Treated effluent from wastewater treatment plants across the country must meet local dissolved oxygen (DO) limits before discharging into receiving waters. The Pipeline Flash Reactor (PFR) facilitates efficient inline gas transfer to address DO challenges.
A PFR is a spool-piece in which a length of pipe serves as an inline-mixing zone. A sidestream – which accounts for as little as 3% to 5% of the total flow rate of the system – is taken off the effluent pipeline and then is highly oxygenated through the use of Venturi injectors. These injectors harness the pressure differential of flowing water to draw in atmospheric air or concentrated oxygen, which is then mixed into solution. The oxygenated sidestream flow then enters the PFR, where it aggressively mixes with the main flow, uniformly transferring the oxygen in the effluent pipeline via the PFR’s precisely placed, patented nozzles. In the space of just a few meters of pipe, the two streams mix thoroughly with the nozzles effectively shearing the entrained bubbles and maximizing the gas-liquid interface, thus enhancing oxygen transfer. The sidestream flow through the PFR is at a constant velocity that is independent of the plant flow, which ensures optimum gas mixing under all plant flow conditions. The PFR introduces the water/oxygen sidestream back into the main water flow at high velocities without the pressure loss of conventional mixing systems, eliminating the need for an additional tank/basin, which drastically reduces the energy consumption and footprint of the system.
Once the PFR is installed, it is virtually maintenance-free and requires minimum operator involvement. Since the head loss through the PFR is negligible, the only energy demand of a PFR system is a pump large enough to push a sidestream through the injectors. A PFR system is a controlled, stable mixing environment.
Mazzei Injector Co. LLC