907 research outputs found

    Solid Waste Mixtures as Constructed Wetlands Filling: Effect of Hydraulic Loading Rate on Nutrient Removal from Wastewater

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    This study aims to contribute to constructed wetlands’ (CWs) eco-efficiency by applying the concepts of circular economy and waste to treat waste. Five sets of lab-scale CWs with different combinations of filling materials were evaluated and the effect of the hydraulic loading rate (HLR) on the nutrient removal efficiencies was studied. Each CW set consisted of two, duplicate, plastic pots with solid waste filling supporting Phragmites australis macrophyte plants. The filling materials were layer combinations of limestone rock fragments, a waste from construction activities, and one of four other solid wastes: cork granulates from the cork industry (LCG); snail shells from the food and catering industry (LSS); coal slag from coal power plants (LCS); and clay brick fragments from construction activities (LBF). A reference set (LO) was filled only with limestone fragments. The CWs were operated using a low-strength wastewater in successive fill-and-drain cycles with a retention time of one to eight days and a one-day rest. Their removal efficiency was evaluated for COD, total phosphorus (TP) and total nitrogen (TN). All four CWs with mixed filling showed COD removal efficiencies higher than the reference CW and above 79%. The highest removal efficiency was achieved by the LCS CW (91 to 97%). The reference LO CW showed the highest TP removal efficiency. With exception of the LSS CW, the mixed filling CWs showed removal efficiencies close to the reference CW (above 55%). All but the LSS CW showed higher TN removal efficiencies than the reference CW (above 51%). The observed effect of HLR depends on the type of CW. The effect on COD, TP and TN removal efficiencies averaged 9%, 15% and 20%, respectively, for a range of HLR from 0.005 to 0.087 m/day. From this study it can be concluded that all tested layer-packed mixed solid waste fillings are adequate substrate combinations for nutrient removal from wastewater. Moreover, high nutrient removal efficiencies were maintained over a wide range of hydraulic loading rates. This innovative combination of waste materials can improve the CW adaptability to specific types of wastewater and contribute to reducing solid waste disposal in landfills.This work was supported by Program FEDER, ref. POCI-01-0145-FEDER-023314, project VALORBIO. The authors acknowledge the collaboration of the Lab.IPT staff and the assistance of the Instituto Politécnico de Tomar maintenance staff.info:eu-repo/semantics/publishedVersio

    Combination of various solid wastes with fragmented limestone as filler for constructed wetlands used for wastewater treatment

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    This study aims to contribute to the development of eco-efficient constructed wetlands through the concept of circular economy and the use of waste to treat waste Combinations of five solid wastes were evaluated as filler materials for CWs used for wastewater treatment To evaluate the combined capability of the waste materials to wastewater treatment, five sets of unplanted lab-scale CWs were established The CWs were operated in a discontinuous mode for three successive fill and drain cycles The highest COD removal rate was obtained for a CW filled with limestone and cork waste 90.3+/-0.9%. The highest total nitrogen removal rate was obtained for a CW filled with limestone and clay brick fragments 84.8+/-0.1%. Total phosphorus removal percentage of 91.8+/-0.1% was achieved for a control CW filled with limestone It was observed that layer packed solid waste combination fillings are adequate in improving COD removal in limestone based CWs, and that all but the limestone snail shells filling have a very good performance for total nitrogen and total phosphorus removal from wastewater.info:eu-repo/semantics/publishedVersio

    Tracer experiments with lithium chloride to evaluate the hydrodynamics of constructed wetlands. Comparison of alternative analytical methods

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    The characterization of water flow dynamics (hydrodynamics) through constructed wetlands is relevant for optimizing wastewater treatment. Although constructed wetlands consist of simple systems, the water flow is complex and irregular, therefore, the study of hydrodynamics requires the use of experimental technics such as tracer experiments. To evaluate the effects of the use of three different analytical methods to compute the concentration of lithium chloride on the main hydrodynamics parameters, tracer experiments were conducted in ten independent lab-scale constructed wetlands. The concentration of lithium chloride in the output flow of the wetlands was calculated by flame photometry, electrical conductivity using a calibration curve and electrical conductivity using the salt molar conductivity. The paired samples T-test or the non-parametric Wilcoxon’s Signed-Ranks test were used to demonstrate that the computed hydraulic retention time and the number of tanks accordingly with the tanks-in-series model were not significantly affected by the selected analytical method.This work has been financially supported by FEDER grant COMPETE-01-0145-023342 to project VALORBIO. Authors acknowledge the support of BIOTEC.ipt and Lab.IPT and the work of Carlos Ferreira, Isabel Silva and Alcino Serras.info:eu-repo/semantics/publishedVersio

    Beyond good intentions: the role of the building passport for the sustainable conservation of built heritage to behavioural change

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    Despite the recognised importance of built heritage for sustainable development, and the multiple tools, recommendations, guidelines, and policies developed in recent years to support decision-making, good sustainable conservation practices often fail to be implemented. Challenges faced by practitioners often relate to external factors, and there is a gap in the understanding of the role of the nature of the designer and the behavioural dimension of the challenges in implementation. This research applies the Theory of Planned Behaviour (TPB) to verify how a building passport for sustainable conservation (BPSC) impacts design students’ intentions and actual design decisions towards built heritage conservation. This research aims to ascertain the role of the BPSC to affect attitudes, subjective norms, and intentions and ultimately change conservation behaviours. The results show that this tool has a positive contribution to reinforce existing attitudinal beliefs. Still, no significant changes were found in the overall conservation behaviours, suggesting that beliefs hindering implementation may more often be related to aesthetic reasons, creativity and innovation, and program requirements, than with beliefs regarding the sustainable performance of the building. This study demonstrates that using the TPB to analyse design processes in the context of built heritage is an innovative methodological approach that contributes to a deeper understanding of the psychological factors affecting sustainability and built heritage conservation decisions.This research was funded by Foundation for Science and Technology (FCT), grant number PD/BD/127853/2016. The APC was funded by TU Delft Library

    Dioxinas y PCBS en la alimentación de pollos de carne : efecto sobre parámetros productivos y utilización de nutrientes

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    Este experimento tiene por objetivo evaluar la repercusión de la adición de grasas que presentan dioxinas (D) y bifenilos policlorados (PCBs) en la alimentación de pollos broiler. Se estudió su efecto sobre el rendimiento productivo, coeficiente de digestibilidad y el depósito de grasa de los animales. 64 pollos broiler hembra línea genética Ross 308 fueron alimentados hasta los 47 días de edad con dos piensos experimentales con un nivel de inclusión del 6% de aceite de pescado. Las dos materias grasas utilizadas diferían en el nivel de contaminación: nivel alto HD 9,78 pg TEQD pg/g y 19,02 pg TEQPCBs/g y nivel bajo LD l,95pg TEQD y 7,69 pg TEQPCBs/g. No se observaron diferencias estadísticamente significativas en el consumo medio diario (CMD), ganancia media diaria (GMD) ni en el índice de transformación (IT) entre los tratamientos experimentales. Se realizaron dos balances de digestibilidad desde el día 14 al 16 y del 37 al 39. No se observaron diferencias estadísticamente significativas en la digestibilidad de la materia seca (DMS), y digestibilidad de la materia orgánica (DMO) si bien la digestibilidad del extracto etéreo (DEE) en primeras edades fue superior para los animales del tratamiento HD (LD 80.57% vs. HD 86.39%; P<0.01). Por otro lado, el rendimiento de la canal fue superior para los animales del tratamiento HD (LD 80.51% vs. HD 81.72%; P< 0.01) sin observarse diferencias estadísticamente significativas en el resto de parámetros estudiados (peso vivo PV, peso canal PC, y grasa abdominal GA). En conclusión, los aceites comerciales de pescado con concentraciones de contaminantes de hasta 9,78 pg TEQD/g y19,02 pg TEQPCB/g, no alteran los parámetros productivos ni el rendimiento en los pollos de carne.An experiment was designed to study the effect of the addition of dioxin and polychlorinated biphenyls PCBs contaminated fats in broiler chickens diets, on the productive yield parameters, the fat digestibility and deposit. Sixty four female broilers (genetic line Ross) were lodged in 16 cages distributed in to two treatments consisting of two experimental diets with 6% of fish oil with 9.78 pg TEQD and 19.02 pg TEQPCB/g ofoil for the high level (HD) and 1.95 pg TEQD and 7.69 pg TEQPCB/g of oil for the low level (LD). The experiment lasted until day 47 oflife ofanimals and productive controls were made at days 22 and 47. Studied parameters included, daily mean intake (CMD), daily mean gain (GMD) and the conversion index (IT). No statistical differences were found in this parameters. From day 14 to 16 and from 37 to 39 two digestibility trials were performed. There was no significant statistical difference in dry matter digestibility (DMS), organic matter digestibility (DMO), but ether extract digestibility (EED) was higher during first trial for HD treatment (LD 80,57% vs. HD 86,39%; P < 0.01). Regarding live weight (W), carcase weight (CW), carcase yield (RC) and abdominal fat (AF), only RC showed statistical differences with highervalues for HD treatment (LD 80,51% vs. HD 81,72%; P<0.01)

    Temporal patterns of the catadromous thinlip grey mullet migration in freshwater

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    The thinlip grey mullet (Chelon ramada Risso, 1827) is a catadromous fish that performs massive migrations to freshwater habitats for feeding purposes that can assume a structuring role on riverine ecology due to the biomass involved in these movements. Seasonal movements of thinlip grey mullet through a vertical slot fish pass located in River Mondego (Portugal) were continuously monitored between 2013 and 2017. The extent of trophic migration, population size structure, biomass and the environmental triggers of bi-directional species' migratory activity were analysed. Between March and November of 2013/2014, ~2 million and 1 million movements were respectively recorded. From a subsampling approach, the upstream movements between 2015 and 2017 were estimated. Annually, around five hundred thousand upstream movements can occur to provide species access to the upstream freshwater reaches. Movements are exclusively diurnal, and the population composed by young adults in their first year of maturity, yet juveniles and larger fish were present (TL range: 90–540 mm). Upstream movements increased with temperatures above 15°C, reaching a peak at around 20°C coupled with a photoperiod of 15 h. Downstream movements attained the higher rates when temperature dropped from 22°C to 20°C and photoperiod to 13 h. However, under wetter hydrological conditions (as in 2014), discharge flows have a higher influence. These finding provide unique information regarding species migration to freshwater habitats in the Atlantic coast, namely the extended periods spent in such environments, overlapping with the spawning migration period. Additionally, highlights the importance of species' trophic migration both for its life cycle and riverine food-web

    An ultra-sensitive electrochemical biosensor using the Spike protein for capturing antibodies against SARS-CoV-2 in point-of-care

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    Funding Information: The authors acknowledge funding through project TecniCov ( POCI-01-02B7-FEDER-069745 ), co-funded by FEDER through COMPETE2020 and Lisboa2020 and CY-Sensors ( POCI-01-0145-FEDER-032359 ) through Fundação para a Ciência e a Tecnologia (FCT) , Portugal. ARC acknowledge funding to National Foundation for Science and Technology , I.P., Portugal ( FCT ) through the PhD. Grant, reference SFRH/BD/130107/2017 . Publisher Copyright: © 2022 The AuthorsThis work presents an innovative ultra-sensitive biosensor having the Spike protein on carbon-based screen-printed electrodes (SPEs), for monitoring in point-of-care antibodies against SARS-CoV-2, a very important tool for epidemiological monitoring of COVID-19 infection and establishing vaccination schemes. In an innovative and simple approach, a highly conductive support is combined with the direct adsorption of Spike protein to enable an extensive antibody capture. The high conductivity was ensured by using carboxylated carbon nanotubes on the carbon electrode, by means of a simple and quick approach, which also increased the surface area. These were then modified with EDC/NHS chemistry to produce an amine layer and undergo Spike protein adsorption, to generate a stable layer capable of capturing the antibodies against SARS-CoV-2 in serum with great sensitivity. Electrochemical impedance spectroscopy was used to evaluate the analytical performance of this biosensor in serum. It displayed a linear response between 1.0 ​pg/mL and 10 ​ng/mL, with a detection limit of ∼0.7 ​pg/mL. The analysis of human positive sera containing antibody in a wide range of concentrations yielded accurate data, correlating well with the reference method. It also offered the unique ability of discriminating antibody concentrations in sera below 2.3 ​μg/mL, the lowest value detected by the commercial method. In addition, a proof-of-concept study was performed by labelling anti-IgG antibodies with quantum dots to explore a new electrochemical readout based on the signal generated upon binding to the anti-S protein antibodies recognised on the surface of the biosensor. Overall, the alternative serologic assay presented is a promising tool for assessing protective immunity to SARS-CoV-2 and a potential guide for revaccination.publishersversionpublishe

    International Centre for Coastal Ecohydrology: applying the ecohydrology approach for the sustainable functioning of coastal ecosystems

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    Coastal areas are among the most sensitive and productive ecosystems around the world, providing for the subsistence of large numbers of people, particularly in developing countries. Human pressure on coastal areas has dramatically increased during the last decades and climate changes will pose new threats to these areas, as expected from sea-level rise and the decrease in freshwater discharges from rivers (Chicharo et al., 2009). The International Centre for Coastal Ecohydrology (ICCE) a newly approved centre under the auspices of UNESCO, in October 2009, is located in the Algarve region (south Portugal). The centre acts as a facilitator and synergetic structure by providing the articulation of different scientific and institutional stakeholders at national and international levels. ICCE aims are to contribute scientific knowledge, capacity-building, educational and dissemination activities to support, design and implement adaptation and mitigation strategies and policies for coastal zones, including the impacts of climate change, addressing the goals of the Strategic Plan of the 7th Phase of UNESCO-IHP, the Millennium Development Goals (UN-MDGs) and the key themes for the United Nations Decade of Education for Sustainable Development (UN-DESD), particularly in African and Mediterranean regions.info:eu-repo/semantics/publishedVersio
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