Análise da viabilidade técnica e econômica da implantação de um sistema de aproveitamento de água pluvial em um posto de combustível

Abstract

Rainwater harvesting is a sustainable alternative for the conservation of water resources, bringing benefits such as reducing water scarcity and minimizing the effects of droughts; aid in flood control, etc. Although unconventional in Brazil, this practice has been gaining ground in initiatives throughout the country and in new civil construction projects, at residential and commercial level. This study analyzed the technical and economic viability of implementing a rainwater harvesting system at the “Sim” gas station, in Santa Maria - RS. To calculate the most recommended reservoir volume, the simulation method was used, to analyze five different volumes (15.000, 20.000, 25.000, 27.500 and 30.000 L), for rainwater capture on a 1250 m² roof. Among the simulations of the rainwater use systems with above 90% efficiency in meeting the demand, which exceeded the 15.000 L reservoir, the 20.000 L reservoir presented the best cost versus benefit, requiring R$ 26.656,51 investment, with a 9 years 2 months and 13 days payback and profits above R$ 22.000,00 in 15 years. The use of larger reservoirs, when compared to the costs of their implementation, did not add significant increases in terms of improving efficiency in attending the system demand. Even though these reservoirs presented a slight reduction in the number of failed days, without meeting demand, lower volume reservoirs obtained lower IRR and payback, which makes them more recommended.