Viabilidade do aproveitamento de água de chuva em zonas urbanas: estudo de caso no município de Belo Horizonte

Abstract

This research aims to evaluate the quality of the rain water collected in Belo Horizonte MG Brazil, and verify the city inhabitants perception over the utilization of this water for nonpotable uses. The quantitative research about the rain water quality was carried out in twoparts of the city, Downtown and Pampulha. Two pilot systems were installed in each region, one of them had the surface built with ceramics tiles and the other with metallic tiles. Physics and chemistry analysis were carried out (pH, turbidity, apparent color, alkalinity, hardness,sulfate, iron, manganese and lead) and microbiologic (total coliforms and Escherichia coli). The water samples were collected from march 2008 to January 2009. The standard total coliforms, apparent color, turbidity, and iron did not reach the standards by preconized the Brazilian norm number 15,527/2007 of the ABNT (Brazilian Technical Standards Association) and governmental decree 518/2004 Health State Department when 2.0 L ofrainwater per m² of roof were discarded. A difference between the quality of the water collected in the two regions analyzed and in the two kinds of tiles was verified. The water collected by the metallic tiles showed a higher microbiologic quality than those collected by the ceramics tiles. Concerning the possibility of the utilization of the rain water in someactivities, this can be an important tool in the struggle against the indiscriminate use of potable water. Meanwhile, to make the use of rainwater feasible, its necessary that the population accept it. In this way, a qualitative study was carried out to evaluate the awareness of the Belo Horizontes inhabitants towards the utilization of the rain water. 18 people were interviewed, 9 with a higher education degree and 9 with incomplete elementary school degree. The data collecting method used in the research was the semi-structured interview and the analysis method was the Discourse of the Collective Subject (DCS). The analysis of the DCSs suggests that the interviewed people had an environmental consciousness and were for the rain water utilization for non-potable uses like cleaning and irrigation plants. It is clear that a financial help provided by the state would be decisive so that many people living in theurban areas could use the rain water. Some facts were mentioned as possible causes for the non-utilization of the rain water in the urban areas such as: lack of space, money and knowledge; potable water in abundance and low level of rain water storage.