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- Wastewater as a nutrient source for hydroponic production of lettuce: Summer and winter growthPublication . Santos, Ounísia; Vaz, Daniela; Sebastião, Fernando; Sousa, Helena; Vieira, JuditeSolutions combining soilless cropping systems with wastewater reuse can offer benefits in the agriculture sector, reducing pressure on water resources, promoting sustainable production, and reclaiming wastewater. However, assessing the sanitary risks associated with wastewater reuse is of utmost importance. This study aimed to investigate the hydroponic growth of lettuce (Lactuca sativa var. crispa L.) in wastewater from an urban treatment plant with different levels of treatment and evaluate potential sanitary risks. Crop growth took place in a greenhouse, during summer and winter periods, using wastewater after primary (PTW) or secondary (STW) treatment, and a nutrient solution (NS), as control. Physical and chemical water quality parameters, morphological crop growth parameters, and environmental conditions inside the greenhouse were monitored. Toxicity analyses were carried out through cell viability assays with the Caco-2 cell line and total coliforms and Escherichia coli (E. coli) were determined. Wastewater-grown plants achieved acceptable growth, even though presenting lower fresh weight than NS-plants. STW-plants’ growth was limited essentially by nutrient deficiency, and PTW-plants were affected by nutrient deficiency, pH values, solid load, and N-NO2 concentration. Higher temperatures in summer led to faster crop growth, and lower temperatures in winter allowed better nutrient uptake by the crop. Wastewater-grown plants did not evidence toxicity in leaf extracts up to 1 % w/v. Coliform enumeration data indicated an accumulation in plant roots, with high removal from the wastewater. E. coli was not detected on plants’ leaves and total coliforms were within acceptable limits. Furthermore, the results point to an improvement in the wastewater quality, with minimum removal values of 75.2 % BOD5, 83.1 % COD, 43.4 % P, 44.9 % N, and 90.4 % K. The results demonstrated the viability of wastewater reuse for hydroponic production allowing a better understanding of its processes and contributing to mitigating water scarcity for food production, and the impacts of treated wastewater discharge in freshwater courses, particularly those associated with nutrient delivery to aquatic systems.
- Nutrient‐efficient catfish‐based aquaponics for producing lamb's lettuce at two light intensitiesPublication . Sebastião, Fernando; Vaz, Daniela C.; Pires, Cristiana L; Cruz, Pedro F; Moreno, Maria João; Brito, Rui M M; Cotrim, Luís; Oliveira, Nelson; Costa, Ana; Fonseca, André; Rodrigues, Maria; Ispolnov, Kirill; Bernardino, Raul; Vieira, JuditeBACKGROUND: Aquaponic systems are sustainable processes of managing water and nutrients for food production. An innovate nutrient-efficient catfish-based (Clarias gariepinus) aquaponics system was implemented for producing two cultivars of two leafy vegetables largely consumed worldwide: lamb's lettuce (Valerianella locusta var. Favor and Valerianella locusta var. de Hollande) and arugula (Eruca vesicaria var. sativa and Eruca sativa). Different growing treatments (4 × 2 factorial design) were applied to plants of each cultivar, grown at two light intensities (120 and 400 ∼mol m−2 s −1). During growth, several morphological characteristics (root length, plant height, leaf number, foliage diameter and biggest leaf length) were measured. At harvest, plants were weighed and examined qualitatively in terms of greenness and health status. Additionally, leaf extracts were obtained and used to determine total phenolic contents, antioxidant capacities, and levels of cytotoxicity to Caco-2 intestinal model cells. RESULTS: After a 5-week growth period, both lamb's lettuce cultivars presented high levels of greenness and health status, at both light intensities, particularly the var. de Hollande that also showed higher average performance in terms of plant morphology. In turn, arugula cultivars showed lower levels of greenness and health status, especially the cultivar E. vesicaria var. sativa submitted to direct sunlight during growth. In addition, plant specimens submitted to higher levels of light intensity showed higher contents in antioxidants/polyphenols. Cultivars with a higher content in antioxidants/polyphenols led to higher Caco-2 cell viability. CONCLUSION: For successful industrial implementation of the aquaponics technology, different and optimized acclimatizing conditions must be applied to different plant species and cultivars. © 2024 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
- Estudo para a requalificação/modernização da ETAR das OlhalvasPublication . Pala, Helena; Vieira, Judite; Oliveira, Mário; Costa, António; Antunes, Raquel; Fernandes, PauloO presente trabalho refere-se a um estudo realizado por uma equipa multidisciplinar do Politécnico de Leiria com o macro objetivo de investigar, identificar e definir as melhores soluções de requalificação/modernização da ETAR das Olhalvas, mitigando o impacto que esta infraestrutura ainda tem no contexto em que se insere e as possibilidades de reutilização de parte do efluente desta unidade numa perspetiva de uso racional da água, evitando assim o uso de água tratada para fins que não o exigem. Partindo de uma análise do funcionamento da ETAR suportada em dados relativos aos anos 2016 a 2020, compreendendo a caracterização dos caudais e cargas afluentes à estação e sua comparação com os valores de projeto, o estudo analisou a eficiência do tratamento e os principais parâmetros indicadores da qualidade, nomeadamente CQO, CBO5, SST, NTotal e PTotal. Esta análise evidenciou o bom funcionamento e adequação para os caudais e características do afluente da ETAR e eficiência muito elevada, traduzindo-se em reduções muito significativas da carga poluente presente no afluente. A ausência de informações objetivas sobre o impacto da descarga do efluente no meio recetor e de caracterização do próprio meio, justificou uma campanha de monitorização das águas superficiais da bacia hidrográfica do rio Lis, entre outubro de 2020 e abril de 2021, monitorizando o Rio Lis a montante e jusante da ETAR e um afluente ao Rio Lis, a Ribeira do Sirol, na sua confluência com este. Esta campanha revelou-se muito importante na quantificação do impacto do efluente sobre o meio recetor, observando-se uma ligeira alteração no padrão de qualidade em alguns meses para os parâmetros NTotal, nitratos (N-NO3) e fosfatos (P-PO4), mas destacando-se que nos restantes parâmetros, a saber, pH, CQO, CBO5, SST, N-NH4 e substâncias tensioativas, não foram detetadas variações. Estas observações suportaram um conjunto de recomendações de medidas de requalificação/modernização, propondo a melhoria dos tratamentos existentes ou a introdução de novos tratamentos. A importância que a comunicação do papel destes equipamentos tem junto daqueles que são os principais beneficiários do seu bom funcionamento, populações servidas e comunidades que habitam o território onde se implantam, nortearam o estudo sobre os planos e estratégia de comunicação deste equipamento. Partindo das boas práticas identificadas em territórios e situações congéneres e valorizando as campanhas emblemáticas do passado deixam-se um conjunto de propostas de estratégia e planos de comunicação que permita aproximar a ETAR de Olhalvas das populações e territórios que servem, visando a sua integração num objetivo maior que é a melhoria contínua da qualidade do Rio Lis.
- Degradation of Oxytetracycline in Aqueous Solutions: Application of Homogeneous and Heterogeneous Advanced Oxidative ProcessesPublication . Giler-Molina, José Miguel; Zambrano-Intriago, Luis Angel; Quiroz-Fernández, Luis Santiago; Napoleão, Daniella Carla; Vieira, Judite dos Santos; Oliveira, Nelson Simões; Rodríguez-Díaz, Joan ManuelOxytetracycline is one of the antibiotics most frequently used in the Shrimp Industry during the control of bacterial diseases. These emerging pollutants, which appear in low concentrations, are persistent and alternative treatments and are required for their elimination. The degradation of oxytetracycline was evaluated in an aqueous solution by applying homogeneous (UV/H2O2 and photo-Fenton) and heterogeneous (UV/TiO2 /H2O2) advanced oxidative processes (AOPs). The studies were carried out using a bench reactor with short-wave ultraviolet lamps (UV-C). We quantified the extent to which the degradation of the drug had been efficient by employing highly efficient liquid chromatography (HPLC) and a PDA detector with a wavelength of 354 nm and a C18 column. The best results were obtained when applying the UV/H2O2 treatment, which attained a degradation of 97% under the initial conditions of a dose of 8 µL of H2O2 and 120 min of radiation. The pseudo-first order kinetic model proposed by Chan and Chu showed that the experimental results had an adequate fit, with values greater than R2 ≥ 0.95. Toxicity tests were applied to verify the effect of AOPs employed, when the drug was present in low concentrations. The test results demonstrated a decrease in the root growth of the species Lactuca sativa and Daucus carota.