Comparison Study on Water Treatment Efficiency Applied Low-Energy Instant Pressurization Method as BAT

This study applies the Flash Pressurized Flotation (FPF) process, which generates stable and uniform microbubbles under low-pressure conditions without a high-pressure saturator, and comparatively evaluates its treatment efficiency and energy-saving performance against the conventional Dissolved Air Flotation (DAF) process from a Best Available Technology (BAT) perspective. The bubble generation characteristics of the FPF process were quantitatively analyzed by evaluating the effects of major operational parameters, including the number of orifices, number of plates, nozzle configuration, flow rate, and pressure. Experiments were conducted using synthetic lake water, where bubble size was measured by the Particle Counter Method (PCM) and bubble volume was determined by the Water Substitution Method. Increasing the number of orifices from 5 to 15 reduced the average bubble size from 4.3 μm to 4.1 μm and increased the bubble volume from 1.1 mL/L to 1.5 mL/L. Under a flow rate of 2.04 L/min and a pressure of 2 atm, the FPF process showed relatively superior bubble generation characteristics with an average bubble size of 26 μm and a bubble volume of 60 mL/L, while the FPF-type dual-plate nozzle exhibited the best performance, producing an average bubble size of 31.5 μm and a bubble volume of 51 mL/L. Compared with the DAF process at the same pressure, the FPF process achieved higher removal efficiencies for phosphorus (94.1%) and turbidity (89.9%), whereas the DAF process showed removal efficiencies of 30.1% and 33.1%, respectively. The specific energy consumption of the FPF process was 0.0024 kWh/m³, representing an approximately 98% reduction compared to that of the DAF process, demonstrating the potential of FPF as a low-energy flotation process suitable for small- and medium-sized water treatment plants and as a BAT.