Dissolved Air Flotation – Industrial

The HyDAF V Range is a high-performance Dissolved Air Flotation (DAF) system specifically designed for wastewater containing high levels of settleable solids. It is particularly suited for meat processing plants and industries where grit and sand are present. The key distinguishing feature of the V Range is its deep conical base, which is fitted with an integrated screw conveyor. This design enables efficient removal of settled solids, which can be discharged periodically via a pump or gravity, minimising manual cleaning requirements and ensuring continuous operation.

Due to its steep-sided conical design, the HyDAF V Range is significantly taller than standard HyDAF units, requiring platforms for access. While the increased depth adds to manufacturing costs, these are typically offset by the substantial reduction in downtime for cleaning and maintenance.

The dosing of chemicals upstream of the HyDAF Dissolved Air Flotation (DAF) system can significantly enhance its performance by improving the separation of solids, fats, oils, and grease. It is not uncommon in the HyDAF system to achieve >95% reduction in suspended solids and grease levels by utilising an appropriate chemical program. However, whether chemical dosing is necessary depends on the quality of treated water required and the specific characteristics of the wastewater. In some cases, particularly where wastewater has a high concentration of emulsified oils, fine suspended solids, or dissolved contaminants, chemical treatment is essential to achieve the desired clarity.

Hydroflux specialises in tailored chemical treatment programs that optimise the performance of the HyDAF Dissolved Air Flotation system while ensuring cost efficiency and minimal sludge generation. The selection of chemicals (such as coagulants and flocculants) is based on wastewater composition, treatment objectives, and operational constraints. By carefully designing the dosing strategy, Hydroflux helps clients maximise separation efficiency, reduce chemical consumption, and minimise sludge disposal costs. For more information on chemical solutions and how they can enhance your treatment process, please click here to visit the Hydroflux Utilities website.

In applications without chemical treatment, the HyDAF Dissolved Air Flotation system can operate effectively across a wide range of flows and solids concentrations, as long as they remain within the system’s design capacity. The system is designed to accept whatever flow it receives and continuously remove suspended solids, fats, oils, and grease, ensuring stable performance without the need for adjustments.

When chemical dosing such as coagulants and flocculants are introduced to enhance solid separation, the system becomes more sensitive to flow rate and contaminant load variations. These fluctuations can impact chemical reaction times and floc formation, leading to inconsistent treatment efficiency. However, depending on the waste stream, it is possible to flow-pace the chemical dosing system using an automated solids or turbidity monitoring system. This approach adjusts the chemical dosing program in real-time, accommodating fluctuations and improving treatment reliability. A more common solution is to install an upstream balance tank, which regulates flow and solids concentration before entering the HyDAF Dissolved Air Flotation unit. This ensures a steady feed rate, optimising chemical dosing efficiency and delivering more consistent wastewater treatment performance.

The dissolved air stream in the HyDAF system is sized based on key parameters to ensure efficient separation of solids, fats, oils, and grease. The primary factors include wastewater characteristics, flow rate, and air-to-solids ratio (A/S ratio).

Higher concentrations of suspended solids or grease require a greater volume of dissolved air to ensure effective flotation. The A/S ratio, typically ranging from 0.01 to 0.05 kg air/kg solids, is carefully calculated to introduce enough microbubbles for efficient solid separation without creating excess turbulence. Additionally, the operating pressure of the air saturation vessel plays a crucial role—higher pressures allow more air to dissolve, improving flotation efficiency but can also increase power consumption.

The dissolved air recycle flow is proportional to amount to dissolved air required and the dissolved air flow affects the surface loading rate. This is why for high solids loading applications where large recycle flows are required, a larger DAF with a greater surface area is necessary to ensure that the surface loading rate remains within the design parameters.

By optimising these factors, the HyDAF system will always achieve high treatment efficiency, energy savings, and reliable performance.

The FlooDAF® Range is a series of Dissolved Air Flotation (DAF) systems developed by Hydroflux’s international partner, Flootech. While the principles of flotation and dissolved air production are similar to the HyDAF, the FlooDAF features a unique design with shallow sidewalls and an alternative sludge removal system. This design allows the units to be fabricated wider and assembled on-site, rather than being delivered as a prefabricated unit, which provides flexibility for larger-scale installations and enables the system to accommodate significantly greater flow capacities in a single unit.

In all applications, Flootech supplies the designs and core equipment, while Hydroflux integrates the design, ensuring the system is specifically tailored to meet unique requirements. Hydroflux also takes full responsibility for the construction and performance of the system, ensuring it adheres to local standards and meets performance expectations. This partnership enables Hydroflux to offer customised solutions that provide the flexibility needed to handle very large flows in a single, efficient unit.

In HyDAF systems, the entire system is typically constructed using 304 stainless steel, providing good resistance to corrosion and ensuring long-term durability in a wide range of wastewater treatment applications. For components that may be exposed to more aggressive chemicals or harsher environments, 316 stainless steel is used due to its superior corrosion resistance, particularly in areas such as the air saturation vessels and internal flotation components.

For larger-scale HyDAF installations, concrete is sometimes used for outer tank structures, offering cost-efficiency.