Jet
Aeration history
Jet
aerators or educators have been utilized for gas/liquid contacting and mixing
for over hundred years. Over the past decades, jet aeration has become
widely accepted, and increasingly popular in waste water treatment technology.
Operating
Principals
Submerged
jet aeration intermixes air with a motive liquid and injects the stream into the
waste water. The aerator itself consists of two jet nozzles. The motive liquid -
recirculated mixed liquor - is discharged from an inner nozzle into an outer
mixing nozzle, within wich compressed atmospheric air is introduced and sheared
into tiny bubbles wich are entrained in the motive liquid stream.
As
the stream is discharged into the surrounding mixed liquor, it forms a highly
turbulent jet plume. The plume entrains the surrounding mixed liquor and brings
it into contact with the tiny air bubbles. The resultant oxygen transfer rate is
extremely high. This efficiency is due to the high air/waste interface area
created by the minuscule bubbles, the turbulence within the jet plume, and the
extended bubble residence time.
Jet
Aeration
Submerged
jet aeration systems have traditionally been designed with their nozzles
discharged horizontally, usually no more than 30 cm/one foot off the reactor
basin floor. Consequently, air blowers are required to operate against static
pressure nearly equal to the basin's total depth.
The actual Jet Aeration Sytems are designed to be mounted higher, usually 75 cm
to 120 cm /2 1/2 to 4 feet above the basin floor. By mounting the nozzles at this higher level, significant savings in blower horsepower can be
realized, thus cutting power costs.
The jet nozzles do not
discharge horizontally, like traditional systems, but at a downward angle of 15
to 30 degrees, depending on the basin's geometry. In most applications, this system is superior in performance, compared to
horizontal systems mounted 60 cm/two feet deeper in the reactor basin.
Advantages of Jet aeration systems
-
High
oxygen transfer efficiency
-
Longterm and stable efficiency
-
Superior mixing capacities, without extra mixing and without extra oxygen
supply (anoxic periods)
-
No aerosols
-
No pre-cooling of the aerated liquid
-
Frost unsensitive
-
Low foam formation sensitivity
-
Highly free of maintenance - corrosion resistant material use in the aeration
basins (FRP/SS)
-
No moving parts in the aeration basins
-
Very suitable for use in deep aeration basins
-
Obstruction unsensitive
-
An average life cycle of more than 20 years !
Job
Experience
Task has ample experience in this
matter in several industrial projects.
Some
recent realizations
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