Korea AQUOSYSㆍ(주)한국아쿠오시스




Provides technical information related to products by AQUOSYS.

HELIFLOT™: Innovation of Dissolved Air Flotation

1. Overview of the general Dissolved Air Flotation (DAF):
DAF is a water treatment technology that purifies water by removing suspended matter through the use of fine bubbles from dissolved air.

Advantages and disadvantages of DAF compare to Sedimentation

Advantages and disadvantages of DAF compare to Sedimentation
Advantages Disadvantages
• High speed treatment
• Produces thick sludge
• Shorter flocculation detention time
• Shorter start-up lead time
• Compact facilities required
• Omissible for recovered sludge thickener
• Requires more complex facilities
• Consumes more electrical power
• Unsuitable for highly silt-laden water
2. Introduction of HELIFLOT™
HELIFLOT™ is a cylindrical DAF unit that runs with helical flows, developed by Aquosys.
  • Raw water and fine bubbles are fed into the flotation tank (①) by an inflow pipe connected to the tangent (②).
  • Suspended materials form flocs with fine bubbles, creating a helical flow with the water to move upwards (⑥) and gather around the center of the water surface (⑧). The flocs are discharged out of the flotation tank through a scum outflow pipe (④).
  • The treated water then creates another helical flow to move downward (⑦) inside of the helical flow moving upwards.
    They are then discharged continuously out of a treated water outflow pipe (③).
  • The water level of the flotation tank is controlled with a flow control valve (⑨) suitable for scum control.
  • Silt or something dense moves to an outer position on the flotation tank by centrifugal force. It settles down to the conical bottom and then evacuates to the outside periodically (⑤).
3. A suspended material removal process by the HELIFLOT™
Simple and high efficiency
4. Applicable wide range of contaminated water treatment
From very low concentrations of algae water to high concentrations of settled sludge:
Algae Water Treatment
Sludge Concentration
5. Comparison with HELIFLOT™ to the conventional DAF
Comparison with HELIFLOT™ to the conventional DAF
Conventional DAF HELIFLOT™
• More complex facilities required:
  – Scum skimmer, subnatant remover and (settling lamella plates) needed.
• Weak on load fluctuation

• Unsuitable for treating high silt-laden water.

• Compact facilities required:
  – Detention time(min):
    Floating: 10 ~ 20.
    Conglomeration: 14 ~ 20.
• Chemical consumption(ppm):
  – Organics: 5 ~ 10
  – Inorganics: 10 ~ 30
    (normally both chemical required)
• Consumes more electric power:
   (1,000 ~ 1,200 kWh/5Ⅹ10³㎥·d)
• Simplified facilities:
  – No scum skimmer, subnatant remover or settling lamella plates needed.
• Stable on wide range of load fluctuation
   (even low flow rate or high solid content)
• Capable for treating high silt-laden water.

• More compact facilities required
  – Detention time(min):
    Floating : 8 ~ 10.
    Conglomeration : 4 ~ 8.
• Chemical consumption(ppm):
  – Organics: 0.5 ~ 2
  – Inorganics: 2 ~ 10
    (available only one chemical used)
• Consumes less electric power:
   (900 ~ 1,000 kWh/5Ⅹ10³㎥·d)
6. Applications of HELIFLOT™:
  • Tap water treatment (for pre-treatment, particularly for microalgae and cyanobacteria removal in replacement of a flocculation and sedimentation process).
  • Sewage and wastewater treatment (for pre-treatment or sludge thickening).
  • Industrial processes (for recovery of valuable effluences).
Removed scum
7. Standard Specifications
Standard Specifications
HLF 250 HLF 500 HLF 1000 HLF 5000 HLF 10000
Treatment rate (㎥/day) 250 500 1000 5000 10000
Flotation tank volume (㎥) 2.2 4.2 8.2 40 77
Conglomeration tank volume (㎥) 2.2 4.2 8.2 40 77
Ground required (㎡) 10 15 25 70 100

* Depending on the suspended solids in the water, the size of the conglomeration tank may be reduced or omitted.

8. Examples of the HELIFLOT™:
2,400㎥ /day
16,000㎥ /day