DAF is a method for separating a liquid or solid from a wastewater. The driving force behind DAF is the micron-sized bubbles, which are generated by dissolving a gas into a liquid under pressure.

The principal behind DAF is based on Henry's Law, which states that the amount of dissolved gas in the liquid is directly proportional to pressure and inversely proportional to temperature.

Henry's Law illustrates how pressure and temperature affect the dissolution process as it relates to air disolving pumps. As stated by Henry's Law, the amount of gas is directly proportional to pressure, meaning that the higher the pumps pressure the greater amount of gas that can be dissolved into a solution.