Degradación de Disruptores Endocrinos de Estructura Fenólica en Procesos de Tratamiento de Aguas Residuales

El trabajo recogido tanto en los resultados como en las conclusiones de la presente tesis está encaminado a esclarecer el comportamiento de algunos de los microcontaminantes orgánicos incluidos en la Directiva 2000/60/CE bajo diversas condiciones de trabajo en estaciones depuradoras de aguas residuales. Para ello se ha estudiado un grupo de microcontaminantes cuya presencia en el medio ambiente, bien sea en la fracción soluble de las aguas continentales o bioacumulados en sedimentos y/o biota, es frecuente. La presencia de dichos compuestos es debida, fundamentalmente, a la industrialización y a los actuales hábitos de la sociedad. Los microcontaminantes tipo elegidos son: octilfenol, 4-n-nonilfenol, t-nonilfenol, estrona, 17α-estradiol, 17β-etinilestradiol, pentaclorofenol y bisfenol-A. Estos microcontaminantes están catalogados como compuestos disruptores endocrinos (CDE). Al comienzo de la presente tesis se evaluaron únicamente a los analitos; octilfenol, 4-n-nonilfenol, t-nonilfenol, estrona, 17α-estradiol y 17β-etinilestradiol, pero debido a la inclusión de pentaclorofenol y bisfenol-A en los Anexos II y III de la Directiva 2008/105/CE respectivamente, estos fueron incluidos posteriormente. Los estudios se realizaron sobre agua residual real, siendo las condiciones de trabajo empleadas, las típicas que presenta una EDAR: condiciones aerobias y anaerobias. Estos experimentos se llevaron a cabo tanto en tratamientos secundarios (a escala planta piloto y planta industrial) como postratamientos (a escala laboratorio y planta piloto). Los tratamientos secundarios propuestos para la eliminación de estos compuestos fueron: planta piloto con un biorreactor anaerobio de membrana sumergida (SAnMBR), planta piloto con un biorreactor aerobio de membrana sumergida (aMBR) y planta industrial de fangos activados (TC). Mientras que los postratamientos fueron: planta piloto operando en configuración UCT y reactor de microalgas operando a escala laboratorio. Los estudios realizados en los sistemas secundarios emplearon como afluente agua proveniente del decantador primario o del desarenador de la planta depuradora de la Cuenca del Carraixet situada en la población de Alboraia (España), mientras que los estudios en postratamientos se llevaron a cabo con el efluente del tratamiento secundario SAnMBR. Para poder realizar los correspondientes balances de masa de los compuestos estudiados, se llevó a cabo la toma de muestra de forma que englobase tanto la fracción soluble como la suspendida. El control de las concentraciones de estos compuestos se evaluó mediante, cromatografía de gases acoplada a detección de espectrometría de masas. De esta forma se ha podido conocer tanto los rendimientos de eliminación, degradación y adsorción de los compuestos en los diferentes procesos de degradación estudiados, así como las cinéticas de degradación de los mismos. El resto de análisis efectuados en la presente tesis se han llevado a cabo mediante técnicas gravimétricas (sólidos suspendidos), espectrofotométricas (nutrientes), volumétricas (alcalinidad, ácidos grasos volátiles y DQO) y bioensayos (DBO). El diseño de experimentos se realizó con el objetivo de facilitar la comparación de los rendimientos de eliminación de cada CDE en los procesos secundarios y postratamientos. De esta forma se pudo conocer cuál es el proceso que mejor rendimiento de eliminación aporta, tanto en la etapa secundaria como postratamiento. Además, se estudió el rendimiento global del proceso conjunto (SAnMBR-UCT, escala planta piloto) formado por una etapa anaerobia de membranas y un postratamiento operando en una configuración UCT. Asimismo se estudió, el proceso conjunto formado por una etapa anaerobia de membranas (planta piloto) y un postratamiento basado en cultivo de microalgas (a escala laboratorio, cultivo de microalgas con iluminación artificial y sin aireación forzada). Los primeros estudios se basaron en la comparación de las concentraciones de los disruptores endocrinos a lo largo de la línea de aguas y fangos en los dos reactores de membranas (SAnMBR y aMBR) y en la planta industrial (TC). A la vista de los resultados obtenidos, especialmente para la planta piloto SAnMBR, se observó la necesidad de incluir una etapa de postratamiento que mejorase los resultados obtenidos por el tratamiento anaerobio. Por este motivo el efluente del SAnMBR se sometió a dos tipos de postratamiento. En el primero se acopló a un postratamiento formado por una etapa aerobia; la planta piloto completa presentó el esquema SAnMBR-UCT. En el segundo el afluente se sometió a un postratamiento basado en un cultivo de microalgas, el cual se llevó a cabo en régimen discontinuo. Otros experimentos se llevaron a cabo de forma simultánea, a escala laboratorio, para comprender el efecto de los parámetros involucrados en la degradación de disruptores en un reactor con cultivo de microalgas. Los parámetros estudiados fueron: oxígeno disuelto, luz y microalgas. El estudio de estos tres parámetros tanto de forma individual como combinados proporcionó la información necesaria para la determinación de los rendimientos de eliminación para cada parámetro, así como los parámetros cinéticos en la etapa de degradación.The results and conclusions reflected in this thesis work aims to explain the behaviour of some organic micropollutants include in Directive 2000/60/EC under various working conditions in wastewater treatment plants. For this reason, a group of micropollutants whose the occurrence in the environment, both in the soluble fraction of inland waters and bioaccumulate in sediment and/or biota, is common. The occurrence of these compounds is due mainly to the industrialization and current habits of society. Micropollutants chosen type are: octylphenol, 4-n-nonylphenol, t-nonylphenol, estrone, 17α-estradiol, 17β-ethynylestradiol, pentachlorophenol and bisphenol-A. These micropollutants are classified as endocrine disrupting compounds (EDC). At the beginning of this thesis they were evaluated only the analytes; octylphenol, 4-n-nonylphenol, t-nonylphenol, estrone, 17α-estradiol and 17β-ethinylestradiol, but due to the inclusion of pentachlorophenol and bisphenol-A in Annexes II and III of Directive 2008/105/EC respectively, these were subsequently included as reference analytes in this thesis. The studies were carried out with real wastewater, employing typical operating conditions of a WWTP: aerobic and anaerobic conditions. These experiments were carried out both in secondary treatments (a pilot plant and industrial plant scale) as post-treatment (laboratory scale and pilot plant scale). The proposed secondary processes for remove these compounds were: an anaerobic submerged membrane bioreactor pilot plant (SAnMBR), an aerobic submerged membrane bioreactor pilot plant (aMBR) and conventional activated sludge (CAS). While the post-treatments were: UCT configuration pilot plant and microalgae photobioreactor configuration operating at laboratory scale. Studies on secondary systems were carried out with the effluent of primary settler or degritter of Carraixet wastewater treatment plant located in the town of Alboraia (Spain), while studies in post-treatments were carried out with secondary treatment SAnMBR effluent. To achieve the corresponding mass balance of the studied compounds, sampling was carried out in both the soluble fraction and suspended fraction. The concentrations of these compounds were monitored by a gas chromatography coupled to mass spectrometric detection technique. Thus, it could know both removal yields in different degradation studied processes and their degradation kinetics. The remaining analyses in this thesis have been carried out by gravimetric techniques (suspended solids), spectrophotometric (nutrients), volumetric (alkalinity, VFA and COD) and bioassays (BOD). The design of experiments was carried out in order to facilitate comparison of the removal efficiencies of each CDE in secondary and post-treatment processes. In this way, it was possible to know which is the process that provides better removal efficiency, both in the secondary treatments and post-treatments. Besides, the global efficiency of the coupled processes was studied (SAnMBR-UCT, pilot plant scale) consisted of an anaerobic membrane process and UCT post-treatment. It was also studied, the global process consists of an anaerobic membrane process (pilot plant) and microalgae culture (a laboratory scale, cultivation of microalgae with artificial lighting without forced aeration). The first studies carried out were the comparison of the concentrations of CDE along the water line in two pilot plants (SAnMBR and aMBR) and conventional activated sludge. Considering the results obtained, especially for SAnMBR pilot plant, it can be observed a post-treatment step was necessary in order to improve the results obtained from anaerobic treatment. For this reason, the effluent of SAnMBR was underwent two types of post-treatment. The first experiment coupled the SAnMBR effluent to a post-treatment consisting of an aerobic stage working in UCT configuration. The second experiment coupled the SAnMBR effluent to a microalgae culture, which was carried out in batch mode. Others experiments were simultaneously carried out in lab-scale for understand the effect of three basic parameters involved in microalgae grown in the degradation and kinetics of CDE. Studied parameters were: dissolved oxygen, light and microalgae. The study of these three parameters both individually and in combination provide the necessary information to determine the removal efficiencies for each parameter, as well as the kinetic parameters in degradation step

Fate of endocrine disruptor compounds in an anaerobic membrane bioreactor (AnMBR) coupled to an activated sludge reactor

[EN] The occurrence and fate of three groups of micropollutants - alkylphenols, pentachlorophenol and hormones - were studied in a pilot plant consisting of an anaerobic membrane bioreactor (AnMBR) coupled to an activated sludge reactor (University of Cape Town configuration - UCT). Under anaerobic conditions, the octylphenol and technical-nonylphenol soluble concentrations increased producing negative degradation ratios (i.e., -175 and -118%, respectively). However, high 4-n-nonylphenol and bisphenol-A degradation ratios (92 and 59% for 4-n-nonylphenol and bisphenol-A, respectively) as well as complete pentachlorophenol, estrone, 17 beta-estradiol and 17 alpha-ethinylestradiol removal were observed. Under aerobic conditions (UCT), octylphenol, technical-nonylphenol, 4-n-nonylphenol and bisphenol-A degradation ratios were higher than 84%. The AnMBR thus removes a high proportion of 4-n-nonylphenol, pentachlorophenol, estrone, 17 beta-estradiol and 17 alpha-ethinylestradiol, but requires a later post-treatment process (such as UCT) to improve bisphenol-A, octylphenol and technical-nonylphenol degradation ratios. The overall AnMBR-UCT degradation ratios were 48% and 70% for octylphenol and technical-nonylphenol, respectively, and higher than 97% for 4-n-nonylphenol and bisphenol-A. The AnMBR produced a higher micropollutant accumulation in the sludge than the UCT: removal by adsorption in the AnMBR process was between 0.5 and 10%, and less than 0.5% in the UCT process. The combination of AnMBR and UCT technologies produces an effluent stream with low concentrations of micropollutants.This work was supported by the Spanish Ministry of Economy and Competitiveness (MINECO, CTM2011-28595-C02-01 and CTM2011-28595-C02-02) and the European Regional Development Fund (ERDF).Abargues Llamas, MR.; Ferrer, J.; Bouzas Blanco, A.; Seco Torrecillas, A. (2018). Fate of endocrine disruptor compounds in an anaerobic membrane bioreactor (AnMBR) coupled to an activated sludge reactor. Environmental Science: Water Research & Technology (Online). 4(2):226-233. https://doi.org/10.1039/c7ew00382jS2262334

Endocrine disrupter compounds removal in wastewater using microalgae: Degradation kinetics assessment

[EN] This paper describes a study carried out to determine the removal kinetics of four micropollutants (4-tert-octylphenol (OP), technical-nonylphenol (t-NP), 4-nonylphenol (4-NP) and bisphenol-A (BPA)) usually found in wastewater streams. The kinetic experiments were carried out in batch reactors containing the effluent of an Anaerobic Membrane BioReactor (AnMBR) in the presence of light, oxygen and microalgae. As the degradation process of the studied micropollutants obeyed a pseudo-first-order kinetics, the second-order kinetics for each micropollutant was then calculated. The second order rate constants for the hydroxyl radical (k.(OH)) ranged from 7.0.10(+10) to 6.6.10(+12) L.mol(-1).min(-1) and for the oxygen (k(O2)) from 77 to 125 L.mol(-1).min(-1). The k(O2) values were significantly lower than the k% OH values, indicating that the hydroxyl radical is a better oxidising agent than oxygen. However, as the concentration of dissolved oxygen was higher than that of the hydroxyl radical, higher oxygen pseudo-first order rate constants were produced (k(O2), ranging from 0.016 to 0.026 min(-1)) than hydroxyl radical pseudo-first order rate constants (k.(OH), ranging from 7.0.10-05 to 6.6.10-03 min(-1)), bringing the degradation process under the control of the oxygen mechanism. The proposed kinetic model was validated by fitting experimental data from a study of supersaturated oxygen concentration and showed good correlation for all the studied micropollutants.This research work was supported by the Spanish Ministry of Economy and Competitiveness (MINECO, CTM2011-28595-C02-01 and CTM2011-28595-C02-02) jointly with the European Regional Development Fund (ERDF), which are gratefully acknowledged.Abargues Llamas, MR.; Giménez García, J.; Ferrer, J.; Bouzas Blanco, A.; Seco Torrecillas, A. (2018). Endocrine disrupter compounds removal in wastewater using microalgae: Degradation kinetics assessment. Chemical Engineering Journal. 334:313-321. https://doi.org/10.1016/j.cej.2017.09.187S31332133

Fate of endocrine disruptor compounds in an anaerobic membrane bioreactor (AnMBR) coupled to an activated sludge reactor

Fate of endocrine disruptor compounds in an anaerobic membrane bioreactor (AnMBR) coupled to an activated sludge reactorMinisterio de Economía y Competitivida