PCL-Series Plate Pack Dissolved Air Flotation Systems
Dissolved Air Flotation systems effectively remove TSS, FOG, and other pollutants from wastewater. Conceptually, the DAF process is simple – tiny bubbles attach to solid contaminants causing them to float and then sludge is skimmed off the surface of the water – but designing a DAF system for a real-world application isn’t quite as simple.
FRC Systems, a JWC Environmental brand, has removed layers of complexity from DAF system design by engineering units for specific applications and flow ranges. That means the DAF used for a soap manufacturing facility is not the same one used for a vegetable processing plant. Each process has its own unique challenges, so each receives its own unique solution. That’s the engineered approach FRC takes for all DAF process and equipment design.
How Dissolved Air Flotation Systems (DAF) Work
Wastewater is fed into a DAF system and hit with a stream of “whitewater”, which is recirculated clarified water from the DAF that’s super saturated with dissolved air. As these two mixtures blend together, microscopic bubbles attach to solid particulates, giving them enough buoyancy to surface in the DAF tank.
As solids accumulate in a floating layer on the top of the DAF tank, a skimmer gently nudges the sludge toward a discharge hopper.
Any solids that don’t float will sink to the “V” bottom of the DAF tank. Settled solids are concentrated and discharged by an automatically controlled pneumatic drain valve.
The clarified water flows out via an under-over weir on either side of the DAF unit. Some of this water is used in the recirculation loop while the rest flows out of the vessel.
Cross-Flow Plate Pack
PCL Dissolved Air Flotation systems are characterized by high-built (tall) tanks with inclined, corrugated plate packs.
Water is introduced into the plate packs in a cross-flow configuration, reducing the distance solids have to float to be effectively separated. As they collide with an angled plate, light solids accelerate upward and heavy particles settle.
Wastewater enters the plate pack heavily laden with flocculated contaminants and exits devoid of suspended and colloidal solids.
Sludge Dewatering Grid
The Dewatering Grid is a rectangular framework of angular steel plates that lock sludge in place as it rises to the surface. Only when sludge has thickened enough to rise above the top edge of the grid can it be skimmed and pushed to the float hopper.
The grid helps:
- Eliminate pre-mature migration of solids
- Reduce shearing and re-entrainment of solids
- Generate drier sludge
Angled Air Dissolving Tube
Where many DAF system manufacturers use a mechanical means to dissolve air into water, i.e. a specialty “whitewater pump,” FRC prefers a more efficient and cost-effective approach.
FRC’s ANSI recycle pump doesn’t do any air dissolving – it just pumps water. That means we can provide higher solids tolerances, use stronger pump materials, operate at lower pressures, and do it at a cost much lower than possible with a specialty whitewater pump.
The air dissolving tube is where whitewater is generated. This short expansion in the recirculation piping allows clarified effluent and a small volume of compressed air to mix until saturation is achieved. The angled configuration allows for increased water and air interface so saturation occurs almost instantly.
This design works so well that we’re constantly retrofitting competitors whitewater pumps with our upgraded aeration system.
The JWC team knows that things happen in wastewater – sometimes without warning. Fortunately we are ready to support you with a plan. For your industrial wastewater needs we can provide DAF rental systems for to help bridge maintenance periods, emergencies or plant expansions. We have a fleet of FRC dissolved gas flotation, dissolved air flotation rental systems as well as belt filter presses that are ready to be deployed to your site. Learn more about DAF rentals here.
- Efficiently removes suspended solids and other pollutants from wastewater
- Designed for specific application reducing complexity and simplifying operations
- Eliminates pre-mature migration of solids
- Reduces shearing and re-entrainment of solids
- Generates drier sludge
- Flow Rates range from 24 to 1,980 gpm
- Free Surface Area ranges from 5.5 to 151 sq. ft.