Biofiltration of volatile compound mixtures from pulp and paper industries

[Resumen] Un biorreactor en dos etapas, consistente en un biofiltro percolador (BTF) como primera etapa y un biofiltro (BF) como segunda etapa, se operó bajo estados estacionario y transitorio, para purificar una mezcla gaseosa compuesta por sulfuro de hidrógeno, metanol y α-pineno. El sulfuro de hidrógeno y el metanol se eliminaron en la primera etapa, mientras que el α- pineno se eliminó fundamentalmente en la segunda etapa. Los biorreactores fueron sometidos a dos tipos de sobrecargas: a largo plazo (66h) con cargas bajas-medias y de corto plazo (12 horas) con altas cargas. Utilizando redes de neuronas artificiales (ANNs), se realizó un modelado para predecir las respectivas eficiencias de eliminación (EEs). Se observó que un perceptrón multicapa con topología 3-4-2 fue capaz de predecir la eliminación del H2S y del metanol en el BTF, mientras que una topología de 3-3-1 fue capaz de aproximar la eliminación del α-pineno en el BF. La misma mezcla gaseosa fue posteriormente examinada en un BTF inoculado con un consorcio microbiano altamente adaptado. Se observó que la presencia del metanol afectó negativamente a la eliminación del α-pineno, sin embargo lo opuesto no sucedió. La eliminación del α-pineno se vió afectada por su propia presencia. El H2S no mostró ningún efecto sobre la eliminación de los otros compuestos. Este BTF también fue modelado usando ANNs y fue también sometido a diferentes tipos de sobrecargas a corto plazo, de cada contaminante por separado. Para el metanol y el sulfuro de hidrógeno, se observó que estas sobrecargas no afectaron significativamente a su propia eliminación, pero la eliminación del α-pineno se vio afectada en un 50%.[Resumo] Un biorreator en dúas etapas consistente nun biofiltro percolador (BTF) como primeira etapa e nun biofiltro (BF) como segunda etapa, foi operado baixo estados estacionario e transitorio, para a purificación dunha mestura gasosa formada por sulfuro de hidróxeno, metanol e α- pineno. O sulfuro de hidróxeno e o metanol foron eliminados na primeira etapa, mentres co α- pineno foi principalmente eliminado na segunda etapa. Os biorreactores foron sometidos a dous tipos de sobrecargas: a longo prazo (66h) con cargas medias-baixas, e de curta duración (12 horas) a cargas elevadas. Utilizando redes de neuronas artificiais (ANNs), realizouse unha modelaxe para prever as correspondentes eficiencias de eliminación (EEs). Observouse que un perceptrón multicapa con topología 3-4-2 foi capaz de prever a eliminación do H2S e do metanol no BTF, mentres que unha topoloxía 3-3-1 foi quen de aproximarse á eliminación do α-pineno no BF. A mesma mestura gasosa foi examinada posteriormente nun BTF inoculado cun consorcio microbiano altamente adaptado. A presenza do metanol afectou negativamente a eliminación do α-pineno, con todo, o contrario non aconteceu. A eliminación de α-pineno, foi afectada pola súa propia presenza. O H2S non mostrou ningún efecto sobre a eliminación dos outros compostos. Este BTF tamén foi modelado utilizando ANNs e tamén foi suxeito a varios tipos de sobrecargas a curto prazo, de cada contaminante por separado. Para o metanol e o sulfuro de hidrógeno observouse que estas sobrecargas non afectaron significativamente as súas eliminacións, pero a eliminación do α-pineno foi afectada nun 50%.[Abstract] A two-stage bioreactor, comprising a biotrickling filter (BTF) as the first-stage and a biofilter (BF) as the second-stage, operated under steady-and transient-state conditions, was tested to remove gas-phase hydrogen sulphide, methanol and α-pinene. Hydrogen sulphide and methanol were removed in the first-stage, while α-pinene, was removed predominantly in the second-stage. The bioreactors were tested with two types of shock loads, long-term (66h) low to medium concentration loads, and short-term (12h) low to high concentration loads. Their performances were modelled using artifitial neural network (ANN), in order to predict the removal efficiencies (REs). It was observed that, a multi-layer perceptron with the topology 3- 4-2 was able to predict RE of methanol H2S in the BTF, while a topology of 3-3-1 was able to approximate RE of α-pinene in the BF. The same gaseous mixture was later examined in a biotrickling filter (BTF), inoculated with a highly adapted microbial consortium. The presence of methanol showed an antagonistic removal pattern for α-pinene, but the opposite did not occur. α-Pinene, removals were affected by itself. H2S did not show any declining effect on the other compounds. This BTF was also modeled using ANNs and subjected to different types of short-term shock-loads. It was observed that, short-term shock-loads of individual pollutants (methanol or hydrogen sulfide) did not significantly affect their own removal, but the removal of α-pinene was affected by 50%

Biofiltration du méthane issu de sites d'enfouissement sanitaire en présence de composés organiques volatils

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 ppmv. The study found that CH4-RE was 41% when its concentration was 2000 ppmv and the concentrations of X and EB were 200 ppmv, at an EBRT of 9 min. Similarly, X and EB-REs were 58% and 57% respectively, at the same concentrations but with a shorter EBRT of 4.5 min. The biodegradation of pollutants in the BF was found to be located at different sections. The highest CH4-RE was in the top section while X and EB-REs were highest in the middle section and were not affected by CH4 concentrations. In the third part of the study, an artificial neural network (ANNs) was used to predict the BF performance. The ANN models accurately predicted dynamic and pseudo-steady-state CH4 and VOCs-REs. The findings suggest the need for a large database to enhance ANN performance in simulating complex CH4 biofiltration kinetics. Overall, this study provides promising results and insights into the simultaneous biofiltration of CH4 with VOCs, highlighting the significance of pollutant concentrations and EBRT. The use of ANNs for performance prediction shows potential for industrial applications, saving time and costs associated with experimentations.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-à-dire 10000 ppmv, une inhibition est apparue à la fois pour les COV et le CH4, réduisant leurs REs respectives de 80%. Ensuite, un mélange ternaire composé de CH4, de X et de l’EB a été traité dans un biofiltre à lit inorganique pour des concentrations de CH4 comprises entre 1000 et 10000 ppmv et des concentrations de COVs variant de 200 à 600 ppmv. L'étude a montré que la RE du CH4 était de 41% lorsque sa concentration était de 2000 ppmv et que les concentrations de X et EB étaient de 200 ppmv, sous un EBRT de 9 minutes. De même, les REs de X et EB étaient de 58% et 57% respectivement, pour des concentrations identiques mais avec un EBRT plus court de 4,5 minutes. La biodégradation des polluants était située dans différentes sections du biofiltre. La RE du CH4 était la plus élevée dans la section supérieure, tandis que les REs de X et de l’EB étaient les plus élevées dans la section intermédiaire et n'étaient pas affectées par les concentrations de CH4. Dans la troisième partie de l'étude, un réseau de neurones artificiels (RNA) a été utilisé pour prédire les performances du biofiltre. Les modèles de RNA ont prédit avec précision les REs dynamiques et pseudo-stationnaires du CH4 et des COVs. Les résultats suggèrent la nécessité d'une grande base de données pour améliorer les performances des RNAs dans la simulation de la cinétique de la biofiltration complexe du CH4. Dans l'ensemble, cette étude fournit des résultats prometteurs et des connaissances sur la biofiltration simultanée du CH4 en présence de COVs et met en évidence l'importance des concentrations de polluants et de l'EBRT. L'utilisation des RNAs pour la prédiction des performances montre un potentiel pour des applications industrielles, ce qui permettrait d'économiser du temps et des coûts liés aux expérimentations

Current Air Quality Issues

Air pollution is thus far one of the key environmental issues in urban areas. Comprehensive air quality plans are required to manage air pollution for a particular area. Consequently, air should be continuously sampled, monitored, and modeled to examine different action plans. Reviews and research papers describe air pollution in five main contexts: Monitoring, Modeling, Risk Assessment, Health, and Indoor Air Pollution. The book is recommended to experts interested in health and air pollution issues

Book of abstracts of the 10th International Chemical and Biological Engineering Conference: CHEMPOR 2008

This book contains the extended abstracts presented at the 10th International Chemical and Biological Engineering Conference - CHEMPOR 2008, held in Braga, Portugal, over 3 days, from the 4th to the 6th of September, 2008. Previous editions took place in Lisboa (1975, 1889, 1998), Braga (1978), Póvoa de Varzim (1981), Coimbra (1985, 2005), Porto (1993), and Aveiro (2001). The conference was jointly organized by the University of Minho, “Ordem dos Engenheiros”, and the IBB - Institute for Biotechnology and Bioengineering with the usual support of the “Sociedade Portuguesa de Química” and, by the first time, of the “Sociedade Portuguesa de Biotecnologia”. Thirty years elapsed since CHEMPOR was held at the University of Minho, organized by T.R. Bott, D. Allen, A. Bridgwater, J.J.B. Romero, L.J.S. Soares and J.D.R.S. Pinheiro. We are fortunate to have Profs. Bott, Soares and Pinheiro in the Honor Committee of this 10th edition, under the high Patronage of his Excellency the President of the Portuguese Republic, Prof. Aníbal Cavaco Silva. The opening ceremony will confer Prof. Bott with a “Long Term Achievement” award acknowledging the important contribution Prof. Bott brought along more than 30 years to the development of the Chemical Engineering science, to the launch of CHEMPOR series and specially to the University of Minho. Prof. Bott’s inaugural lecture will address the importance of effective energy management in processing operations, particularly in the effectiveness of heat recovery and the associated reduction in greenhouse gas emission from combustion processes. The CHEMPOR series traditionally brings together both young and established researchers and end users to discuss recent developments in different areas of Chemical Engineering. The scope of this edition is broadening out by including the Biological Engineering research. One of the major core areas of the conference program is life quality, due to the importance that Chemical and Biological Engineering plays in this area. “Integration of Life Sciences & Engineering” and “Sustainable Process-Product Development through Green Chemistry” are two of the leading themes with papers addressing such important issues. This is complemented with additional leading themes including “Advancing the Chemical and Biological Engineering Fundamentals”, “Multi-Scale and/or Multi-Disciplinary Approach to Process-Product Innovation”, “Systematic Methods and Tools for Managing the Complexity”, and “Educating Chemical and Biological Engineers for Coming Challenges” which define the extended abstracts arrangements along this book. A total of 516 extended abstracts are included in the book, consisting of 7 invited lecturers, 15 keynote, 105 short oral presentations given in 5 parallel sessions, along with 6 slots for viewing 389 poster presentations. Full papers are jointly included in the companion Proceedings in CD-ROM. All papers have been reviewed and we are grateful to the members of scientific and organizing committees for their evaluations. It was an intensive task since 610 submitted abstracts from 45 countries were received. It has been an honor for us to contribute to setting up CHEMPOR 2008 during almost two years. We wish to thank the authors who have contributed to yield a high scientific standard to the program. We are thankful to the sponsors who have contributed decisively to this event. We also extend our gratefulness to all those who, through their dedicated efforts, have assisted us in this task. On behalf of the Scientific and Organizing Committees we wish you that together with an interesting reading, the scientific program and the social moments organized will be memorable for all.Fundação para a Ciência e a Tecnologia (FCT

Proceedings of the 10th International Chemical and Biological Engineering Conference - CHEMPOR 2008

This volume contains full papers presented at the 10th International Chemical and Biological Engineering Conference - CHEMPOR 2008, held in Braga, Portugal, between September 4th and 6th, 2008.FC

Recycled Materials in Civil and Environmental Engineering

The aim of this reprint was to report recent innovative studies based on the use of secondary raw materials for applications in civil and environmental engineering. To this purpose, papers were related to the preparation of innovative construction materials and to the treatment of wastes for environmental applications. The investigations were characterized by a common purpose, i.e., to find a way to reduce the amount of waste generated, thus reducing the need for landfilling and optimizing the values of these novel materials, which are an abundant resource that can be easily reused for different applications