RESUMO
Water availability pressures, competing end-uses and sewers at capacity are all drivers for change in urban water management. Rainwater harvesting (RWH) and greywater reuse (GWR) systems constitute alternatives to reduce drinking water usage and in the case of RWH, reduce roof runoff entering sewers. Despite the increasing popularity of installations in commercial buildings, RWH and GWR technologies at a household scale have proved less popular, across a range of global contexts. For systems designed from the top-down, this is often due to the lack of a favourable cost-benefit (where subsidies are unavailable), though few studies have focused on performing full capital and operational financial assessments, particularly in high water consumption households. Using a bottom-up design approach, based on a questionnaire survey with 35 households in a residential complex in Bucaramanga, Colombia, this article considers the initial financial feasibility of three RWH and GWR system configurations proposed for high water using households (equivalent to >203 L per capita per day). A full capital and operational financial assessment was performed at a more detailed level for the most viable design using historic rainfall data. For the selected configuration ('Alt 2'), the estimated potable water saving was 44% (equivalent to 131 m3/year) with a rate of return on investment of 6.5% and an estimated payback period of 23 years. As an initial end-user-driven design exercise, these results are promising and constitute a starting point for facilitating such approaches to urban water management at the household scale.
Assuntos
Conservação dos Recursos Hídricos/economia , Conservação dos Recursos Hídricos/métodos , Habitação , Chuva , Águas Residuárias , Colômbia , Água Potável , Abastecimento de Água/economiaRESUMO
A ocorrência de Aeromonas spp móveis foi verificada em um total de 730 amostras de água de consumo humano de diferentes origens, sendo 495 da rede de abastecimento público tratada, 208 de soluções alternativas (compreendendo 65 de poços artesianos, 69 de poços rasos, 74 de minas), além dessas foram analisadas 27 amostras de água mineral envasada. Os resultados mostraram que 6,3%, 55,3% e 11,1% das amostras de água da rede de abastecimento público tratada, soluções alternativas e água mineral envasada estavam contaminadas com Aeromonas spp, respectivamente. Verificou-se que nem sempre a ocorrência de Aeromonas estava associada à presença de indicadores fecais. Das 613 cepas de Aeromonas isoladas 75,4% pertenciam a espécie Aeromonas hydrophila, seguidos por 9,8% de Aeromonas caviae e 0,6% de Aeromonas sobria. Estes achados mostram que estudos adicionais são necessários para avaliar possíveis riscos que a presença de Aeromonas spp poderia acarretar à saúde pública.
The presence of motile Aeromonas spp was investigated in a total of 730 samples of drinking water from different origins: 495 samples from the treated water distribution system, 208 from alternative water supply (65 from artesian wells, 69 from shallow wells, and 74 from springs), and 27 samples of bottled mineral water. The present study indicated that 6.3%, 55.3% and 11.1% of samples from treated water distribution system, alternative water supply, and bottled mineral water were contaminated with Aeromonas spp, respectively. The highest counts of Aeromonas spp were not always associated to the presence of faecal indicators. Aeromonas hydrophila was the most frequently isolated phenospecies in water, followed by Aeromonas caviae (9.8%) and Aeromonas sobria (0.6%). These findings show that further studies are necessary to evaluate the possible risks that the occurrence of Aeromonas spp may pose to public health.