Full Flow Pressurization
Full flow pressurization is just what the term implies. All the waste water (influent) has air injected into it. Then it is pumped to a retention tank under pressure, so the added air is dissolved into the waste water. It then enters the flotation cell where the pressure is relieved and the injected air is released in the form of tiny bubbles which form on the solid particles causing the particles to rise to the surface of the flotation cell where they are skimmed off.
Recycle pressurization
Recycle pressurization represents the most significant deviation from the previously described mode. As can be seen in the schematic in Figure 4-2 the same basic functions occur as in the full flow pressurization mode. The primary difference is that the injected air is induced into a portion of recycled clarified effluent which is recycled specifically for the purpose of adding the pressurized air to the influent. The recycled flow is blended with the raw waste water flow (influent) either in the flotation cell or in an inlet manifold.
