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Dissertação de Mestrado em Gestão Sustentável do Ciclo Urbano da Água apresentada à Faculdade de Ciências e Tecnologia Atualmente, a escassez de água representa uma problemática de grande relevância no nosso quotidiano, cujo impacto implica a otimização na disponibilização e gestão dos recursos hídricos. Face às crescentes necessidades deste recurso limitado, torna-se necessário refletir sobre as aplicações atuais da água e adotar estratégias que privilegiem o conceito da economia circular, assentes em princípios que promovam redução, reutilização e recuperação deste recurso. O interesse pela reutilização de águas residuais tratadas tem aumentado exponencialmente, ganhando destaque enquanto componente estratégica crítica para a adoção de políticas de gestão integrada dos recursos hídricos. Nesta dissertação pretendeu-se abordar o potencial de produção de água para reutilização da estação de tratamento de águas residuais da Sertã, e a sua aplicação na rega do Jardim da Serrada, como uma medida de conservação dos recursos hídricos, reduzindo assim as necessidades de captação e, ao mesmo tempo, protegendo os meios recetores. No sentido de obter um correto enquadramento técnico e legal dessa reutilização, foi efetuada uma revisão bibliográfica sobre o tema em estudo. Posteriormente, numa primeira fase foi feita a avaliação entre as disponibilidades de água para reutilização (quantidade e qualidade), e possível aplicação na rega do Jardim da Serrada. Seguidamente, numa segunda fase, foi efetuada uma análise sucinta de forma a verificar a viabilidade da sua reutilização e elaborado o modelo de gestão, sendo que foram definidas as medidas de gestão e de monitorização adequadas face à utilização prevista para a água para reutilização. Como tal, foi possível verificar que do ponto de vista quantitativo, as necessidades hídricas do jardim representavam 8% da capacidade produtiva da estação de tratamento de águas residuais da Sertã. Do ponto de vista qualitativo, inicialmente verificou-se a não conformidade dos sólidos suspensos totais e carência biológica de oxigénio face à legislação em vigor, 35 mg/l e 25 mg/lO2, respetivamente. No entanto, tendo em conta que o efluente passa ainda pelo processo de filtração e posteriormente desinfeção, e perante a adoção de medidas restritivas no acesso ao jardim durantes os períodos de rega, permitiram verificar a conformidade dos parâmetros legalmente exigidos, viabilizando a utilização das águas para reutilização, para a rega do jardim. Em conclusão, a produção de água para reutilização, obtida a partir do tratamento de águas residuais, bem como a sua utilização é abordada nesta dissertação como uma solução ou recurso relevante na rega paisagística. Pelo que perante a análise dos requisitos necessários foi encontrada uma solução viável para a sua aplicação na rega do Jardim da Serrada, Sertã. Currently, water scarcity is a major issue in our daily life, whose impact implies the optimization of the availability and management of water resources. Given the growing needs of this limited resource, it is necessary to reflect on the current applications of water and adopt strategies that favours the concept of circular economy, based on principles that promote reduction, reuse and recovery of this resource. The interest in the reuse of treated wastewater has increased exponentially, gaining prominence as a critical strategic component for the adoption of integrated water resources management policies. In this dissertation we intended to address the potential of water for reuse produced by the wastewater treatment plant of Sertã, and its application in the irrigation of green spaces of the town, more specifically the irrigation of the Serrada Garden. The reuse of this wastewater will be a measure of conservation of water resources, reducing the needs for abstraction, protecting the receiving media, and also enhancing the recovery of nutrients. In order to obtain a correct technical and legal framework for this reuse, a literature review was conducted on the subject under study. In a first phase, an evaluation was made between the availability of water for reuse (quantity and quality), and possible application in the irrigation of the Serrada Garden. Then, in a second phase, a brief analysis was made in order to verify the feasibility of its reuse and elaborate the appropriate management model and monitoring measures, in view of the planned use of water for reuse. As such, it was possible to verify that from a quantitative point of view, the water needs of the garden represented 8% of the production capacity of the Sertã wastewater treatment plant. From a qualitative point of view, initially it was verified that the total suspended solids and biological oxygen demand did not comply with the legislation in force, 35 mg / l and 25 mg/lO2, respectively. However taking into account that the effluent still goes through the filtration process and then disinfection, and after the adoption of restrictive measures in the access to the garden during the irrigation period, it was possible to verify the compliance of the legally required parameters, enabling the use of water for reuse, to irrigate the garden. In conclusion, the production and use of water for reuse, obtained from the treatment of wastewater, was proved to be a solution and a relevant resource in landscape irrigation, which can be applied in the irrigation of the garden of Serrada, Sertã.

HighlightBacterial growth in fecally-contaminated water is highly variable and dependent on several factors.Regrowth occurs after chlorination (low doses, no residual).Indigenous microbial communities variably impact bacterial growth.A combination of treatments can both inactivate and inhibit growth.The Blue Diversion AUTARKY Toilet is a urine-diverting toilet with on-site treatment. The toilet is being developed to provide a safe and affordable sanitation technology for people who lack access to sewer-based sanitation. Water used for personal hygiene, hand washing, and flushing to rinse urine- and feces-collection bowls is treated, stored, and recycled for reuse to reduce reliance on external water supplies. The system provides an opportunity to investigate hygiene of water for reuse following treatment. Treatment in the toilet includes a Biologically Activated Membrane Bioreactor (BAMBi) followed by a secondary treatment technology. To identify effective secondary treatment, three options, including granular activated carbon (GAC) only, GAC+chlorine (sodium hypochlorite), and GAC+electrolysis are considered based on the bacterial inactivation and growth inhibition efficiency. Four different hygiene-relevant bacteria are tested: Escherichia coli, Enterococcus faecalis, Pseudomonas aeruginosa, and Salmonella typhimurium. Our evaluation demonstrates that—despite treatment of water with the BAMBi—E. coli, P. aeruginosa, and S. typhimurium have the potential to grow during storage in the absence of microbial competition. Including the indigenous microbial community influences bacterial growth in different ways: E. coli growth decreases but P. aeruginosa growth increases relative to no competition. The addition of the secondary treatment options considerably improves water quality. A column of GAC after the BAMBi reduces E. coli growth potential by 2 log10, likely due to the reduction of carbon sources. Additional treatments including chlorination and electrolysis provide further safety margins, with more than 5 log10 inactivation of E. coli. However, reactivation and/or regrowth of E. coli and P. aeruginosa occurs under in the absence of residual disinfectant. Treatment including the BAMBi, GAC, and electrolysis appear to be promising technologies to control bacterial growth during storage in water intended for reuse.

• Bacterial growth in fecally-contaminated water is highly variable and dependent on several factors. • Regrowth occurs after chlorination (low doses, no residual). • Indigenous microbial communities variably impact bacterial growth. • A combination of treatments can both inactivate and inhibit growth. The Blue Diversion AUTARKY Toilet is a urine-diverting toilet with on-site treatment. The toilet is being developed to provide a safe and affordable sanitation technology for people who lack access to sewer-based sanitation. Water used for personal hygiene, hand washing, and flushing to rinse urine- and feces-collection bowls is treated, stored, and recycled for reuse to reduce reliance on external water supplies. The system provides an opportunity to investigate hygiene of water for reuse following treatment. Treatment in the toilet includes a Biologically Activated Membrane Bioreactor (BAMBi) followed by a secondary treatment technology. To identify effective secondary treatment, three options, including granular activated carbon (GAC) only, GAC+chlorine (sodium hypochlorite), and GAC+electrolysis are considered based on the bacterial inactivation and growth inhibition efficiency. Four different hygiene-relevant bacteria are tested: Escherichia coli, Enterococcus faecalis, Pseudomonas aeruginosa, and Salmonella typhimurium. Our evaluation demonstrates that—despite treatment of water with the BAMBi—E. coli, P. aeruginosa, and S. typhimurium have the potential to grow during storage in the absence of microbial competition. Including the indigenous microbial community influences bacterial growth in different ways: E. coli growth decreases but P. aeruginosa growth increases relative to no competition. The addition of the secondary treatment options considerably improves water quality. A column of GAC after the BAMBi reduces E. coli growth potential by 2 log10, likely due to the reduction of carbon sources. Additional treatments including chlorination and electrolysis provide further safety margins, with more than 5 log10 inactivation of E. coli. However, reactivation and/or regrowth of E. coli and P. aeruginosa occurs under in the absence of residual disinfectant. Treatment including the BAMBi, GAC, and electrolysis appear to be promising technologies to control bacterial growth during storage in water intended for reuse., Frontiers in Environmental Science, 5, ISSN:2296-665X