Browsing by Author "Mesquita, Raquel B. R."
Now showing 1 - 10 of 163
Results Per Page
Sort Options
- Aerobic granular sludge sequencing batch reactor performance under fluorinated pharmaceuticals shock loadingsPublication . Moreira, Irina S.; Amorim, Catarina L.; Ribeiro, Ana R.; Maia, Alexandra S.; Mesquita, Raquel B. R.; Calheiros, Cristina S. C.; Rangel, António O. S. S.; Loosdrecht, Mark C. M.; Tiritan, Maria E.; Castro, Paula M. L.The widespread usage of pharmaceuticals is of increasing concern. Aerobic granular sludge sequencing batch reactors (AGS-SBR) constitute a promising technology for the treatment of wastewaters, however how the removal of carbon and nutrients can be affected by such micropollutants is largely unknown. This study evaluates the impact of different fluorinated drugs (ofloxacin, norfloxacin, ciprofloxacin and fluoxetine) on the performance of an AGS-SBR. During 468 days, a sequence of intermittent, alternating and/or continuous shock loads of pharmaceuticals were apllied to an AGS-SBR and the effects on the main biological processes were evaluated. Here we report on the effect of fluoroquinolones on reactor performnce. The organic removal, measured by COD, was not markedly affected by pharmaceuticals shock loads. Ammonium and nitrite were practically not detected in the bioreactor effluent indicating that the presence of the pharmaceuticals did not inhibit nitrification, whereas accumulation of nitrate in the effluent was observed, indicating that denitrification was affected. Phosphate removal was affected to some extent. There was no evidence of biodegradation whereas adsorption of the target pharmaceuticals to the AGS was observed, which were gradually released into the medium after withdrawal from the inlet stream.
- Aerobic granules in a sequencing batch bioreactor under fluoroquinolone shock loadingsPublication . Amorim, Catarina L.; Maia, Alexandra S.; Mesquita, Raquel B. R.; Rangel, António O. S. S.; Tiritan, Maria E.; Castro, Paula M. L.The growing occurrence of human and veterinary pharmaceuticals in the environment is causing increasing concern. Fluoroquinolones (FQs) are broad-spectrum antibiotics that play an important role in the treatment of serious bacterial infections. Antibiotics can reach wastewater treatment plants (WWTP) from different routes. Domestic effluents are considered the major contributor but effluents from pharmaceutical industries and hospitals are also of great concern. Granular sequencing batch reactors (SBR) constitute a novel biofilm technology for wastewater treatment extremely promising for the treatment of effluents containing toxic compounds. Aerobic granular sludge has several advantages over activated sludge, such as excellent settling properties, high biomass retention, ability to deal with high organic loading rates and to perform simultaneously diverse biological processes, such as Chemical Oxygen Demand (COD), N and P removal. This study focused on the effect of intermittent and alternating feeding of different FQs, namely Ofloxacin (OFL), Norfloxacin (NOR) and Ciprofloxacin (CPF), on bioreactor performance and diversity of the microbial population. Activated sludge from a municipal WWTP was used as the inoculum for the start-up of the SBR. The aerobic granules grew under aerobic conditions and after ca. 3 months of reactor operation stable granules were observed. The FQs affected the granular sludge in terms of morphology, causing a decrease in granule size. The granules started to disintegrate and an increase in the levels of solids in the effluent after exposure to FQs occurred due to wash-out of unstable granules, concomitant with a decrease in the SBR bed volume. The effect of the target fluorinated pharmaceuticals on the main biological processes occurring in the granular sludge SBR, such as nitrification and phosphate removal, was evaluated. Ammonium and nitrite were practically not detected in the treated effluent (maximum concentration of 0.03 and 0.01 mM for NH4+-N and NO2--N, respectively) indicating that neither ammonia oxidizing bacteria (AOB) nor nitrite oxidizing bacteria (NOB) were inhibited by the presence of the FQs, whereas phosphate removal was affected. The phosphate released into the bulk liquid by the phosphate accumulating organisms (PAO) during the anaerobic feeding period was not completely removed and the levels of phosphate in the bioreactor effluent increased. The organic removal, measured by COD, was not markedly affected by FQ shock loads. Changes in the bacterial community from aerobic granules related to FQs shock loadings were examined using denaturing gradient electrophoresis (DGGE) of 16S rRNA. The clustering analysis suggested that samples clustered according to the temporal factor. The gradual succession observed in the bacterial assemblage composition was related with the exposure to FQs. Also, the microbial population present in the aerobic granules was also investigated by culture-dependent methods. Several bacterial isolates belonging to α- and ɣ-branch of the Proteobacteria phylum were retrieved from the granules. After ca. 2 months without FQs exposure, the SBR bed volume was recovered and the solid content at the bioreactor effluent returned to normal levels.
- Amostragem inteligente como abordagem expedita para monitorização de iões de metal em águas naturais: projeto Aqua_SmartPublication . Pereira, Mafalda G.; Melo, Maria M. P.; Mesquita, Raquel B. R.; Ribas, Tânia C. F.; Machado, Ana; Rangel, António O. S. S.
- Amostragem inteligente como abordagem expedita para monitorização de iões de metal em águas naturais: projeto Aqua_SmartPublication . Pereira, Mafalda G.; Melo, Maria M. P.; Mesquita, Raquel B. R.; Ribas, Tânia; Machado, Ana; Rangel, António O. S. S.O projeto Aqua_Smart (FCT ref. 2022.08713.PTDC) foi concebido com o objetivo de desenvolver um conceito de amostragem inteligente integrada numa monitorização automática do teor de iões potencialmente tóxicos em águas, permitindo monitorizar alterações ambientais que podem ter impacto na saúde pública, promovendo uma abordagem “One Health”. Neste trabalho reporta-se a utilização de uma PIM como suporte de troca aniónica, explorando a tendência para formar cloro complexos de cobalto, permitindo a determinação deste ião. Neste enquadramento, tornou-se relevante combinar com a determinação do teor em anião cloreto, usando um reagente colorimétrico de baixa toxicidade.
- Aplicação de um sistema de análise por injecção sequencial à monitorização da eficiência de operação de um leito de plantasPublication . Mesquita, Raquel B. R.; Santos, Inês C.; Calheiros, Cristina S. C.; Castro, Paula M. L.; Rangel, António O. S. S.
- Application of mid- and near-infrared spectroscopy for the control and chemical evaluation of brine solutions and traditional sea saltsPublication . Galvis-Sánchez, Andrea C.; Santos, Inês C.; Mesquita, Raquel B. R.; Lopes, João A.; Rangel, António O. S. S.; Delgadillo, IvonneMid- and near-infrared spectroscopy methodologies were explored for the analysis of brine solutions and traditional sea salt samples. Brine solutions from different salt pans, corresponding to different stages of sodium chloride crystallisation, were collected. A total of 61 dried and non-dried traditional sea salts were also analysed. Partial least squares regression with leave-one-out cross-validation strategy was applied for the calibration of inorganic constituents Ca2+, Mg2+ and K+, alkalinity as HCO (3) (-) , SO (4) (2-) , NO (2) (-) and NO (3) (-) and phosphate in brine solutions. Promising results were obtained with the near-infrared (NIR) methodology for brine solutions with coefficients of determination R (2) > 0.90 for Mg+2, K+, HCO (3) (-) and SO (4) (2-) . Using mid-infrared, the calibration for H2PO (4) (-) was R (2) = 0.85. In relation to the sea salt samples, the strategy adopted was the re-sampling based cross-validation using different spectral pre-processing treatments. In this case, the calibrations using the two IR methodologies fell bellow acceptable levels for the techniques; however, by comparing the R (2) coefficient, the results were slightly better when using the NIR spectra of dried sea samples. In general, these results open a new possibility for the IR applications and also bring an opportunity for continuing with the NIR characterization for dried sea salt samples.
- Assessment of collagen content in fish skin: development of a flow analysis method for hydroxyproline determinationPublication . Melo, Maria M. P.; Mesquita, Raquel B. R.; Coscueta, Ezequiel R.; Pintado, Manuela E.; Rangel, António O. S. S.This work describes the development of a flow injection method to determine hydroxyproline (HYP), one of collagen's most abundant amino acids. Collagen is a protein with several applications and high nutritional value. Evaluating the feasibility of using collagen from fish skin over its mammalian source is essential. The determination of HYP requires the pre-treatment and hydrolysis of the fish skin to break down collagen into its amino acids, and the HYP value quantified relates to the collagen content. The determination was based on the HYP oxidation with permanganate in an alkaline medium and the consequent decrease of colour intensity registered. Under optimal conditions, the developed method enables the determination of the HYP within the dynamic range of 23.8 to 500 mg L −1, with a limit of detection (LOD) of 2.6 mg L −1 and a limit of quantification (LOQ) of 23.8 mg L −1. Different samples were processed, and the digests were analysed by the proposed method and with the conventional procedure with good correlation (relative error < 7%). Moreover, the analyte quantification is performed faster, simpler, and more accurately, with less toxic solutions. The reproducibility of the developed method was also evaluated by calculating the relative standard deviation of the calibration curve slope (RSD < 1%).
- Assessment of the impact synthetic Fe(III)-chelates amendment in soil microbial community dynamicsPublication . Machado, Ana; Mesquita, Letícia S.; Rangel, Maria; Mesquita, Raquel B. R.; Rangel, António O. S. S.; Bordalo, Adriano A.
- Assessment of the impact synthetic Fe(III)-chelates amendment in soil microbial community dynamicsPublication . Machado, Ana; Mesquita, Raquel B. R.; Mesquita, Letícia S.; Rangel, Maria; Rangel, António O. S. S.; Bordalo, Adriano A.Background Iron has a crucial role in plant nutrition, being an essential element for plant growth. However, one-third of the Earth soil is iron deficient, resulting in iron deficiency chlorosis (IDC) growth of several crops worldwide, including staple foods. The use of synthetic Fe(III)-chelates is one of the most effective measures to correct IDC in plants, but their environmental impact must be mastered. Therefore, the search for more effective Fe-chelates remains an important issue. Previously [1], a 3,4-HPO Fe-chelate was proposed as a novel-fertilizing agent. Since the increase of nutrients availability in soil is thought to have an impact on the microbial composition, this question needs to be addressed. Therefore, the aim of the study was to investigate the effect of iron complexes of the 3,4-HPO class of ligands on soil bacterial dynamics to better understand their pathways. Method Laboratory scale soil columns (LSSC) were set up, with different soils origin and characteristics (Agricultural, Forestry and Urban), and exposed to two iron-chelates using rain simulations. The structure and abundance of the bacterial community was evaluated by automated ribosomal intergenic spacer analysis (ARISA) and qPCR (rpoB) approaches. Results & Conclusions Cluster analysis of ARISA profiles revealed that the soil characteristics were the major driving selection for the microbial community composition, with the samples from the same soil type clustering together, disregarding the amendment performed. Also, it emerged that the microbial community of forestry and agricultural soils were more similar (46%) than the one present in urban soil, as expected due to the plant influence. Considering each soil type individually, it was possible to observe a clear response to Fe(III) amendment on the microbial assemblage. Additionally, it seems that one of the compounds, the Fe-chelate derived from the ligand Deferiprone, induced greater and/or faster changes, and that the forestry soil was more prone to the microbial shift. These changes can underline a selection for bacteria that can use Fe(III) in its metabolism, or more tolerant to its presence, that needs to be better understood.
- Biparametric sequential injection system with on-line solid phase extraction for the determination of copper and zinc in watersPublication . Ribas, Tânia C. F.; Croft, Charles F.; Almeida, Inês G. S.; Mesquita, Raquel B. R.; Rangel, António 0. S. S.