ISSN: 1659-2751



System Design for Collection and Filtering Rain Water for Domestic Use


One of the solutions to resolve the problem of scarce drinking water is to take advantage of precipitation. In this study, an integrated system of storage and purification of rainwater was designed, to supply the student residences and avoid the use of drinking water in everyday activities. The chemical and microbiological components of rainwater were studied through analysis of several samples collected from the roof of a student residence, at various times throughout the year. Samples of rainwater were filtered through polypropylene, cellulose, activated carbon, and gravel-sand, and the samples were analyzed for chemical and microbiological properties to determine the effectiveness of each filter for cleaning the water. The filters chosen for the system were the activated carbon and gravel-sand because they were the most efficient for the filtration of the rainwater. To determinate the size of the storage tank, precipitation data for the last ten years (collected at the meteorological station nearest to the student residence) was considered, as well as the water consumption in these buildings in the last five years. This data was used to formulate a probabilistic analysis of the rainfall at 75 %, 85 % and 90 %. In addition, consumption data from the last five years in the students´ buildings was used to evaluate the maximum consumption with an 85 % probability. With these data and the total rainfall collection area in the residence (1052 m2), different tank sizes were evaluated to satisfy, with an 85 % probability, the water consumption of the students throughout the year. To supply the 139 m3 of water used every week by the students, the proposal was to install four tanks of 40 m3 each.

Key words: potable water, water storage, water decontamination, design, filters, precipitation.

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