What are Key Considerations for the Daily Operation of DAF System

Solid Liquid Separator September 15, 2025 Dissolved Air Flotation

Water Level in the Saturation Tank of DAF System:
During inspection, check the water level in the saturation tank through the observation port. Ensure the level is not so high that it submerges the packing layer (which would reduce air dissolution efficiency), and not lower than 0.6 m (to prevent excessive undissolved air in the effluent).
Surface Condition of the Tank:
During inspection, observe the surface of the flotation tank. If the scum layer in the contact zone is uneven or local turbulence is observed, it may indicate that some releasers are clogged or detached, requiring timely maintenance or replacement. If the scum layer in the separation zone appears flat but large bubbles frequently emerge, it suggests poor adhesion between bubbles and floc particles, requiring adjustment of chemical dosage or a change in coagulant type.
Operation in Winter Conditions:

In winter, low water temperature reduces coagulation efficiency. In addition to increasing the chemical dosage, efficiency can also be improved by increasing the recycle flow or raising the dissolved air pressure to generate more microbubbles and enhance their attachment to floc particles. This compensates for reduced flotation performance caused by higher water viscosity, thereby maintaining effluent quality.
Sludge Skimming:
To avoid compromising effluent quality, the water level in the tank must be raised during sludge skimming. Operators should accumulate operational experience to determine the optimal thickness and moisture content of the scum layer. Regularly operate the skimmer to remove accumulated sludge and establish a sludge skimming schedule suited to actual conditions.
Chemical Dosing Adjustment:
Based on changes in the flocculation process in the reaction tank, the scum layer in the separation zone, and effluent quality, adjust the coagulant dosage in a timely manner. Frequently check the dosing pipelines to prevent blockages, particularly during winter.