|Aeration Products for Energy-Efficient Biological Treatment.pdf||PDF | 6.56 MB|
Numerous blower options are available to meet specific wastewater treatment plant requirements.
Rotary lobe blowers offer the advantage of low upfront capital investment costs and low efficiency. A pair of spinning rotors delivers a fixed volume of air for each rotation. Rotary lobe blowers rely upon external compression where the air is compressed by the system backpressure.
Screw rotor blowers provide higher efficiency than other positive displacement blowers thanks to the use of internal compression. A pair of intermeshing screws progressively reduce the volume of air as it moves along the length of the screw element.
Multi-stage centrifugal blowers are employed for larger flows and require less capital investment than other types of centrifugal blowers. Multiple impellers are mounted on a single low-speed shaft normally operating at a fixed speed.
Single-stage, integrally geared blowers are more efficient than positive displacement and multi-stage centrifugal blowers. A single impeller achieves higher rotational speed via a step-up gear. These can be equipped with variable inlet guide vanes and diffuser vanes to achieve high efficiency over a range of operating flows.
Variable-speed, single-stage, high Speed direct-drive Turbo blowers are more efficient for higher flows in comparison to positive displacement and multistage blowers. A dual impeller or preferably a single impeller for better efficiency is mounted directly onto the shaft of a high-speed motor with the low-friction magnetic or air foil bearings. The integrated variable frequency drive (VFD) matches pressure and flow rate demands.