AWWA ACE63181

To tackle the highly deteriorated raw water quality of River Godavari, the existing raw water treatment plant at Maharashtra State Electricity Board's Nasik Thermal Power Station was augmented by retrofitting one of its three streams. Apart from additional flow requirement over the years, the primary purpose was to increase the removal efficiency of organic matter in raw water. The vertical flow sludge blanket tanks were retrofitted with rapid mix-slow mix and tube settling system. This required a change in flow pattern from predominantly vertical to horizontal. The location of mixers in the hopper bottom tank with a non-regular geometry complicated the issue. All modifications were completed in thirty days. Initial results are encouraging. Turbidity reduction has been satisfactory, along with substantial reduction in organics. However, it will be some time before the system potential is completely established for reduction in organics and confirmation of the advantages thereof. Includes 18 references, figures.