Surface water quality in and around Dhaka City

The quality of water, from both surface and groundwater sources, has recently being endangered by many factors, natural and man-made, which have caused a deterioration. The quality of the water sources used in Bangladesh is at high risk, especially in the capital city of Dhaka, due to increased pollution resulting from unlimited migration of rural people. Consequently, the existing groundwater-based water supply system is not adequate to fulfil the water demand of the mega-city Dhaka. To alleviate the city's present severe water crisis, the question has been asked as to why the Dhaka Water Supply and Sewerage Authority (DWASA) is not using the rivers around Dhaka as a source of water. In this context, DWASA is seriously considering two options: (i) introduction of a separate water supply system for domestic purposes other than drinking water by pumping available river water around the city; and (ii) installation of a small-scale treatment plant for water supply using river water around the city as a source of raw water. Implementation of either of these options will require a study on the quality of the water sources, and development of appropriate cost-effective treatment methods. A study has been conducted at the Bangladesh University of Engineering and Technology (BUET) to evaluate the important physical, chemical, and biological water quality parameters of the five rivers around Dhaka City. Test results indicate that the water of all rivers around Dhaka City is highly polluted during the dry season, except for water of the River Sitalakhya. The important water quality parameters in the dry and wet seasons, when compared with earlier values, indicate that the degree of pollution of these rivers is gradually increasing with time. This paper focuses on the study and analysis of important water quality parameters of river waters around Dhaka City.