Modelling Biofilm Systems for Wastewater Treatment: Impact of Microscale Features on Global Modelling Results

Biofilm models are effective tools that allow the mathematical description of biofilm systems,the prediction of their removal performance as well as their conceptual exploration. Models have the advantage of being less resource and time consuming than laboratory experiments and being more flexible regarding the scenarios that can be analyzed. Due to the high complexity of biofilms, it is virtually impossible to develop a model that comprises all the phenomena occurring within the biofilm. Simplifications are considered a substantial part of the modelling process, and even the most comprehensive models developed until now make use of assumptions and simplifications. Nevertheless, the vast majority of models fulfill their purpose and are useful to both researches and practitioners (Wanner et al. 2006). The decision on which model is better for which modelling task relies on the data available, the level of understanding of the phenomena occurring in the system and the objective of the modelling task. In the specific case of biofilms, a trade-off between microscale features and global modelling results is often present. A more detailed description of the microscale features does not necessarily lead to more compelling modelling results, and occasionally it can compromise the identifiability and the determination of relevant parameters. However, neglecting microscale features can result in inaccurate representations of the system and thus the explanatory power of the model may be diminished. Depending on the system and its specific conditions, the modeler is presented with a dilemma: Which microscale features are worth including, which simplifications can be afforded and which simplifications are compulsory due to the lack of information. Two microscale features are of special interest in this work: microbial community composition and dimensionality. Three biofilm systems were used to explore the impact that these two microscale features have on the global modelling results and on the model’s explanatory power: A biologically active Granular Activated Carbon (bGAC) filter, a Moving Bed Bioreactor (MBBR) and a Membrane Aerated Biofilm Reactor (MABR). An individual publication is dedicated to each one of these systems. These systems were used to showcase alternative modelling approaches and to illustrate the effect of choosing simple or more complex descriptions of the microscale features of interest. The first and second publication, P1 and P2 respectively, focus on the microbial community composition. Publication P1 deals with DOC removal from WWTP effluents in a bGAC-filter. Within the filter, DOC is removed by simultaneous adsorption and biodegradation, therefore a suitable model should include both mechanisms. It proposes a model that integrates a traditional one-dimensional biofilm model with the ideal adsorbed solution theory that can be applied within the activated sludge model framework. A simplified microbial community composed solely composed of aerobic heterotrophic bacteria is selected. The developed model is able to describe the DOC breakthrough curves at different empty bed contact times and it also shows the relative contribution of biodegradation and adsorption to the total DOC removal. Publication P2 analyzes the behavior of heterotrophic bacteria in an MBBR reactor operating as a Partial Nitritation/ Anammox (PN/A) system. It discusses the growth strategies that hetrotrophic bacteria pursue when facing substrate scarcity. The effect of the yield-strategy is analyzed in two scenarios. In the first scenario a group of heterotrophic bacteria growing on endogenous COD is investigated, whereas in the second scenario, external COD is allowed into the system and a second group of heterotrophs (rate strategist) growing on the more available external COD is added. The competition between both groups over space, and electron acceptor is assessed. In both scenarios the pursuing of the yield strategy seems to be crucial for the diversity of the heterotrophic community. Effluent concentrations as well as heterotrophic produced dinitrogen gas is strongly affected by the growth-strategy that the heterotrophs selected, higher denitrification activities are observed when the yield strategy is selected. Finally dimensionality is the microscale feature of interest in the third publication P3. An MABR reactor used for PN/A is modelled. Publication P3 compares a traditional one-dimensional model and different pseudo two-dimension models that allow the implementation of concentration gradients in the bulk liquid and the gas phase, individually and simultaneously as well as in counter or parallel flow. The results show that the one-dimensional model underestimates the effluent’s total dissolved nitrogen concentration in comparison to the prediction delivered by the pseudo two-dimensional models. Differences in the axial gradients in the biofilm are also observed between the two evaluated modelling approaches. P3 also demonstrates that the concentration gradients in the gas phase have a more significant impact on the modelling results than the concentration gradients in the bulk liquid. The importance of the microscale features: microbial composition and dimensionality is explored. Alongside, the implications on the global modelling results, product of the simplifications of microscale features are investigated. In the case of microbial composition, although more information has been made available due to the new experimental techniques (molecularbiology, imagining etc.) there are still disparities between what can be determined experimentally and how this can be implemented into the existent modelling frameworks. In the case of dimensionality, longitudinal gradients seem to be more influential than it was previously assumed and need to be taken into account to better describe MABRs. The adequate level of complexity required for a microscale feature and in general for a model should be decided based on the modelling goals, the current understanding of the system and the available data

Judicialización de la política y moralización del derecho, un reto para los consultorios jurídicos en Colombia: Una mirada desde el aprendizaje de servicio solidario

Este trabajo presenta el aprendizaje servicio solidario (APS) como una estrategia pedagógica pertinente para abordar, desde la responsabilidad social universitaria (RSU), la judicialización de la política y la moralización del derecho, como reto particular de los consultorios jurídicos, entendidos como escenarios de formación práctica de los estudiantes de derecho. El presente artículo es el resultado de investigación del proyecto denominado: “Laboratorio de Innovación social Universitaria – UNILAB”,  que con el aprendizaje servicio solidario mediado por las Tecnologías de Información y Comunicación (TICS) conforma una comunidad de aprendizaje mutuo para el desarrollo de la comunidad y generación de competencias para la acción política y aprehensión de valores ciudadanos, necesarios para madurar la responsabilidad social del estudiante de derecho y el fortalecimiento de la organización comunal como máxima expresión de participación ciudadana organizada en el Distrito de Cartagena

Analysis of Security Mechanisms Based on Clusters IoT Environments

Internet of things is based on sensors, communication networks and intelligence that manages the entire process and the generated data. Sensors are the senses of systems, because of this, they can be used in large quantities. Sensors must have low power consumption and cost, small size and great flexibility for its use in all circumstances. Therefore, the security of these network devices, data sensors and other devices, is a major concern as it grows rapidly in terms of nodes interconnected via sensor data. This paper presents an analysis from a systematic review point of view of articles on Internet of Things (IoT), security aspects specifically at privacy level and control access in this type of environment. Finally, it presents an analysis of security issues that must be addressed, from different clusters and identified areas within the fields of application of this technology

Método de autoconfiguração para proxies corporativos

Introduction: The proxy servers offer many advantages in business and academia. One of their main uses is to protect both the network and its users, offering a secure and fast connection to multiple users who require a service such as Internet. However, manual proxy settings require time and expertise by the end user, which leads to the network being less user friendly. The article was written in 2016 in the faculty of Engineering of the Universidad Distrital Francisco José de Caldas, Bogotá, Colombia. Methology: The paper has been elaborated at Colombia using a Cascade Model. Results: The article presents an introduction to proxy auto configuration and proxy servers, as well as a detailed explanation of the configuration methods. Conclusions: The study demonstrates methods and times that can lead to the reduction in standard connection time through manual configuration vs. automatic proxy configuration. This was implemented as a real case study in a company.Introducción: los servidores proxy ofrecen muchas ventajas en los negocios y la academia. Uno de sus usos principales es proteger, tanto a la red como a sus usuarios, ofreciendo una conexión segura y rápida a múltiples usuarios que requieren un servicio como el Internet. Sin embargo, los ajustes manuales de los sevidores proxy requieren tiempo y experticia por parte del usuario final, lo que hace que la red sea menos fácil de usar. Este artículo fue escrito en el 2016 en la Facultad de Ingeniería de la Universidad Distrital Francisco José de Caldas, Bogotá, Colombia. Metodología: el trabajo se elaboró en Colombia utilizando un modelo en cascada. Resultados: el artículo presenta una introducción a la configuración automática de proxy y servidores proxy, así como una explicación detallada de los métodos de configuración. Conclusiones: el estudio expone métodos y tiempos que pueden conducir a la reducción del tiempo de conexión estándar, comparando la configuración manual con la configuración automática de proxy. Los hallazgos fueron implementados como estudio de caso real en una empresa.Introdução: os servidores proxies oferecem muitas vantagens nos negócios e na academia. Um de seus usos principais é proteger tanto a rede quanto seus usuários e oferecer uma conexão segura e rápida para múltiplos usuários que requerem um serviço como a internet. Contudo, os ajustes manuais dos servidores proxies requerem tempo e destreza por parte do usuário final, o que faz com que a rede seja menos fácil de usar. Este artigo foi escrito em 2016 na Faculdade de Engenharia da Universidad Distrital Francisco José de Caldas, Bogotá, Colômbia. Metodologia: o trabalho foi elaborado na Colômbia utilizando um modelo em cascata. Resultados: este artigo apresenta uma introdução à configuração automática de proxy e servidores proxies, bem como uma explicação detalhada dos métodos de configuração. Conclusões: o estudo expõe métodos e tempos que podem conduzir à redução do tempo de conexão padrão, comparando a configuração manual com a automática de proxy. Os achados foram implantados como estudo de caso real numa empresa

Instalación y configuración de servicios zentyal para la prestación de servicios.

La finalidad de este artículo es mostrar el trabajo individual de cada integrante y el compilado grupal realizado con los conceptos aprendidos en el curso, creando un trabajo con cada una las temáticas elegidas dadas por la rúbrica de actividades, y que pueden ser puestas en marcha en una empresa en cualquier momento.The purpose of this article is to show the individual work of each member and the group compilation made with the learned concepts in the course, creating an assignment with each one of the chosen themes by the activity rubric and that can be ran in a company anythime

Colombian consensus recommendations for diagnosis, management and treatment of the infection by SARS-COV-2/ COVID-19 in health care facilities - Recommendations from expert´s group based and informed on evidence

La Asociación Colombiana de Infectología (ACIN) y el Instituto de Evaluación de Nuevas Tecnologías de la Salud (IETS) conformó un grupo de trabajo para desarrollar recomendaciones informadas y basadas en evidencia, por consenso de expertos para la atención, diagnóstico y manejo de casos de Covid 19. Estas guías son dirigidas al personal de salud y buscar dar recomendaciones en los ámbitos de la atención en salud de los casos de Covid-19, en el contexto nacional de Colombia

Socializing One Health: an innovative strategy to investigate social and behavioral risks of emerging viral threats

In an effort to strengthen global capacity to prevent, detect, and control infectious diseases in animals and people, the United States Agency for International Development’s (USAID) Emerging Pandemic Threats (EPT) PREDICT project funded development of regional, national, and local One Health capacities for early disease detection, rapid response, disease control, and risk reduction. From the outset, the EPT approach was inclusive of social science research methods designed to understand the contexts and behaviors of communities living and working at human-animal-environment interfaces considered high-risk for virus emergence. Using qualitative and quantitative approaches, PREDICT behavioral research aimed to identify and assess a range of socio-cultural behaviors that could be influential in zoonotic disease emergence, amplification, and transmission. This broad approach to behavioral risk characterization enabled us to identify and characterize human activities that could be linked to the transmission dynamics of new and emerging viruses. This paper provides a discussion of implementation of a social science approach within a zoonotic surveillance framework. We conducted in-depth ethnographic interviews and focus groups to better understand the individual- and community-level knowledge, attitudes, and practices that potentially put participants at risk for zoonotic disease transmission from the animals they live and work with, across 6 interface domains. When we asked highly-exposed individuals (ie. bushmeat hunters, wildlife or guano farmers) about the risk they perceived in their occupational activities, most did not perceive it to be risky, whether because it was normalized by years (or generations) of doing such an activity, or due to lack of information about potential risks. Integrating the social sciences allows investigations of the specific human activities that are hypothesized to drive disease emergence, amplification, and transmission, in order to better substantiate behavioral disease drivers, along with the social dimensions of infection and transmission dynamics. Understanding these dynamics is critical to achieving health security--the protection from threats to health-- which requires investments in both collective and individual health security. Involving behavioral sciences into zoonotic disease surveillance allowed us to push toward fuller community integration and engagement and toward dialogue and implementation of recommendations for disease prevention and improved health security

Membrane Aerated Biofilm Reactors – How longitudinal gradients influence nitrogen removal – A conceptual study

Membrane-aerated biofilm reactors are becoming more important for nitrogen removal in the wastewater sector. One-dimensional (1D) models are widely used to study the performance of such systems; however, 1D models are not able to simulate the longitudinal gradients that exist in the reactor. Although there is experimental evidence that points to the existence of longitudinal gradients simple modeling approaches that consider these gradients are not yet developed. This study proposes a novel multi-compartment model that simulates the longitudinal substrate and oxygen gradients. It assesses the effects of temperature, biofilm thickness, number of compartments, and flow configuration (liquid and gas phase) on the modeling results. Additionally, it compares the capabilities of a traditional 1D model with those of the novel multi-compartment model. Our results show that a classical 1D model predicts a lower total dissolved nitrogen concentration (TDN) in the effluent in contrast to the predictions of the multi-compartment model. In the worst-case scenario, the TDN predicted by the traditional 1D model was three times lower than the prediction of the multi-compartment model. The results delivered by the models differ also in the axial gradients. The traditional 1D model, for example, predicted an oxygen concentration at the membrane surface of 0.4 mg-O2/l while the multi-compartment model predicted a concentration of 2.9 mg-O2/l. Finally, the results of this study show that the longitudinal oxygen gradient has an important effect on both, biomass distribution and effluent TDN, whereas the longitudinal substrate exclusively affected the effluent TDN

Comunidad de aprendizaje de servicio solidario mediado por las Tics: Una estrategia pedagógica para enfrentar la crisis de la enseñanza del derecho en Colombia

Este trabajo presenta una reflexión realizada sobre resultados obtenidos en uno de los casos sistematizados en el proyecto de investigación: “Sistematización de experiencia educativa del consultorio jurídico de la Escuela de Derecho de la Universidad del Sinú Sede Cartagena, período 2012 – 2018”, como escenario de construcción de ciudadanía y formación en valores éticos, cívicos y morales. Mediante el cual se pudo establecer, como constructo teórico, que la comunidad de aprendizaje de servicio solidario mediado por las TICS, resulta una estrategia idónea para enfrentar la crisis en la enseñanza del derecho en Colombia. Dicha enseñanza está caracterizada por la débil responsabilidad social del profesional del derecho con la justicia, la comunidad y con el desarrollo humano sostenible de la comunidad. Los resultados de la sistematización muestran que la incorporación en el aprendizaje de los servicio de las TICS con la metodología b-learnig, permite a las comunidades de aprendizaje superar los obstáculos y limitaciones. Ya que se optimiza en docentes, estudiantes y líderes sociales, el proceso de construcción de valores morales, éticos y cívicos, para la promoción del desarrollo humano sostenible, a través del ejercicio político de una ciudadanía activa. El enfoque de investigación como proyecto se desarrolló bajo el paradigma cualitativo, con sistematización de la experiencia educativa; la técnica de recolección de datos, bajo la observación de los participantes, la revisión documental, así como entrevistas a profundidad y semiestructuradas. Como técnica de análisis de datos se desarrolló la teoría fundamentada que le da cuerpo a esta investigación

Judicialización de la política y moralización del derecho, un reto para los consultorios jurídicos en Colombia: Una mirada desde el aprendizaje de servicio solidario

Este trabajo presenta el aprendizaje servicio solidario (APS) como una estrategia pedagógica pertinente para abordar, desde la responsabilidad social universitaria (RSU), la judicialización de la política y la moralización del derecho, como reto particular de los consultorios jurídicos, entendidos como escenarios de formación práctica de los estudiantes de derecho. El presente artículo es el resultado de investigación del proyecto denominado: “Laboratorio de Innovación social Universitaria – UNILAB”,  que con el aprendizaje servicio solidario mediado por las Tecnologías de Información y Comunicación (TICS) conforma una comunidad de aprendizaje mutuo para el desarrollo de la comunidad y generación de competencias para la acción política y aprehensión de valores ciudadanos, necesarios para madurar la responsabilidad social del estudiante de derecho y el fortalecimiento de la organización comunal como máxima expresión de participación ciudadana organizada en el Distrito de Cartagena