Technical and Economic Feasibility Study of Greywater Reuse System Using the Bim Methodology

Rapid urban growth, combined with a lack of investment in infrastructure and pollution of water sources, has led to a shortage of drinking water in Brazil. According to the literature, billions of people in the world lack drinking water and adequate treatment of their domestic wastewater. Therefore, the depletion of water resources in recent decades has required the attention of governments to the need to create environmental policies aimed at the environmental awareness of the population and the search for technological advances in water treatment and management, such as the greywater reuse system. The objective of this work is to carry out a case study on the feasibility of the greywater reuse system in a single-family house using the BIM tool, which allows the technical, economic and social analysis of the project and the comparison with possible scenarios. In the proposed project, water from showers, tanks and sinks will be used for toilet flushing, garden irrigation and washing of waterproofed areas. The methodology consists of the theoretical study of the impact of the subject on the social aspect, followed by sizing calculations for technical analysis, budget of works and financial feasibility study, applying the concepts of payback and return on investment. As a result, a viable project was obtained regarding the social and technical aspect, since the system raises awareness of the population about water waste, reduces the effects of the water crisis and results in the production of greywater greater than the demand for non-potable water. Regarding the financial aspect, the BIM tool was used to project scenarios with 1 bathroom, 2 bathrooms and 3 bathrooms, all of which were found to be infeasible. The payback period for all projects was over 80 years and the ROI period was 100%. Therefore, it is necessary to analyse new parameters for the feasibility of the system.