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Projects on Rainwater Harvesting

Collecting precipitated water for domestic use, or rainwater harvesting, is not a new concept; it was practiced by indigenous cultures for thousands of years. With global water scarcity due current water system problems, several projects designed to examine and improve existing methods for rainwater harvesting are underway. Such projects involve examining storage and collecting systems of various techniques, and measuring the quantity and quality of collected rainwater.

  1. Pollutants

    • Researchers from the University of Newcastle, Australia published a study in the journal "Science of the Total Environment" which investigated the amount of heavy metals in rainwater at different points of the collection system. Iron was found most in roof runoff water, while zinc, lead and arsenic were present most in water collected from polyvinyl chloride (PVC) pipes. Copper was more abundant in water from hot water taps with copper piping. The project concluded that a high variability in metals was found at the different sites, and that piping was a major factor in the amount and type of metal found.

    Feasibility

    • The feasibility of a rainwater harvesting system to provide sufficient quality water for drinking and cooking use was assessed by a team from the University of Science and Technology in Sylhet City, Bangladesh. The system provided 34.09 cubic meters of rainwater per year, while the annual requirement for the family of five involved in the project was 9 cubic meters. The collected rainwater also met the requirements of the Bangladesh Quality Standards of biochemical oxygen demand (BOD), iron and fecal bacteria contaminants.

    Climate

    • A project assessing the effects of climate and water demand on the economic viability of household rainwater systems in four Australian cities -- Perth, Darwin, Sydney and Melbourne -- was published in the "Journal of Environmental Management" in September 2009. Sydney had the highest amount of rainfall and was able to cover the cost of the harvesting system in the shortest time, making it the city with the highest potential for applying rainwater harvesting.

    Drinking Quality

    • Researchers from the University of Patras in Greece conducted a project to assess the quality of collected rainwater for drinking purposes. In addition to metals, the amount of organic compounds such as organochloride pesticides (OCPs) and polycyclic aromatic compounds were measured. The samples all met EU guidelines on chemical contaminants. Microbes were found in very low concentrations and were dependent on the hygienic level of the collection area.

    Roofing Material

    • A project on the effect of the type of roofing material used in rainwater harvesting systems was published in the journal "Water Research" in December 2010. All roofs had similar levels of metal and microbe contamination; however; shingle and green roofs had higher concentrations of dissolved organic carbon (DOC). It was concluded that rainwater collected from all roof material examined would need further treatment before satisfying the U.S. Environmental Protection Agency standards for drinking water.

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