Hi Anish, I am working on ...

Hi Anish, I am working on projects in Australia upgrading STPs that are over 30 years old. I have found switching the old aeration technology to fine and ultrafine bubble technology to give an immediate reduction in energy costs in the order of magnitude of 2-3 times. 

You can get rid of the clarifier by retrofitting membranes into the existing aeration tanks to convert them into an MBR type process. My company has successfully done this in a number of STPs. This will reduce your footprint by about 1/3.

MBR is much smaller, easier to install, operate and maintain than conventional activated sludge processes. This is the standard process my company is implementing across Asia and Australia at the moment. BOD is