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- Nexus água-nutrientes-energia: uma abordagem integrada no tratamento de efluentes suinícolasPublication . Oliveira, Margarida; Pena, L.; Fragoso, Rita; Duarte, ElizabethA preocupação com os impactes ambientais associados a explorações pecuárias de produção intensiva tem vindo a aumentar nos últimos anos. Em especial, a elevada concentração de azoto e fósforo dos efluentes suinícolas poderá induzir a poluição dos cursos de água, se a sua gestão não for adequada. Com a crescente procura por energias alternativas às fósseis, novas perspetivas têm sido aplicadas à gestão dos efluentes suinícolas, onde para além do tratamento e redução da carga contaminante dos efluentes, se dá importância à sua valorização. Neste trabalho, estudou-se a depuração dos efluentes suinícolas por Lemna minor e a valorização energética da biomassa produzida por co-digestão anaeróbia. Foram realizados ensaios experimentais comparativos do crescimento da Lemna minor em meio artificial sintético e em efluente suinícola simulando as condições da última lagoa de uma suinicultura. A eficiência de remoção de CQO nos ensaios de depuração foi de 60,0 ±1,0 %. A maior taxa de crescimento observada em efluente suinícola foi de 28,7 ± 2,3 g m-2 dia-1 e as taxas de absorção de nutrientes obtidas foram de 140 mg N m-2 dia-1 e de 3,5 mg P m-2 dia-1. A avaliação do potencial de valorização energética da biomassa foi considerado em ensaios de co-digestão anaeróbia, comparando os ensaios de digestão anaeróbia utilizando efluente suinícola como mono-substrato e a co-digestão, utilizando Lemna minor como co-substrato. Os resultados obtidos evidenciaram o aumento na taxa de produção de biogás e da produção específica de metano em 40% e 44%, respetivamente. Esta abordagem integrada baseada no nexus-água-nutrientes-energia revelou-se promissora para a gestão de efluentes suinícolas. Novos estudos deverão explorar os benefícios combinados e potenciais vantagens e desvantagens destas tecnologias em diferentes escalas.
- Potential of duckweed for swine wastewater nutrient removal and biomass valorisation through anaerobic co-digestionPublication . Pena, Luis; Oliveira, Margarida; Fragoso, Rita; Duarte, ElizabethOver the last decades, phytodepuration has been considered an efficient technology to treat wastewaters. The present study reports a bench scale depuration assay of swine wastewater using Lemna minor. The highest observed growth rate obtained in swine wastewater was 3.1 ± 0.3 gDW m−2 day−1 and the highest nitrogen and phosphorus uptake were 140 mg N m−2 day−1 and 3.47 mg P m−2 day−1, respectively. The chemical oxygen demand removal efficiency in the swine wastewater assay was 58.9 ± 2.0%. Furthermore, the biomass valorisation by anaerobic co-digestion with swine wastewater was assessed. Results showed a clear improvement in specific methane production rate (around 40%) when compared to mono-substrate anaerobic digestion. The highest methane specific production, 131.0 ± 0.8 mL CH4 g−1 chemical oxygen demand, was obtained with a mixture containing 100 g of duckweed per liter of pre-treated swine wastewater. The water-nutrients-energy nexus approach showed to be promising for swine waste management.
- Water and wastewater management for sustainable viticulture and oenology in South Portugal – a reviewPublication . Costa, Joaquim; Oliveira, Margarida; Egipto, R.; Cid, J. F.; Fragoso, Rita; Lopes, C. M.; Duarte, ElizabethAssessing sustainability of the wine industry requires improved characterization of its environmental impacts, namely in terms of water use. Therefore, quantification of water inputs and wastewater (WW) outputs is needed to highlight inefficiencies in wine production and related consequences for the environment. Water use and WW generation in irrigated viticulture and oenology remains insufficiently quantified for dry Mediterranean regions (e.g. South Portugal). This paper is focused on wine production under warm and dry climate conditions in the winegrowing region of Alentejo (South Portugal). This region experiences increasingly dry conditions, while the irrigated area keeps expanding, which puts exacerbates the pressure on existing local and regional water resources. Additionally, more erratic variation in climate conditions and the tendency for increasingly extreme climate events (e.g. heat waves) pose more challenges to Alentejo’s wine sector. We conclude that quantitative information on water use and management is not always easy to obtain or access, which hinders improved strategies and/or policies for water use at farm, winery and region-level. Up-to-date statistics and robust metrics can help to better characterize water use and WW flows for Alentejo’s wine region, while optimizing management in vineyards and wineries, in companies and region-wide. The paper is focused on a “Farm-Winery” scenario, which is the most common in South Portugal’s wine sector
- Challenges for modern wine production in dry areas: dedicated indicators to preview wastewater flowsPublication . Oliveira, Margarida; Costa, J. M.; Fragoso, Rita; Duarte, ElizabethWine production is an important socio-economic activity in Mediterranean countries. This study is focused on wine production under warm and dry climate conditions in south Portugal, in two major wine-producing regions (Tejo and Alentejo), characterized by small to medium sized wineries. Vineyards have been expanding in this region of Portugal, where about 50–70% of the vineyards are irrigated, increasing regional water demand. The aim of this study is to propose an integrative approach for wine production, where a simple calculation model has been developed and validated to preview water consumption and wastewater production, as functions of winemaking periods and type of processed grapes. Results revealed a global ratio of 2.2 ± 0.45 and 2.1 ± 0.17 Lwater/Lwine. Concerning dedicated indicators, 60–75% of the wastewater was produced during Period I and the red wine production represented a 50–64% increase in water consumption. This tool will enable winemakers to calculate Global and Dedicated Indicators, based on their own parameters, which provide information on flow volumes and peak flows. In this context, it will be possible to identify improvements for wastewater treatment and management towards water reuse as a promising solution for the wine sector in the framework of the circular economy.