In high-efficiency dissolved air flotation machines treating industrial wastewater, precise control of dissolved air volume is crucial for ensuring treatment effectiveness and operational efficiency. The dissolved air volume directly affects the number, size, and uniformity of microbubbles generated, thus determining the adhesion efficiency between pollutants and bubbles, and the solid-liquid separation effect. Its control requires comprehensive implementation from multiple dimensions, including selection of the dissolved air method, control of dissolved air pressure, setting of the reflux ratio, optimization of the dissolved air tank design, selection of the release device, water quality monitoring, and automated control.
The selection of the dissolved air method must be based on the characteristics of the wastewater and the treatment requirements. Pressurized dissolved air flotation uses a dissolved air pump to pressurize and dissolve air in water, then depressurizes it through a release device to form microbubbles; this method is suitable for treating large volumes of wastewater with high suspended solids concentrations. Vacuum dissolved air flotation utilizes a vacuum system to draw in air; it has lower energy consumption but requires strict control of the vacuum level and dissolved air time. In practical applications, the most suitable dissolved air method must be selected based on the wastewater composition, treatment scale, and cost requirements.
Dissolved air pressure is a key parameter for controlling the dissolved air volume. Low pressure leads to insufficient air solubility and reduced microbubble generation; high pressure may cause bubble coalescence, increasing the proportion of ineffective bubbles, while also increasing energy consumption and equipment wear. Generally, the dissolved air pressure needs to be set within a reasonable range based on the wastewater properties and treatment objectives, and monitored in real time by pressure sensors, dynamically adjusted by an automatic control system to ensure stable dissolved air volume.
The reflux ratio directly affects the dissolved air water generation efficiency. A reflux ratio that is too small results in insufficient dissolved air water and reduced microbubble generation; a reflux ratio that is too large may increase equipment load and energy consumption, while also causing unstable water flow in the tank, affecting effluent quality. In practice, the optimal reflux ratio needs to be determined through experiments, and the reflux ratio parameter should be adjusted periodically based on water quality changes and treatment effects.
Optimized design of the dissolved air tank is crucial for dissolved air volume control. The dissolved air tank needs sufficient volume and a reasonable structure to ensure thorough mixing and dissolution of air and water. The tank can be equipped with baffles, baffles, or packing to enhance turbulence, promote water-air contact, and improve dissolved air efficiency. Meanwhile, the inlet and outlet valves of the dissolved air flotation tank must be fully open to avoid damming and premature bubble release, which would affect the dissolved air effect.
The selection and arrangement of the release device directly affects the quality of microbubble generation. High-efficiency dissolved air flotation machines require release devices capable of generating uniform microbubbles, such as perforated plates, microporous tubes, or dedicated release heads, and the release device positions should be reasonably arranged to ensure uniform distribution of dissolved air and water. The release device needs to be checked and cleaned regularly to prevent clogging, which could lead to abnormal bubble generation and affect the treatment effect.
Water quality monitoring is the foundation of dissolved air volume control. Parameters such as suspended solids concentration, oil content, pH value, and temperature in the wastewater need to be monitored regularly, and the dissolved air volume, coagulant dosage, and reflux ratio adjusted according to changes in water quality. For example, when the suspended solids concentration increases, the dissolved air volume and coagulant dosage need to be appropriately increased to enhance the adhesion efficiency between microbubbles and pollutants.
The application of automated control technology can significantly improve the accuracy of dissolved air volume control. The high-efficiency dissolved air flotation machine can be equipped with a PLC automatic control system, integrating pressure sensors, flow meters, level gauges, and other devices to monitor key parameters such as dissolved air tank pressure, dissolved air volume, and reflux ratio in real time, and automatically adjust the equipment's operating status according to preset programs. Through intelligent control, dynamic optimization of dissolved air volume can be achieved, reducing the need for manual intervention and improving operational stability and processing efficiency.
