Wingecarribee Shire Council is currently upgrading the Mossvale wastewater treatment plant due to overloading.
They were struggling to maintain compliance during the upgrade process. Not surprising considering the existing plant was designed for 9,000EP (Equivalent Population) but is currently treating 16,000EP!
The two IDEA (Intermittently Decanted Extended Aeration) basins with a water level of less than 2.5m are installed with membrane diffusers, which were failing to meet the oxygen demand.
Ian Freere, Wastewater Treatment Supervisor for Wingecarribee Shire Council
investigated options for supplemental aeration during the upgrade process and recalled seeing the aerdisc® Directional Aerator at Ozwater’23 in Sydney so contacted Aeris Global Australia.
This was a unique application because it required an aeration technology able to operate above the existing membrane diffusers but without dislodging or damaging them and certainly not reducing their efficiency.
Aeris Global theorised the introduction of horizontal velocity using aerdisc® would not only provide supplemental aeration but would also improve the efficiency of the diffused air system.
aerdisc® is a directional aerator and typically operates in shallow water (<2.5m) so a strong discharge velocity is necessary to maximise the bubble dwell time.
In the absence of a horizontal velocity, bubbles exiting membrane diffusers will take a beeline to the surface so, correspondingly, bubble dwell time will be low and oxygen transfer efficiency poor.
Bubbles coalesce almost immediately without horizontal velocity and each doubling of bubble size results in a 400% increase in bubble rise rate!
Once again aerdisc® delivered the results by dramatically improving the performance of the plant within days.
