The OXFINITI system is housed within a self-contained 20 foot intermodal box. It can be integrated into a SCADA system, or run independently as it was in the Wessex Water trial. It can be operated delivering a base load or controlled to deliver its oxygen in response to changing dissolved oxygen demand in the basin.
93% pure oxygen is directly injected from a generator into a side-stream taken from the ditch. The super oxygenated stream is then introduced into the effluent, where required, increasing the DO levels very quickly to the desired levels.
The OXFINITI system delivers at least 60% of its dissolved oxygen in a 'molecular' form rather than a 'bubble' as in conventional aerators.
This molecular oxygen enables a vastly greater and more efficient oxygen take up by the microbes.
Also, this form of oxygen stays longer in solution compared to conventional bubble systems.
In the Wick, St Lawrence trial, only 20% of the oxygen delivered by the SA units into the basin was in a form that was actually assimilated by the basin. In contrast, the OXFINITI box confirmed field test results of 99% efficiency in delivering oxygen in the optimal form for assimilation in the basin.
The OXFINITI box achieves a "Quantum Leap" in aeration technology and provides a radically new approach to aerating activated sludge. More than 50% of the treated water flow from the OXFINITI box contains molecular oxygen "in solution" in a concentration of up to 100 mg/l or more. Approximately a further 20% of the supersaturated oxygenated water is embedded and entrained with submicron or nano size oxygen bubbles providing for a very efficient transfer of oxygen to the aerobic wastewater treatment process. The rest of the oxygen is delivered in a combination of fine and coarse bubbles.
Oxygen transfer rates (OTR) are typically measured in clean water at standard conditions (SOTR), and then taking the power (P) usage into consideration are expressed as 'Aeration Efficiencies' (AE =OTR/P). For different conventional aerators (i.e. FBD, SA, Jet, etc.) these AE's at standard conditions (SAE) are compared on a 'like for like' basis by process designers in selecting aeration technology. However, in process conditions these AE's are significantly reduced up to 75% in fine bubble diffusers as compared to the OXFINITI system, due to the presence of high levels (000's mg/l) of suspended solids.
The actual AE's are corrected by using alpha factors (α) (e.g. αAE for FBD, MLSS 4000mg/l, α= 0.25). Aeration transfer rates are measured using air. In contrast OXFINITI uses 93% pure oxygen making direct comparison impossible. However in terms of alpha factor the OXFINITI box delivers values >0.9. This is 3-4 times higher than traditional FBD aerators.