Search

The aim of this study was to assess the potential environmental impacts associated with microalgae systems for wastewater treatment and bioproducts recovery. In this sense, a Life Cycle Assessment was carried out evaluating two systems treating i) urban wastewater and ii) industrial wastewater (from a food industry), with the recovery of bioproducts (i.e. natural pigments and biofertilizer) and bioenergy (i.e. biogas). Additionally, both alternatives were compared to iii) a conventional system using a standard growth medium for microalgae cultivation in order to show the potential benefits of using wastewater compared to typical cultivation approaches. The results indicated that the system treating industrial wastewater with unialgal culture had lower environmental impacts than the system treating urban wastewater with mixed cultures. Bioproducts recovery from microalgae wastewater treatment systems can reduce the environmental impacts up to 5 times compared to a conventional system using a standard growth medium. This was mainly due to the lower chemicals consumption for microalgae cultivation. Food-industry effluent showed to be the most promising scenario for bioproducts recovery from microalgae treating wastewater, because of its better quality compared to urban wastewater which also allows the cultivation of a single microalgae species. In conclusion, microalgae wastewater treatment systems are a promising solution not only for wastewater treatment but also to boost the circular bioeconomy in the water sector through microalgae-based product recovery., This research was funded by the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie Grant Agreement No 676070 (SuPER-W). This communication reflects only the author's view and the Research Executive Agency of the EU is not responsible for any use that may be made of the information it contains. Authors acknowledge the AL4BIO project “RTI2018-099495-B-C21” (MCIU/AEI/FEDER, UE) and are grateful to the Government of Catalonia (Consolidated Research Group 2017 SGR 1029). Marianna Garfí is grateful to the MINECO (RYC-2016-20059)., Peer Reviewed, Postprint (author's final draft)

Indium (In) is a critical raw material heavily demanded in the optical-electronics industry. With its high supply risk, sustainable technologies are needed to recover In(III) from secondary sources, such as leachates from sludge produced by zinc processing industries (e.g., jarosite) and indium tin oxide etching wastewater. This study presents In(III) biosorption as an eco friendly alternative to conventional physicochemical recovery technologies., This study was partly supported by METGROW+, a project of the European Union’s Horizon 2020 research and innovation programme under grant agreement No 690088. N. R. N. acknowledges the UGent Special Research Fund (BOF) for the PhD scholarship. L. O. G. acknowledges METGROW+ for the post-doctoral scholarship. L. A. acknowledges the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 676070 (MSCA-ITN project SuPER-W) for her PhD scholarship. M. G. acknowledges the Spanish Ministry of Economy and Competitiveness (RYC-2016-20059)., Postprint (updated version)

The present study evaluated the efficiency of a high rate algal pond (HRAP) at pilot scale to remove pharmaceuticals and personal care products (PPCPs) from urban wastewater, including UV-filters and parabens (10), benzotriazoles (4), antibiotics (15), anti-inflammatories (3) and other pharmaceuticals (3). A total of 35 compounds were targeted, of which 21 were detected in the influent wastewater to the HRAP. Removals (RE%) for pharmaceuticals were variable, with efficient eliminations for atenolol (84%) and sulfathiazole (100%), whereas the anti-inflammatories naproxen and ketoprofen were only partially removed <50%. Benzotriazoles showed elimination rates similar to those of conventional WWTPs, with RE% ranging from no elimination to 51% for the UV filter benzophenone-3 (BP3) and 100% for 4-methylbenzilidenecamphor (4MBC). Hazard quotients (HQs) were estimated for those compounds not fully eliminated in the HRAP, as well as the cumulative ecotoxicity in the resulting effluent. The majority of the compounds yielded HQs < 0.1, meaning that no environmental risk would be derived from their discharge. Overall, these results clearly indicate that HRAPs are a reliable, green and cost-effective alternative to intensive wastewater treatment, yielding promising results removing these contaminants, M.J. García-Galán and M. Garfí would like to thank the Spanish Ministry of Economy and Competitiveness for their research grants (IJCI-2017-34601 and RYC-2016-20059, respectively). Lucas Vassalle would like to acknowledge the National Council for Scientific and Technological Development from Brazilian Ministry of Education—CNPQ (scholarship 204026/2018-0). Larissa T. Arashiro is grateful to the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie Grant Agreement No 676070 (SuPER-W). This communication reflects only the author’s view and the Research Executive Agency of the EU is not responsible for any use that may be made of the information it contains. The authors would like to thank Antonio Ortiz Ruiz for his help on the design of Figure 1., Peer Reviewed, Postprint (published version)

The aim of this study was to investigate the cultivation of Nostoc sp., Arthrospira platensis and Porphyridium purpureum in industrial wastewater to produce phycobiliproteins. Initially, light intensity and growth medium composition were optimized, indicating that light conditions influenced the phycobiliproteins production more than the medium composition. Conditions were then selected, according to biomass growth, nutrients removal and phycobiliproteins production, to cultivate these microalgae in food-industry wastewater. The three species could efficiently remove up to 98%, 94% and 100% of COD, inorganic nitrogen and PO43--P, respectively. Phycocyanin, allophycocyanin and phycoerythrin were successfully extracted from the biomass reaching concentrations up to 103, 57 and 30 mg/g dry weight, respectively. Results highlight the potential use of microalgae for industrial wastewater treatment and related high-value phycobiliproteins recovery., Peer Reviewed, Postprint (author's final draft)

The present study evaluated the efficiency of a high rate algal pond (HRAP) at pilot scale to remove pharmaceuticals and personal care products (PPCPs) from urban wastewater, including UV-filters and parabens (10), benzotriazoles (4), antibiotics (15), anti-inflammatories (3) and other pharmaceuticals (3). A total of 35 compounds were targeted, of which 21 were detected in the influent wastewater to the HRAP. Removals (RE%) for pharmaceuticals were variable, with efficient eliminations for atenolol (84%) and sulfathiazole (100%), whereas the anti-inflammatories naproxen and ketoprofen were only partially removed <50%. Benzotriazoles showed elimination rates similar to those of conventional WWTPs, with RE% ranging from no elimination to 51% for the UV filter benzophenone-3 (BP3) and 100% for 4-methylbenzilidenecamphor (4MBC). Hazard quotients (HQs) were estimated for those compounds not fully eliminated in the HRAP, as well as the cumulative ecotoxicity in the resulting effluent. The majority of the compounds yielded HQs < 0.1, meaning that no environmental risk would be derived from their discharge. Overall, these results clearly indicate that HRAPs are a reliable, green and cost-effective alternative to intensive wastewater treatment, yielding promising results removing these contaminants.

This study assessed the recovery of natural pigments (phycobiliproteins) and bioenergy (biogas) from microalgae grown in wastewater. A consortium of microalgae, mainly composed by Nostoc, Phormidium, and Geitlerinema, known to have high phycobiliproteins content, was grown in photobioreactors. The growth medium was composed by secondary effluent from a high rate algal pond (HRAP) along with the anaerobic digestion centrate, which aimed to enhance the N/P ratio, given the lack of nutrients in the secondary effluent. Additionally, the centrate is still a challenging anaerobic digestion residue since the high nitrogen concentrations have to be removed before disposal. Removal efficiencies up to 52% of COD, 86% of NH4+-N, and 100% of phosphorus were observed. The biomass composition was monitored over the experimental period in order to ensure stable cyanobacterial dominance in the mixed culture. Phycocyanin and phycoerythrin were extracted from harvested biomass, achieving maximum concentrations of 20.1 and 8.1 mg/g dry weight, respectively. The residual biomass from phycobiliproteins extraction was then used to produce biogas, with final methane yields ranging from 159 to 199 mL CH4/g VS. According to the results, by combining the extraction of pigments and the production of biogas from residual biomass, we would not only obtain high-value compounds, but also more energy (around 5–10% higher), as compared to the single recovery of biogas. The proposed process poses an example of resource recovery from biomass grown in wastewater, moving toward a circular bioeconomy., This research was funded by the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie Grant Agreement No 676070 (SuPER-W). This communication reflects only the author’s view and the Research Executive Agency of the EU is not responsible for any use that may be made of the information it contains. Authors acknowledge the AL4BIO project “RTI2018-099495-B-C21” (MCIU/AEI/FEDER, UE) and are grateful to the Government of Catalonia (Consolidated Research Group 2017 SGR 1029). Marianna Garfí is grateful to the MINECO (RYC-2016-20059). Authors acknowledge Antera Martel, Mireia Sánchez, and Noelia Robles from the Spanish Bank of Algae for their helpful assistance with microalgae species identification and phycobiliproteins extraction. Authors are also thankful to Carme Maynés, Izia Lena and Caroline Bayeux for their contribution., Peer Reviewed, Postprint (published version)

Tesi en modalitat de cotutela: Universitat Politècnica de Catalunya i Universiteit Gent, Premi extraordinari doctorat UPC curs 2019-2020, àmbit d’Enginyeria Civil i Ambiental, Water is undoubtedly the most essential resource of humanity. However. supplying the human population with clean water has been a major challenge for decades. Contaminants in wastewaters endanger water bodies and the treatment of these effluents represent a high energy demand. The development of efficient wastewater treatment technologies is thus becoming increasingly important. In the context of a circular and bio-based economy. microalgae biomass has shown its great potential to treat wastewater streams. while recovering sustainable bioproducts. However. although extensive research has been done in this field. there is still need for improvements and realistic information in order to implement these systems at large scale. This PhD thesis aims to contribute to this quest by performing holistic studies on microalgae systems for wastewater treatment combined with different strategies for biomass valorisation. The overall content of this PhD thesis is divided in two main parts. The first part consists in experimental studies combining wastewater treatment and resources recovery using microalgae-based systems. while the second part is dedicated to the environmental analyses. through Life Cycle Assessment (LCA). of the technologies and biomass valorisation techniques investigated in this thesis. The first part presents investigated a well-known microalgae system. high rate alga! pond (HRAP). in order to simplify its maintenance. reduce costs and the footprint. This study showed that removing the primary treatment preceding a HRAP did not significantly affect the wastewater treatment efficiency. Moreover. the co-digestion with primary sludge could significantly improve the methane yield and kinetics of microalgae mono-digestion (2382:58 ml CH4/g VS compared to 1892:25 ml CH4/g VS. Following. a second study investigated the cultivation of cyanobacteria-dominated biomass using centrate diluted in secondary effluent from the HRAP system at different ratios. Results showed, El agua es sin duda el recurso más esencial de la humanidad. Sin embargo, el suministro de agua limpia a la población humana ha sido un gran desafío durante décadas. Los contaminantes en las aguas residuales ponen en peligro los cuerpos de agua y el tratamiento de estos efluentes representa una gran demanda de energía. El desarrollo de tecnologías eficientes de tratamiento de aguas residuales se está volviendo cada vez más importante. En el contexto de una bioeconomía circular, la biomasa de microalgas ha demostrado su gran potencial para tratar las ofertas de corrientes de aguas residuales, al tiempo que recupera bioproductos sostenibles, implementando así conceptos de biorefinería. Sin embargo, aunque se ha realizado investigaciones em este tema, aún se necesitan mejoras e información realista para implementar estos sistemas a gran escala. Esta tesis doctoral tiene como objetivo contribuir a esta búsqueda mediante la realización de estudios holísticos sobre sistemas de microalgas para el tratamiento de aguas residuales. El contenido general de esta tesis doctoral se ha dividido en dos partes. La primera parte consistió en estudios experimentales, mientras que la segunda parte se ha dedicado a los análisis ambientales, a través del Análisis del Ciclo de Vida (ACV). La primera parte ha investigado un conocido sistema de microalgas, la laguna algal de alta tasa (HRAP), para simplificar su mantenimiento y reducir los costos. Este estudio mostró que la eliminación del tratamiento primario que precede la HRAP no afectó significativamente la eficiencia del tratamiento de aguas residuales. Además, la codigestión con lodo primario podría mejorar significativamente el rendimiento de metano y la cinética de la mono-digestión de microalgas (2382:58 ml en comparación con 1892:25 mL de CH4/g sólidos volátiles (SV)). A continuación, un segundo estudio investigó el cultivo de cianobacterias utilizando concentrado diluido en efluente secundario del sistema HRAP a diferentes propor, Neerlandeès . De huidige globale milieuproblematiek roept onvermijdelijke uitdagingen op om natuurlijke grondstoffen beter te beheren met het oog op een duurzame ontwikkeling. Water is ongetwijfeld de meest essentiële grondstof van de mens en genoeg zuiver water voorzien is reeds tientallen jaren een grote uitdaging. Verontreinigingen in huishoudelijk, industrieel en landbouw afvalwater vormen een gevaar voor de waterlichamen en de behandeling van deze effluenten vraagt veel energie. De ontwikkeling van efficiënte technologieën voor afvalwaterbehandeling wordt dus steeds belangrijker. Vanwege hun metabolische flexibiliteit zijn microalgen interessante biologische systemen voor de behandeling van verschillende types afvalwater. Zeker in de context van een circulaire en biogebaseerde economie heeft microalgenbiomassa haar grote potentieel getoond om afvalwaterstromen te behandelen en tegelijkertijd duurzame bioproducten te produceren en dus het bioraffinageconcept te implementeren. Hoewel uitgebreid onderzoek is gedaan om microalgensystemen te optimaliseren wat betreft werking en economische haalbaarheid, is er nog steeds behoefte aan verbeteringen en realistische informatie om deze systemen op grote schaal te implementeren. Dit doctoraatsonderzoek beoogt een bijdrage te leveren aan deze zoektocht door een holistische studie uit te voeren op microalgensystemen van microalgensystemen voor afvalwaterbehandeling in combinatie met verschillende valorisatiestrategieën voor de resulterende biomassa. De algemene inhoud van dit proefschrift is verdeeld in twee delen. Het eerste deel bestaat uit experimentele studies waarin afvalwaterzuivering wordt gecombineerd met terugwinning van grondstoffen met behulp van op microalgen gebaseerde systemen, terwijl het tweede deel is gewijd aan Life Cycle Assessment (LCA) van de technologieën en valorisatietechnieken voor biomassa die in dit proefschrift zijn onderzocht. Het eerste deel presenteert dus de onderzochte alternatieven van afva, Award-winning, Postprint (published version)

The present study evaluates the removal capacity of two high rate algae ponds (HRAPs) to eliminate 12 pharmaceuticals (PhACs) and 26 of their corresponding main metabolites and transformation products. The efficiency of these ponds, operating with and without primary treatment, was compared in order to study their capacity under the best performance conditions (highest solar irradiance). Concentrations of all the target compounds were determined in both water and biomass samples. Removal rates ranged from moderate (40–60 %) to high (>60 %) for most of them, with the exception of the psychiatric drugs carbamazepine, the ß-blocking agent metoprolol and its metabolite, metoprolol acid. O-desmethylvenlafaxine, despite its very low biodegradability in conventional wastewater treatment plants, was removed to certain extent (13–39 %). Biomass concentrations suggested that bioadsorption/bioaccumulation to microalgae biomass was decisive regarding the elimination of non-biodegradable compounds such as venlafaxine and its main metabolites. HRAP treatment with and without primary treatment did not yield significant differences in terms of PhACs removal efficiency. The implementation of HRAPs as secondary treatment is a feasible alternative to CAS in terms of overall wastewater treatment, including organic micropollutants, with generally higher removal performances and implying a green, low-cost and more sustainable technology, Peer Reviewed, Postprint (author's final draft)

The aim of this study was to assess the effect of primary treatment on the performance of two pilot-scale high rate algal ponds (HRAPs) treating urban wastewater, considering their treatment efficiency, biomass productivity, characteristics and biogas production potential. Results indicated that the primary treatment did not significantly affect the wastewater treatment efficiency (NH4+-N removal of 93 and 91% and COD removal of 62 and 65% in HRAP with and without primary treatment, respectively). The HRAP without primary treatment had higher biodiversity and productivity (20 vs. 15 g VSS/m2d). Biomass from both systems presented good settling capacity. Results of biochemical methane potential test showed that co-digesting microalgae and primary sludge led to higher methane yields (238–258 mL CH4/g VS) compared with microalgae mono-digestion (189–225 mL CH4/g VS). Overall, HRAPs with and without primary treatment seem to be appropriate alternatives for combining wastewater treatment and bioenergy recovery., Peer Reviewed, Postprint (author's final draft)

Los humedales construidos son tecnologías naturales capaces de eliminar los contaminantes de las aguas residuales, proporcionando un tratamiento de calidad y permitiendo la reutilización de las aguas para el uso de riego, o bien, para poder verterlas directamente en el entorno habiendo recibido un tratamiento previo, evitando de este modo la contaminación de los espacios naturales. Esta tecnología se implementa en la zona rural de Perú, en las cercanías del centro poblado de Chamaya, Jaén. Donde el tratamiento del agua residuales escaso y no suelen recibir ningún tratamiento, siendo evacuadas directamente en el entorno contaminando el terreno y ríos cercanos. Con el fin de mejorar esta situación, se realiza este trabajo en el cual se desarrolla el dimensionamiento, construcción y análisis de la primera muestra obtenida de un humedal construido pudiendo participar directamente en el proyecto haciendo una estancia en Perú durante todo el periodo en el que se llevó a cabo el proyecto. El análisis se produce comparando la concentración de contaminante del afluente con la del efluente, con la finalidad de comprobar si cumplen los estándares de calidad de Perú y algunos de los indicadores agronómicos de calidad de las aguas de riego. De tal modo que podamos verificar si las aguas son aptas para el riego. Obteniendo de esta primera muestra resultados positivos, con el humedal construido trabajando a la mitad de su capacidad, destacando la gran eficiencia en la eliminación de amonio, con parámetros del 86,1% y de DBO5 llegando a una eficiencia del 60%.

The aim of this study was to assess the potential environmental impacts associated with high rate algal ponds (HRAP) systems for wastewater treatment and resource recovery in small communities. To this aim, a Life Cycle Assessment (LCA) was carried out evaluating two alternatives: i) a HRAP system for wastewater treatment where microalgal biomass is valorized for energy recovery (biogas production); ii) a HRAP system for wastewater treatment where microalgal biomass is reused for nutrients recovery (biofertilizer production). Additionally, both alternatives were compared to a typical small-sized activated sludge system. An economic assessment was also performed. The results showed that HRAP system coupled with biogas production appeared to be more environmentally friendly than HRAP system coupled with biofertilizer production in the climate change, ozone layer depletion, photochemical oxidant formation, and fossil depletion impact categories. Different climatic conditions have strongly influenced the results obtained in the eutrophication and metal depletion impact categories. In fact, the HRAP system located where warm temperatures and high solar radiation are predominant (HRAP system coupled with biofertilizer production) showed lower impact in those categories. Additionally, the characteristics (e.g. nutrients and heavy metals concentration) of microalgal biomass recovered from wastewater appeared to be crucial when assessing the potential environmental impacts in the terrestrial acidification, particulate matter formation and toxicity impact categories. In terms of costs, HRAP systems seemed to be more economically feasible when combined with biofertilizer production instead of biogas. On the whole, implementing HRAPs instead of activated sludge systems might increase sustainability and cost-effectiveness of wastewater treatment in small communities, especially if implemented in warm climate regions and coupled with biofertilizer production., Peer Reviewed, Postprint (author's final draft)