Case Studies 2. Robuschi Blower Retrofit

Date of compressed air installation: June 2016

Location: A wastewater treatment works in Moray.

Description: Our customer required a new blower to be retro-fitted to their wastewater aeration system. Replacing their Aerzen GM90S - which had developed an oil seal leak - was a new Robuschi rotary lobe blower type RBS125/F. This low-pressure 3 lobe blower has its own patented system, 'LOWPULSE' which eliminates pressure and delivery pulsation. This system, in conjunction with the three special profile lobes, reduces the residual pressure pulsation of the conveyed gas to below 2% of the operating pressure.

The Process:  Aeration diffusers are critical in providing a continuous supply of regulated air to oxygenate the micro-organisms essential in the aerobic digestion of fecal matter. Aeration basins, as well as grit chambers, require regular oxygen top-ups to meet the biochemical demand of the protozoa which consume the matter. These organisms are also kept mobile by the 'oxygen currents' in the water as they process the waste material transferring it into: nitrogen gas, water and carbon dioxide. Essential to the running of any wastewater treatment facility, blowers are also one of the most energy-hungry items of plant on site and can account for up to 70% of the plant's power consumption. But with such a critical process it's vital that the blower selected is as energy-efficient and as reliable as possible.

Compact in its design and with long-life bearings (designed for a lifespan of 100,000 hours), the new Robuschi blower was hoisted into position. Connected to an ABB 132kw motor and controlled by an ABB variable speed drive (to maximise the control of the motor and, in turn, the blower), a new pulley and belt were fitted and the blower set to 580 mbar. The blower was tested and the output checked to ensure it met the required demand.

Benefits: The successful blower installation means that the customer now has a brand new blower at a very cost-effective price. The blower being retro-fitted within a day ensured that CAPEX costs and downtime were kept to a minimum.