency when the load was increased by 1.5 and 2 times instantaneously. Overload of methanol was observed during the methanol shock loading test with 2.5 times the regular methanol concentration. However, the system recovered 4 hours after the short-term shock loadings, and two days after the long-term shock loadings. The MBRs started to shown inhibitory effects after the long-term black liquor carryover test with 8 mL black liquor per litre condensate. During the black liquor carryover test with 16 mL black liquor per litre condensate, methanol removal efficiency was greatly decreased and this negatively influenced TOC and chemical oxygen demand (COD) removal efficiencies. However, the system recovered 4 hours after the short-term shock loadings, and two days after the long-term shock loadings. During the tests, the colour of the MBR permeates remained relatively constant while the dissolved solids concentrations of the permeates increased slightly. Methanol, TOC, and COD utilization coefficients decreased during the shutdown period. However, the MBR system recovered along with resumption of loading fairly well. The MBR was capable of handling the 10-day shutdown period and recovered in 4 days to full capacity. No deleterious effects from 10-day shutdown were observed.
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 ».