Humidais construídos para a depuración de augas residuais urbanas: eliminación de nitróxeno, ensaios biolóxicos e respirometría en diferentes configuracións híbridas

Programa Oficial de Doutoramento en Ciencia e Tecnoloxía Ambiental . 5006V01[Resumo] Existen aínda moitas carencias na comprensión dos mecanismos de depuración e nos métodos de deseño dos humidais construídos (HC) para a depuración de augas residuais, especialmente en relación coa aplicación de sistemas híbridos. O obxectivo da presente investigación é contribuír a un mellor coñecemento dos HC, a través dos seguintes obxectivos específicos: a) o desenvolvemento de metodoloxías de laboratorio destinadas a describir os procesos e á obtención de parámetros cinéticos e estequiométricos, b) a obtención destes parámetros cinéticos e estequiométricos para un substrato sintético que simula augas residuais domésticas; c) o avance na concepción e deseño de sistemas HC híbridos. Desenvolvéronse ensaios aerobios, anóxicos e anaerobios, así como as técnicas respirométricas para a súa aplicación na caracterización destes sistemas. Os HC simuláronse a escala de laboratorio mediante columnas de fluxo descendente que permiten reproducir as condicións reais, tanto de saturación hidráulica como de non saturación, de sistemas híbridos constituídos por varias unidades en serie. Ademais, prestouse de atención aos parámetros relacionados coa obstrución do medio filtrante e as emisións de gases de efecto invernadoiro. Os HC híbridos constituídos por unidades de fluxo horizontal (FH) e vertical (FV) subsuperficial buscan unha nitrificación e desnitrificación efectivas mediante a combinación de condicións anaerobias, anóxicas e aerobias. Foron estudadas a configuración de dobre etapa e paso único (FH + FH, FV + FV), a configuración Bp(VF + HF) (con bypass de alimentación) e o sistema R (FH + FV) (con recirculación de efluente). A eliminación porcentual de SST, DQO e DBO5 foi en xeral superior ao 95% en todos os sistemas. Os sistemas de paso único mostraron unha eliminación de NT inferior ao 50% e baixas taxas de eliminación (0,6-1,2 g de NT/m2·d), se ben o sistema FV+FV alcanzou o 63% e 3,5 g NT/m2·d de eliminación a altas velocidades de carga. O sistema Bp (FV+FH) requiriu un ratio de by-pass de 40-50% e aumentou as taxas de eliminación de NT a un 50-60% de forma sostible. A recirculación do efluente mellorou significativamente a eficiencia e taxa de eliminación de NT. O sistema R(FH+FV) mostrou unha eliminación estable de NT de aproximadamente o 80% a taxas de carga que variaron de 2 a 8 g NT/m2·d.[Resumen] Todavía hay muchas lagunas en la comprensión de los mecanismos de depuración y métodos de diseño de humedales construidos (HC) para aguas residuales, especialmente en relación con la aplicación de sistemas híbridos. El propósito de esta investigación es contribuir a un mejor conocimiento de la HC, a través de los siguientes objetivos específicos: a) el desarrollo de metodologías de laboratorio destinados a describir los procesos y la obtención de los parámetros cinéticos y estequiométricos, b) la obtención de estos parámetros para un sustrato sintético que simula aguas residuales domésticas; c) el avance en las concepción y diseño de HC híbridos. Se han desarrollado ensayos aerobios, anóxicos y anaerobios, así como técnicas respirométricos, para su aplicación en la caracterización de estos sistemas. Los HC se simularon mediante columnas de flujo descendente a escala de laboratorio que reproducen las condiciones reales, tanto de saturación hidráulica como de no saturación. Además, se ha prestado atención a los parámetros relacionados con la obstrucción del medio filtrante y las emisiones de gases de efecto invernadero. Los HC híbridos basados en unidades de flujo horizontal (FH) y vertical (FV) subsuperficial buscan una nitrificación y desnitrificación eficaz mediante la combinación de condiciones anaerobias, anóxicas y aerobias. Se estudiaron la configuración de doble etapa y paso simple (FH + FH, VF + VF), la configuración Bp(VF + HF) (con bypass) y la R(FH + FV) (recirculación de efluente). El porcentaje de eliminación de SST, DQO y DBO5 fue generalmente mayor al 95% en todos los sistemas. Los sistemas de paso único mostraron una eliminación de NT menor del 50% y velocidades de eliminación bajas (0,6-1,2 g NT/m2·d), aunque el sistema FV+FV alcanzó el 63% y 3,5 g NT/m2·d de eliminación a altas velocidades de carga. El sistema Bp(FV + FH) requiere un bypass de 40-50% y aumentó la eliminación de NT al 50-60% de forma sostenible. La recirculación del efluente ha mejorado significativamente la eficiencia y la tasa de eliminación de NT. El sistema R(FH+FV) mostró una eliminación constante de NT aproximadamente del 80% a velocidades de carga de 2 a 8 g NT/m2·d.[Abstract] Nowadays there are still numerous lacks in the understanding of the mechanisms of depuration as in the methods of design of the constructed wetlands (CWs), especially in relation to the application of hybrid systems. The goal of the present research is to contribute to a better knowledge of treatment CWs, through the following specific goals: a) the development of laboratory methodologies aimed at describing the processes and obtaining kinetic and stoichiometric parameters, b) obtaining these kinetic and stoichiometric parameters for a synthetic substrate simulating domestic wastewater; and c) the advance in the conception and design of hybrid CW systems. Aerobic, anoxic and anaerobic essays, as well as respirometric techniques were developed and applied in order to characterize these systems. CWs were simulated at lab scale through down flow columns that allow reproducing the real conditions, both of hydraulic saturation and non-saturation, of hybrid systems constituted by several units in series. In addition, attention was paid to parameters related with medium clogging and greenhouse gas emissions. Hybrid CWs including subsurface horizontal flow (HF) and vertical flow (VF) steps look for effective nitrification and denitrification through the combination of anaerobic/anoxic and aerobic conditions. Several CW configurations including single pass systems (HF+HF, VF+VF), the Bp(VF+HF) arrangement (with feeding by-pass) and the R(HF+VF) system (with effluent recirculation) were tested. The percentage removal of TSS, COD and BOD5 was usually higher than 95% in all systems. The single pass systems showed TN removal below the threshold of 50% and low removal rates (0.6-1.2 g TN/m2·d), except the VF+VF system which reached 63% and 3.5 g TN/m2·d removal but only at high loading rates. Bp(VF+HF) system required by-pass ratios of 40-50% and increased TN removal rates to approximately 50-60% in a sustainable manner. Effluent recirculation significantly improved the TN removal efficiency and rate. The R(HF+VF) system showed stable TN removals of approximately 80% at loading rates ranging from 2 to 8 g TN/m2·d

Separate Collection of Bio-Waste in General Areas of University Centers

Traditionally, the separate collection of different fractions of waste in university centers was limited to the collection of paper/cardboard and packaging waste, while the collection of bio-waste was introduced only for dining and cafeteria services. It was based on the consideration that in general areas of the centers, such as classrooms, corridors, administrative areas, or offices, organic waste was not generated. However, eating habits and lifestyles have been changing and food remains becoming more frequent in these areas. The inspections carried out in the UDC in 2015 showed that 25% of the waste belonged to the bio-waste category, and subsequent inspections indicated that in some cases it may constitute the main waste fraction. Having verified this fact, the conclusion was that the intra-center waste segregation model should be revised, introducing a specific collector for bio-waste in all areas of the university centers. This communication describes the separate collection model and presents the results achieved in five centers of the UDC. The results achieved were very positive, approaching or exceeding in most cases the threshold of 85% correct content in the bins, a value that is considered minimum to classify it as a separate collection for quality recycling. The capture of materials for recycling exceeded 70% of the waste generated

Evaluation of the Green Campus Program at the University of A Coruña

Green Campus (GC) is an international program launched by the Foundation for Environmental Education (FEE) which includes the philosophy, methodology and experience of Eco-schools, adapted to the specific university needs and problems. Through its seven-steps methodology, the GC program can be considered a kind of environmental management system, which includes external evaluation and pursues continuously improved environmental performance. The GC program began at the UDC in 2014, with autonomous implementation at the center level, promoting bottom-up initiatives in combination with other top-down initiatives. In 2022 it had reached all 20 UDC teaching centers, more than half of them having already achieved program certification (green flag award). This paper analyses the evolution and performance of the GC program at UDC, through two on-line surveys addressed to 1) students in general, and 2) coordinators and members of the environmental committees. Some difficulties identified are low involvement and participation of students and overload of tasks of all kinds, which hinders the volunteer participation of committee members. Nevertheless, a good overall rating was given to the program from participating staff and students. A SWOT analysis is also presented, summarizing the information obtained through surveys, together with the Office for the Environment's experience in the coordination of the different centers involved in the program. Finally, a strategy is proposed to improve the visibility of the GC among students and enhance their participation

Fatigue and fracture behavior of composites with metal matrix

Los materiales compuestos son un sistema formado por una mezcla o composición de dos o más micro - macro constituyentes que difieren en forma y composición química y son insolubles entre sí. Las funciones de la matriz en un material compuesto son: - Mantener la armadura en la posición de trabajo y distribuir la carga entre ellos. - Proteger el refuerzo del deterioro mecánico y químico. - Evitar la propagación de grietas. Los materiales compuestos también se pueden clasificar de acuerdo con el tipo de refuerzo. Las propiedades del material compuesto se basan en las propiedades de las fases constituyentes, sus proporciones relativas y la geometría de la armadura, la forma, tamaño, distribución y orientación. Los compuestos de matriz metálica contienen refuerzos cerámicos en una matriz de aleación metálica. La matriz puede ser una aleación de Al o Ti, mientras que los refuerzos pueden ser Al2O3 o SiC. Los compuestos de matriz metálica reforzados con partículas son los más económicos y los más populares. Estos compuestos ofrecen una mayor rigidez, resistencia a temperatura elevada y resistencia al desgaste.Ingeniería Industria

Integration of Food Waste Composting and Vegetable Gardens in a University Campus

Financiado para publicación en acceso aberto: Universidade da Coruña/CISUG[Abstract] Local composting (household, community and small scale applications) is considered a sustainable option for bio-waste recovery and is receiving increasing demand from society. Higher education institutions are no exception, but detailed and comprehensive long-term studies on composting programs on university campuses are lacking. The local composting program of the University of A Coruña (UDC) offers a decentralized service for the treatment of food waste from 11 university canteens using static and dynamic composters located in 9 different composting areas. Considering the three pillars of sustainability, this work describes the characteristics of the different composting technologies used and their investment and operational costs, the routine monitoring process and product quality, the integration of the composting systems as living labs for biotechnology and environmental engineering courses, and the use of compost in the university vegetable gardens. The agents involved in the project are the canteen staff, the university gardening company, external composting operators, university researchers and teachers, sustainability scholarship students and volunteer people. Organic waste is usually delivered directly by canteen staff to composters. The gardening service provides green waste from UDC campus (crushed pruning) that is used as bulking material. The monitoring and maintenance of the composting areas is currently in charge of external staff provided by a local NGO dedicated to cooperation and job reintegration of the unemployed. The service also allows the incorporation of volunteers and scholarship students as operators and process monitoring supervisors. The main result of this project was the prevention of a large amount of waste that did not require collection and transportation, or disposal or incineration. This is being done in an economically sustainable way, as decentralized composting costs have been lower than the average costs of municipal solid waste treatment in the region. The lower investment costs of static composters largely offset the higher labour costs and result in lower overall costs than those of the dynamic composter. The dissemination of composting practice to society was another important outcome of the project

‘Campus, Home, City: Laboratories of Change’, the Education or Sustainability Program of the University of A Coruña

[Abstract]: The program 'Campus, home, city: laboratories of change', aims to promote the students and citizenship formation in the basic concepts of environmental and social sustainability, responding to the priority challenges for our society such as climate change, waste production, circular economy or sustainable mobility. The proposed service-learning, hands-on activities takes advantage of the housing, the university and the city as places for researching and experimentation. A feature of this program is the use of online ICT tools for fieldwork, in particular the survey and mapping of waste generation and footprint, water use efficiency, transport footprint and consumption of energy. The project has the collaboration of the Alcoa Foundation and is now in its 6th Edition, adding up the participation of more than 11,000 people. In the last two editions, the project has been extended to primary, secondary and vocational training centers in the region of A Mariña.The project was funded in part by the Alcoa Foundation. The authors are grateful for the collaboration of the UDC Green Campus coordinators, the sustainability scholarship students, the OMA volunteers, the participating UDC staff, and A Mariña centers staff

‘Campus, Home, City: Laboratories of Change’, the Education or Sustainability Program of the University of a Coruña

The program 'Campus, home, city: laboratories of change', aims to promote the students and citizenship formation in the basic concepts of environmental and social sustainability, responding to the priority challenges for our society such as climate change, waste production, circular economy or sustainable mobility. The proposed service-learning, hands-on activities takes advantage of the housing, the university and the city as places for researching and experimentation. A feature of this program is the use of online ICT tools for fieldwork, in particular the survey and mapping of waste generation and footprint, water use efficiency, transport footprint and consumption of energy. The project has the collaboration of the Alcoa Foundation and is now in its 6th Edition, adding up the participation of more than 11,000 people. In the last two editions, the project has been extended to primary, secondary and vocational training centers in the region of A Mariña

Mapeando a eficiencia no consumo da auga

[Resumo] A enquisa sobre o consumo de auga desenvolta polo Emapic e a Oficina de Medio Ambiente da UDC é unha ferramenta en liña que ten por obxectivos crear o mapa da eficiencia no consumo de auga na Galiza e no mundo, aumentar a concienciación da poboación e reducir o gasto de auga mediante hábitos e equipamentos máis eficientes. Con metodoloxía sinxela no rexistro en vivendas e edificios públicos, fai uso das TIC para mellora da aprendizaxe de conceptos de sustentabilidade ambiental, fomentando hábitos de consumo responsábel. Unha vez feita a enquisa, a persoa participante recibe información e recomendacións para o aforro de auga, así como a comparación cos datos acumulados. Activa desde abril de 2018, conta actualmente con 150 rexistros, que poden referirse a un único baño, p.ex. vivenda, ou a todos os equipamentos dun edificio público, p.ex. facultade. Desta forma, xa inclúe 250 billas e 184 cisternas. Os resultados pódense consultar de forma libre e analizar segundo diferentes criterios: caudal medio das billas, tipo de cisternas, existencia de información para uso responsábel, presenza de sistemas aforradores de auga. A ferramenta é de especial utilidade para a educación ambiental e social, tanto non formal como en calquera dos niveis educativos, e para a xestión da auga nos ámbitos institucionais. Debería servir tamén para poñer en evidencia a entidades que seguen introducindo equipamentos ineficientes que derraman a auga que non temos.[Abstract] The water consumption survey developed by Emapic and the Office for the Environment UDC is an online tool that aims to create the map of water consumption efficiency in Galiza and the world, to increase public awareness and to reduce water spending through more efficient habits and equipment. Using a simple methodology in the registration of homes and public buildings, it makes use of ICTs to improve the learning of concepts for environmental sustainability, promoting responsible consumption habits. Upon completion of the survey, the participant receives information and recommendations for water saving as well as comparability with accumulated data. Active since April 2018, it currently has 150 records, which can refer to a single toilet, e.g. housing, or all the equipment of a public building, e.g. faculty. Thus, it already includes 250 taps and 184 tanks. The results are accessible for free and can be analyzed according to different criteria: average flow rate of taps, type of tanks, existence of information for responsible use, presence of water-saving systems. The tool is especially useful for environmental and social education, at any non-formal and formal educational levels, and for institutional water management. It should also serve to highlight entities that continue introducing inefficient equipment that spills the water that we don´t have.https://doi.org/10.17979/spudc.978849749775

Determination of 18 organophosphorus flame retardants/plasticizers in mussel samples by matrix solid-phase dispersion combined to liquid chromatography-tandem mass spectrometry

This study presents the development and validation of a new analytical method based on matrix solid-phase dispersion (MSPD), integrating sample extraction and clean-up in one single step, followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the simultaneous determination of 18 organophosphorus flame retardants and/or plasticizers (OPEs) in marine mussel (Mytilus edulis and Mytilus galloprovincialis) samples. Among these OPEs, 5 (tetraethyl 1,2-ethanediylbis(phosphonate), 6H-dibenzo[c,e] [1,2]oxaphosphinine 6-oxide, tris(2,3-dibromopropyl) phosphate, 2,2-propanediyldi-4,1-phenylene bis(phosphate) and resorcinol bis(diphenyl phosphate)) are considered here for the first time in marine samples. Different parameters affecting the MSPD (clean-up sorbent and elution solvent) were optimized to obtain a good compromise between analyte recoveries and extract clean-up. Also, particular attention was paid to tackle blank issues. The overall method was validated in terms of trueness, precision and detection and quantification limits. Percentages of recovery varied from 69% to 122% with relative standard deviations below 24%. Detection limits ranged from 0.06 to 5 ng g−1 and quantification limits from 0.19 to 17 ng g−1 dry weight. Finally, the method was applied to the analysis of 7 mussel samples collected in the coast of Galicia (Spain). 8 OPEs were detected in these samples at concentrations ranging from the LOQ to 291 ng g−1 dry weight.This work was financially supported by the Spanish Agencia Estatal de Investigación (ref. CTM2017-84763-C3-2-R), the Galician Council of Culture, Education and Universities (ref. ED431C2017/36 and Verónica Castro predoctoral contract, ref. ED481A-2017/156), cofunded by FEDER/ERDFS

Determination of human metabolites of chlorinated phosphorous flame retardants in wastewater by N-tert-butyldimethylsilyl-N-methyltrifluoroacetamide-derivatization and gas chromatography-high resolution mass spectrometry

The analysis of wastewater for the determination of human biomarkers of exposure (human metabolites) is a non-intrusive, economic and complementary alternative to the analysis of urine in the monitoring of human exposure to chemicals of concern. This study provides the first gas chromatography-based method for the determination of three metabolites of chlorinated organophosphorous flame retardants (OPFRs: bis(2-chloroethyl) phosphate, bis(chloropropyl) phosphate and bis(1,3-dichloro-2-propyl) phosphate) in wastewater. A solid-phase extraction procedure based on the use of mixed-mode reversed-phase weak anion exchange sorbents was optimized including a fractionated elution of OPFRs and their metabolites. Analytes derivatization was investigated by comparing two silylating reagents, N-tert-butyldimethylsilyl-N-methyltrifluoroacetamide and N-methyl-N-(trimethylsilyl)trifluoroacetamide, the first one providing better results. Determination was performed by gas chromatography-high resolution mass spectrometry with a quadrupole-time-of-flight system (GC-QTOF) in order to improve selectivity. Furthermore, the use of GC-QTOF combined with the specific ion obtained from silylated metabolites (m/z 154.9924) can be exploited to screen for other phosphate ester metabolites. Under final conditions, the overall method performance was satisfactory, affording method detection limits ranging from 1.1 to 4.6 ng/L, percentages of recovery from 90% to 110%, and relative standard deviations below 13%. The analysis of composite raw wastewater samples collected over 24 h in the NW of Spain allowed to quantify, for the first time in this matrix, the metabolite bis(chloropropyl) phosphate at levels over 60 ng/LThis work was financially supported by the Spanish Agencia Estatal de Investigación (project no. CTM2017-84763-C3-2-R), the Galician Council of Culture, Education and Universities (ED431C2017/36, VC predoctoral contract, ED481A-2017/156, and IGM postdoctoral contract, Plan Galego I2C-Modalidade B, ED481D 2017/003), Gil Dávila Foundation (VC research grant) and FEDER/ERDFS