Estudo da viabilidade técnica, econômica e social do aproveitamento de água de chuva em residências na cidade de João Pessoa

• Autor(a) principal: Dias, Isabelly Cícera Souza
• Data de Publicação: 2007
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UFPB
• Texto Completo: https://repositorio.ufpb.br/jspui/handle/tede/5570
• topic: Água pluvial; Viabilidade técnica; Análise econômica; Opinião da sociedade; Rainwater; Technical viability; Economical analysis; Social acceptability

Potable water scarcity is an ancient problem ant it is being accentuated nowadays, mainly because of human population increase and the pollution of water resources. This situation has led the human beings to look for other water sources. The catchment of rainwater in residences appears to be an option of good perspectives, since it substitutes the use of potable for rain water where the first is not required. In the rain water catchment process, impermeable areas, such as the roof, are utilized. The rainwater is collected by drips and conducted through pipes to an underground reservoir where it can be stored. This water is general used for non potable usages, such as in toilet, showers, sink, wash-house and also for car wash and garden watering. This work deals with to study of the technical, economical and social viability of rainwater catchment in residences in the city of João Pessoa, state of Paraíba, in northeast Brazil.The catchment system comprised the roof, drips, pipes, sand filter, chlorination, lower reservoir and upper reservoir. The water treatment stage along with the good quality of rainwater allows it to be used for all domestic demands, except the potable one. Therefore, in this work, only the kitchen demand was considered for the potable water and all the other demands for non potable water. Three socio-economical residence standards were considered: a popular, a medium and a high one. Potable and non potable usages were assumes based on literature review and were considered 84,62, 87,65 and 89,63% for the non potable usage in the popular, medium and high socio-economical residence standards, respectively. The net present value (NPV) and the benefit/cost ratio were calculated for a twenty-year period for a residential rainwater system. The pay-back period was also calculated. These economical indicators were calculated for several lower reservoir capacities, varying from a ten-day equivalent capacity to a maximum of that calculated by the Rippl method. For the present water tax scenario the rainwater catchment showed to be an unviable alternative for the popular and medium socio-economical standards. For the high socio-economical standard the alternative showed to be economically viable, with NPV varying from R$ 1278,17 a R$ 2254,00, benefit/cost ration varying from 1,29 to 1,47 and payback period varying from 8,17 to 10,36 years. Furthermore, for future expected scenarios of water taxes, the rainwater cathment in residences showed to be an economical viable alternative, with NPV of up to R$ 32386,11for the high socio-economical residence standard and water tax equivalent to four times the current one. In order to discovery the population acceptability, 800 interviews were applied. Results showed that 66,1% of João Pessoa population have the knowledge of rainwater usage in residences, of which, 54,37% make use of it. Including the people who would use rainwater in residence if they knew the alternative, the potential use of this water would increase almost two thirds of the city population.