Screening of Solid Waste as Filler Material for Constructed Wetlands

The reuse of solid waste can contribute to reducing Earth’s resource depletion, directly through use in the original production processes or by valorisation in alternative applications. In the present work, ten solid wastes were evaluated as candidates for filling material in constructed wetlands (CWs). For that purpose, physical characterization, leaching and adsorptiontests were conducted. Limestone fragments and brick fragments resulting from construction activities, coal slags resulting from power plants, snail shells resulting from the food and catering industry, and cork granulates resulting from the cork industry have potential for use as CW fillers. These five materials have adequate physical properties and some capacity to adsorb phosphorous and organic compounds from wastewater. On the other hand, crushed eggshells resulting from egg farms, dealcoholized grape pomaces resulting from alcohol distilleries, olive seeds waste from olive-oil mills, and pine bark fragments and wood pellets resulting from forestry cleaning activities, wood mills and pulp mills did not demonstrate sufficient potential to be used as CW fillers, either because they have very low adsorption capacities or leach compounds in contact with water, or because they have less adequate physical properties. None of the tested solid wastes showed the ability to adsorb nitrogen compounds. Although the five selected materials do not present a special capability for adsorption of nitrogen, phosphorous and organic compounds, they can all be valued as CW fillers, representing a way to reduce the amount of solid waste sent to 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 students of chemical and environmental technology courses held at Instituto Politécnico de Tomar. Special thanks to Alcino Serras, Ana Alves, Isabel Silva, Joel Nunes and Nuno Graça.info:eu-repo/semantics/publishedVersio

Bioenergy routes for valorizing constructed wetland vegetation: An overview

Valorizing constructed wetlands vegetation into biofuels can be a way to contribute to mitigating the increasing energy demand, avoiding the use of arable land, freshwater, and fertilizers consumption, while simultaneously treating wastewater with eco-friendly technology. This work shortly overviews the main genera of wetland plants and the main routes of vegetal biomass conversion into biofuels including biochemical and thermochemical processes, and through a cross-search, in the Scopus database, the research intensity in bioenergy application for each genus was assessed. A total of 283 genera of wetland plants were identified and classified into five groups, from very common to very rare genera. The very common group includes 10 genera and contributes to 62% of the literature hits, while the 147 genera classified as very rare contribute to only 3% of the hits. Concerning the bioenergy applications, four genera stand out from the remaining. The plants of the genus Sorghum are the most referred to in bioenergy applications, followed by the genera Brassica, Miscanthus, and Saccharum. Miscanthus is a less common wetland plant, while the other genera are rarely applied in constructed wetlands. The relevance of bioenergy routes depends on the plants' group. For common wetland plants, the most relevant applications are biogas production, followed by bio-ethanol production, and pyrolysis processing. As a recommendation for future research works the genera with high energy potential should be evaluated as wetland vegetation, and it is recommended that the goal to recover wetland vegetation for bioenergy applications be viewed as an integral step of the design and implementation of constructed wetlands facilities.info:eu-repo/semantics/publishedVersio

Sustainable Production of Reclaimed Water by Constructed Wetlands for Combined Irrigation and Microalgae Cultivation Applications

Considering the increasing pressure on freshwater resources due to the constant increase in water consumption and insufficient wastewater control and treatment, recovering waste water is a path to overcoming water scarcity. The present work describes the potential of reusing treated wastewater (reclaimed water) for irrigation and production of microalgae biomass in an integrated way, through experimental evaluation of plant and microalgae growth, and creation of an application model. First, two parallel experiments were conducted to evaluate the use of reclaimed water produced by a constructed wetland filled with a mix of solid waste: the irrigation of a set of small pots filled with soil and planted with Tagetes patula L., and the cultivation of microalgae Chlorella sp.and a mixed microalgae population with predominant species of the genus Scenedesmus sp. in shaken flasks and tubular bubble column photobioreactors. Results indicated no negative effects of using the reclaimed water on the irrigated plants and in the cultivated microalgae. The growth indicators of plants irrigated with reclaimed water were not significantly different from plants irrigated with fertilized water. The growth indicators of the microalgae cultivated with reclaimed water are within the range of published data. Second, to apply the results to a case study, the seasonal variability of irrigation needs in an academic campus was used to propose a conceptual model for wastewater recovery. The simulation results of the model point to a positive combination of using reclaimed water for the irrigation of green spaces and microalgae production, supported by a water storage strategy. Water abstraction for irrigation purposes can be reduced by 89%, and 2074 kg dry weight microalgae biomass can be produced annually. Besides the need for future work to optimize the model and to add economical evaluation criteria, the model shows the potential to be applied to non-academic communities in the perspective of smarter and greener cities.The authors acknowledge the support from the Smart Cities Research Center(Ci2), from the Laboratory of Bioenergy and Applied Biotechnology (Biotec.IPT), and from the staff of the Lab.IPT. The work of Carolina Masseno, an exchange student from Universidade Federal Fluminense, Brasil, and the help of Orlando Fonseca is also acknowledged.N/Ainfo:eu-repo/semantics/publishedVersio

Study of Metal/Polymer Interface of Parts Produced by a Hybrid Additive Manufacturing Approach

Acknowledgments This research work was supported by the Portuguese Foundation for Science and Technology (FCT) and Centro2020 through the Project reference: UID/Multi/04044/2013, PAMI - ROTEIRO/0328/2013 (Nº 022158) and Portuguese National Innovation Agency (ANI) through the Project reference POCI-01-0247-FEDER-017963, NEXT.parts – Next Generation of Advanced Hybrid Parts (co-promotion nº 17963).The additive manufacturing of multimaterial parts, e.g. metal/plastic, with functional gradients represents for current market demands a great potential of applications [1]. Metal Polymer parts combine the good mechanical properties of the metals with the low weight characteristics, good impact strength, good vibration and sound absorption of the polymers. Nevertheless, the coupling between metal and polymers is a great challenge since the processing factors for each one of them are very different. In addition, a system that makes the hybrid processing - metal/polymer - using only one operation is unknown [2, 3]. To overcome this drawback, a hybrid additive manufacturing system based on the additive technologies of SLM and SL was recently developed by the authors. The SLM and SL techniques joined enabling the production of a photopolymerization of the polymer in the voids of a 3D metal mesh previously produced by SLM [4]. The purpose of this work is the study on the metal/polymer interface of hybrid parts manufactured from the hybrid additive manufacturing system [5]. For this, a core of tool steel (H13) and two different types of photopolymers: one elastomeric (BR3D-DL-Flex) and another one rigid (BR3D-DL-Hard) are considered. A set of six samples for each one of metal core/polymer combination was manufactured and submitted to tensile tests.info:eu-repo/semantics/publishedVersio