Follow this link "Dissolved Air Flotation Separator Design Parameters" for information on the accurate design and sizing of Dissolved Air Flotation Separators and Flotation Systems
HydroFlo Tech' FloatPac™ series of dissolved air flotation systems, or "DAF", is an effective, economical process for removing hard to separate suspended solids from wastewater and also for resolving overall water clarity issues.
By the addition of our inclined plate pack technology to our dissolved air flotation (DAF) systems, we are able to achieve exceptional results in a compact, high efficiency floatation system.
The FloatPac™ series of dissolved air floatation systems resolves suspended solids and clarity issues by reintroducing a slip stream of treated water (from the system's effluent) back to the system's influent. This pressurized, recycled water is saturated with dissolved air. When the pressure is released at the system's influent, the air comes out of solution on the surface of suspended solids particles throughout the dissolved air flotation (DAF) influent mixing chamber. As these billions of micro bubbles come out of solution, they float the suspended solids particle to the surface of the dissolved air flotation (DAF) separation chamber, where they are removed by a surface skimmer.
• Standard Engineering
The Hydro-Flo DAF recirculation system is a micro bubble generator. A key factor for maximizing the efficiencies of a DAF is the generation of equally sized micro bubbles. These bubbles, ranging from 20 to 50 microns in diameter, will give the suspended solids an equal and steady rise rate of 10 to 12 inches per minute, to the tank surface.
Our recirculation system is designed to completely saturate the recycle stream with air. By properly sizing our system (atomized water surface area, air dissolving rate, etc.) we can dissolve the maximum amount of air, physically possible, into the recycled water.
When the re-circulated flow reaches the DAF's influent, it passes through a pressure release valve where it is released into the tank and allowed to return to normal atmospheric pressure. Fine micron bubbles spontaneously boil out of the recycled water solution.
As stated above, these billions of fine micron bubbles attach themselves to the suspended water particles in the wastewater, causing them to float to the tank surface where they form a firm surface sludge mat.
HydroFlo Tech manufactures complete dissolved air flotation (DAF) systems with recycle/air diffusion system including recycle pump, air saturation vessel and related controls. The DAF is sized to provide a surface loading rate equal to 1.5 lbs/ft2/hour of TSS and FOG combined. The HydroFlo dissolved air flotation system is designed to separate floatable particles of oil or solids by floating them to the surface with air bubbles. Our DAF system incorporates a high efficiency, high pressure air to water saturation contact recycle tank system, and a DAF separation cell with surface skimmer. The air bubbles form at the release of pressure and intimately contact the raw, incoming wastewater with a specially designed reaction nozzle system that promotes air bubble impingement with raw incoming wastewater particles and the forming air bubbles. The surface flight skimmer assembly drags the floated material to the skimming beach and into the float chamber.
The basic system is comprised of a separation cell, recycle / air dissolving system and related controls.
DAF Separation Cell:
The DAF separation cell is designed using elements of American Petroleum Institute's publication 421 Feb. 1990, “Design of Oil-Water Separators” to ensure the best possible use of particle rise rate performance. The addition of the FloatPac™ inclined plate greatly increases the efficiency of the separation cell by increasing the units effective surface area. The separation cell is fabricated with a “V” bottom. The DAF cell is typically manufactured from carbon steel, but other materials of construction are available as an option.
DAF Flotation Tank Surface Skimmer:
HydroFlo provides a removable float skimming system with frame assembly and drive motor, sprockets, chains and full width stainless steel skimming blades. The skimmer blades are mounted on swivel pins that are fastened to the skimmer chains, which maintain the blades in a down position at all times. The conveyer chains are provided with drive sprockets on a full width shaft at the drive end and four independent idler sprockets at the return end. The skimmer system frame comes equipped with a sprocket tension adjustment device and the carrying and return tracks for the chain. The entire system is self supporting with side and end channels, and cross members with lifting lugs that permit removal of the skimmer assembly as a complete unit for easy cleaning and service. The skimmer drive system comes with a hollow shaft, maintenance free gear reducer. The skimmer system can be made vapor tight with the addition of optional cover panel.
Recycle / Air Dissolving System (RAD):
The HydroFlo dissolved air flotation system comes standard with a recycle water air dissolving system rated at 50% of the DAF design flow, providing an air to solids ratio (A/S) of between 0.015 and 0.040 lbs air/lbs. solids. Standard models are designed for 100 psi, 100 degree F. The air dissolution tank is fitted with an internal water cascading nozzle system to ensure efficient mass transfer and air/water contact. The tank is provided with an independent safety pressure relief valve and pressure gauge. The air dissolution tank is provided with an external, clear sight tube with water/air interface level float sensor system for automatic water/air level control. Manual flow control valves are provided for balancing the recycle rate, for the rate control of the air addition, the saturated recycle rate to the DAF inlet reaction jet, and the pump by-pass flow volume.
Bottom Sludge Auger (Optional):
As an option the DAF can be provided with a ribbon flight auger made from 304 stainless steel. The auger has converging flights to gently move settled sludge toward the sludge outlet nozzle, and is driven at 3-5 RPM by an industrial duty TEFC motor with gear box speed reduction.
All HydroFlo dissolved air flotation systems are fully automated. Control packages (depending on your specific requirements) are available in either basic relay logic control, or a fully state of the art PLC with touch screen HMI and our sophisticated treatment algorithms. The relay logic controls package allow basic reconfiguration of the original system settings, while the PLC based package allows maximum flexibility to change the process parameters, as well as tight control that minimizes chemical usage. We can include a variety of options including digital data logging of critical process parameters, Ethernet access to process data, communication with Building Management Systems, and even remote system access using cellular wireless technology.
All enclosures are NEMA 4X. Where metallic enclosures are used, they are provided with epoxy or polyester finishes for corrosion resistance. All conduit is plastic coated, where possible. Low voltage 24VDC is used throughout to minimize service personnel exposure to high voltage. All panels are OSHA LOTO and NFPA 79 compliant. UL-508 listing is available.
Effluent Monitoring: As mandated by the local controlling authority, the effluent quality must be continuously monitored. A two pen recorder is to be used to monitor effluent flow rate and pH. The recorder is to be equipped with a flow totalizer. Any effluent pH deviations will trigger an alarm and system discharge will be halted.
The system is supplied as a completely fabricated "turnkey" package. All devices are pre-wired and plumbed.
You need to make the plumbing connections to and from the system and a single electrical connection point for incoming power. The disconnect on the MCP provides OSHA Lock Out / Tag Out and NFPA 79 compliance. Systems requiring compressed air require only one connection, and the valve is supplied for OSHA LOTO.