Method and apparatus for dissolved air flotation with aeration

A method for aeration of wastewater exterior to a flotation container as part of a wastewater treatment system where the flotation and settling of particles occurs, comprising the steps of:

• withdrawing wastewater from the flotation container where the flotation and settling of particles occurs;
• pumping the wastewater from the flotation container into the top of a pressure tank above the wastewater level;
• pressurizing from an external source of compressed air said pressure tank to a predetermined pressure to provide continuous flow of wastewater to maximize the entrainment of air in the water;
• applying pressurized air from the pressure tank to each of a plurality of external aeration means;
• regulating the flow of pressurized air through the external aeration means;
• pumping the pressurized wastewater from the bottom of the pressure tank through each of the plurality of said external aeration means in the form of a high-pressure stream;
• injecting the regulated pressurized air from said pressure tank into the high-pressure stream of wastewater in each of the plurality of the external aeration means to entrain the air therein to aerate said wastewater;
• returning the aerated wastewater from each of the plurality of the external aeration means back into the pressure tank at a location below the wastewater level;
• regulating the flow of the aerated wastewater from each of the external aeration means returned to the pressure tank;
• mixing the aerated wastewater from the pressure tank with raw sewage in a surge tank pipe;
• and
• recycling the aerated wastewater mixed with raw sewage into a chamber within the flotation container where flotation and settling of particles occurs, the chamber minimizing turbulence in the flotation container.