Physicochemical and Microbiological Quality of Roof-harvested Rainwater in Urban Areas: A Review

Abstract

This work proposes to consider the quality of roof-collected rainwater. There are three main stages. In the first stage, rainfall washes out the urban atmosphere with contaminants from aerosols and gases. The second stage refers to the catchment, where there is contamination due to the wash-off of particles settled on the roof’s surface roofing materials. The third stage refers to the first-flush, storage and plumbing system. In each stage, different processes take place and add specific contaminants to the initial precipitation. Only in the third stage, after the discard of the high-polluted initial rainwater, some physical processes (for example sedimentation and correction of pH) can also improve the quality of the rainwater harvest. This approach offers a clear view of the overall contamination processes that take place in a rainwater harvesting system.The most common microbiological and physicochemical contaminants that can be found in rainwater harvesting system were considered, together with the eventual presence of waterborne pathogens and emerging chemical contaminants, according to an extensive review of previous scientific works. Keywords: Rainwater, Physicochemical, Microbiological, Contaminants, waterborne DOI: 10.7176/JEES/12-10-05 Publication date: October 31 st 2022