Importance of Bubble Bed Characteristics in Dissolved-air-flotation

Removal of Sulfate Ions by Precipitation and Flotation

“…This decrease is probably due to the fact that the concentration of microbubbles and the air mass/solid mass ratio increase when increasing the volume of water saturated with air. Flotation efficiency increases when the number of microbubbles increases, due to the probability of collision, adhesion, and the capture of microbubbles in the porous structure of the flocs, thus decreasing their density and increasing their flotation velocity (Jung et al, 2017;Amaral et al, 2016;Ortiz-Oliveros, Flores-Espinosa, Jiménez-Domínguez, Jiménez-Moleón, and Cruz-González, 2012;Al-Shamrani, James, and Xiao, 2002). A removal rate of 70,3% was achieved when tests with 10% of recycling were performed, in comparison with the 81,1% achieved in tests with 30% of recycling.…”

“…For the removal of aluminum precipitates containing sulfate ions, different methods of solid/liquid separation can be used, for example, sedimentation and dissolved air flotation (DAF). However, flotation compared to sedimentation is a more effective method since it has a higher treatment capacity (40 m 3 .m −2 .h −1 ), produces less sludge volume, and is efficient for turbidity removal (Jung, Park, Han, and Kim, 2017;Bahadori, A., Zahedi, Zendehboudi, and Bahadori, M., 2013). DAF is a solid/liquid separation method in which microbubbles (with a diameter between 10 and 100 microns) adhere to the solid particles suspended in the liquid, forming aggregates with a density lower than water.…”