Dynamical Modelling and Simulation of Waste water Filtration Process by Submerged Membrane Bioreactors

A mathematical model was developed for the filtration process and the influence of aeration on Submerged Membrane Bioreactors. The dynamics of sludge attachment to and detachment from the membrane, in relation to the filtration and a strong intermittent aeration, were included in the model. The influence on the membrane fouling of intermittent aeration injected on the membrane surface, and its synchronization with intermittent filtration, were studied numerically and experimentally. For the evaluation of filtration cake development, the assumption of the presence of two cake layers (one dynamic and the other stable) was considered. The model development and simulation focused on the description of existing relationships among important system variables like mixed liquor suspended solids concentration, aeration, temperature of the sludge suspension, transmembrane pressure, and the fouling increase during the filtration process. The model obtained offers the possibility of improving the design configuration and operation strategies of Submerged Membrane Bioreactors in wastewater treatment, and it allows the of aeration-filtration cycles to be optimized

Desarrollo de modelos dinamicos para la simulacion y optimizacion de biorreactores con membrana sumergida para el tratamiento de aguas residuales

This thesis studies a submerged membrane bioreactor (MBR) technology that is used to treat effluents. We present in detail the modeling of this process, the validation of developed models, and the results of simulation and optimization carried out with the above mentioned models. The new contributions to scientific knowledge of this work are the following: - A new dynamic model that integrates for such systems, many of the variables and the main phenomena occurring during the process of filtration in MBR wastewater treatment. That constitutes an original contribution to the analysis and development of this technology. – The simulation allows to achieve the quantification of the influence and effect of aeration on the process (membranes fouling) and the influence of the sequencing of the filtration and coarse bubbles aeration cycles. All that takes into account the behavior of biomass, the generation of exopolymeric substances and inlet characteristics. The results provided by the model are validated by comparison with experimental results. – An optimization of MBR operating conditions using the experimental design for simulation, is reported based on the results obtained using the developed model

Modelling of submerged membrane bioreactor: Conceptual study about link between activated slugde biokinetics, aeration and fouling process

A mathematical model was developed to simulate filtration process and aeration influence on Submerged Membrane Bioreactor (SMBR) in aerobic conditions. The biological kinetics and the dynamic effect of the sludge attachment and detachment from the membrane, in relation to the filtration and a strong intermittent aeration, were included in the model. The model was established considering soluble microbial products (SMP) formation-degradation. The fouling components responsible of pore clogging, sludge cake growth, and temporal sludge film coverage were considered during calculation of the total membrane fouling resistance. The influence of SMP, trans-membrane pressure, and mixed liquor suspended solids on specific filtration resistance of the sludge cake was also included. With this model, the membrane fouling under different SMBR operational conditions can be simulated. The influence of a larger number of very important process variables on fouling development can be well quantified. The model was developed for evaluating the influence on fouling control of an intermittent aeration of bubbles synchronized or not with the filtration cycles, taking into account the effects of shear intensity on sludge cake removal

Modelación y optimización de biorreactores con membranas para el tratamiento de aguas residuales

El uso de los biorreactores con membranas (BRM) ha ganado un espacio importante en el tratamiento de aguas residuales urbanas e industriales en los últimos años, debido fundamentalmente a las ventajas que ofrecen sobre los procesos convencionales tales como: mayor calidad del agua, menor impacto ambiental y un mejor control de los procesos. En el presente trabajo se realiza un análisis de la evolución de la modelación de estos sistemas tan complejos, en el que se muestra el gran avance que se ha podido alcanzar en los últimos años en la modelación tanto del sistema biológico como del sistema de filtración. Se destaca, la importancia de la Dinámica Computacional de Fluidos en el estudio del funcionamiento de estos sistemas, específicamente, en el estudio del proceso de colmatación de la membrana. Se explica, además, la tendencia actual al empleo de modelos que integran los procesos de degradación biológic a con la hidrodinámica y los de filtración con membranas, con lo que se logra una descripción más fenomenológica del funcionamiento de los BRM. Por último, se resalta la importancia de los modelos integrados en la optimización de su funcionamiento mediante su implementación a través de herramientas computacionales, lo que permite realizar estudios con un considerable ahorro de recursos y de tiemp

Perspectivas y experiencias en el empleo de tecnologias no convencionales en el tratamiento de residuales liquidos

Parte de los residuales que genera la industria y la actividad social son corrientes acuosas, que pueden contener compuestos tóxicos y poco biodegradables, donde el tratamiento biológico analiza la importancia de las técnicas no convencionales en el tratamiento de residuales y la descontaminación de aguas. Entre los procesos novedosos se encuentran el ultrasonido, la oxidación catalítica y los reactores con biomembranas. El ultrasonido se emplea en la degradación de compuestos refractarios que no pueden ser tratados por métodos biológicos, en mejorar la degradación biológica y en la desintegración de lodos. La oxidación catalítica es más prometedora desde el punto de vista económico, para el tratamiento de aguas residuales con contaminantes persistentes. El empleo del carbón activado como catalizador en el tratamiento de residuales por oxidación catalítica abre un camino importante en el uso extensivo de este proceso. Los biorreactores de membranas ofrecen un grupo de ventajas relacionadas con la calidad y su reutilización, la reducción de lodos, la estabilidad del permeado con independencia de picos de carga y menores requerimientos de espacio. Estas tecnologías pueden emplearse combinadas entre sí o con los procesos convencionales. La elección del esquema de tratamiento dependerá de las características del residual a tratar o del agua a recuperar, de los volúmenes y de los requisitos que se establezcan para el agua tratada

A filtration model applied to submerged anaerobic MBRs (SAnMBRs)

The aim of this study was to develop a model able to correctly reproduce the filtration process of submerged anaerobic MBRs (SAnMBRs). The proposed model was calibrated and validated in a SAnMBR demonstration plant fitted with industrial-scale hollow-fibre membranes. Three suspended components were contemplated in the model: total solids concentration; dry mass of cake on the membrane surface; and dry mass of irreversible fouling on the membrane surface. The model addressed the following physical processes: the build-up and compression of the cake layer during filtration; cake layer removal using biogas sparging to scour the membrane; cake layer removal during back-flushing; and the consolidation of irreversible fouling. The short- and long-term validation of the model resulted in correlation coefficients (R-2) of 0.962 and 0.929, respectively.This research has been supported by the Spanish Ministry of Economy and Competitiveness (MINECO Project CTM2011-28595-C02-01/02) jointly with the European Regional Development Fund (ERDF), which are gratefully acknowledged.Robles Martínez, Á.; Ruano García, MV.; Ribes Bertomeu, J.; Seco Torrecillas, A.; Ferrer, J. (2013). A filtration model applied to submerged anaerobic MBRs (SAnMBRs). Journal of Membrane Science. (444):139-147. https://doi.org/10.1016/j.memsci.2013.05.021S13914744

Europa ante su futuro. Una visión desde Euskadi

Jornada: Europa ante su futuro. Una visión desde Euskadi 27 de octubre de 200

Table S1: List of the best fitting-models for the nucleotide phylogenetic analyses according to BIC value. The lower the BIC value, the better the model fits with the data. AIK, Akaike Information Criterion; BIC, Bayesian Information Criterion; INL, Natural log lik

There is only one exception to strict maternal inheritance of mitochondrial DNA (mtDNA) in the animal kingdom: a system named doubly uniparental inheritance (DUI), which is found in several bivalve species. Why and how such a radically different system of mitochondrial transmission evolved in bivalve remains obscure. Obtaining a more complete taxonomic distribution of DUI in the Bivalvia may help to better understand its origin and function. In this study we provide evidence for the presence of sex-linked heteroplasmy (thus the possible presence of DUI) in two bivalve species, i.e., the nuculanoid Yoldia hyperborea(Gould, 1841)and the veneroid Scrobicularia plana(Da Costa,1778), increasing the number of families in which DUI has been found by two. An update on the taxonomic distribution of DUI in the Bivalvia is also presented

Modélisation et simulation dynamique du traitement des effluents par bioréacteurs à membranes immergées.

Le traitement des effluents et eaux usées par bioréacteurs à membranes immergées (BAMI) permet d’obtenir une haute qualité de perméat par une dégradation biologique et une séparation physique. Néanmoins, le procédé de filtration est limité par l'influence de facteurs très complexes, en particulier le colmatage de la membrane. Le but du travail est de développer un modèle dynamique et de simuler le procédé de filtration dans les BAMI. Le développement et la simulation des modèles ont été ciblés sur la description des rapports existants entre les variables les plus importantes du système, comme la pression transmembranaire (PTM), les matières en suspension (MES), et le développement du colmatage pendant la filtration. L'influence sur l'évolution du colmatage d'une aération syncopée, injectée à la surface de membrane, et sa synchronisation avec une filtration intermittente ont été étudiées, par voie numérique et expérimentale. Pour l'évaluation du développement du gâteau de filtration, l'hypothèse de la croissance de deux couches de gâteau (une dynamique et l'autre stable) a été émise. Le modèle ainsi développé permet l'étude, le contrôle et l'optimisation des BAMI. Le développement du gâteau et l'influence des cycles intermittents d'aération-filtration sur le colmatage de la membrane et sur l’évolution des résistances à la filtration ont pu être simulés. Le rôle des MES et de l’injection intermittente de grosses bulles à la surface de la membrane, ainsi que son influence sur la croissance du gâteau, ont été pris en considération dans la construction du modèle. Ce dernier permet alors de prévoir le comportement de la PTM

Optimization of wastewater filtration process in submerged membrane bioreactors : applicability of a dynamic model to scale up.

Abstract. The application of a hybrid mathematical model, which takes into account the effect of main variables in Submerged Membrane Bioreactor (SMBR) systems, was established in order to simulate and optimize the FILTRATION process into SMBR, on the base of experimental data performed on a bench and pilot scale bioreactors. The validity of the numerical process in the scale up of the water treatment process was checked. Numerical simulations of the wastewater treatment process were performed in order to find the optimal filtration conditions for both different scale bioreactors. Various operating conditions (idlefiltration time, aeration intensity, solids retention time, hydraulics retention time, and total suspended solids concentration) were tested. Different optimization criteria were considered to minimize the transmembrane pressure and energy consumption, and to maximize filtrate flow