WPL Dissolved Air Flotation (DAF)

The WPL Dissolved Air Flotation (DAF) wastewater treatment plant is typically used in a wide range of industrial applications to mitigate the financial impact of trade effluent charges and maintain environmental compliance.

The WPL DAF wastewater treatment system is widely used for the reduction of Chemical Oxygen Demand (COD) present in fats, oils and greases, colour, organic matter, biological sludges and colloidal material. The WPL DAF process has also been successfully applied to sensitive industrial applications, such as petrochemical, chemical production, pharmaceutical and paper production and is ideal for new projects and existing plant upgrades.

As shown on the table below up to 90% of COD and suspended solids can be removed with a DAF process. The table gives removal efficiencies that can be achieved for different applications.

As shown below up to 90% of COD and suspended solids can be removed with a DAF process. The table below gives removal efficiencies that can be achieved for different applications

Note: The table above is subject to wastewater constituents, temperature and competence of operators.


Why you should choose the WPL Dissolved Air Floatation (DAF):

  • Performance – up to three times more efficient than gravity settlement processes and with a higher quality effluent discharged to sewer further reducing costs.
  • Modular – fully integrated treatment package for adaptation in to existing process streams.
  • Adaptable – various chemical injection and sampling points, manufactured to customer requirements.
  • Robust – constructed in grade 304 or 316 stainless steel, with flocculation and coagulation units manufactured in MDPE to ensure an extended life.
  • Reduced operational input – fully automated control system, removes the need for manual operation.
  • Compliant – CE marked and built to European norms.
  • Small footprint – only requires a small footprint in comparison to other technologies.
  • Transportable – comes complete with options for access and portability.
  • Low maintenance – reinforced plastic components reduce corrosion.

    Hire and trial options are also available.

Typical WPL DAF industrial wastewater applications include:

The WPL DAF system is ideal for:

  • New projects
  • Existing plant upgrades
  • Replacement plants

WPL DAF System Specification Information

Image of technical drawing of DAF (Dissolved Aerated Flotation System)

Image of DAF (Dissolved Aerated Flotation System) specification table for industrial wastewater treatment used most efficiently for minimising sludge waste from activated sludge

Larger WPL DAF units can be bespoke manufactured on request

How does a Dissolved Air Floatation (DAF) system work

The WPL Dissolved Air Flotation system is a purely physical process which operates on a simple design philosophy. Incoming effluent may require pre-treatment as necessary; for example the addition of chemical coagulant(s) and/or flocculant(s) may be required with associated mixing and coagulation/flocculation stages. Adjustment of pH may also be necessary to ensure optimum operating conditions.

The incoming effluent enters the flotation vessel where it comes into contact with recycled, treated effluent (sometimes termed white water). The percentage of the total effluent flow into which air is dissolved under pressure and subsequently recycled will be determined by several factors. Increasing the pressure within the vessel where the air is being dissolved ensures that a higher concentration of air dissolves into the liquid phase than is possible at atmospheric pressure.

Once this saturated effluent enters the flotation tank, the pressure is released back to atmospheric pressure. This immediately results in the recycled flow becoming supersaturated, generating micro bubbles as the dissolved air comes back out of solution.

These bubbles attach to, and form within the solids or chemical flocculants entering the vessel; causing them to float to the surface where they are retained and subsequently removed by a mechanical skimmer.

Within the rectangular flotation tank, the skimmer mechanism consists of a series of paddles or flights which run on a plastic corrosion-resistant chain, and skim just below the surface of the tank removing the float into a trough for recovery of the sludge. To eliminate the risk of sludge build-up on the flotation tank floor, the design may also incorporate a floor scraper.


Why industrial wastewater treatment is as challenging as it is varied?

Simon Kimber discusses why industrial wastewater is as challenging as it is varied, which is why careful assessment and customised solutions are required.

Industrial processes can produce effluents that are challenging in terms of their strength, variability and composition. Careful assessment of the physical, chemical and biological characteristics of the load can deliver a cost-effective and efficient treatment process.

Read full article

Image of WPL dissolved air flotation DAF wastewater treatment tank with engineer