A Study on Using Rainwater Harvesting for Meeting Non-potable Water Demand in Urban Areas

Abstract

Climate change is affecting the natural resources such as water and experts are searching for solutions. Rainwater harvesting is a method of collecting a volume of water from raindrops. Rainwater harvesting can be used as s supplementary source for non-potable uses of water. Non-potable uses of rainwater include flushing toilets, watering garden and washing floors and cars. However, treated rainwater can be used for drinking, bathing, and cooking and washing clothes if it treated and became free from harmful contaminants. The volume of rainwater collected from rainwater harvesting system varying from one country to another. In a tropical country like Malaysia it is easy to collect 2 m3 in a single rain while 10 m3 was collected annually in Zambia, Africa from a roof of almost of the same size. The main advantages of rainwater harvesting systems are conserving water resources and reducing surface water pollution. Other advantages are helping in controlling flash floods and adaptation of climate change. In the present study, a rainwater harvesting system was installed in the Faculty of Engineering, University Putra Malaysia, Selangor, Malaysia and the system composed of the catchment (roof), gutter, pipe, steel tank and treatment unit. From 20 different rain events, the collected volume of rainwater in the tank ranges between 0.4 m3 and 2 m3. The daily water consumption by students was monitored for one month and compared with the collected rainwater volume. In order to check the quality of rainwater, samples of rainwater were collected from the gutter of the rainwater harvesting system. The main standard tests conducted in the laboratory on the rainwater samples were pH, turbidity, BOD5, dissolved solids, total solids, total coliform, lead, etc. The rainwater was found to be acidic in nature (pH < 7).