Removal of contaminants of emerging concern (CECs) from wastewater using Pilot Ozonation Technology
Notice bibliographique
Résumé
There is a growing concern about contaminants of emerging concern (CECs) found in the environment. These CECs include pharmaceuticals, personal care products and illicit drugs that are often not easily removed using conventional treatment technologies. Aclarus has developed a low-cost, low energy ozonation system that may be applied to the treatment of wastewater. The objective of this thesis was to test the potential of the ozonation used as a disinfection technology, to remove CECs and reduce toxicity. The evaluation was performed using the Aclarus AOWWT-10 pilot ozonation unit applied to the secondary effluent at the wastewater treatment plant in Peterborough, Ontario. The unit was operated in parallel to a full-scale ultraviolet (UV) disinfection unit. A suite of illicit drugs and indicator compound were selected as a representative sample of CECs in wastewater. Wastewater samples collected prior to and after ozone or UV treatment were extracted using solid-phase extraction, and thereafter quantified for target compounds using LC/MS-MS (Orbitrap XL, Thermo) and subjected to toxicity testing. From experimental results, ozonation treatment led to disinfection levels comparable to the level obtained in the full-scale UV treatment system (>99% disinfection based on Escherichia coli counts), but yielded much higher CEC removals for a large variety of target compounds, with an average of 86% for ozonation compared to an average of 7% for UV. Statistical analysis showed that both flow rate of water through the ozonation system, as well as the level of ozone generation (i.e. ozone dose) significantly affected the removal of CECs, while the interaction between the two factors, and also system pressure had no significant effects. Based on the results of a factorial design experimental plan, optimal CEC removal can be obtained by running the Aclarus system at a flow rate of 5 gal/min, with the use of two ozone generators fed by oxygen, corresponding to an ozone dose of 5.3 mg/L. Flow rates lower than 5 gal/min were found to cause no significant additional removal of CECs.Toxicity analysis of the samples using the Microtox systems indicated that ozone-treated samples had decreased toxicity as compared to pre-treated water (secondary effluent), whilst post-UV treated water were shown to have increased toxicity after UV treatment. These results confirm our hypothesis that ozonation has additional benefits, CEC removal and decreased toxicity, even when used as a disinfection unit.
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Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| 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 | 0,001 | 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) | 0,001 | 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 source (Gemma direct ou Codex distillé), 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 ».