Aproveitamento da água da chuva para fins não potáveis: Estudo de caso aplicado a duas edificações padrões da UNIFAP

Abstract

Cities are experiencing increasing difficulties to ensure the public supply of drinking water. Given the current scenario of population increase and the non-rational use of water resources in Macapá-AP, the present work was motivated to seek the technical and economic feasibility to propose a sustainable solution for the use of rainwater, in order to minimize problems related to water supply and stormwater management (urban drainage) in the current and future scenario at the Federal University of Amapá (UNIFAP) campus mark zero. This study evaluates the technical and economic feasibility of using rainwater for non-potable purposes as an alternative source of water supply in two standard buildings at UNIFAP. Initially, to analyze the technical feasibility, the catchment areas were surveyed, the rainfall data of the region was collected, the total and non-potable water demand was estimated. Subsequently, the computer program Netuno was used to determine the volume of the lower reservoir, which indicated an ideal volume of 20 m³ for the reservoir, for the upper reservoir the volume of 5m³ was previously adopted, whose together represented a potential saving of drinking water of 21.27%. For the assessment of economic viability, the cost of implementing the investment, labor costs, maintenance costs and the savings resulting from the use of drinking water before and after the installation of the system were considered. This was done by applying the local water tariff, and a balance of the period needed to recover the investment. The economic analysis showed that the estimated cost of implementing the system would be R$56,947.49, and compared to the annual savings of R$19,972.77, brought about by replacing 21.27% of drinking water with rainwater, results in an estimated payback period of 2 years, 10 months and 10 days. The advantages resulting from this system are not only financial, but also environmental and cultural. The reduction in the volume of precipitation, thanks to the stored portion, can mitigate the impact of precipitation capable of generating flooding on campus.