Treatment of milk industry effluent by dissolved air flotation

In this work, the application of the flotation technique by dissolved air (FAD) to the treatment of milk industry effluent (milky effluent) is analyzed. Initially, batch studies were carried out in a column built of acrylic with an external diameter of 2.5 cm and 50 cm in height. Afterwards, the performance of a flotation tank with a 5.5 L capacity in the treatment of the milky effluent was addressed. In continuous mode of operation, separation efficiencies up to 90% were obtained for the experiments carried out at a saturation pressure of 4 atm and having a ratio of feed flow rate (Q(a)) to saturated liquid flow rate equal to 1. The separation efficiency for flocculated milk was estimated from the overall mass balance for the flotation tank. Separation efficiencies obtained agreed very well with the experimental results collected for Q(a)/Q(Ls) ratios lower than 1.