AERATION
The Slot Injector’s pressure pumping system allows for higher efficiency impellers
Traditional methods,
technical advantages
An advanced jet aeration and mixing technology, introduced into the UK by Aquabio, is set to make a difference
at high rate industrial processes. Its shape and performance mark it out as an attractive investment
A
quabio Ltd has introduced an advanced injector are similar to that of an ejector or ■ The higher velocity jet plume means that
jet aeration and mixing technology into eductor. Within the propulsion jet chamber there slot jet nozzles can be raised in the tank and
the UK. The new ‘slot’ aerators are is a zone of extreme negative pressure angled more acutely downwards, resulting in
aimed at high rate industrial processes, industrial enhancing gas entrainment, as well as a mixing lower pressure blowers.
‘rich’ municipal streams and high MLSS biomass. chamber providing the characteristic ‘pressure ■ The slot air to liquid ratio operating
Due to increased shear and high alpha recovery’ zone. The result is a device that can window, along with the higher pressure
characteristics the system is particularly suited to dissolve large quantities of gas with significantly pumping system lends itself to optimizing
industrial and more viscous biomass which is less liquid recirculation. system performance by varying both the pump
encountered in SBR and MBR processes. ■ The Slot Injector has all the traditional and blower flow. Aquabio’s proprietary control
Like conventional jet aerators, slot injectors are advantages of conventional jet aerators, (e.g. high and automation system uses variable speed
two phase gas/liquid contactors, but are alpha factor in industrial wastewater, no pumps and blowers to optimise energy
differentiated by the shape and performance mechanical parts in the tank, no deteriation in efficiency and performance within the
characteristics of the slot shaped propulsion jet performance due to scaling or biofouling, very biological system.
(inner nozzle) and mixing chamber (outer low maintenance etc.). However the reduced ■ Two phase flow control allows for maintaining
air/liquid nozzle) as follows: liquid flow and higher nozzle discharge pressure optimum gas/liquid ratios with the result being
of the slot has some important advantages over the highest level of energy efficiency over a wide
■ The slot shaped mixing chamber offers a conventional jet aeration. band of operating conditions.
greater contact surface than a circular one of ■ The 50-60% reduction in liquid flow results in
identical area, and the transition within the smaller and/or fewer pumps as well as significant In the UK slot systems are now installed and
chamber from circle to slot, without any reductions in the size of liquid piping/valves and operating successfully in MBR systems in the
reduction in flow area, allows for the gas/liquid fittings both inside and outside the tank. This food, chemicals and malting industries. ■■■
plume to retain more of it’s kinetic energy as it is feature provides considerable capital savings.
discharged into the bulk liquid. This results in ■ The higher pressure pumping system allows For further information on slot aeration and
more effective gas dissolution. for higher efficiency impellers compared with the mixing, please contact Steve Wilcox on 01905
■ The operating characteristics of the slot lower pressure systems. 641966 or s.wilcox@aquabio.co.uk
24 Water & Wastewater Treatment September 2009