Tendo em vista a crescente problemática quanto à eutrofização de corpos dágua em países em desenvolvimento, devido ao lançamento de esgoto mesmo que tratado em nível secundário, o processo de lodo ativado vem sendo estudo e aprimorado para efetuar a remoção conjunta de matéria orgânica, nitrogênio e o fósforo, nutrientes limitantes para ocorrência da eutrofização. Neste contexto, o presente trabalho pretende contribuir com informações quanto à remoção biológica de nutrientes de esgoto sanitário através de estudo em escala piloto em um sistema cíclico de lodo ativado. Este sistema, operado em regime de bateladas sequenciais, difere da configuração habitual, pois possui três compartimentos internos, zonas 1, 2 e 3 que apresentam condições anaeróbias/anóxicas, anóxicas e aeróbias respectivamente, além do retorno de lodo da zona 3 para zona 1 durante o período de reação, sob vazão de 20% da vazão afluente a unidade. Cada batelada possui duração de 4 horas, distribuídas em 4 etapas de 1h cada, sendo elas o enchimento com aeração, reação, sedimentação e descarga. Com essas características o sistema cíclico de lodo ativado do presente estudo, demonstrou no tratamento de esgoto sanitário, elevada eficiência na remoção de matéria orgânica, sempre acima de 90%, além da boa eficiência de remoção nitrogênio através do processo de nitrificação e desnitrificação, cuja concentração média de amônia e nitrato no efluente final foram respectivamente de 2,8 e 11,4 mgN.L-1 para idade de lodo de 25 dias e quando operado com 12 dias de idade, o efluente apresentou concentração de 6,6 e 12,4 mgN.L-1. Também foram determinadas via respirometria as taxas máximas de crescimento (n,max) para bactérias nitrificantes e nitratantes, os valores obtidos foram respectivos, de 0,45 d-1 e 0,37 d-1 para idade de lodo de 12 dias, resultados próximos a literatura. A remoção biológica de fósforo foi obtida com melhor resultado na segunda etapa, superando 95% de eficiência, produzindo efluente final com teor de fósforo total inferior a 0,5 mgP.L-1. / Given the growing problem regarding the eutrophication of water bodies in developing countries, due to discharge of sewage treated even at the secondary level, the activated sludge process has been enhanced to study and perform the joint removal of organic matter, nitrogen and phosphorus, the limiting nutrient for the occurrence of eutrophication. In this context, this work aims to contribute information for biological nutrient removal from wastewater by pilot scale study in a cyclic activated sludge system. This system operated in sequential batch system differs from typical configuration because it has three internal compartments, zones 1, 2 and 3 show that anaerobic / anoxic, aerobic and anoxic respectively, beyond the conditions of return sludge from zone 3 to zone 1 during the reaction, flow rate under 20% of the influent flow unit. Each batch has a duration of 4 hours, distributed into 4 stages each 1H, they aeration and filling, reaction, settling and discharge. With these characteristics the cyclic activated sludge system of the present study showed for the treatment of sewage, high efficiency in the removal of organic matter, always above 90%, besides the good efficiency of nitrogen removal by nitrification and denitrification, which average concentration of ammonia and nitrate in the final effluent were respectively 2.8 and 11.4 mgN.L-1 for sludge age of 25 days, when operated at 12 days of age, the effluent showed a concentration of 6.6 to 12 4 mgN.L-1. Were also determined via respirometry maximum growth rates (n, max) for nitrifying bacteria and nitratantes, the respective value obtained were, 0.45 d-1 and 0.37 d-1 for sludge age of 12 days, results Nearby literature. Biological phosphorus removal was obtained with better results in the second stage, surpassing 95% efficiency, producing the final content of the effluent below 0.5 mgP.L-1 total phosphorus.

Tendo em vista a crescente problemática quanto à eutrofização de corpos dágua em países em desenvolvimento, devido ao lançamento de esgoto mesmo que tratado em nível secundário, o processo de lodo ativado vem sendo estudo e aprimorado para efetuar a remoção conjunta de matéria orgânica, nitrogênio e o fósforo, nutrientes limitantes para ocorrência da eutrofização. Neste contexto, o presente trabalho pretende contribuir com informações quanto à remoção biológica de nutrientes de esgoto sanitário através de estudo em escala piloto em um sistema cíclico de lodo ativado. Este sistema, operado em regime de bateladas sequenciais, difere da configuração habitual, pois possui três compartimentos internos, zonas 1, 2 e 3 que apresentam condições anaeróbias/anóxicas, anóxicas e aeróbias respectivamente, além do retorno de lodo da zona 3 para zona 1 durante o período de reação, sob vazão de 20% da vazão afluente a unidade. Cada batelada possui duração de 4 horas, distribuídas em 4 etapas de 1h cada, sendo elas o enchimento com aeração, reação, sedimentação e descarga. Com essas características o sistema cíclico de lodo ativado do presente estudo, demonstrou no tratamento de esgoto sanitário, elevada eficiência na remoção de matéria orgânica, sempre acima de 90%, além da boa eficiência de remoção nitrogênio através do processo de nitrificação e desnitrificação, cuja concentração média de amônia e nitrato no efluente final foram respectivamente de 2,8 e 11,4 mgN.L-1 para idade de lodo de 25 dias e quando operado com 12 dias de idade, o efluente apresentou concentração de 6,6 e 12,4 mgN.L-1. Também foram determinadas via respirometria as taxas máximas de crescimento (n,max) para bactérias nitrificantes e nitratantes, os valores obtidos foram respectivos, de 0,45 d-1 e 0,37 d-1 para idade de lodo de 12 dias, resultados próximos a literatura. A remoção biológica de fósforo foi obtida com melhor resultado na segunda etapa, superando 95% de eficiência, produzindo efluente final com teor de fósforo total inferior a 0,5 mgP.L-1. / Given the growing problem regarding the eutrophication of water bodies in developing countries, due to discharge of sewage treated even at the secondary level, the activated sludge process has been enhanced to study and perform the joint removal of organic matter, nitrogen and phosphorus, the limiting nutrient for the occurrence of eutrophication. In this context, this work aims to contribute information for biological nutrient removal from wastewater by pilot scale study in a cyclic activated sludge system. This system operated in sequential batch system differs from typical configuration because it has three internal compartments, zones 1, 2 and 3 show that anaerobic / anoxic, aerobic and anoxic respectively, beyond the conditions of return sludge from zone 3 to zone 1 during the reaction, flow rate under 20% of the influent flow unit. Each batch has a duration of 4 hours, distributed into 4 stages each 1H, they aeration and filling, reaction, settling and discharge. With these characteristics the cyclic activated sludge system of the present study showed for the treatment of sewage, high efficiency in the removal of organic matter, always above 90%, besides the good efficiency of nitrogen removal by nitrification and denitrification, which average concentration of ammonia and nitrate in the final effluent were respectively 2.8 and 11.4 mgN.L-1 for sludge age of 25 days, when operated at 12 days of age, the effluent showed a concentration of 6.6 to 12 4 mgN.L-1. Were also determined via respirometry maximum growth rates (n, max) for nitrifying bacteria and nitratantes, the respective value obtained were, 0.45 d-1 and 0.37 d-1 for sludge age of 12 days, results Nearby literature. Biological phosphorus removal was obtained with better results in the second stage, surpassing 95% efficiency, producing the final content of the effluent below 0.5 mgP.L-1 total phosphorus.

The microbial aggregates (flocs) formed during secondary biological treatment of wastewater shield microbes from exposure to ultraviolet (UV) light, and decrease the efficiency of disinfection, causing the tailing phenomena. This thesis investigates whether the formation of compact cores within flocs induces higher levels of UV resistance. Moreover, it investigates the effect of secondary treatment conditions on the physicochemical properties of flocs’, effluent quality, and UV disinfection performance. Compact cores were isolated from the flocs using hydrodynamic shearing. The UV dose response curves (DRC) were constructed for flocs and cores, and the 53-63 μm cores showed 0.5 log less disinfectability, compared to flocs of similar size. Based on a structural model developed for the UV disinfection of flocs, floc disinfection kinetics was sensitive to the core’s relative volume, their density, and viability. The UV disinfection and floc properties of a conventional activated sludge (CAS) system, and a biological nutrient removal (BNR-UCT) system, including both biological nitrogen and phosphorus removal, was compared. The 32-53 μm flocs and the final effluent from the BNR-UCT reactor showed 0.5 log and 1 log improvement in UV disinfectability, respectively, compared to those from the CAS reactor. The BNR-UCT flocs were more irregular in structure, and accumulated polyphosphates through enhanced biological phosphorus removal. Polyphosphates were found to be capable of producing hydroxyl radicals under UV irradiation, causing the photoreactive disinfection of microorganisms embedded within the BNR-UCT flocs, accelerating their UV disinfection. Comparing the UV disinfection performance and floc properties at various operating conditions showed that increasing the operating temperature from 12 ºC to 22 ºC, improved the UV disinfection of effluent by 0.5 log. P-Starved condition, i.e. COD:N:P of 100:10:0.03, decreased the average floc size and sphericity, both by 50%. Despite the higher effluent turbidity of the P-Starved reactor, the final effluent’s UV disinfection improved by at least 1 log compared to the P-Normal and P-Limited conditions. The improvement in the floc and effluent disinfectability were accompanied by a decrease in floc sphericity and a decrease in the number of larger flocs in the effluent, respectively.

The microbial aggregates (flocs) formed during secondary biological treatment of wastewater shield microbes from exposure to ultraviolet (UV) light, and decrease the efficiency of disinfection, causing the tailing phenomena. This thesis investigates whether the formation of compact cores within flocs induces higher levels of UV resistance. Moreover, it investigates the effect of secondary treatment conditions on the physicochemical properties of flocs’, effluent quality, and UV disinfection performance. Compact cores were isolated from the flocs using hydrodynamic shearing. The UV dose response curves (DRC) were constructed for flocs and cores, and the 53-63 μm cores showed 0.5 log less disinfectability, compared to flocs of similar size. Based on a structural model developed for the UV disinfection of flocs, floc disinfection kinetics was sensitive to the core’s relative volume, their density, and viability. The UV disinfection and floc properties of a conventional activated sludge (CAS) system, and a biological nutrient removal (BNR-UCT) system, including both biological nitrogen and phosphorus removal, was compared. The 32-53 μm flocs and the final effluent from the BNR-UCT reactor showed 0.5 log and 1 log improvement in UV disinfectability, respectively, compared to those from the CAS reactor. The BNR-UCT flocs were more irregular in structure, and accumulated polyphosphates through enhanced biological phosphorus removal. Polyphosphates were found to be capable of producing hydroxyl radicals under UV irradiation, causing the photoreactive disinfection of microorganisms embedded within the BNR-UCT flocs, accelerating their UV disinfection. Comparing the UV disinfection performance and floc properties at various operating conditions showed that increasing the operating temperature from 12 ºC to 22 ºC, improved the UV disinfection of effluent by 0.5 log. P-Starved condition, i.e. COD:N:P of 100:10:0.03, decreased the average floc size and sphericity, both by 50%. Despite the higher effluent turbidity of the P-Starved reactor, the final effluent’s UV disinfection improved by at least 1 log compared to the P-Normal and P-Limited conditions. The improvement in the floc and effluent disinfectability were accompanied by a decrease in floc sphericity and a decrease in the number of larger flocs in the effluent, respectively.

Con el aumento de la población y de la demanda de bienes y servicios a escala global, se ha producido un deterioro en la calidad y disponibilidad del agua, poniendo de manifiesto la necesidad inminente de un cambio de mentalidad en la sociedad. Este cambio debe incluir, tanto la intensificación de las disposiciones legales que permitan prevenir la contaminación, como el desarrollo e implementación de tecnologías de depuración más eficaces, sostenibles y respetuosas con el ambiente. En la actualidad, en la mayoría de países desarrollados el tratamiento de aguas residuales urbanas está basado en los sistemas de fangos activados como tratamiento principal. Estos sistemas se caracterizan por presentar un elevado consumo energético y una alta generación de fango biológico, que debe ser sometido a algún tratamiento de estabilización previo a su reutilización o disposición final. Una alternativa a estas tecnologías son los sistemas basados en procesos anaerobios, cuya implementación supone mayor sostenibilidad, menor coste económico y energético, y menor impacto ambiental. Sin embargo, es necesario superar las limitaciones asociadas a las bajas velocidades de crecimiento de la biomasa anaerobia (en comparación con los microorganismos aerobios) y a la baja eficacia en la separación de la biomasa mediante procesos de sedimentación. La combinación del proceso anaerobio de degradación de la materia orgánica con un proceso de filtración con membranas, permite superar los inconvenientes mencionados, pudiéndose establecer tiempos de retención celular elevados sin necesidad de incrementar el volumen de reacción y obtener un efluente de alta calidad. Una de las ventajas de los sistemas anaerobios es la recuperación de parte de la energía contenida en la materia orgánica en forma de metano. Sin embargo, cuando hay presencia de sulfato en el medio se desarrollan bacterias sulfatorreductoras, las cuales compiten por los sustratos, reduciéndose la eficiencia en la conversión de materia orgánica a metano, y generando sulfuro de hidrógeno (sulfurogénesis), que inhibe los procesos biológicos y disminuye la calidad del biogás generado. Debido a la importancia que tiene el proceso de sulfurogénesis en los sistemas de tratamiento de aguas residuales, varios autores han propuesto modelos matemáticos que incluyen los procesos biológicos, físicos y químicos asociados a las bacterias sulfatorreductoras. Sin embargo, no existe un modelo global que permita simular en conjunto los procesos que tienen lugar tanto en la línea de agua como en la de fango, y donde esté incluido este proceso. También es destacable la ausencia de una metodología sistemática para la calibración de los parámetros de los modelos anaerobios de tratamiento de aguas residuales. El objetivo principal de la presente tesis doctoral es la modelación matemática del tratamiento anaerobio de aguas residuales urbanas con elevado contenido de sulfato. Con este fin, se ha desarrollado un modelo matemático capaz de describir el proceso biológico de sulfurogénesis y se ha propuesto una metodología de calibración de los parámetros. El modelo desarrollado ha sido incorporado al modelo global Biological Nutrient Removal Model No. 2 (BNRM2). Tanto el modelo como la metodología de calibración han sido validados mediante simulación con el programa DESASS, comparando los resultados predichos por el modelo con los valores experimentales obtenidos en un biorreactor anaerobio de membranas a escala demostración / Durán Pinzón, F. (2013). Modelación matemática del tratamiento anaerobio de aguas residuales urbanas incluyendo las bacterias sulfatorreductoras. Aplicación a un biorreactor anaeroio de membranas [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/34778 / TESIS

In conventional wastewater treatment plants, methanol, ethanol, and acetate are used as carbon source for the denitrification process in the biological nutrient removal. However, growing concern regarding economical costs and carbon footprints from the fossil-based production of these chemicals have forced the companies to look for other alternatives. VFAs have shown a great potential in replacing the conventionally used carbon sources. If implemented this will result in lower chemical cost and a drastic decrease in carbon footprint as well as striving WWTPs towards sustainable development. In this work denitrification has been analysed using different variations of VFAs such as fermented potato protein liquor, food waste and chicken manure VFA. This was done using a basic laboratory setup of a denitrification reactor which used basic stirring agitation and nitrogen purging to ensure anoxic conditions. Nutrients and excess sCOD were added to ensure the highest denitrification rates. The denitrifying biomass was collected at Gryaab AB in the form of k1-carriers making this process a MBBR. The most influential characteristic of the VFAs is the distribution of the acids in the VFA effluent. Butyric acid along with caproic acid showed the best potential for efficient denitrification. The possibility of concentration of VFA effluent showed a high potential when using a nanofiltration system. A C/N ratio of 4.5 conventionally used when methanol is added showed to be the most optimal condition for VFA addition. The combination of VFAs together with conventional used carbon sources showed the best potential in denitrification efficiency proving to be as good or even better than pure synthetic ones. VFAs effluents showed the best potential in removing the intermediate nitrite from the wastewater at high rates. Overall, VFAs shown a great potential for replacing conventionally used carbon sources, demonstrating the potential of substitution, which if implemented will result in lower carbon footprint and a strive towards sustainable development.

The wastewater treatment plays an important role in the maintenance of natural water resources. However, regardless of the technology used or the level of treatment required, the treatment plants of the XXI century are highly complex systems that not only need to meet technical requirements, but also environmental and economic criteria. In this context, decision support systems for environmental domains (English, Environmental Decision Support Systems or EDSS) are configured as an effective tool to support the selection and evaluation of integrated water treatment alternatives. The EDSS designed can be defined as interactive software, flexible and adaptable, which links the numerical models / algorithms, techniques and environmental ontologies, knowledge-based environment, and is capable of supporting decision making, either in choosing between different alternatives, improving potential solutions, or in the integrated assessment using methodologies ranging from environmental (Life Cycle Analysis) to economic / La depuració d’aigües residuals juga un paper fonamental en el manteniment dels recursos hídrics naturals. Tanmateix, sigui quina sigui la tecnologia emprada o el nivell de depuració requerit, les plantes de tractament del segle XXI són sistemes d’alta complexitat, que no només han de satisfer requeriments de tipus tècnic, sinó també de tipus ambiental i econòmic. En aquest context, els sistemes de suport a la decisió en dominis ambientals (en anglès, Environmental Decision Support Systems o EDSS) es configuren com una eina eficaç per donar suport a la selecció i a l’avaluació integrada de diferents alternatives de depuració d’aigües. El EDSS dissenyat pot definir-se com un programari interactiu, flexible i adaptable, que vincula els models numèrics/algoritmes amb tècniques basades en el coneixement i ontologies ambientals, i que és capaç de donar suport a la presa de decisió, ja sigui en l’elecció entre diferents alternatives, millorant una solució, o bé en l’avaluació integrada a través de metodologies ambientals (Anàlisi de Cicle de Vida) i econòmiques