What factors affect the efficiency of dissolved air flotation devices

The nature of suspended particles in the water matters greatly. Particles with low density and small size are harder to attach to microbubbles, reducing separation efficiency.

Surface charge of particles also plays a role, as particles with similar charges repel each other, preventing aggregation and making bubble-particle adhesion difficult.

Water temperature affects both the solubility of air in water and the activity of particles. Lower temperatures increase air solubility but may slow particle movement, while higher temperatures can reduce air retention time in water.

Coagulants and flocculants are often added to enhance particle aggregation. The type of chemical agent must match the water quality; using an inappropriate agent can lead to ineffective floc formation or even destabilize the particles.

The dosage of the chemical is also crucial, as insufficient dosage fails to form large enough flocs, and excessive dosage may cause re-stabilization of particles or increase operational costs.

The air dissolution pressure determines the amount of air dissolved in the water. Too low pressure results in insufficient microbubbles, while excessive pressure may lead to bubble coalescence into larger bubbles, which rise too quickly and reduce contact time with particles.

The recirculation ratio of the water affects the concentration of microbubbles. An improper ratio can either decrease the number of bubbles or disrupt the flow field in the flotation tank.

The hydraulic retention time in the tank is essential; insufficient time limits the contact between bubbles and particles, while excessive time may cause settled flocs to re-suspend.

The structure of the air dissolving tank affects the air-water mixing effect. Poor mixing leads to uneven air dissolution.

The layout of the bubble release device determines the distribution of microbubbles in the flotation tank. Uneven bubble distribution results in local areas with insufficient separation capacity.

The shape and size of the flotation tank also matter, as an unreasonable design can cause dead zones or turbulent flows, reducing the separation efficiency.