WASA, Dhaka an organisation named Dhaka Water and Sewerage Authority was established in 1963. Historically, a water purification plant at Chadnighat and a pure water supply network in the city was set up in 1847 by Nawab khwaja abdul ghani. The sewerage network in Dhaka was introduced in 1923. After the partition of India in 1947, the government created the Department of Public Health Engineering (DPHE) to take up safe water supply and sewerage services in urban and rural areas. Earlier in 1946, a drainage network was introduced and developed by the then public Health Engineering Department. And finally in 1963,WASA constituted exclusively for facilitating the city dwellers with the supply of safe drinking water and sewerage facilities took over the responsibility from DPHE. The command area of Dhaka WASA was confined within the metropolitan area up to 1989. But in 1990s, Narayanganj was included in the command area. At present (2011) Dhaka WASA renders its services to the city dwellers of both Dhaka and Narayanganj through its eleven zones, of those 10 are located in Dhaka and the rest is in Narayanganj.
At present Dhaka WASA has a capacity of supplying 1950 million liters of water daily against the requirement of 2100 million liters. The source of 87% suppled water is deep tube-well and the rest are collected from surface and shallow water bodies. The main components of Dhaka WASA's water supply network are its 539 deep tube wells and four water purification plants. Moreover it has 274 diesels run generators. In the summer, when the requirement of water goes up and power crisis is intensified, these generators are used to prevent any possible interruption in the water supply network of Dhaka City. Dhaka WASA also owns 31 water tankers, 30 trolley vehicles and eleven tractors which are used to carry water to any place in the city facing acute shortage of water. The number of subscribers of Dhaka WASA is 280 thousand, of them 11,636 are from Narayanganj. There are 1209 and 434 roadside water taps in Dhaka City and Narayangonj respectively.
The Quality Control and Research Department of Dhaka WASA regularly conducts qualitative test of water by collecting samples from underground and surface. The quality of underground water supplied by Dhaka WASA is up to the mark. The arrangements of chlorination have already been made at sources in the supply line. After treatment, the surface water is put in chlorination process and then put in the water supply line. The level of Arsenic and other toxic elements like Chromium, Cadmium, Lead, Mercury, Zinc and Aluminum in underground water is examined every month. The level of ammonia nitrate, phosphate, sulphate, BOD and COD is also examined. In the water treatment plants, these tests are done in every quarter to make the water collected from rivers safe.
'System loss' is a very challenging problem for Dhaka WASA. The gap between the volume of water produced and supplied in line, and bills realised against the volume water is regarded as the system loss. The loss incurred due to technical reasons including leakage in supply line and existence of out of order meters is called technical system loss and the loss occurred for various seasons including weak billing method and illegal connections is regarded as administrative system loss. The situation has improved a lot with the steps taken up for leasing out revenue collection and billing system to private firms although the average system loss of Dhaka WASA now reduced to 35%.
The sewerage network introduced about a century ago was developed further in phases. But it could not cover a part of Mohammadpur and all the areas of Mirpur, Shyamoli, Kallyanpur and Uttara due to dearth of capital. A master plan is being prepared for the development of sewerage system in these areas. WASA has 60277 sewerage connections, 881.02 kilometre of sewerage line, 29 lift stations and a sewerage treatment plant in Dhaka City.
The DPHE introduced and developed drainage network in Dhaka in 1946. The drainage system of the capital was given to Dhaka WASA in 1989. The drainage infrastructures developed so far from 1946 include: 290 Kilometre of storm water line (having 450 to 3000 mm diameter); 9 kilometre of box culvert; 65 Kilometre of open canal; two permanent pumping stations to drain on stagnant water one each at Dholaikhal and Kallyanpur; and 160 square Kilometres area brought under water removal system. [Taksim A Khan]