Sources of Pollution in Rooftop Rainwater Harvesting Systems and Their Control

Abstract

Contrary to the popular perception that rainwater harvested from rooftops is nearly as clean as pure water, a number of contaminants can be present in such a water-this is borne out by numerous studies reviewed by the authors. Once this fact is acknowledged, it is possible to control the water quality and to bring it within acceptable levels with simple and inexpensive devices. The authors address these issues. Besides reviewing the status of the quality of harvested rainwater, they trace the pathways by which pollutants can enter in a rainwater harvest. In this backdrop the authors discuss the strategies to manage the water quality at preharvest as well as postharvest stages.

Water quality and public health risks associated with roof rainwater harvesting systems for potable supply: Review and perspectives

“…The quality of rainwater shows considerable spatial and temporal variability. Literature suggests that the spatial and temporal variability of roof water quality depends on roof materials, catchment characteristics, precipitation properties, local weather and chemical properties of pollutants (Förster, 1996;Vazquez et al, 2003;Meera et al, 2006;Abbasi and Abbasi, 2011). Several other studies have investigated the impacts of these factors, and their interaction on roof water quality (e.g., Adeyini and Olabanji, 2005;Mendez et al, 2010;Meera and Ahammed, 2011).…”

Assessment of Water Quality in Roof-Harvested Rainwater Barrels in Greater Philadelphia

“…Roof-harvested rainwater has been shown to be contaminated with multiple types of microbiological, chemical, and heavy metal pollutants [29], raising concerns regarding potential public health risks when RHRB owners are exposed to rainwater during its use. In the current study of 38 urban and peri-urban Philadelphia RHRB, gardening was the most frequently reported use of stored rainwater, indicating the most relevant potential public health risks are likely to be from exposure to RHRW during garden hose usage [48] or consumption of raw produce irrigated with RHRW [49].…”

Efficiency of a closed-coupled solar pasteurization system in treating roof harvested rainwater

“…Roof harvested rainwater may serve as an alternative source of drinking water, but only if the water meets the international standards of drinking water as stipulated by the World Health Organization (WHO, 2011). Contamination of the rainwater may however, occur while the water traverses through the air, on contact with the roofing system (catchment area), drainage pipes and in the storage tank of the rainwater harvesting system (Abbasi and Abbasi, 2011). Numerous chemical and microbial pollutants have thus been detected in untreated rainwater sources (Spinks et al, 2006;Ahmed et al, 2008Ahmed et al, , 2010Ahmed et al, , 2012Huston et al, 2012) and if the harvested rainwater is utilized as a primary potable water source, this could result in adverse health effects.…”