Types and efficiency of rainwater treatment units: a literature review

Abstract The use of rainwater in buildings is an attractive alternative as a water source. However, to enable its use, rainwater must be treated in order to achieve the necessary quality. Filters are widely used for this purpose, and they are available in a variety of models. In order to assess different filtration systems, the results obtained by using each treatment unit and the limits recommended by ABNT (2007) were compared. The different systems’ efficiency were also compared with each other. A review was undertaken based on research studies available in the literature. This project aimed to organize information on state-of-the-art treatment units around the world and to contribute to consolidate these systems of rainwater treatment. The study detected a lack of standardisation in the methods and parameters analysed, which hinders a more precise analysis of which models would be most suitable to treat rainwater. The study also verified that the water quality required by the Brazilian regulation was not achieved by any of the filters. Nevertheless, the models studied showed promising results, i.e., they achieved high efficiency for most parameters, ranging between 60% and 100%.