Aproveitamento de águas pluviais: influência do volume de descarte e da filtração na qualidade da água

Abstract

The capture of Rainwater and subsequent use for non-potable purposes such as cleaning sidewalks and cars and watering gardens has become a common practice due to the possibility of preservation of water resources. However, even for less demanding uses, minimum standards must be met water quality. In this project, samples of rainwater were collected through a catchment system located in a residence in the neighborhood Orleans in Curitiba. Subsequently, two filters home were built, the first sand and second consists of a triple layer of gravel, coal and sand. Were evaluated the turbidity, pH and total coliform of the samples before and after filtration to verify the efficiency of the filters. For the parameter pH, there was an increase after the use of both filters. For the turbidity parameter, the triple-layer filter was efficient, the sand did not produce the expected results depending on the particle size used. The reduction in turbidity after passage through triple-layer filter was 44.9%. For the parameter coliforms, the samples showed a reduction in both filters: 19.44% for the filter of sand and 73.33% for the triple-layer filter. Addition to this analysis, was also performed a procedure to verify the influence of the first flush volume on volume reserved because there is a contact interface of water exclusion with water that is directed to the reservoir. By means of a dye solution and measurements with a spectrophotometer, it was found a transfer material of 18.22%, due to that interface. This indicates that, in the case of purely hydraulic device, part of impurities in the volume of discharge was directed to the reservoir, influencing he quality of the water reserved in the feedback system used.