Dissolved Air Flotation (DAF)

What is a DAF?

DAF stands for Dissolved Air Flotation. A DAF unit is a type of clarifier.  But instead of gravity settling as in a traditional clarifier the DAF uses microscopic bubbles that attach to the floc and cause it to float. The standard DAF will have a surface rake that collects the floating floc from the floatation chamber into a sludge holding tank. From the sludge holding tank the sludge can be de-watered in a de-watering box, filter press or belt press. The treated water is often of sufficient quality to be discharged directly from the DAF to the sewer outfall.

When is a DAF used?

DAFs are commonly used when the produced floc is lite and either floats or does not settle well — as is the case when treating oily waste water.