Floating Aerator Aerators are used in biological treatment to convert organic matter into biological cell mass thereby reducing the BOD. The biological matter consumes dissolved oxygen for respiration and mechanical surface aerators are provided to replenish oxygen thus used up.
Mechanism Aerators are efficient circulators, drawing liquid from below and distributing it with intense disturbance over the liquid surface. This positive circulating action is the reason for continuous, rapid and complete mixing which occurs in an aeration tank and which is fundamental to the success of the activated sludge method of treatment.
Conventional methods of aeration involve the use of reinforced concrete tanks or channels with fixed aerators supported by substantial bridges spanning the tank or channel in which they operate.
An alternative to this is the floating aerator in which the unit is mounted on a catamaran-type or four-pod support structure depending on the degree of stability demanded by the application.
There are currently two kinds of structures for floating aerators based on the best marine engineering concepts.
The first type is the four-pod type and is akin to sea-moored drilling rigs. It is suitable for applications where severe weather situations need to be met.
The second type of floating aerator is the catamaran type. It finds application in circumstances that do not demand extreme stability.
Special Features
- Low speed (56 to 41 RPM), thus facilitating smooth movement of biomass without fragmentation.
- Non-clogging type impeller
- Curved vanes in impeller to provide smooth water gliding and thus no erosion
- Conical skirt provides automatic reduction in power consumption with drop in water level
- High tank depths up to 9m possible with draft tube
- Adjustable weir available for water level control
- Various flow combinations can be done to avoiding vortexes and stilling zones
- High efficient gear box with drywell arrangement
- Modular design that can be upgrded without much change
- Clockwise and anticlockwise direction to facilitate good mixing possible by proper combinations
- Can be easily used in various tank configurations (rectangular / circular / elliptical) with suitable depths
- Aerator cones are statically / dynamically balanced (if required).
Applications Aerators are typically used for wastewater applications like sewage and effluent treatment. Typical applications include oxygenation for sewage and effluent treatment in balancing tanks, concrete aeration channels i.e. activated sludge process, SBR, etc. or in low cost lagoon type aeration systems (floating aerators). Floating aerators can be used equally well for oxygenation of harbours, rivers, canals, lakes and reservoirs.
Range Voltas has aerators ranging from 2 HP (1.5 kW) to 120 HP (90 kW) motor capacities.
Material of Construction (Aerator Cones and Under Water Parts) Mild Steel Epoxy Coated / Galvanized / FRP Coated / Stainless Steel 304 / Stainless Steel 316
Performance
Voltas' aerators have an oxygenation capacity averaging between 1.8 Kg/kWh and 2.0 Kg/kWh at standard conditions depending on the model.
Typical Aerator Performance Curves
Model: VA 20 - 25
Blade Immersion
(mm)
|
Power at Aerator Output Shaft
(kW)
|
Oxygenation Capacity at 20 oC
(Kg/h)
|
Oxygenation Capacity Efficiency (std.)
(Kg/kWh)
|
216
|
5.7
|
15.60
|
2.76
|
241
|
6.6
|
19.50
|
2.96
|
267
|
7.7
|
20.00
|
2.60
|
292
|
9.5
|
26.80
|
2.83
|
318
|
10.6
|
29.30
|
2.75
|
345
|
13.7
|
39.60
|
2.90
|
368
|
15.7
|
44.00
|
2.81
|
381
|
16.8
|
52.20
|
3.10
|
Note: Details of other models of aerators will be available on request.
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