Water board looking to produce green energy from sewage water

The water board is working on generating green energy from sewage water being treated at the sewage treatment plant in Amberpet which, incidentally, is the biggest STP in Asia. 

HYDERABAD: The water board is working on generating green energy from sewage water being treated at the sewage treatment plant in Amberpet which, incidentally, is the biggest STP in Asia. At present, the 339 MLD of treated sewage water is directly let into river Musi. The board has now decided to use the treated sewage water for generation of 160 MW of power using Archimedean Screw Turbine technology with an investment of `3.5 crore. The central government will be tapped for the fund. The energy so produced will be utilised by the water board for operations such as pumping and maintenance.

Though several technologies are available to generate electricity from flowing water, the Archimedean Screw Turbine (AST) can generate electricity from 1 to 10 metre head by taking the capacity ranging 0.4 cubic metre to 10 cubic metres per second. Board officials told Express that AST is the most efficient and viable option for low head sites with low initial investment due to its easy installation and minimum civil work. 

The project cost is estimated to cost `3.50 crore, of which 30 pc equity will be `1.05 crore. As per enhanced subsidy, the developer can avail a subsidy of around `58 lakh. HMWS&SB will invite expression of interest this month and the work will be completed in September. The treated water flowing into the river will have a minimum fall of 1 to 6 metres depending on the elevation of the influent channel. In order to allow the treated water flow into the river, the influent channel and all other process equipment in the STP have to be designed at higher level to have kinetic energy and a natural fall is created having a head ranging I to 6 metres depending on design.

This water fall can be utilised to generate electricity if  a suitable turbine for rotation can be procured. The Archimedean screw is a non-pressurised operating system which  operates at low revolution speed.

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The New Indian Express
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