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- Assessment of culturable endophytic community of Canna flaccida plants growing in a constructed wetlandPublication . Calheiros, Cristina; Pereira, Sofia; Castro, Paula M. L.Sustainable water management urges for the treatment of wastewater in an efficient way. With the latter purpose, ecotechnologies arise as promising solutions for rural and mountain areas lacking a sewage network. Constructed wetlands (CW) coupled with preliminary/primary systems foresee enhancement of the water quality and its possible reuse. The challenge presented in this work reflects the application of a CW to domestic wastewater treatment coming from a tourism house, situated in a rural area. The use of different ornamental plants species to treat the wastewater was an important component of the system, increasing biodiversity and supporting the local ecosystem. Performance of the CW was assessed in terms of physic-chemical and microbial parameters. The endophytic culturable bacteria of a selected plant species, Canna flaccida, were evaluated.
- Constructed wetlands for tannery wastewater treatment in Portugal: ten years of experiencePublication . Calheiros, Cristina S. C.; Rangel, António O. S. S.; Castro, Paula M. L.Wastewaters from tannery industry are complex in composition and providing adequate treatment can be difficult. Constructed wetlands (CW) are regarded as an alternative treatment to the conventional biological systems, as a developing cost-effective and environmentally friendly phytoremediation technology. The present review compiles and integrates information on CWs technology for the needs of the tannery sector. The following issues arise as crucial for the implementation of such systems, namely i) an accurate wastewater characterization and an effective pretreatment before reaching the CW, ii) choosing the plants species better adapted to the imposed conditions, iii) substrate selection and iv) range of organic loadings applied. The examples practiced in Portugal give indication that horizontal subsurface flow systems, with expanded clay media, are a suitable option to be considered when dealing with high organic loading tannery wastewater (up to c.a. 3800 kgCODha−1d−1), being resilient to a wide range of hydraulic variations. Plants such as Phragmites and Typha have shown to be adequate for tannery wastewater depuration, with Arundo donax proving resilient to high salinity wastewaters. The flexibility of implementation allows the CW to be adapted to different sites with different configurations, being suitable as main secondary or tertiary treatment stage.
- 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.
- Biological processes for industrial wastewater treatment- case study in the leather industryPublication . Calheiros, Cristina S. C.; Rangel, António O. S. S.; Castro, Paula M. L.
- Toxicity abatement of wastewaters from tourism units by constructed wetlandsPublication . Calheiros, Cristina S. C.; Castro, Paula M. L.; Gavina, Ana; Pereira, RuthThe present research intended to investigate the toxicity abatement of domestic wastewater after passing a biosystem composed of a constructed wetland (CW) followed by a pond. The wastewater was generated in a tourism house in a rural and mountainous context and passed through a septic tank before being diverted to a CW followed by a pond. A battery of ecotoxicological tests, comprising microalgae (Raphidocelis subcapitata), macrophytes (Lemna minor), cladocerans (Daphnia magna), and bacteria (Aliivibrio fischeri), was used to assess the toxicity of the wastewater collected before and after the CW and the water of the pond. Physicochemical parameters (pH, conductivity, chemical oxygen demand, biochemical oxygen demand, total suspended solids, phosphates, ammonium, and nitrate) were also determined. The CW was able to remove carbon and nutrients from the water with a concomitant reduction of its toxicity. This study, reinforced the added value of using toxicity tests as a complement to CW operational monitoring to validate the solution and to analyze possible readjustments that may be required to improve efficiency. This study lends further support to the claim that CWs can be a sustainable solution for treating small volumes of domestic wastewater in a rural context.
- Spatial-temporal changes in removal of fecal indicators and diversity of bacterial communities in a constructed wetland with ornamental plantsPublication . Calheiros, Cristina S. C.; Pereira, Sofia I. A.; Franco, Albina R.; Castro, Paula M. L.The present study was undertaken in a constructed wetland (CW), setup in a tourism house, for domestic wastewater treatment. The influence of season variations on the abundance of fecal indicator organisms (total coliforms and Escherichia coli) in the wastewater and in the substrate and the roots of plants inhabiting the inlet and outlet zones of the CW was evaluated along three consecutive years. The structure and diversity of bacterial communities associated to the CW’s substrate of inlet and outlet zones was also analyzed overtime. Wastewater was characterized for physicochemical and microbiological parameters and the bacterial communities colonizing the substrate surface, were analyzed by Denaturing Gradient Gel Electrophoresis (DGGE). The CW was effective in removing COD, BOD5, TSS, PO43−, NH4+, NO3−, and NO2− . It was also effective in removing fecal indicators, with a generalized decrease of total coliforms and E. coli in the substrate and in the wastewater from inlet to outlet of up to 2–3 log. The structure and composition of bacterial communities associated with the substrate was mainly influenced by the year rather than by the season or the CW zone.