Evaluation of solid waste stratified mixtures as constructed wetland fillers under different operation modes

Based on the strategy that all processes can and should be modified to contribute to a circular economy, this work evaluates the recovery of waste solids as filler material in Constructed Wetlands (CWs) used for wastewater treatment. Five sets of lab-scale CWs were assembled with mixtures of five waste solids and operated to evaluate the removal of chemical oxygen demand (COD) and nutrients from urban and industrial-types of wastewater. The adaptation and growth of the macrophyte Phragmites australis in the mixed-filler CWs was also monitored. Although all evaluated waste solids showed to be acceptable substrates for macrophyte development and wastewater treatment, CWs assembled with mixtures of limestone waste and coal slag showed the best plant growth indicators and wastewater treatment efficiencies. The CWs assembled with mixtures of limestone waste and clay brick fragments or cork granulates showed to be suitable alternatives. With exception for CWs filled with mixtures of limestone and snail shells, pollutant removal efficiencies up to 95%, 86% and 83% were obtained respectively for COD, total phosphorous and total nitrogen, depending on the type of wastewater and mode of operation. Removal efficiencies were not significantly affected by increased hydraulic rate. The CWs can be operated to a hydraulic loading rate of 0.056 m/d, which corresponds to a retention time of 1.5 days. The valorisation of solid waste as a filler can contribute to CWs closely participating in the creation of circular flows for the reuse of waste solids.The work was partially supported by COMPETE2020 under the grant POCI-01-0145-FEDER-23314. The authors acknowledge the support of the Lab.IPT staff, particularly, Alcino Serras, Isabel Silva and Pedro Costa, the research fellows Ana Alves and Nuno Graça. The authors also acknowledge the contribution of Carlos Ferreira, from IPT’s maintenance services, and Fátima Paiva, from IPT’s language centre.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

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

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

Lossy-to-Lossless Compression of Biomedical Images Based on Image Decomposition

The use of medical imaging has increased in the last years, especially with magnetic resonance imaging (MRI) and computed tomography (CT). Microarray imaging and images that can be extracted from RNA interference (RNAi) experiments also play an important role for large-scale gene sequence and gene expression analysis, allowing the study of gene function, regulation, and interaction across a large number of genes and even across an entire genome. These types of medical image modalities produce huge amounts of data that, for several reasons, need to be stored or transmitted at the highest possible fidelity between various hospitals, medical organizations, or research units

Design of calibrators for extruded profiles. Part I: modelling the thermal interchanges

The parameters influencing the calibration/cooling stage of profile extrusion are discussed, and a numerical finite-volume method code to model the heat transfer is described and validated. For this purpose, the numerical predictions are compared with the analytical solution of a simple problem, with results available in the literature and with those produced by a commercial software. The routines developed are then used to identify the main process parameters and boundary conditions and to estimate their relative importance. The investigation clearly shows the advantages of using several calibrators separated by annealing zones, relative to a single calibrator of the same total length, and the large impact of the contact resistance between extrudate and cooling unit while showing negligible impact of other boundary conditions. A decrease of the extrudate velocity is seen to be also an effective control parameter, but it decreases the production rates

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

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

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

Clonagem in vitro via cultivo de meristema de pimenteira-do-reino: assepsia e estabelecimento de cultura.

A cultura da pimenteira-do-reino tem grande importância econômica no Brasil, mas há restrição de cultivo devido a vulnerabilidade genética da mesma à doença fusariose causada pelo fungo Fusarium solani f. sp.piperis. A forma de propagação vegetativa é disseminadora da doença e métodos de controle da doença são pouco exitosos. Programas de melhoramento em execução visam gerar híbridos resistentes à doença em questão, além de agregar características agronômicas competitivas. Doenças viróticas ocorrem em todas as cultivares e há necessidades de limpeza clonal dessas cultivares via cultura de tecidos. Há dificuldades de obtenção de explantes assépticos devido a problemas de bactérias e fungos endógenos. Este trabalho teve por objetivo o estabelecimento de meristema (<1,0 mm) in vitro para a limpeza clonal via micropropagação. A partir de plantas originadas de estacas, meristemas (apicais e laterais) foram excisados a partir segmentos nodais e apicais, previamente submetidos a diferentes tratamentos de assepsia. Os meristemas foram inoculados em meio básico de cultura MS suplementado com BAP 0,5 mg.L-1 e AIA 0,2 mg.L-1. As respostas dos meristemas das diferentes cultivares foram avaliadas quanto a oxidação e contaminação, e os explantes verdes foram transferidos para meios frescos visando a diferenciação de brotos. Dos meristemas de nove cultivares utilizadas, apenas alguns das cultivares IAÇARÁ e genótipo 239 apresentaram desenvolvimento satisfatório. As demais não desenvolveram, oxidaram e/ ou sofreram contaminação por fungos e/ ou bactérias