Browsing by Author "Halwatura, Lahiruni M."
Now showing 1 - 4 of 4
Results Per Page
Sort Options
- Antibiotic resistance and organic micropollutants monitoring in municipal full-scale constructed wetlands systemsPublication . Teixeira, A. Margarida; Matos, Diana; Halwatura, Lahiruni M.; Aga, Diana S.; Vaz-Moreira, Ivone; Castro, Paula M. L.; Manaia, Célia M.
- Dynamics and interrelationships between antibiotic resistance, organic micropollutants and bacterial communities in full-scale rural constructed wetlandsPublication . Teixeira, A. Margarida; Matos, Diana; Coelho, Norberta; Halwatura, Lahiruni M.; Vaz-Moreira, Ivone; Castro, Paula M. L.; Aga, Diana S.; Manaia, Célia M.Constructed wetlands systems (CWs) are increasingly regarded as promising alternatives or complements to conventional wastewater treatment processes. However, the fate of chemical and biological contaminants in realworld treatment processes is understudied in this type of systems. This study aimed to fill this gap by evaluating the response of three horizontal subsurface flow CWs, in Northern Portugal, planted with Phragmites australis, in operation for >7 years, to reducing the load of fecal contamination, antibiotic resistance genes and organic micropollutants (OMPs). Influent, effluent and sediments samples (n = 36) were examined for abundance of cultivable Escherichia coli and total coliforms, total bacteria (16S rRNA gene), 10 genetic biomarkers associated with anthropogenic contamination (uidA, crAssphage, intI1, sul1, ermB, ermF, mefC, qacEΔ1, tetX and aph(3″)-Ib) by quantitative PCR, non-target LC-MS of OMPs and 16S rRNA gene-based bacterial community analysis. The three CWs showed reduction values (log-units/mL) up to 4.8 of E. coli and 3.6 of biomarkers, with the highest values observed in warmer periods. No evidence of for the accumulation microbiological contaminants in the sediments was observed. Among the 59 OMPs detected, reduction rates varied, and the concentration of the most abundant pharmaceutical compounds in the final effluent varied –reaching ng/L concentrations of ~36 000 for fenofibric acid, ~14 000 for acetaminophen, ~3000 for oxazepam and ~2000 for irbesartan, which can be considered high to discharge in the receiving environment. The bacterial community was dominated by members of the class Gammaproteobacteria, with treatment contributing to significant reduction of the relative abundance of members of the classes Clostridia, Bacilli and Actinomycetes. Compared with wastewater, sediments had significantly higher relative abundance of Alphaproteobacteria. The study confirms that CWs are an adequate alternative for the treatment of domestic wastewater in small communities, although it warns of the need for regular monitoring and adjustment of treatment conditions, especially during cooler periods.
- Fecal contamination, antibiotic resistance and organic micropollutants in full-scale constructed wetlands in northern Portugal rural areasPublication . Teixeira, Ana Margarida Ribeiro; Matos, Diana; Coelho, Norberta; Halwatura, Lahiruni M.; Abaya, Liezel Mari; Vaz-Moreira, Ivone; Castro, Paula M. L.; Aga, Diana S.; Manaia, Célia M.Background and Aims Constructed wetlands (CWs) are recognized as a promising alternative or complement to traditional wastewater treatments. Their cost-effectiveness and seamless integration into natural landscapes, fostering wildlife habitats, are notable advantages. This study aimed to assess the efficacy of three horizontal subsurface flow CWs with Phragmites australis for reducing fecal contamination, antibiotic resistance, and organic micropollutants (OMPs). Methods Influent, effluent, and sediments samples (n=36) collected throughout 2023 were examined for cultivable Escherichia coli and total coliforms, 10 biomarkers for anthropogenic contamination and 16S rRNA gene by qPCR, 119 OMPs by LC-HRMS, and 16S rRNA-based bacterial community analysis. Results The reduction in fecal contamination (log-units) was of <4.8 for E. coli, <4.0 for total coliforms, and <3.6 for genetic biomarkers. Target OMPs showed variable removal rates, with different substances persisting after treatment (e.g. acetaminophen, fenofibric acid, irbesartan, oxazepam). The bacterial community was dominated by Pseudomonadota (>40%), and treatment led to the reduction of Bacillota and Actinomycetota and increase of the “Halobacterota” and Verrumicrobiota relative abundance. Conclusions The results reveal that the growth of macrophytes and climatic conditions, particularly temperature, influenced the treatment effectiveness, improved during summer. However, the capacity of the plants to uptake bacteria/genes from wastewater has been suggested and its meaning in pathogens ecology is being investigated.
- Resistência a antibióticos e micropoluentes orgânicos em três sistemas de zona húmida construída implementados na região Norte de PortugalPublication . Teixeira, A. Margarida; Matos, Diana; Halwatura, Lahiruni M.; Vaz-Moreira, Ivone; Castro, Paula M. L.; Aga, Diana S.; Manaia, Célia M.As zonas húmidas construídas, também conhecidas como fito-estações de tratamento de águas residuais (fito-ETAR), têm vindo a ser consideradas promissoras alternativas ou complementos para os processos convencionais de tratamento de águas residuais. A relação custo-benefício e a integração na paisagem natural, com a criação de habitats para a vida selvagem, são vantagens importantes destas soluções naturais. Este estudo envolveu três fito-ETAR, localizadas num raio de 20 km, que operam com fluxo horizontal e leito de macrófitas (Phragmites australis) para tratar efluentes de comunidades com menos 400 habitantes. O principal objetivo foi o de avaliar a capacidade para reduzir a carga de contaminação fecal, genes de resistência a antibióticos e micropoluentes orgânicos nos efluentes e avaliar a possível acumulação de genes de resistência nos sedimentos, enquadrados pela observância dos valores recomendados para parâmetros padrão (ex: CBO, CQO, SST, N, P). As amostras (afluente, efluente e sedimentos, n=36) foram colhidas nos meses de março, maio, julho e outubro do ano de 2023 e foram examinadas quanto à abundância de Escherichia coli e coliformes totais, 10 biomarcadores associados à contaminação antropogénica (contaminação fecal: uidA, crAssphage; recombinação genética de genes adquiridos: intI1 e resistência: sul1, ermB, ermF, mefC, qacEΔ1, tetX e aph(3’’)-Ib) a e de bactérias totais: gene rRNA 16S, por PCR quantitativo, micropoluentes (LC-HRMS) e análise da comunidades bacterianas com base na sequenciação do gene rRNA 16S. A redução da contaminação fecal (em unidades logarítmicas de UFC ou número de cópias de genes/volume de amostra) variou entre 0,8 e 4,8 para coliformes totais e E. coli e entre -0,1 e 3,6 para os biomarcadores genéticos. A prevalência de genes foi significativamente inferior em sedimentos do que em afluente e efluente sugerindo que não há acumulação de resistência nos sedimentos. Os 59 micropoluentes detetados apresentaram taxas de remoção variáveis, com o paracetamol, ácido fenofíbrico, irbesartan e oxazepam persistindo após o tratamento. Afluente, efluente e sedimentos apresentaram comunidade bacterianas distintas e variáveis ao longo do ano, com os efluentes a denotarem persistência de Arcobacteraceae em março e acentuado aumento de Rhodocyclaceae e Sulfurimonadaceae em julho. Apesar de tais variações, as três fito-ETAR apresentaram eficácia semelhante, sendo que temperaturas mais elevadas e o crescimento das macrófitas pareceram favorecer a remoção de contaminantes microbiológicos. O estudo confirma que as fito-ETAR podem ser boas alternativas para o tratamento descentralizado de efluentes domésticos.