The water being supplied by Surat Municipal Corporation (SMC) to 50 lakh people in Surat city is barely potable. At times, the dissolved oxygen (DO) level is found to be just 1 or 2 particles per million (PPM). The basic requirement is between 6.5 and 8 PPM of dissolved oxygen. The quality of raw water is at the edge of the prescribed parameter of the Central Pollution Control Board (CPCB).
For water to be of drinking quality, it must have less of carbon oxygen demand (COD) and biological oxygen demand (BOD), but higher dissolved oxygen demand (DOD).
SMC has started artificial aeration process in its intake wells to increase dissolved oxygen (DO) in the water. This will remove foul smell and reduce the effects of soluble gases like hydrogen sulphide, sulphur dioxide and hydro sulphur carbons in the water due to sewage.
“We have been doing this to make water potable for the people. Otherwise, the water is polluted and as per CPCB standards, it is not potable,” additional city engineer, in-charge of hydraulic department, SMC, KH Khatwani said.
The Gujarat Pollution Control Board (GPCB) monitors water quality of Tapi at four places at Kathore Bridge on National Highway Number-8, VarachhaKhadi, Rander causeway and Hazira. Regional officer GPCB M S Dasari said, “Water quality deteriorates the moment sewage gets mixed with it. The work to close 11 sewage outlets should be taken up on priority basis.”