Una nova xarxa promourà el tractament i reciclatge d'aigües residuals de les pimes iberoamericanes

La Xarxa TRITÓN, finançada pel programa CYTED i constituida per nou grups de recerca, quatre pimes tecnològiques i altres quatre pimes usuàries de vuit països diferents, utilizarà solucions sostenibles fonamentades en processos biològics per tractar i reciclar aigües industrials de les petites i mitjanes empreses a tota iberoamèrica. El grup de recerca GENOCOV de la UAB coordina la xarxa.La Red TRITÓN financiada por el programa CYTED, y constutída por nueve grupos de investigación, cuatro pymes tecnológicas y otras cuatro pymes usuarias de ocho países diferentes, utilizará soluciones sostenibles basadas en procesos biológicos para tratar y reciclar aguas industriales de las pequeñas y medianas empresas en toda Iberoamérica. El grupo de investigación GENOCOV de la UAB coordina la red.The TRITON network, funded by the CYTED program, aims to promote the treatment and recycling of wastewater from the small and medium enterprises (SMEs) in the Latin American region by using sustainable solutions based in biological processes. It consists of nine research groups and eight SMEs from eight different countries. The GENOCOV research group from the UAB is the coordinator of the network

Aguas residuales industriales en Iberoamérica

El agua es un recurso absolutamente imprescindible para la vida en nuestro planeta y, por ende, para los seres humanos. A pesar de la abundancia de agua en la Tierra, tan solo el 2,5% del total es agua dulce. Si restamos el agua dulce contenida en glaciares, hielos perpetuos y capas subterráneas, el agua dulce más accesible (ríos, lagos y embalses) solo representa el 0,3% del agua dulce total. Actualmente, el constante incremento de la población mundial, junto a los problemas medioambientales, están provocando graves problemas de disponibilidad de agua con suficiente calidad para las diversas actividades humanas. El agua utilizada en esas actividades se contamina transformándose en lo que denominamos aguas residuales. Estas aguas residuales deben ser depuradas adecuadamente antes de ser devueltas a las masas naturales de agua (mares, ríos, acuíferos o lagos) ya que si no, provocan serios problemas medioambientales. Sin embargo, el 80% de las aguas residuales producidas en el planeta no son tratadas de forma adecuada por lo que se hace necesario tomar medidas más eficaces que las desarrolladas hasta la actualidad. Una de las actividades humanas que consume más agua y que, por consiguiente, genera más aguas residuales es la actividad industrial. Las aguas industriales son muy heterogéneas y sus características varían mucho según el sector industrial que las produce. Además, el grado de depuración de las aguas residuales industriales no es homogéneo en todo el planeta. Mientras que en los países desarrollados se ha avanzado mucho en el tratamiento y reutilización de este tipo de aguas, en los países en vías de desarrollo, el tratamiento de estas aguas es bastante deficiente. Este problema se agrava cuando el proceso industrial es realizado por pequeñas y medianas empresas (PYMES) que tienen menos recursos económicos que las grandes empresas para afrontar la correcta depuración de sus aguas residuales. En Iberoamérica hay diversos sectores industriales en los que la actividad de las PYMES es esencial y, en muchos casos, la depuración de las aguas residuales de estos sectores industriales es un problema ambiental importante. El primer paso hacia la adecuada implementación de medidas correctoras de esta contaminación es hacer un buen diagnóstico del problema y para ello se requiere información objetiva y contrastada. Así pues, el presente libro pretende ayudar en ese diagnóstico presentando un exhaustivo informe sobre las características de las aguas residuales producidas en diversos sectores industriales iberoamericanos en los que las PYMES juegan un rol esencial. Este libro es el resultado del trabajo colaborativo de diversos grupos de investigación iberoamericanos en el marco de la red temática "Tratamiento y reciclaje de aguas industriales mediante soluciones sostenibles fundamentadas en procesos biológicos, TRITÓN" del Programa Iberoamericano de Ciencia y Tecnología para el Desarrollo, CYTED. El objetivo de la red TRITÓN es promover el tratamiento y reciclaje de aguas residuales de las PYMES iberoamericana mediante soluciones sostenibles fundamentadas en procesos biológicos

Ammonium oxidation activity promotes stable nitritation and granulation of ammonium oxidizing bacteria

Two-stage partial nitritation/anammox (PN/AMX) processes have been pointed out as a feasible configuration for achieving mainstream anammox. For two-stage configurations, stable partial nitritation has been reported feasible in granular sludge reactors. This study aimed to explore the operating conditions involved in the development of an autotrophic aerobic granular sludge using floccular sludge as inoculum. The influence of different parameters such as free ammonia concentration, settling time, superficial gas flow velocity and ammonium oxidation rate was investigated. Enhancing ammonium oxidation activity since the early phase of the operation (i.e. using conventional activated sludge as inoculum enriched with a fraction of a floccular nitrifying biomass) promoted a fast development (ca. 30 days) of an autotrophic aerobic granular sludge performing stable nitritation. When the seeded sludge presented a low nitrifying activity (lower than 0.1 g N L−1 d−1), the increase of the air-flow rate triggered the formation of an autotrophic aerobic granular sludge since ammonium oxidation activity was promoted. Contrarily, imposing low settling times (10 min) or strong free ammonia inhibitory conditions (FA concentrations higher than 50 mg N L−1) were shown to negatively influence the achievement of high ammonium oxidation rates, hampering the development of an autotrophic aerobic granular sludge. This study demonstrated the importance of ensuring high ammonium oxidation rates (higher than 0.2 g N L−1 d−1) for the proper development of an autotrophic partial nitritation granular sludge

Coupling anammox and heterotrophic denitrification activity at mainstream conditions in a single reactor unit

Altres ajuts: Acord transformatiu CRUE-CSICMainstream partial nitritation/anammox (PN/AMX) has attracted large attention in the last decade. Two-stage configurations have been pointed out as an appealing technology for the application of the PN/AMX process at mainstream conditions. However, the process requires of an efficiency improvement by designing a new technology to remove the nitrate produced by anammox bacteria. A new reactor configuration was developed by coupling anammox to heterotrophic denitrification in a single reactor unit while avoiding competition between both processes. The addition of acetate as an external C-source allowed the removal of nitrate by heterotrophic microorganisms without hampering the anammox process by maintaining high nitrogen removal rates (0.16 ± 0.03 g N L-1 d-1) and nitrogen removal efficiencies (91 ± 8 %) (on average from acetate addition periods). Further, a proper organic load management showed to be effective to face the drawbacks derived from previous mainstream treatment stages (i.e. undesired nitrate production), without compromising effluent COD concentrations. By withdrawing samples along the sludge bed, nitrogen compounds and COD concentrations were determined at different reactor heights. This set of experimental data demonstrated that the combination of anammox and heterotrophic denitrification in a single reactor unit was possible as anammox activity dominated within bottom sludge bed sections, while heterotrophic denitrification occurred within middle and upper sludge sections. Microbial diversity results of 16S rRNA gene-targeted sequencing analyses confirmed that anammox and heterotrophic denitrifiers communities occupied two differentiated sludge bed sections along the reactor being dominated by Candidatus Brocadia (30 %) and Thauera (33 to 46 %), respectively. When heterotrophic denitrification occurred, the average N2O emissions with COD addition was ca. 50 % lower than that in periods without COD addition

Sequentially alternating pollutant scenarios of phenolic compounds in a continuous aerobic granular sludge reactor performing simultaneous partial nitritation and o-cresol biodegradation

Industrial wastewater treatment plants must operate properly during the transient-state conditions often found in the industrial production. This study presents the performance of simultaneous partial nitritation and o-cresol biodegradation in a continuous aerobic granular reactor under sequentially alternating pollutant (SAP) scenarios. Three SAP scenarios were imposed during the operation of the granular reactor. In each one, a secondary recalcitrant compound (either p-nitrophenol (PNP), phenol or 2-chlorophenol (2CP)) were added for a short period of time to the regular influent containing only ammonium and o-cresol. Partial nitritation and o-cresol biodegradation were not inhibited by the presence of PNP or phenol and both compounds were fully biodegraded. On the contrary, the presence of 2CP strongly inhibited both processes within 2 days. However, the reactor was recovered in a few days. These findings demonstrate that treatment of complex industrial wastewaters with variable influent composition is feasible in a continuous aerobic granular reactor

Review about bioproduction of Volatile Fatty Acids from wastes and wastewaters : Influence of operating conditions and organic composition of the substrate

Acord transformatiu CRUE-CSICVolatile fatty acids (VFAs) are a group of carboxylic acids considered as building block chemicals. Nowadays, commercial production of VFAs is performed using fossil fuel sources. As an alternative, acidogenic fermentation of wastes by mixed microbial cultures (MMC) is starting to be considered as a potential bioproduction process that would replace conventional production processes and contribute to the circular economy. Nevertheless, more research is needed to control the VFA production yields and to precisely drive the fermentation process to the production of a certain VFA or a mixture of VFAs, either by modifying the operational parameters or by appropriately tunning the substrate composition. Following this gap, this review starts screening the metabolic routes that yield VFAs by anaerobic fermentation. Subsequently, the effect of different operational parameters on VFA production yield and VFA composition distribution is extensively discussed depending on the organic composition of the waste in terms of proteins, carbohydrates and lipids. To the best of our knowledge, previous review articles analyzed the impact of these parameters for different types of wastes, but without specifically considering their organic composition in terms of proteins, carbohydrates and lipids. Afterwards, energy-based metabolic models are presented as the one of the best modelling approaches to predict VFA composition. Then, polyhydroxyalkanoates (PHAs) production by MMC is described since it is one of the most promising applications of waste derived VFAs. Finally, we highlight the research gaps that should be further investigated to develop a large scale VFA bioprocess based on MMC platform from waste streams

Low-strength wastewater treatment in an anammox UASB reactor : effect of the liquid upflow velocity

Aquest article pertany al grup de recerca GENOCOV https://ddd.uab.cat/collection/genocovTwo-stage systems have been proposed to overcome the drawbacks associated to the implementation of the autotrophic biological nitrogen removal process in the mainstream of urban wastewater treatment plants. In this study, an upflow anammox sludge blanket (UAnSB) reactor was successfully operated for 325 days treating a low-strength synthetic influent mimicking mainstream conditions. A nitrogen loading rate of up to 1.8 ± 0.2 g N L⁻¹ d⁻¹ was achieved at 26 ºC and the nitrogen removal rate obtained (1.7 ± 0.1 g N L⁻¹ d⁻¹) resulted considerably higher than most of the previously reported values for systems treating low-strength wastewater at similar temperatures. Fluorescence in situ hybridization analysis showed a high enrichment in the anammox specie Candidatus Brocadia anammoxidans during the whole operation. The evolution of the granule diameter was followed throughout the operation of the UAnSB reactor and a direct correlation of the average granule diameter with the liquid upflow velocity (Vup) was established, being the higher the Vup, the bigger the granules. A stable granule diameter of 790 ± 40 μm was achieved by maintaining a Vup of 1.0 ± 0.1 m h⁻¹. The low VupS applied avoid the use of effluent recirculation which would present a huge inconvenient to implement UAnSB reactors at real scale, however these low VupS led to external mass transfer problems in the reactor. In spite of the mass transfer limitations, not only a high specific anammox activity (0.26 ± 0.02 g N g⁻¹ VS d⁻¹) was achieved in the UASB reactor but also a high nitrogen removal (80 ± 3%)

Biodegradation of a high-strength wastewater containing a mixture of ammonium, aromatic compounds and salts with simultaneous nitritation in an aerobic granular reactor

Long-term operation (390 days) of a continuous airlift reactor with aerobic granular biomass was successfully applied to treat a highly complex wastewater composed of: ammonium (1000 mg N L⁻¹), o-cresol (100 mg L⁻¹), phenol (100 mg L⁻¹, quinoline (50 mg L⁻¹) and salts (16 g salts L⁻¹). High nitrogen loading rate (1.1 g N L⁻¹ d⁻¹) and organic loading rate of 0.7 (g COD L⁻¹ d⁻¹) were achieved for the simultaneous nitritation and complete biodegradation of the aromatic compounds. The successful operation of the granular airlift reactor can be related to (i) the growth of specialized microorganisms in the aerobic granules and (ii) the continuous feeding regime. Aerobic granules were maintained stable in spite of the high salinity conditions. Dissolved oxygen (DO) concentration and DO/ammonium concentrations ratio were the key parameters to select a suitable effluent for anammox or heterotrophic denitrification via nitrite. Besides, nitrous oxide emissions were related to the DO concentration in the reactor

Stable partial nitritation for low-strength wastewater at low temperature in an aerobic granular reactor

This study was supported by the AGAUR and ACC1Ó through the ANFIBIO project (2010VALOR0096). J. Pérez acknowledges the mobility fellowship (PRX12/00418, Ministerio de Educación, Cultura y Deporte, through the Programa Nacional de Movilidad de Recursos Humanos del Plan Nacional de I + D + I 2008-2011) provided by the Spanish Government.Partial nitritation for a low-strength wastewater at low temperature was stably achieved in an aerobic granular reactor. A bench-scale granular sludge bioreactor was operated in continuous mode treating an influent of 70 mg N-NH₄⁺ L⁻¹ to mimic pretreated municipal nitrogenous wastewater and the temperature was progressively decreased from 30 to 12.5ºC. A suitable effluent nitrite to ammonium concentrations ratio to a subsequent anammox reactor was maintained stable during 300 days at 12.5ºC. The average applied nitrogen loading rate at 12.5 ºC was 0.7 ± 0.3 g N L⁻¹ d⁻¹, with an effluent nitrate concentration of only 2.5 ± 0.7 mg N--NO₃ L⁻¹. The biomass fraction of nitrite-oxidizing bacteria (NOB) in the granular sludge decreased from 19% to only 1% in 6 months of reactor operation at 12.5ºC. Nitrobacter spp. where found as the dominant NOB population, whereas Nitrospira spp. were not detected. Simulations indicated that: (i) NOB would only be effectively repressed when their oxygen half-saturation coefficient was higher than that of ammonia-oxidizing bacteria; and (ii) a lower specific growth rate of NOB was maintained at any point in the biofilm (even at 12.5ºC) due to the bulk ammonium concentration imposed through the control strategy

Aerobic biodegradation of a mixture of monosubstituted phenols in a sequencing batch reactor

A sequencing batch reactor (SBR) was inoculated with p-nitrophenol-degrading activated sludge to biodegrade a mixture of monosubstituted phenols: p-nitrophenol (PNP), PNP and o-cresol; and PNP, o-cresol and o-chlorophenol. Settling times were progressively decreased to promote biomass granulation. PNP was completely biodegraded. The PNP and o-cresol mixture was also biodegraded although some transitory accumulation of intermediates occurred (mainly hydroquinone and catechol). o-Chlorophenol was not biodegraded and resulted in inhibition of o-cresol and PNP biodegradation and complete failure of the SBR within a few days. The biomass had very good settling properties when a settling time of 1 min was applied: sludge volume index (SVI₅) below 50 mL g⁻¹, SVI₅/SVI₃₀ ratio of 1 and average particle size of 200 μm