Study of performance of nitrification process

AbstractThe objective of this paper was to study the static behavior and the performance of an experimentally validated model for nitrification process using a single reactor high activity ammonia removal over nitrite (SHARON) process. The model consists of mass balances of total ammonium, total nitrite, ammonium oxidizers, and nitrite oxidizers. The steady state analysis allowed the construction of practical diagrams that show the effect of operating conditions (dilution rate and ammonium feed concentration) as well as kinetic parameters on the performance of the bioreactor. The focus is made on the region that allows for the conversion of ammonium to nitrite and the prevention of further oxidation of nitrite to nitrate. The findings of this study are applicable which can delineate the effect of process variables on the performance of the bioreactor

Modelado neuronal de un proceso de digestión aeróbica de aguas residuales

Los procesos biológicos para el tratamiento de agua residual son sistemas altamente no lineales que están sometidos a incertidumbres y perturbaciones externas, se ha creído ampliamente que los modelos que describen las reacciones bioquímicas y procesos de sedimentación son muy complejos y difíciles de manejar exactamente con fines de control. Por tal motivo se requieren estrategias avanzadas para la identificación, estimación de parámetros no medibles del proceso y control.En este trabajo se propone una red neuronal no lineal en tiempo discreto en presencia de perturbaciones externas y estimación de los estados dinámicos difíciles de medir en un proceso de digestión aerobia para tratamiento de agua residual. Se presentan resultados de estimación vía simulación, donde se demuestra que el modelo neuronal propuesto es eficiente para la estimación de las dinámicas de los estados en presencia de perturbaciones. Con este modelo neuronal será posible diseñar una estrategia de control para optimizar el rendimiento de la degradación de materia orgánica en un proceso de digestión aerobia usando técnicas de control óptimo y estimación neuronal.Keywords— Modelo ASM1, Red neuronal, dinámicas no lineales, agua residual

Development of attached growth microbial fuel cell (ag-mfc) for treatment of spent caustic wastewater and energy recovery

Insufficiently treated wastewater and dependability to fossil fuel as the main source of energy led to serious water pollution and depletion of energy resources problem. Spent caustic wastewater is a highly toxic wastewater generated by the petroleum chemical plants. Due to its noxious properties, it required special management for its disposal. Chemical and thermal treatment methods which produced partial oxidation of spent caustic of wastewater are the common industrial practice. This study aims to produce effective treatment of spent caustic wastewater and energy recovery using Attached Growth Microbial Fuel Cell (AG-MFC). AG-MFC a system integrating the MFCs application with suspended GAC as bacterial attachment medium. The GAC addition into the system allowed the presence of attached biomass which has higher growth rate leading to a higher amount of microorganism. Attached biomass are also more resistant to physical and chemical force. These features improved the biomass adaptability in spent caustic. The study began with determination of optimum GAC dosage whereby 0 g to 25 g of GAC dosage was tested. Then, its optimum operating conditions in terms of Mixed Liquor Suspended Solid (MLSS), Solid Retention Time (SRT) and Organic Loading Rate (OLR) were determined by varying the operating conditions of MLSS from 2500 to 4000 mg/L, SRT from 10 to 30 days and OLR at from 700 to 900 mg COD/L.d. The AG-MFC performance was evaluated based on chemical oxygen demand (COD) and sulfide removal and voltage output. The dominant bacteria attached was identified using the molecular method and their morphology was observed using microscopic analysis. Finally, the COD fractionations of spent caustic wastewater were determined using respirometric analysis and the design parameters that described the biological process in the AG-MFC were determined using Activated Sludge Model No. 1 (ASM1). The finding demonstrated 10 g of GAC its optimum dosage since it produced the highest COD and sulfide removal of 97.56% and 96.25% respectively and high voltage output of 583 mV. Higher GAC addition from 0 to 10 g increased the biomass attached. However, there was excessive microorganisms at GAC dosage of higher than 10 g which was not favourable for the AG-MFC operation. The optimum operating conditions of the AG-MFC were at MLSS of 3500 mg/L, SRT of 20 days and OLR of 700 mg/L.d as AG-MFC possessed highest COD removal trend of beyond than 90% at these conditions. High MLSS and SRT were favourable for AG-MFC operation since a higher MLSS increased the amount of microorganisms and higher SRT prolonged the time for bacteria to reproduce. Higher OLR reduced the AG-MFC removal efficiency due to excessive substrates beyond the degradation capacity of the microorganisms. The AG-MFC biomass was dominated with Proteobacteria, which are Gram-negative and have flagella for mechanical attachment on GAC. Increasing OLR has also increased the slowly biodegradable COD (Xs) fraction which explained the low removal efficiency of AG-MFC at high OLR. From the dynamic simulation, it is found that increasing OLR reduced the maximum specific growth rate of heterotrophic microorganisms (μmaxH) and increased heterotrophic decay (bH). This condition indicated higher new soluble and non-biodegradable fractions generated from the decaying biomass which caused low removal at high OLR. This study has demonstrated AG-MFC capacity in producing complete degradation of spent caustic wastewater and is most suitable to serve as the secondary treatment of spent caustic wastewater in the refinery industr

Modelagem por redes neurais do sistema biológico do tratamento de efluentes em refinarias de petróleo

Resumo: A necessidade de preservação do meio ambiente tem direcionado atenção do setor industrial às unidades de tratamento de efluentes. Dentre as diversas tecnologias existentes, o tratamento biológico por lodos ativados é uma das mais utilizadas, devido a sua excelente robustez. Na indústria do petróleo, não é diferente, devido principalmente a sua elevada eficiência na remoção de nitrogênio amoniacal. No entanto, a eficiência desta tecnologia está diretamente relacionada com a qualidade do efluente a ser tratado. Uma variação brusca na composição da entrada do sistema pode provocar choques químicos no sistema biológico, ou seja, inibir as reações, alterando significativamente a qualidade do efluente tratado, com o risco de não se atender a legislação. Desta forma, é muito importante prever os resultados da planta quando há uma perturbação nas variáveis de entrada, de forma que ações preventivas possam ser tomadas, minimizando os impactos. No entanto, elaborar um modelo fenomenológico de um sistema de tratamento biológico é uma tarefa extremamente difícil e exaustiva, devido à complexidade das reações envolvidas e a não linearidade do sistema. Devido a isto, a modelagem do sistema de lodos ativados utilizando a técnica de Redes Neurais torna-se uma alternativa viável e interessante. A modelagem por redes neurais foi aplicada no sistema biológico de tratamento de efluentes da Refinaria Presidente Getúlio Vargas - Petrobras, com o objetivo de estimar o teor de nitrogênio amoniacal no efluente tratado, a partir de dados de qualidade da carga e de variáveis medidas diretamente na planta. Os teores de DQO e NH3 na entrada do sistema, os teores de oxigênio dissolvido e os valores de pH do meio foram utilizados como dados de entrada da rede e são dados reais obtidos da unidade. Foram simuladas diversas estruturas utilizando o programa Simulated Annealing, como algoritmo de otimização. Os resultados obtidos na modelagem deste sistema mostram o potencial desta ferramenta na predição do teor de contaminantes no efluente tratado, que pode no futuro, ser implantada na unidade e servir como base para a tomada de decisão de ações preventivas quando da ocorrência de distúrbios operacionais

Avaliação dos modelos matemáticos ASM1 e ASM3 calibrados com dados de monitoramento padrão de um sistema de lodos ativados

O uso de modelos matemáticos de lodos ativados combinados com softwares computacionais tem sido amplamente empregado nas últimas décadas. Essa é uma ferramenta que possibilita avaliar condições de operação do tratamento e identificar pontos críticos do sistema de lodos ativados, que podem ser otimizados. Existem numerosos softwares disponíveis para modelagem e simulação de plantas de lodos ativados, entretanto a aplicação prática dessas ferramentas é bastante limitada. Uma das principais razões para tal situação é a dificuldade do processo de calibração dos modelos, que requer dados não incluídos no plano de monitoramento padrão de Estações de Tratamento de Esgoto – ETE. Como exemplo, caracterização detalhada e dados de monitoramento afluente e efluente de cada etapa do tratamento, fracionamento das concentrações de Demanda Química de Oxigênio – DQO e Nitrogênio – N, além de caracterização de parâmetros cinéticos e estequiométricos. Nesse cenário, a finalidade deste trabalho consistiu em avaliar a aplicabilidade dos modelos matemáticos ASM1 e ASM3 calibrados com dados de monitoramento padrão de um sistema de lodos ativados. O software de simulação computacional Stoat 5.0 foi utilizado para estruturar um sistema de lodos ativados, que opera com capacidade para tratar 444 L/s, aos modelos matemáticos a ASM1 e ASM3. Os modelos foram estruturados utilizando informações do projeto hidráulico e operação da ETE. Com os modelos estruturados e calibrados, a qualidade do efluente tratado foi simulada em resposta a variação da razão de retorno do lodo, de descarte do lodo, e temperatura. Os resultados demonstram que o conjunto de dados de monitoramento padrão disponíveis da ETE foi suficiente para calibrar os modelos e simular o desempenho do sistema considerando condições de operação em estado estacionário. Sendo assim, pode ser útil para diferentes finalidades, incluindo: treinamento de operadores da ETE, observação da resposta da planta às mudanças nos parâmetros operacionais básicos como: fluxos de retorno e vazão de descarte do lodo, e resposta em função da variação de fatores externos, como a temperatura. Os modelos ASM1 e ASM3, após serem calibrados, responderam de forma similar nos cenários analisados. A calibração estática dos modelos matemáticos ASM1 e ASM3 aplicados em simuladores computacionais são ferramentas que podem ter elevado utilidade na gestão de sistemas de lodos ativados.The use of mathematical models of activated sludge process combined with computational softwares has been widely used in recent decades. This is a tool that allows you to evaluate the operating conditions of the treatment and identify the critical points of the activated sludge system, which can be optimized. There is numerous software available for modeling and simulation of activated sludge plants, however, the application of these tools is quite limited. One of the main reasons for this situation is the difficulty in the model calibration process, which requires data not included in the standard monitoring plan for Wastewater Treatment Plants - WWTPs. As an example, detailed characterization and data of the monitoring influents and effluents from each treatment unit process, Chemical Oxygen Demand - COD and Nitrogen – N fractions, in addition to characterization of kinetic and stoichiometric parameters. In this scenario, the purpose of this paper was to evaluate the applicability of the mathematical models ASM1 and ASM3 calibrated with standard monitoring data from an activated sludge system. The computer simulation software Stoat 5.0 was used to structure a system of activated sludge, which operates with the capacity to treat 444 L / s, using the mathematical models ASM1 and ASM3. The models were structured using information from the WWTP hydraulic project and operation. With the structured and calibrated models, the quality of the effluent was simulated in response to the variation of the sludge return rate, sludge wastage, and temperature. The results demonstrate that the standard monitoring data available from the WWTP was enough to calibrate the models and simulate the performance of the system considering operating conditions in steady state. Therefore, it can be useful for different purposes, including: training of WWTP operators, observation of the plant's response to changes in basic operating parameters such as: return flows and sludge wastage flow, and response depending on the variation of external factors , such as temperature. The ASM1 and ASM3 models, after being calibrated, responded similarly in the analyzed scenarios. Static calibration of the mathematical models ASM1 and ASM3 applied in computer simulators are tools that can be highly useful in the management of activated sludge systems

Determinación de la calidad de absorción visual en las unidades de paisajes del páramo Llanganates, laguna de Pisayambo.

This research project focuses on determining the quality of visual absorption in the landscape units of the Llanganates páramo, Pisayambo Lagoon, located in Santiago de Píllaro canton, Tungurahua province. The objectives were to analyze the current situation of the Llanganates páramo landscape, identify landscape units and visual absorption capacity, and establish a proposal for páramo conservation. The methodology applied in the research is the inductive method, which allows us to determine the most valuable information within the study area. The chosen technique for data collection was photographic records, using the Bureau of Land Management (BLM) 1980 methodology for the evaluation and characterization of the visual quality of the landscape, taking into account aspects such as terrain morphology, vegetation, water, color, and scenic context. Yeomans' methodology (1986) was used to provide evaluation criteria and scoring on aspects such as slope, erodibility, regeneration capacity, vegetation diversity, vegetation/soil contrast, rock/soil contrast, and anthropization. The results obtained indicate the current conditions of the landscape, which is classified as Class A, corresponding to a high-quality landscape with areas of medium fragility and medium regeneration capacity. It can be concluded that the páramo requires conservation efforts in the environmental, economic, cultural, social, and political realms, starting with raising awareness among the population and regulating anthropogenic activities that affect this ecosystem.El presente proyecto de investigación está enfocado en la determinación de la calidad de absorción visual en las unidades de paisajes del páramo Llanganates, Laguna de Pisayambo ubicado en el cantón Santiago de Píllaro, provincia de Tungurahua, cuyos objetivos fueron analizar la situación actual del paisaje del páramo Llanganates, Laguna de Pisayambo, identificar las unidades del paisaje y capacidad de absorción visual y establecer una propuesta de conservación del páramo. La metodología aplicada en la investigación es el método inductivo que nos permite determinar la información más apreciable dentro de la zona de estudio, se optó por la técnica de registros fotográficos, la metodología Bareau of Land Management (BLM) 1980 para la evaluación y caracterización de la calidad visual del paisaje tomando en cuenta aspectos como la morfología del terreno, vegetación, agua, color y contexto esenico, la metodología de Yeomans (1986) para dar criterios de evaluación y puntuación en aspectos como la pendiente, erosionabilidad, capacidad de regeneración, diversidad de vegetación, contraste vegetación/suelo, contraste roca/suelo y antropización, los resultados obtenidos son las condiciones actuales del paisaje el cual es de clase A que corresponde a un paisaje de Calidad Alta de áreas correspondientes a un paisaje con fragilidad media con áreas de capacidad de regeneración media. Se puede concluir que el páramo requiere de una conservación en el ámbito ambiental, económico, cultural, social y político que parta de la concientización a la población y regulación de las actividades antropogénicas que se desarrollan de este ecosistema

Determinación de los componentes que forman las unidades del paisaje y calidad de absorción visual en el páramo de Secas Prada provincia de Napo, propuesta de conservación 2022.

The present research work arises with the purpose of determining the components that form the landscape units (UP) and quality of visual absorption in the Secas Prada páramo, located in the Province of Napo, where the identification of the components that form was carried out. part of the UP, the Visual Absorption Capacity (C.A.V.) was determined and finally a landscape conservation proposal was elaborated. The methodology that was established was descriptive - deductive that allowed the collection of qualitative and quantitative data for their respective analysis and systematization, in addition to using the ArcGIS software, for the elaboration of the cartographic maps of the study area. The current state of the páramo was diagnosed, and 6 landscape units were established, including agricultural and livestock areas, human settlements, wetland areas, wooded areas and eroded areas based on the recognition of the different activities present in the study area. For the determination of visual quality, the BLM method was applied, while to determine the C.A.V. The YEOMANS method was used, which allow qualifying in a qualitative-quantitative way through its weighting scales to the landscape units through photographs. The results show that currently the Seca Prada páramo presents a High Visual quality with unique features characteristic of these natural ecosystems, establishing a class II with moderate visual quality, considering it as a landscape of medium fragility and moderate visual sensitivity, with priority being given to the establishment of activities under the political, economic, social, cultural and environmental components for its conservation.El presente trabajo de investigación surge con la finalidad de determinar los componentes que forman las unidades del paisaje (UP) y calidad de absorción visual en el páramo Secas Prada, ubicado en la Provincia de Napo, donde se realizó la identificación de los componentes que forman parte de las UP, se determinó la Capacidad de Absorción Visual (C.A.V.) y finalmente se elaboró una propuesta de conservación paisajística. La metodología que se estableció fue descriptiva - deductiva que permitió la recopilación de los datos cualitativos y cuantitativos para su respectivo análisis y sistematización, además de utilizar el software ArcGIS, para la elaboración de los mapas cartográficos de la zona de estudio. Se diagnosticó el estado actual del páramo, y se estableció 6 unidades del paisaje entre ellas zonas agrícolas, ganaderas, asentamientos humanos, zona de humedales, zonas boscosas y zonas erosionadas a partir del reconocimiento de las distintas actividades presentes en la zona de estudio. Para la determinación de la calidad visual se aplicó el método de BLM, mientras que para determinar la C.A.V. se empleó el método de YEOMANS, mismos que permiten calificar de manera cuali-cuantitativa mediante sus escalas de ponderación a las unidades de paisaje por medio de las fotografías. Los resultados muestran que en la actualidad el páramo Seca Prada presenta una calidad Visual Alta con rasgos singulares característicos de estos ecosistemas naturales, estableciendo una clase II con una calidad visual moderada considerándose como un paisaje de fragilidad media y una sensibilidad visual moderada, siendo prioritario el establecimiento de actividades bajo los componentes políticos, económicos, sociales, culturales y ambientales para su conservación

Valoración del paisaje natural de la parroquia Canchagua del cantón Saquisilí en la provincia de Cotopaxi, propuesta de conservación de las unidades del paisaje, 2022.

The present research project was developed with the purpose of evaluating the quality of the existing natural landscape in the Canchagua Parish, located in the Saquisili canton, Cotopaxi Province, for which the analysis of the conditions of the natural landscape was established, and a methodology was proposed that focuses on the determination of the landscape units, production systems and quality of visual absorption (CAV) for which different methodologies were applied, Among these, the methodology applied was based on the guidelines established by the Bureau of Land Management (BLM) method, which allowed establishing qualitative and quantitative values established in numerical weighting scales focused on the determination of the components (texture, color, relief, erodibility, slope, vegetation, scenic context, line, spatial configuration) that form the landscape units based on subjective evaluations presented by the researcher through the analysis of photographs of the study area; For this purpose, field visits and surveys were carried out based on non-probabilistic random sampling in order to learn directly about the different activities that take place in the area. The results show that the area has a high visual quality and a moderate quality of visual absorption, which requires management activities and conservation of the natural landscape. Based on these results, conservation, regeneration and maintenance activities were proposed for the study area.El presente proyecto de investigación se desarrolló con la finalidad de valorar la calidad del paisaje natural existente en la Parroquia Canchagua, ubicado en el cantón Saquisili Provincia de Cotopaxi para lo cual se estableció el análisis de las condiciones del paisaje natural , mismo que se planteó una metodología que se enfoque en la determinación de las unidades del paisaje, sistemas de producción y calidad de absorción visual (CAV) para ellos se aplicaron distintas metodologías, entre estas la metodología que se aplico estuvo basada en los lineamientos establecidos por el método Bureau of Land Management (BLM) quien permitió establecer valores cualitativos y cuantitativos establecidos en escalas de ponderación numérica enfocadas hacia la determinación de los componentes (textura, color, relieve, erosionabilidad, pendiente, vegetación, contexto escénico, línea, configuración espacial) que forman las unidades del paisaje partiendo de valoraciones subjetivas que presenta el investigador mediante el análisis de fotografías del área de estudio; para ello se establecieron visitas de campo y encuestas en función del muestreo no probabilístico al azar con la finalidad de conocer de manera directa las distintas actividades que se desarrollan en el lugar. Los resultados permiten evidenciar que, la zona presenta una calidad visual alta y una calidad de absorción visual moderada, por lo que requiere actividades de manejo y conservación del paisaje natural, en función de estos resultados se plantearon actividades de conservación, regeneración y mantenimiento del área de estudio

Estado del arte para la determinación de las fracciones de la Demanda Química de Oxígeno como aplicación en aguas residuales en la Provincia de Cotopaxi año 2020.

The main rivers of the Cotopaxi Province are contaminated by various human activities, which affects the health of the population, since many people who live on the banks of the bodies of water of the Province, directly use this resource to carry out various activities. In spite of this, the treatment that wastewater receives is inefficient, which is why it requires a detailed characterization of the components of the wastewater. Therefore, a methodological proposal was developed to determine the fractionation of the Chemical Oxygen Demand through the Activated Sludge Model (ASM1). The application of a combined methodology was proposed: physical- chemical, developed by the Dutch Foundation for Applied Research (STOWA Protocol) by its acronym in Dutch, and a biological methodology (Respirometry), through which procedures were expressed to determine the main fractions of the Chemical Oxygen Demand. As there is no standard methodology, data were collected from studies on COD fractionation, applying the STOWA Protocol and respirometry methods in several treatment plants. To represent the effectiveness of the STOWA Protocol, biokinetic graphs were made for which the most representative values were taken, expressed by Sanchez, Ribes et al (2017), Baquero et al (2016) and Vazquez et al (2013), jointly using standard stoichiometric values presented by the ASM1 model. Also, percentages estimated by the International Water Association were compared, based on the presence of the fractions of the Chemical Oxygen Demand in untreated wastewater, with percentages presented by authors such as: Kappeler and Gujer (1992), Sozen et al (1998), Pluciennik, Jakubaszek et al (2017) and Ekama et al (1986) which used respirometry methods. The results obtained show a significant variation between methodologies, this is due to the diverse composition of the wastewater and the specific conditions in which they are found, in the biokinetic graphs was observed a percentage of error by adjustment of variables, however, the methods analyzed are considered applicable to determine the fractionation of COD because the graphs did not show negative values.Los principales ríos de la Provincia de Cotopaxi se encuentran contaminados por diversas actividades antrópicas, lo que incide en la afectación de la salud en la población, ya que muchas personas que habitan a orillas de los cuerpos de agua de la Provincia, emplean directamente este recurso para realizar diversas actividades. A pesar de esto, el tratamiento que reciben las aguas residuales es ineficiente, motivo por el cual precisan de una caracterización minuciosa de los componentes del agua residual. De manera que, se elaboró una propuesta metodológica para determinar el fraccionamiento de la Demanda Química de Oxígeno a través del modelo de Lodos Activados (ASM1) por sus siglas en inglés, se planteó la aplicación de una metodología combinada: físico química, desarrollada por la Fundación Holandesa de Investigación Aplicada (Protocolo de STOWA) por sus siglas en holandés, y una metodología biológica (Resprirométrica), mediante las cuales se expresaron procedimientos para determinar las fracciones principales de la Demanda Química de Oxígeno. Al no existir una metodología estándar, se recopilaron datos de estudios sobre el fraccionamiento de la DQO, aplicando el Protocolo STOWA y métodos respirométricos en diversas plantas de tratamiento. Para representar la eficacia del Protocolo STOWA se realizaron gráficas de biocinética para las cuales se tomaron los valores más representativos, expresados por Sánchez, Ribes et al (2017), Baquero et al (2016) y Vázquez et al (2013), conjuntamente se utilizaron valores estequiométricos estándar que presenta el modelo ASM1. También, se compararon porcentajes estimados por la Asociación Internacional del Agua, en base a la presencia de las fracciones de la Demanda Química de Oxígeno en aguas residuales sin tratar, con porcentajes presentados por autores como: Kappeler y Gujer (1992), Sozen et al (1998), Pluciennik, Jakubaszek et al (2017) y Ekama et al (1986) los cuales emplearon métodos respirométricos. Los resultados obtenidos muestran una variación significativa entre metodologías, esto radica en la composición diversa de las aguas residuales y las condiciones específicas en las que se encuentran, en las gráficas de biocinética se observó un porcentaje de error por ajuste de variables, sin embargo, los métodos analizados se consideran aplicables para determinar el fraccionamiento de la DQO ya que las gráficas no arrojaron valores negativos