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

  • Optimised chemistry, using our own in-house experts and laboratory.
  • Energy efficient treatment of wastewater.
  • Higher quality effluent discharged to sewer, further reducing costs.
  • Reduced sludge volume with higher dry solids content.
  • Can be used for recovery and recycling of non-emulsified oils with no further treatment required.

 

Modular

  • Fully integrated treatment package for adaptation into existing process streams.
  • Multiple systems installed in parallel for higher or variable flows.
  • Discreet independent modules for each element of the process train.
  • Transportable and fitted on site with a ‘plug and play’ approach to design, with options for access and portability.
  • Full dosing packages to compliment DAF performance if required.

 

Chemical

  • Multiple chemical injection and sampling points, manufactured to customer requirements.
  • Chemical dosing regime designed by WPL to meet the site requirements.

 

Compliant

  • CE marked.
  • Built to European norms.

 

Robust

  • Constructed in grade 304 or 316 stainless steel, with flocculation and coagulation units manufactured in MDPE to ensure an extended life and reduce risks of corrosion.
  • Manufactured to the highest European norms.

 

Reduced operational input

  • Fully automated control system, removes the need for manual operation.
  • Can be integrated with site BMS (building management systems).
  • Full integrated monitoring of final discharge to sewer or further treatment.

 

Low maintenance

  • Reinforced plastic components reduce wear and corrosion.
  • White water system utilises a pressure vessel to negate the need for diffusers within the floatation tank.

 

Small footprint

  • Only requires a small footprint in comparison to other technologies.

 

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 can be used as a purely physical process for the separation of readily separable contaminants, operating based on a simple design philosophy. Incoming effluent may require the addition of chemical coagulant(s) and/or flocculant(s) to enhance the separation of colloidal, emulsified or suspended contaminants. Adjustment of pH may also be necessary to ensure optimum operating conditions and consent compliance.

The incoming effluent enters the flotation vessel after chemical addition (if required) where it mixes with a small stream of recycled or treated effluent that has passed through a pressure vessel. It then goes on to mix with air creating an air saturated water phase. 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 supersaturated water phase releasing air and generating micro bubbles, commonly known as white water.

These bubbles attach to the free particulate or the flocs created by the chemical addition 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. The flights can be timed to operate intermittently increasing the sludge dry solids content depending on what is required.  To eliminate the risk of sludge build-up on the flotation tank floor, the hopper bottom can be manually emptied via a valve or timed to discharge via an actuated system.


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