HUBER Dissolved Air Flotation Plant HDF Effective and efficient wastewater purification and treatment for industrial applications through flotation with micro bubbles
Versatile wastewater treatment for numerous industrial applications
- Compact and modular design for throughputs up to 300 m³/h
- Simple, reliable saturation system using a multiphase pump
- Low space requirement due to an integrated lamella separator
- Suitable for the pre-treatment of industrial wastewater or secondary treatment of municipal wastewater
- Very high reduction rates for COD, solids and phosphate
- Combined with a DIGIT-DOSE Chemicals Dosing system up to 30% less operating costs
Principle of Flotation:
During dissolved air flotation, very fine gas bubbles of 20 ‒ 40 μm are released, which together with the particles present in the wastewater, form an agglomerate.
This agglomerate has a lower density than water and rises to the water surface. Nonflotatable particles are separated via conical selection chambers. The particle-free clear water passes through an immersion wall and is then available for further use.
If a tube flocculator is installed upstream of the flotation plant, so-called precipitants and flocculants can be added, which improve the clarification performance accordingly.
Functional description of the HUBER Dissolved Air Flotation Plant HDF
The (waste) water to be treated enters the flotation plant via the tube feeder (1) and is directly mixed with the released pressure water (white water). The micro bubbles (20 ‒ 40 μm dia.) generated when the pressure is suddenly released are brought into close contact with the suspended material in a tube feeder (special pipe-in-pipe system) (14).
The gas bubbles attach to the surface of solids. Due to their increased buoyancy, the light aggregates of solids and air bubbles float to the water surface. The blended influent flows upward into the tank of the dissolved air flotation unit where it is evenly distributed over the total tank width. The laminar flow conditions ensure optimum phase separation.
The solids/gas flocs rise to the water surface where they form a scum (or flotate) layer that is skimmed off into the flotate hopper (3) by a scraper (2). The scraper joists with their special design dewater the flotate additionally. The flotate is either collected in a container or by an eccentric screw pump delivered to further treatment stages (e.g. sludge dewatering with HUBER Screw Press Q-PRESS) (15).
The non-clogging lamella separator (5) increases the effective clarifier area, for maximum hydraulic loads on a small footprint. While the water flows down through the gaps between the inclined lamella plates, buoying flocs rise a short distance and attach at the lower surface of the upper lamella and dense particles sink a short distance to the upper surface of the lower lamella.
The lamellae retain thin layers until they are grown into thick and compact layers that finally detach from the surface and slide quickly up or down along the lamella surface. Detached light aggregates slide up and rise to the water surface where they form a floating scum layer. Heavy sludge aggregates slide and sink down to the bottom of the tank into the sediment hopper (6) from where they are either removed by an eccentric screw pump or gravity discharged by means of a pneumatically controlled valve.
The clarified waterwater flows behind the baffle plate (7) to an effluent box (8) from where the water falls over a height-adjustable weir into the clarified water outlet (9).
Up to 30 % of the effluent is recirculated for the generation of pressure water. A multi-stage centrifugal pump (10) generates a pressure of about 6 bar. In this process, air is introduced into the pump impeller housing and intensively mixed with the water. This pressurized water flows through the pressurized water line (12) to the pressure relief valve of the tank.
There, the micro bubbles with a diameter of 20 to 40 microns are generated through pressure relief (13) to ambient pressure. In the tube feeder (14), the micro bubbles thoroughly blend with the influent to be treated so that all solids get in close contact with a sufficient number of micro bubbles.
Increased separation efficiency through pre-treatment in a chemical treatment stage
- Individual project-specific tube flocculator for optimal chemicals dosing
- Ideal admixture of chemicals due to a flow-optimised design
- Compact unit directly beside the HUBER Dissolved Air Flotation Plant HDF
- Accommodating individual preferences for sampling / dosing points / measurement instrumentation
- Optional integration of the innovative HUBER Chemicals Dosing DIGIT-DOSE for an automatically optimal chemicals dose in real time.
Applications of Dissolved Air Flotation
HUBER Dissolved Air Flotation Plant HDF units are used for a wide variety of industrial and municipal applications, such as:
- Slaughter houses
- Meat processing and packing
- Fish processing
- Dairies
- Convenience food production
- Gastronomy
- Disposal companies
- Soap works
- Land remediation
- Chemical industry
- Petro chemical industry
- Iron and steel industry
- Leather & textile industry
- Cosmetics industry
- Galvanizing, electroplating
- Municipal wastewater treatment
- Activated sludge separation
- Phosphate after treatment plants
- Rendering plants
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