Examinando por Autor "Mohedano, Ángel F."

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Contamination of N-poor wastewater with emerging pollutants does not affect the performance of purple phototrophic bacteria and the subsequent resource recovery potential
(2020) Martínez, Fernando; de las Heras, Igor; Molina, Raúl; Segura, Yolanda; Hülsen, Tim; Molina, María Carmen; Gonzalez-Benítez, Natalia; Melero, Juan Antonio; Mohedano, Ángel F.; Puyol, Daniel
Propagation of emerging pollutants (EPs) in wastewater treatment plants has become a warning sign, especially for novel resource-recovery concepts. The fate of EPs on purple phototrophic bacteria (PPB)-based systems has not yet been determined. This work analyzes the performance of a photo-anaerobic membrane bioreactor treating a low-N wastewater contaminated with 25 EPs. The chemical oxygen demand (COD), N and P removal efficiencies were stable (76 ± 8, 62 ± 15 and 36 ± 8 %, respectively) for EPs loading rate ranging from 50 to 200 ng L-1 d-1. The PPB community adapted to changes in both the EPs concentration and the organic loading rate (OLR) and maintained dominance with >85 % of total 16S gene copies. Indeed, an increment of the OLR caused an increase of the biomass growth and activity concomitantly with a higher EPs removal efficiency (30 ± 13 vs 54 ± 11 % removal for OLR of 307 ± 4 and 590 ± 8 mgCOD L-1 d-1, respectively). Biodegradation is the main mechanism of EPs removal due to low EPs accumulation on the biomass, the membrane or the reactor walls. Low EPs adsorption avoided biomass contamination, resulting in no effect on its biological methane potential. These results support the use of PPB technologies for resource recovery with low EPs contamination of the products.
Cosmetic wastewater treatment by upflow anaerobic sludge blanket reactor
(Elsevier, 2011) Puyol, Daniel; Monsalvo, Victor M.; Mohedano, Ángel F.; Sanz, José Luis; Rodríguez, Juan José
Anaerobic treatment of pre-settled cosmetic wastewater in batch and continuous experiments has been investigated. Biodegradability tests showed high COD and solid removal efficiencies (about 70%), being the hydrolysis of solids the limiting step of the process. Continuous treatment was carried out in an upflow anaerobic sludge blanket reactor. High COD and TSS removal efficiencies (up to 95% and 85%, respectively) were achieved over a wide range of organic load rate (from 1.8 to 9.2 g TCOD L−1 day−1). Methanogenesis inhibition was observed in batch assays, which can be predicted by means of a Haldane-based inhibition model. Both COD and solid removal were modelled by Monod and pseudo-first order models, respectively.
Towards biohydrogen overproduction and valorization of food waste by genetic engineering of Rhodobacter capsulatus
(2024-09) Valverde- Cañas, Ángel; Cuesta- Belvis, Daniel; Cicimov, Viktor; de Nicolás, Amanda P.; Díez, Mario P.; Díaz, Elena; de la Rubia, María Ángeles; Mohedano, Ángel F.; Puyol, Daniel; Barahona , Emma
Non-sulfur red bacteria, such as Rhodobacter capsulatus, produce H2 through photofermentation via nitrogenase. These bacteria offer several advantages over other hydrogen bioproduction systems, including high substrate conversion efficiency, the use of a wide variety of carbon sources, the ability to operate under environmental conditions, reduced energy consumption, and high purity of the hydrogen produced. Despite these advantages, higher production rates and more economical carbon sources are required to compete with conventional H2 production methods. For this reason, our ongoing work focuses on two main objectives: genetically redesigning R. capsulatus to increase its H2 production rates, and optimizing and improving the process by valorizing the material and energy content of food waste. In the H2 production experiments with R. capsulatus, both the wild-type strain and a mutant defective in uptake hydrogenase (ΔhupAB) were evaluated. Process water obtained from the hydrothermal carbonization of food waste and a minimal RCV medium were used as substrates in the photofermentation process. The experiments were carried out in batch mode under continuous illumination. The highest levels of H2 production were observed under the condition where the hupAB mutant was growing in RCV medium without a nitrogen source (almost 110 mL of H2/gCOD). However, H2 production values were similar to those obtained using process water as a substrate during the first 24 hours, thereby demonstrating that R. capsulatus can produce H2 from food waste.
Valorization of process water from hydrothermal carbonization of food waste by dark fermentation
(Elsevier, 2024-09-21) Díez, Mario P.; Barahona, Emma; De la Rubia, M. Ángeles; Mohedano, Ángel F.; Diaz, Elena
Hydrothermal carbonization (HTC) of food waste produces hydrochar—a suitable biofuel—and process water (PW), which has a high organic content suitable for material and energy recovery. In this work, we study the effect of pH (4.8, 5.3, and 6.0) and organic loading rate (OLR; 2.5, 5.0, and 7.5 gCOD L- 1 d- 1) throughout the dark fermentation (DF) of PW from the HTC of food waste (180 ◦C, 1 h) in a continuous stirred tank reactor. The highest hydrogen yield (197.5 mL H2 L- 1 d- 1) was reached at pH 4.8 and OLR 5 gCOD L- 1 d-1, associated with a prevalence of Clostridium bacteria. The highest volatile fatty acids concentration (10.2 gCOD⋅L- 1) was achieved at pH 4.8 and OLR 7.5 gCOD L- 1 d- 1, with a dominance of Actinobacteria phylum. The integrated system HTC-DF allowed a potential energy recovery of 11.2 MJ kg􀀀 1.