Dissolved Air Flotation (DAF) is the process of removing suspended solids, oils and other contaminants via the use of air bubble flotation. Air is dissolved into water, mixed with the waste stream and released from solution while in contact with the contaminants. Air bubbles form, attach to the solids, increase their buoyancy and float the solids to the water's surface. Air is injected under pressure into a recycle stream of clarified DAF effluent. This recycle stream is then combined and mixed with incoming wastewater in an internal contact chamber where dissolved air comes out of solution in the form of very fine bubbles that attach to the contaminants. The bubbles and the contaminants rise to the surface and form a floating bed of material that is removed by a surface skimmer into an internal hopper for further handling.
Dissolved Air Flotation Systems are designed to remove fats, oils & grease (FOG), suspended solids (TSS), biological oxygen demand (BOD), food/animal production/processing wastes, industrial wastes, hydrocarbon oils/emulsions and many other contaminants. Chemical pre-treatment can often help to improve the performance of the DAF system.
It is a proven and effective physical/chemical technology for treating a variety of industrial process and wastewater streams, including those from food processors, and biological wastewater treatment systems.
The DAF systems have been developed over the last ten years of basic research and have been installed in a variety of industries. These systems provide basic features not found with other DAF systems:
• Different units to meet a variety of applications and flow ranges
• Skid-mounted design
• Reliable, conservative design for assured treatment performance
• Rectangular profile for maximum space utilization
• High quality stainless steel or epoxy-coated carbon steel construction
• Quality drive and pump components for long-term reliability
• Multi-step quality control program
• Full construction an component warranties
• Expert technical support before and after installation
The DAF systems are available with number of options to provide a complete pretreatment system:
• Advanced control panels including programmable logic controllers (PLCs), variable frequency
drives (VFDs), and multi-line operator interfaces
• Reliable monitoring and control systems for process pH and flow
• Packaged polymer make-up and feed systems including mixing tanks, mixers, and dosing pumps
• Flocculation tubes and tanks for influent conditioning prior to flotation
• Skimming handling packages including level control, transfer pumps, and storage tanks
• Non-clogging, stainless steel plate-pack to enhance laminar flow and increase usable DAF surface