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- Evaluation of solid waste stratified mixtures as constructed wetland fillers under different operation modesPublication . Mateus, D.M.R.; Pinho, Henrique J. O.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.
- Screening of Solid Waste as Filler Material for Constructed WetlandsPublication . Mateus, D. M. R.; Pinho, Henrique J. O.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.
- Tracer experiments with lithium chloride to evaluate the hydrodynamics of constructed wetlands. Comparison of alternative analytical methodsPublication . Pinho, Henrique J. O.; Mateus, D. M. R.; Alves, Ana; Graça, NunoThe 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.
- Remote Monitoring of Energy-autonomous Constructed WetlandsPublication . Lopes, Simão; Barros, F.M.; Ferreira, Carlos; Mateus, D. M. R.; Matos, Pedro; Neves, Pedro; Pinho, Henrique J. O.Constructed Wetlands systems (CW) are nature-based and sustainable technology for treating wastewater, contributing to the management and protection of freshwater resources. Moreover, CW can contribute to valorizing waste materials, producing reclaimed water for diverse applications, and producing plant biomass that can be material and energetically valorized. Because CW efficiency depends on several mechanisms such as physical, chemical, and biological, its real-time monitoring is essential to provide a better use of this technology. This work describes a smart framework for monitoring CW based on IoT devices and sensors, and data science tools providing real-time processing of gathered water quality parameters and environmental variables. Furthermore, the framework manages renewable energy sources to provide the required energy for CW operation and monitoring. Data collected from the sensor network show significant daily variations in water quality parameters. The future processing of these data can provide the development of models to improve the efficiency of the CW.
- Solid Waste Mixtures as Constructed Wetlands Filling: Effect of Hydraulic Loading Rate on Nutrient Removal from WastewaterPublication . Pinho, Henrique J. O.; Alves, Ana; Graça, Nuno; Mateus, D. M. R.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.
- Combination of various solid wastes with fragmented limestone as filler for constructed wetlands used for wastewater treatmentPublication . Mateus, D. M. R.; Graça, Nuno; Alves, Ana; Pinho, Henrique J. O.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.
- Descrição e objetivos do projeto ValorBioPublication . Pinho, Henrique J. O.; Mateus, D. M. R.; Pinho, Henrique J. O.; Mateus, D. M. R.
- Solid Waste Valorisation for Wastewater Treatment ProcessesPublication . Cartaxo, Marco; Rosa, Manuel; Nogueira, Isabel; Nunes, Valentim; Pinho, Henrique J. O.; Mateus, D. M. R.The present work was part of a research project, which pursued the treatment and reuse of urban and industrial wastewaters as well as solid waste. Its main goal was the development of modular systems for wastewater treatment based on constructed wetlands (CWs). The project involves the concept of circular economy and the rationale of "using waste to treat waste", exploring the possibility of the treatment systems being composed of solid waste and by-products from significant industrial sectors. The work thereof presented describes the physical and chemical characterization of five waste solids, which were used as lab-scale fillers. Optical microscopy observations, μFRX and FTIR-ATR analyses were conducted to characterize the solid wastes before and after use in the CWs treating urban type wastewater. Results indicated that, among the five solid wastes studied, limestone fragments from construction showed favorable conditions to biofilm growth, and coal slags from power plants and cork granulates showed the highest indication of adsorption of organic compounds.
- Projeto VALORBIO Tratamento de Águas Residuais por Zonas Húmidas Construídas Modulares - Uma contribuição para a economia circularPublication . Pinho, Henrique J. O.; Mateus, D. M. R.O projeto VALORBIO, Valorização de resíduos através de zonas húmidas construídas modulares usadas para tratamento de águas residuais, foi cofinanciando por fundos FEDER (POCI-01-0145-FEDER-23314). O projeto foi desenvolvido durante 18 meses, entre julho de 2017 e janeiro de 2019, e visou o tratamento de águas residuais através de Zonas Húmidas Construídas (ZHCs), que consistem em sistemas biológicos baseados em plantas, também designados por fito-ETARs (Estações de Tratamento de Águas Residuais baseadas em plantas) ou Leitos de Macrófitas.
- Cultivation of Energy Crops in Constructed Wetlands for Wastewater Treatment: An OverviewPublication . Pinho, Henrique J. O.; Mateus, D. M. R.The need for sustainable, clean, and secure energy sources is a current issue for all nations. All kinds of vegetal biomass can be used as energy-source or as raw material for biofuel production, but some species are commonly classified as energy crops. This work evaluates the energy potential of 35 species of energy crops when produced in constructed wetlands (CW). Producing energy crops in CW is a route to link wastewater treatment to energy production, avoiding the abstraction of freshwater for crop irrigation, and simultaneously avoiding the use of arable land. However, for most of the energy crops, there are no data available in the literature about biomass productivity in CWs. Although 20 of the 35 crops have been tested as CW vegetation, the biomass productivity in CWs was only found for 13 species. Reported biomass productivity in CW is similar to or even higher than the productivity reported for conventional production, but most reported data is for pilot-scale CW, which points to the need for future work in full-scale systems. From the combination of biomass productivity and the biomass calorific value, Arundo donax, Miscanthus x giganteus, Cynodon dactylon, Phragmites australis, and Typha latifolia show higher ranges up to 3064 MJ/ha year for Arundo donax. Future works on CW design can be focused on the potential of using energy crops as vegetation.