Rainwater: A Potential Alternative Source for Scarce Safe Drinking and Arsenic Contaminated Water in Bangladesh

Although Bangladesh receives plenty of rainwater during its monsoon, both rural and urban areas suffer from shortages of safe drinking water during dry season. Arsenic contamination of ground water affects many rural areas, whilst some urban areas including the capital, Dhaka City, lack sufficient potable ground water to meet the demand. To cope with the problem, this research explore: the feasibility of harvesting rainwater during monsoon as a source of quality safe drinking water in Dhaka City. A questionnaire survey was conducted about potable water shortage in four slums of Dhaka City. Rainwater was collected using a non-toxic waterproof cloth as a catchment during monsoon and stored in a ferro-cement storage tank with an initial flushing device attached at the inlet of the tank. Different important physical, chemical and bacteriological parameters were tested throughout the storage period of 4 months. The efficiency of the rainwater harvesting system increased from 51% to 80% before and after installing the system. The test results were compared with the Bangladesh water quality standards. The tests have revealed slightly higher pH value (8.1 to 8.3) and enormity of color beyond the acceptable range. Although the presence of total coliform was detected after three months, traditional filtering of that stored rainwater showed a promising solution to mitigate potable water shortages in Bangladesh.