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269 results on '"Buelna, Gerardo"'

7. Prolonged operation of a methane biofilter from acclimation to the failure stage.

Author

Ferdowsi, Milad, Khabiri, Bahman, Buelna, Gerardo, Jones, J. Peter, and Heitz, Michèle

Subjects
GREENHOUSE gas mitigation, BIOFILTERS, METHANE, ACCLIMATIZATION
Abstract

Global warming needs immediate attention to reduce major greenhouse gas emissions such as methane (CH4). Bio-oxidation of dilute CH4 emissions in packed-bed bioreactors such as biofilters has been carried out over recent years at laboratory and large scales. However, a big challenge is to keep CH4 biofilters running for a long period. In this study, a packed-bed lab-scale bioreactor with a specialized inorganic-based filter bed was successfully operated over four years for CH4 elimination. The inoculation of the bioreactor was the active leachate of another CH4 biofilter which resulted in a fast acclimation and removal efficiency (RE) reached 80% after seven weeks of operation for CH4 inlet concentrations ranging from 700 to 800 ppmv and an empty bed residence time (EBRT) of 6 min. During four years of operation, the bioreactor often recorded REs higher than 65% for inlet concentrations in the range of 1900–2200 ppmv and an EBRT of 6 min. The rate and interval of the nutrient supply played an important role in maintaining the bioreactor's high performance over the long operation. Forced shutdowns were unavoidable during the 4-year operation and the bioreactor fully tolerated them with a partial recovery within one week and a progressive recovery over time. In the end, the bioreactor's filter bed started to deteriorate due to a long shutdown of twelve weeks and the extended operation of four years when the RE dropped to below 8% with no sign of returning to its earlier performance. [ABSTRACT FROM AUTHOR]

Published
2024
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16. Air biofilters for a mixture of organic gaseous pollutants: an approach for industrial applications.

Author

Ferdowsi, Milad, Khabiri, Bahman, Buelna, Gerardo, Jones, J. Peter, and Heitz, Michèle

Subjects
BIOFILTERS, POLLUTANTS, WASTE gases, WASTE treatment, AIR pollutants, MICROBIAL diversity, BIOSURFACTANTS
Abstract

Hazardous airborne pollutants are frequently emitted to the atmosphere in the form of a gaseous mixture. Air biofilters as the primary biotechnological choice for waste gas treatment (low inlet concentration and high gas flow rate) should run properly when the feed contains multiple pollutants. Simultaneous removal of pollutants in biofilters has been extensively studied over the last 10 years. In this review, the results and findings of the mentioned studies including different groups of pollutants, such as methane (CH4) and volatile organic compounds (VOCs) are discussed. As the number of pollutants in a mixture increases, their elimination might become more complicated due to interactions between the pollutants. Parallel batch studies might be helpful to better understand these interaction effects in the absence of mass transfer limitations. Setting optimum operating conditions for removal of mixtures in biofilters is challenging because of opposing properties of pollutants. In biofilters, concerns, such as inlet gas composition variation and stability while dealing with abrupt inlet load and concentration changes, must be managed especially at industrial scales. Biofilters designed with multi-layer beds, allow tracking the fate of each pollutant as well as analyzing the diversity of microbial culture across the filter bed. Certain strategies are recommended to improve the performance of biofilters treating mixtures. For example, addition of (bio)surfactants as well as a second liquid phase in biotrickling filters might be considered for the elimination of multiple pollutants especially when hydrophobic pollutants are involved. [ABSTRACT FROM AUTHOR]

Published
2023
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19. Methane biofiltration from sanitary landfills in the presence of volatile organic compounds

Author

Heitz, Michèle, Jones, Peter, Buelna, Gerardo, Benyoussef, El-Hadi, Malhautier, Luc, Merouani, El Farouk Omar, Heitz, Michèle, Jones, Peter, Buelna, Gerardo, Benyoussef, El-Hadi, Malhautier, Luc, and Merouani, El Farouk Omar

Abstract

Global warming is a growing concern due to the increase in greenhouse gases (GHG) in the atmosphere. Methane (CH4) contributes to 11% of global GHG emissions and landfills generate 17% of global anthropogenic CH4 emissions. Biotechnologies such as biofiltration offer sustainable solutions for the biotreatment of CH4 (at concentrations lower than 5% v/v), although the presence of other pollutants such as volatile organic compounds (VOCs) in landfill gas (LFG) and low CH4 mass transfer issues need to be considered. Biofiltration of CH4 in complex mixtures with VOCs is yet to be fully understood, with further studies required to strengthen knowledge in this field. This study focuses on the simultaneous biofiltration of CH4 with two aromatic compounds, xylene (X) and ethylbenzene (EB), by studying the effect of operational parameter changes such as empty bed residence time (EBRT) and concentration of CH4, X and EB on biofiltration performances. First, a literature review discussing LFG emissions, conventional LFG abatement methods, the suitability of biotechnologies for LFG removal in old and small landfills, and the challenges and advantages of biofiltration for LFG were provided. Secondly, the simultaneous biofiltration of CH4 in the presence of either X or EB was carried out in inorganic packed bed biofilters (BFs) at an EBRT of 4.5 min at CH4 concentrations in the range of 1000-10000 ppmv and individual VOC concentrations between 200-500 ppmv. The study found that low concentrations of CH4 (2000-6000 ppmv) had a minor effect on the removal efficiency (RE) of the VOCs, with average RE remaining above 85% for VOCs at 200 ppmv. However, at higher CH4 concentrations i.e. 10000 ppmv, inhibition became apparent for both VOCs and CH4, reducing both their REs by 80%. Thirdly, a ternary mixture consisting of CH4, X and EB was treated in an inorganic based-bed BF for CH4 concentrations in the range of 1000-10000 ppmv and VOC concentrations varying from 200 to 600 p, Le réchauffement climatique est une préoccupation croissante en raison de l'augmentation des gaz à effet de serre (GES) dans l'atmosphère. Le méthane (CH4) contribue à 11% des émissions mondiales de GES et les sites d’enfouissement sanitaires (SES) génèrent 17% des émissions anthropiques mondiales de CH4. Les biotechnologies telles que la biofiltration offrent des solutions durables pour le traitement biologique du CH4 (à des concentrations inférieures à 5% v/v), bien que la présence d'autres polluants tels que les composés organiques volatils (COVs) dans le gaz des sites d’enfouissement (GSE) doit être prise en compte. La biofiltration du CH4 dans des mélanges complexes en présence de COVs nécessite des études supplémentaires pour renforcer les connaissances dans ce domaine. Cette étude se concentre sur la biofiltration simultanée du CH4 en présence de deux composés aromatiques, le xylène (X) et l'éthylbenzène (EB) ; l'effet des changements de paramètres opérationnels tels que le temps de séjour en fût vide (EBRT) et la concentration de CH4, de X et de l’EB sur les performances de la biofiltration a été étudiée. Tout d'abord, une revue de littérature a porté sur les émissions de GSE, les méthodes conventionnelles de réduction des GSE, l'adéquation des biotechnologies pour l'élimination des GES dans les anciens SES ou les SES de faible taille, ainsi que sur les défis et avantages de la biofiltration des GES. Ensuite, la biofiltration simultanée du CH4 en présence de X ou de l’EB a été effectuée dans des biofiltres à lit inorganique sous un EBRT de 4.5 minutes pour des concentrations de CH4 comprises entre 1000 et 10000 ppmv et des concentrations individuelles de COVs comprises entre 200 et 500 ppmv. L'étude a révélé que les faibles concentrations de CH4 (2000-6000 ppmv) avaient un effet mineur sur la conversion (RE) des COVs, avec une RE moyenne supérieure à 85% pour les COVs (concentration de 200 ppmv). Cependant, pour des concentrations de CH4 plus élevées, c'est

Published
2023

45. Efficiency of an up-flow Anaerobic Sludge Blanket reactor coupled with an electrochemical system to remove chloramphenicol in swine wastewater

Author

Romero-Soto, Itzel, primary, Garcia-Gomez, Celestino, additional, Leyva-Soto, Luis, additional, Napoles-Armenta, Juan, additional, Concha-Guzman, María, additional, Díaz-Tenorio, Lourdes, additional, Ulloa-Mercado, Ruth, additional, Drogui, Patrick, additional, Buelna, Gerardo, additional, Rentería-Mexia, Ana María, additional, and Gortáres-Moroyoqui, Pablo, additional

Published
2021
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49. An insight into an electro-catalytic reactor concept for high value-added production from crude glycerol: Optimization, electrode passivation, product distribution, and reaction pathway identification

Author

Khosravanipour Mostafazadeh, Ali, primary, De La Torre, Maria Samantha, additional, Padilla, Yessika, additional, Drogui, Patrick, additional, Brar, Satinder Kaur, additional, Tyagi, Rajeshwar Dayal, additional, Le Bihan, Yann, additional, Buelna, Gerardo, additional, and Moroyoqui, Pablo Gortares, additional

Published
2021
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