Principle and function of pressurized floating removal

Water comes in from the central part of the side of the pressurized floating removal settling tank and flows into the feed box in the tangent line direction. Since the inflow feed box has a water regulating function, it can evenly guide incoming water to the tank to facilitate floating or settling. When air is dissolved in wastewater under pressure, it will flocculate pollutants in water into small floc, allowing wastewater with over-saturated air to the floating removal tank after depressurization. Due to abrupt depressurization, over-saturated air will be precipitated, forming numerous amounts of minute bubbles combining with suspended particles in wastewater and floating to the top. Thus, floating separation can be done and solids are separated from liquids by gravity.

Upper purified liquid will spill from the weir plate of the perimeter outflow channel. After being collected at the outflow channel, purified water will discharge from the discharge pipe. Settled sludge will be collected in the sludge pit at the bottom of the tank by the scraping board of the scraper and then be discharged from the sludge discharge pipe. For floating scum produced atop the surface, it will be scraped to the scum funnel by using the scum baffle and the skimmer plate before it is discharged from the scum pipe.

Comparison with other floating removal methods

The bubble size is small, normally at the range of 30~120μm. The smaller the size, more bubbles there are under the same amount of air supply, and the contact areas are larger, so are more chances for suspended particles in wastewater to attach with each other. Therefore, the floating separation efficiency will be better. Since the bubble is small, it takes longer to float upward, increasing its retention time and in turn, increasing more collision chances with suspended particles and thus dramatically increasing the floating removal effect.

Operation and maintenance

This equipment can be operated after confirming the gas liquid ratio and the reflux ratio. Care should be taken on the operating pressure, air flow and reflux ratio of the pressurized drum on a daily basis. The liquid receiving part and the walking cart are all made of SUS304. Therefore, there is no problem on maintenance of corrosion of tank. The only job is to regularly apply lubricants to each rotating shaft.