Comparison of Thermophilic and Mesophilic Anaerobic Digestion for simulated thin stillage in Fluidized Bed Reactors
Notice bibliographique
Résumé
Anaerobic digestion is a widely used, convenient and long-standing method of sludge treatment before disposal. The process includes hydrolysis, acidogenesis/acetogenesis and methanogenesis. A single or multiple reactor (tank) can be used. However, fluidized bed reactors (AnFBRs) are increasingly becoming popular to promote anaerobic digestion when digesting sludge before final disposal. AnFBRs are characterized by a uniform temperature gradient in the reactor. However, this study has been carried out to establish which media are most optimal for the AnFBRs. Likewise, research has been done to establish the efficiency of the process when either mesophilic or the thermophilic organisms are dominant, keeping in mind the optimum temperature range where these organisms are most efficient. The third part of the study was devoted to investigate how how vomitoxin (deoxynivalenol [DON]), associated with plant pathogens, affected biological methane production kinetics during mesophilic anaerobic digestion.The role of different media on mesophilic anaerobic digestion of simulated thin stillage using fluidized bed reactors was investigated in the first phase. Zeolite, a mineral based medium and plastic, a synthetic media was employed in two lab-scale AnFBRs. The reactor with zeolite showed an increase in the amount of attached biomass (32.4 mg VSS/g of media) when compared with plastic media (19.7 mg VSS/g of media). The maximum thickness of biomass in zeolite was 370 µm compared with 200 µm in the plastic media. From an operational perspective, zeolite was more suitable for the AnFBRs with less floating issue. The zeolite media was better in resisting floatation compared to the plastic media, which floated to the top even with 50% less superficial velocity that was sustained by the zeolite media. The second part compares the operational parameters and efficiency between mesophilic and thermophilic anaerobic digestion of simulated thin stillage conducted in AnFBRs. Two 7-liter working volume AnFBRs were operated mesophilically (37±1˚C) and thermophilically (55 ±1˚C) over different hydraulic retention times (HRT). The plastic media with a diameter of ( dm) in the range of 600-2000 µm was employed as carrier media. Each experimental run continued over a six-month period. At 16, 6 and 4-days HRT, while maintaining the constant chemical oxygen demand (COD) concentration in the feed, Methane composition in biogas from the thermophilic reactor was between 10-15 % more than the amount of methane produced by the mesophilic reactor. Results also suggest that the thermophilic reactor could be operated at lower HRT without the loss of performance. Also, during this operation, it was observed that there was no foaming issue in the reactor. The third part of the study investigated the effects of vomitoxin on biogas and methane production. The anaerobic digestion was conducted in batch reactors. Results indicate that the presence of vomitoxin, even at a high level of 20 ppm, did not harm the anaerobic digestion process of the liquefied corn. The cumulative methane production from reactors with vomitoxin and without vomitoxin remained almost the same. Liquefied corn with 0 g/L vomitoxin (control) produced around 458 mL of methane, while the samples with 1, 5, 10, and 20 ppm of vomitoxin produced around 443, 456, 453, and 459 mL, of methane, respectively. Methane fractions in the biogas for all the bottles were between 51 and 56%. Biogas production and the methane content both remain unaffected even under the presences of 20 ppm of vomitoxin.
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 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) | 0,001 | 0,000 |
| Méta-épidémiologie (sens large) | 0,001 | 0,001 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,001 | 0,001 |
| 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 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 ».