Combining Vermifiltration with Hydroponics to Treat Organic Wastewaters and Produce Food

Pork is extensively consumed worldwide. Large-scale pig farming responds to the consumer demand but also generates great amounts of waste, rich in pathogenic bacteria, organic matter, nitrogen and phosphorus. The typical piggery waste treatment is insufficient to eliminate the risk of pollution. Vermicomposting and vermifiltration have shown capacity to remove organic matter, control pathogens and promote ammonia and nitrite oxidation in animal wastes and wastewaters. Hydroponic plants have shown ability to remove nitrate and phosphorus from wastewaters and decrease eutrophication risks. A partially continuous pilot-scale system combining a trickling vermifilter with a downstream hydroponic deep-water culture unit was built. Organic matter, faecal pathogens, and forms of nitrogen were analysed in the vermifiltration stage; nitrogen and phosphorus were the focus of hydroponic treatment analysis. Nitrifying bacterial communities were analysed in different sampling spots in the system. A reflection on the possibility to upscale the system for real-life use was presented. Vermifiltration removed ammonia (≤100%), nitrite (≤100%), organic matter (≤83% BOD5), and coliform bacteria (≤54%). A variety of pointed cabbage and radicchio initially grew hydroponically but showed signs of nutrient deficiencies, stalled growth and death over time. Modest abundances of AOB and NOB were found in the liquid phase of the system, and further study of solids and biofilms are needed. Hydroponic treatment of the vermifilter effluent removed more BOD5 (≤83%), ammonia (≤98%), nitrite (≤99%) and phosphorus (≤55%), removal limited probably by ecological factors. Nitrate was not efficiently removed by hydroponic treatment. Coliforms recovered in the hydroponic unit. The results suggest the need to monitor and correct physical conditions and nutrient content in the feed, and to control the micro-organisms throughout the system. Batch systems are advisable for preliminary studies. Implementation of similar systems on pig farms facilities is possible, although requiring investment in construction, monitoring, maintenance and personnel

Nutrient‐efficient catfish‐based aquaponics for producing lamb's lettuce at two light intensities

ACKNOWLEDGMENTS We acknowledge funding provided by FCT/MCTES (PIDDAC): LA/P/0045/2020 (ALiCE), UIDB/50020/2020 & UIDP/50020/2020 (LSRE-LCM), UIDB/00313/2020 & UIDP/00313/2020 (CQC-IMS) and Rede Nacional de Ressonância Magnética Nuclear (RNRMN, UC-NMR).BACKGROUND: 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.info:eu-repo/semantics/publishedVersio

(In)formación sobre pictogramas de sustancias peligrosas: (re)conociendo impactos sobre el medio ambiente y la salud es

Considerando que o conhecimento dos pictogramas de substâncias perigosas é fundamental para promover atitudes que minimizem impactes no ambiente e na saúde, foi levado a cabo o trabalho que aqui se apresenta, alicerçado nos seguintes objetivos: i) avaliar o nível de perceção dos estudantes de Cursos Técnicos Superiores Profissionais de uma instituição do ensino superior sobre os pictogramas de substâncias perigosas, definidos pelo GHS, ii) compreender de que modo a estratégia formativa trabalhada com os estudantes contribuiu para a mudança conceptual sobre a interpretação dos pictogramas de substância perigosas e iii) realçar a importância do conhecimento dos pictogramas de substâncias perigosas de forma a minimizar o potencial de ocorrência de acidentes ambientais, acidentes de trabalho e de doenças profissionais. Foi analisada a compreensão destes pictogramas por parte de 669 estudantes, antes e após formação sobre o tema. A análise dos dados por pictograma em função da área de formação, idade e estatuto de trabalhador estudante ou não, foi efetuada com ferramentas de estatística descritiva e através de testes de hipóteses. Em média, o nível de compreensão correto dos pictogramas após a formação (61.19%) foi superior ao observado antes da formação (30.75%). A formação em risco químico é essencial para melhorar o nível de compreensão dos respetivos pictogramas, e deverá ser valorizada e incluída nos currículos escolares desde a escolaridade obrigatória até ao ensino superior.info:eu-repo/semantics/publishedVersio

A Combined Vermifiltration-Hydroponic System for Swine Wastewater Treatment

Intensive swine farming causes strong local environmental impacts by generating effluents rich in solids, organic matter, nitrogen, phosphorus, and pathogenic bacteria. Insufficient treatment of hog farm effluents has been reported for common technologies, and vermifiltration is considered a promising treatment alternative that, however, requires additional processes to remove nitrate and phosphorus. This work aimed to study the use of vermifiltration with a downstream hydroponic culture to treat hog farm effluents. A treatment system comprising a vermifilter and a downstream deep-water culture hydroponic unit was built. The treated effluent was reused to dilute raw wastewater. Electrical conductivity, pH, and changes in BOD5, ammonia, nitrite, nitrate, phosphorus, and coliform bacteria were assessed. Plants were monitored throughout the experiment. Electrical conductivity increased due to vermifiltration; pH stayed within a neutral to mild alkaline range. Vermifiltration removed 83% of BOD5, 99% of ammonia and nitrite, and increased nitrate by 11%. Hydroponic treatment removed BOD5 (63%), ammonia (100%), nitrite (66%), nitrate (27%), and phosphorus (47% total and 44% dissolved) from vermifiltered water. Coliforms were reduced by vermifiltration but recovered in the hydroponic unit. Plants showed the ability to grow on vermifiltered wastewater, although requiring nutrient supplementation. Vermifiltration combined with hydroponics is a promising treatment for swine wastewater, although optimization will be needed for a sustainable real-scale implementation

Reconocimiento de la sinalética de seguridad: su influencia en la reducción de accidentes y minimización del impacto ambiental

[Resumo] Os grandes desastres ambientais têm sido uma realidade ao longo dos vários anos, e com consequências desastrosas para o Homem e para o ambiente que o rodeia. As causas são variadas e será impossível evitá-los na sua totalidade. Contudo, a possibilidade de minimização existe e as escolas terão um papel fundamental, no sentido de consciencializar e formar os alunos no reconhecimento e atuação perante alguns perigos e riscos. Os sinais de segurança são um exemplo, desde que os saibamos descodificar para assim podermos agir em conformidade. O trabalho que aqui se apresenta pretende destacar a importância da formação e informação dos jovens adultos que estão ou estarão a curto prazo em contexto laboral, nomeadamente os estudantes do ensino superior politécnico de Leiria, como contributo futuro para a mitigação de eventos que possam originar perdas humanas e ambientais insubstituíveis e irreversíveis. Para este estudo foi elaborada uma ficha de trabalho com nove sinais de segurança apresentados de forma aleatória, abrangendo as diferentes tipologias, na qual se pedia a estudantes de Cursos Técnicos Superiores Profissionais, ministrados no Politécnico de Leiria, que elaborassem uma legenda para cada um dos sinais, antes e depois da formação ministrada. Pela análise da informação recolhida, verifica-se que apesar das diferenças existentes ao nível do conhecimento dos estudantes inquiridos no início de cada ano letivo, observa-se que após a formação há melhoria no reconhecimento da sinalética de segurança pela grande maioria dos inquiridos, perspetivando-se assim uma redução dos acidentes com minimização dos impactes ambientais.[Abstract] Major environmental disasters have been a reality for several years, with disastrous consequences for man and the environment around him. The causes are varied and it will be impossible to avoid them in their entirety. However, the possibility of minimization exists and schools will have a fundamental role, in the sense of raising awareness and training students in recognizing and acting in the face of some dangers and risks. Safety signs are an example, as long as we know how to decode them so we can act accordingly. The work presented here intends to highlight the importance of training and information for young adults who are or will be in the short term in a work context, namely students of polytechnic higher education in Leiria, as a future contribution to the mitigation of events that may cause losses irreplaceable and irreversible human and environmental risks.For this study, a worksheet was created with nine safety signs randomly presented, covering the different typologies, in which students of Higher Technical Professional Courses, taught at the Polytechnic of Leiria, were asked to prepare a caption for each of the signs, before and after the training. By analyzing the information collected, it appears that despite the differences in knowledge of the students surveyed at the beginning of each school year, it is observed that after training there is an improvement in the recognition of safety signs by the vast majority of respondents, anticipating a reduction in accidents with minimization of environmental impacts.[Resumen] Los grandes desastres ambientales son una realidad desde hace varios años, con consecuencias desastrosas para el hombre y el medio ambiente que lo rodea. Las causas son variadas y será imposible evitarlas en su totalidad. Sin embargo, existe la posibilidad de minimización y las escuelas tendrán un papel fundamental, en el sentido de sensibilizar y formar a los estudiantes en el reconocimiento y actuación ante algunos peligros y riesgos. Las señales de seguridad son un ejemplo, siempre que sepamos cómo decodificarlas para poder actuar en consecuencia. El trabajo aquí presentado pretende resaltar la importancia de la formación y la información para los jóvenes adultos que están o estarán en el corto plazo en un contexto laboral, es decir, estudiantes de la educación superior politécnica en Leiria, como una contribución futura a la mitigación de eventos que puedan causar pérdidas irremplazables e irreversibles riesgos humanos y ambientales.Para este estudio se elaboró ​​una hoja de trabajo con nueve rótulos de seguridad presentados al azar, abarcando las diferentes tipologías, en la que se solicitó a los estudiantes de Cursos Técnicos Superiores Profesionales, impartidos en la Politécnica de Leiria, que elaboraran un pie de foto para cada uno de los rótulos, antes de y después de la formación impartida. Al analizar la información recolectada, parece que a pesar de las diferencias de conocimiento de los estudiantes encuestados al inicio de cada año escolar, se observa que luego de la capacitación se observa una mejora en el reconocimiento de las señales de seguridad por parte de la gran mayoría de los encuestados, con la perspectiva de reducir así los accidentes con la minimización de los impactos ambientales

Optimization of an Indoor DWC Hydroponic Lettuce Production System to Generate a Low N and P Content Wastewater

Hydroponic production raises economic and environmental issues related to the treatment, recovery or disposal of hydroponic wastewater, which can be rich in eutrophication-related nutrients, nitrogen (N) and phosphorus (P). Little focus has been put on the influence of the growth conditions on the N and P content in hydroponic wastewater, which is of uttermost importance when it is intended to reuse the wastewater for irrigation or other purposes with reduced impact on the environment. This study aimed to optimize an indoor non-recirculating deep-water culture (DWC) hydroponic system for lettuce (Lactuca sativa L. var. crispa) production, in terms of daily light integral (DLI) and volume of nutrient solution (NS) per plant, to maximize both the biomass production and the N and P removal, allowing for the wastewater to meet the criteria established for reusing in irrigation and minimizing the eutrophication impacts. A small-scale DWC hydroponic system with a fluorescent light fixture was built to study lettuce growth indoors for 35 days after transplanting (DAT). A first experiment was conducted under 14, 20 or 23 mol m−2 d−1 DLI and with 1.5 or 2 L of NS per plant. A pronounced inner leaf tip burn was observed, regardless of the volume of NS solution used, related to the unventilated conditions under high radiation. Total biomass was similar in all treatments and N and P removal was higher than 95% and 94%, respectively, at 35 DAT. Lettuces grown in 2 L of NS per plant exhibited higher average biomass. A second experiment was performed under 8, 10 or 12 mol m−2 d−1 DLI and with 2 or 3 L of NS per plant, making it possible to achieve healthy biomass at 35 DAT with higher water and light-use efficiency when compared to the first experiment. A DLI of 10 or 12 mol m−2 d−1 with 2 L of NS per plant and a DLI of 12 mol m−2 d−1 with 3 L of NS per plant made it possible to achieve both the best total biomass production and the highest N and P removal from water. Under those conditions, hydroponic wastewater complied with N and P criteria for reuse in irrigation, showing potential to be used as an alternative resource for agriculture and to minimize negative impacts on the environment

Optimization of an Indoor DWC Hydroponic Lettuce Production System to Generate a Low N and P Content Wastewater

Hydroponic production raises economic and environmental issues related to the treatment, recovery or disposal of hydroponic wastewater, which can be rich in eutrophication-related nutrients, nitrogen (N) and phosphorus (P). Little focus has been put on the influence of the growth conditions on the N and P content in hydroponic wastewater, which is of uttermost importance when it is intended to reuse the wastewater for irrigation or other purposes with reduced impact on the environment. This study aimed to optimize an indoor non-recirculating deep-water culture (DWC) hydroponic system for lettuce (Lactuca sativa L. var. crispa) production, in terms of daily light integral (DLI) and volume of nutrient solution (NS) per plant, to maximize both the biomass production and the N and P removal, allowing for the wastewater to meet the criteria established for reusing in irrigation and minimizing the eutrophication impacts. A small-scale DWC hydroponic system with a fluorescent light fixture was built to study lettuce growth indoors for 35 days after transplanting (DAT). A first experiment was conducted under 14, 20 or 23 mol m−2 d−1 DLI and with 1.5 or 2 L of NS per plant. A pronounced inner leaf tip burn was observed, regardless of the volume of NS solution used, related to the unventilated conditions under high radiation. Total biomass was similar in all treatments and N and P removal was higher than 95% and 94%, respectively, at 35 DAT. Lettuces grown in 2 L of NS per plant exhibited higher average biomass. A second experiment was performed under 8, 10 or 12 mol m−2 d−1 DLI and with 2 or 3 L of NS per plant, making it possible to achieve healthy biomass at 35 DAT with higher water and light-use efficiency when compared to the first experiment. A DLI of 10 or 12 mol m−2 d−1 with 2 L of NS per plant and a DLI of 12 mol m−2 d−1 with 3 L of NS per plant made it possible to achieve both the best total biomass production and the highest N and P removal from water. Under those conditions, hydroponic wastewater complied with N and P criteria for reuse in irrigation, showing potential to be used as an alternative resource for agriculture and to minimize negative impacts on the environment