Loading...
8 results
Search Results
Now showing 1 - 8 of 8
- Toxicity assessment of high salinity tannery wastewater for the treatment in constructed wetlands.Publication . Silva, Gabriela; Calheiros, Cristina S.C.; Quitério, Paula V.B.; Crispim, Luís F.C.; Brixc, Hans; Moura, Sandra G.C.; Castro, Paula M.L.
- Constructed wetland implemented in a tourism unit for wastewater treatmentPublication . Calheiros, Cristina S. C.; Mesquita, Raquel B. R.; Brix, Hans; Rangel, António O. S. S.; Castro, Paula M. L.
- Assessment of culturable bacterial endophytic communities colonizing Canna flaccida inhabiting a wastewater treatment constructed wetlandPublication . Calheiros, Cristina Sousa Coutinho; Pereira, Sofia Isabel Almeida; Brix, Hans; Rangel, Antonio Osmaro Santos Silva; Castro, Paula Maria LimaMicroorganisms, including the bacterial populations living inside plant tissues (endophytes), and vegetation are components of constructed wetland (CW) systems playing pivotal roles in the water treatment process and in the ecosystem establishment. The present study focuses on the assessment of the culturable endophytic bacterial communities of Canna flaccida plants, the dominant plant species in a polycultured CW treating wastewater from a tourism facility. Bacterial endophytes were grouped by random amplified polymorphic DNA and identified by 16S ribosomal RNA gene sequencing. From the bacterial isolates, 103 were considered for phylogenetic analysis, falling in 25 genera within the γ-, β-, α-Proteobacteria, Flavobacteria, Sphingobacteria, Actinobacteria and Bacilli classes. Forty-nine percent of the isolates belonged to the Enterobacteriaceae family, suggesting that the plants in CW systems may act as a sink of potential human pathogenic microorganisms; nevertheless their abundance on the plant tissues was reduced from the inlet (62%) to the outlet zone (38%). High diversity in terms of genera was found in C. flaccida tissues, although the number of genera common to both sampling zones was low, which suggests that the processes occurring within the CW, including the water characteristics gradient from the inlet to the outlet (e.g. total suspended solids, organics and fecal loads), had the ability to shape the diversity of the endophytic communities.
- Implementação de leitos de plantas para o tratamento de águas residuais em unidades de turismo de habitaçãoPublication . Calheiros, Cristina S. C.; Bessa, Vânia S.; Mesquita, Raquel; Brix, Hans; Rangel, António O. S. S.; Castro, Paula M. L.
- Constructed wetland with a polyculture of ornamental plants for wastewater treatment at a rural tourism facilityPublication . Calheiros, Cristina S. C.; Bessa, Vânia S.; Mesquita, Raquel B. R.; Brix, Hans; Rangel, António O. S. S.; Castro, Paula M. L.Sewage management in remote rural and mountain areas constitutes a challenge because of the lack of adequate infrastructure and economic capability. Tourism facilities, in particular, possess a special challenge because of huge variability in sewage production and composition as a consequence of variations in number of guests and their activities. Constructed wetlands (CWs) are recognized as a robust and economical ecotechnology capable of meeting these challenges. A horizontal subsurface flow CW system was established at a guest house located in a rural and mountain area of Portugal. The substrate of the bed was an expanded clay substrate, and the system was planted with a polyculture of ornamental flowering plants (Canna flaccida, Zantedeschia aethiopica, Canna indica, Agapanthus africanus and Watsonia borbonica). The load and composition of sewage varied significantly seasonally (17–579 kg COD ha−1 d−1), but removal efficiencies of BOD and COD were generally high (>90%) and independent of the loading conditions. The system also reduced PO43− (up to 92%), NH4+ (up to 84%) and total coliform bacteria (up to 99%). The ornamental polyculture provided an aesthetic pleasing system with different appearance during the seasons. Of the five species tested, four grew well (C. flaccida, C. indica, Z. aethiopica and W. borbonica), whereas A. africanus was outcompeted. The system owner cut flowers from the CW system and used them for decorations at the guest house. It was demonstrated that CW systems planted with a polyculture of ornamental plant species, besides the water treatment function, possess several additional benefits including aesthetics and biodiversity enhancement.
- Toxicity of high salinity tannery wastewater and effects on constructed wetland plantsPublication . Calheiros, Cristina S. C.; Silva, Gabriela; Quitério, Paula V. B.; Crispim, Luís F. C.; Brix, Hans; Moura, Sandra C.; Castro, Paula M. L.The toxicity of high salinity tannery wastewater produced after an activated sludge secondary treatment on the germination and seedling growth of Trifolium pratense, a species used as indicator in toxicity tests, was evaluated. Growth was inhibited by wastewater concentrations >25% and undiluted effluent caused a complete germination inhibition. Constructed wetlands (CWs) with Arundo donax or Sarcocornia fruticosa were envisaged to further polish this wastewater. Selection of plant species to use in CWs for industrial wastewater treatment is an important issue, since for a successful establishment they have to tolerate the often harsh wastewater composition. For that, the effects of this wastewater on the growth of Arundo and Sarcocornia were assessed in pot assays. Plants were subject to different wastewater contents (0/50/100%), and both were resilient to the imposed conditions. Arundo had higher growth rates and biomass than Sarcocornia and may therefore be the preferred species for use in CWs treating tannery wastewater. CWs planted with the above mentioned plants significantly decreased the toxicity of the wastewater, as effluent from the CWs outlet stimulated the growth of Trifolium at concentrations <50%, and seed germination and growth even occurred in undiluted effluent.
- Reutilização de Água para Irrigação Através de Leitos de Plantas: Solução Integrada Aplicada ao Turismo no Espaço RuralPublication . Calheiros, Cristina S. C.; Bessa, Vânia S.; Mesquita, Raquel; Brix, Hans; Rangel, António O. S. S.; Castro, Paula M. L.
- Use of constructed wetland systems with Arundo and Sarcocornia for polishing high salinity tannery wastewaterPublication . Calheiros, Cristina S.C.; Quitério, Paula V.B.; Silva, Gabriela; Crispim, Luís F.C.; Brix, Hans; Moura, Sandra C.; Castro, Paula M.L.Treatment of tannery wastewater is problematic due to high and variable concentrations of complex pollutants often combined with high salinity levels. Two series of horizontal subsurface flow constructed wetlands (CWs) planted with Arundo donax and Sarcocornia fruticosa were set up after a conventional biological treatment system operating at a tannery site. The aim of the CWs was polishing organics and nitrogen from the high salinity effluent (2.2e6.6 g Cl L 1). Both plant species established and grew well in the CW. Arundo, however, had more vigorous growth and a higher capacity to take up nutrients. The CWs were efficient in removing COD and BOD5 with removal efficiencies varying between 51 and 80% for COD (inlet: 68e425 mg L 1) and between 53 and 90% for BOD5 (inlet: 16e220 mg L 1). Mass removal rates were up to 615 kg COD ha 1 d 1 and 363 BOD5 kg ha 1 d 1. Removal efficiencies were 40e93% for total P, 31e89% for NH4 þ and 41e90% for Total Kjeldahl Nitrogen. CW systems planted with salt tolerant plant species are a promising solution for polishing saline secondary effluent from the tannery industry to levels fulfilling the discharge standards.