For recovering the proteins from the whey wastewater, a two-stage foam separation technology was developed with the column of inclined foam phase. Effects of inclined angle, initial pH, volumetric air flow rate and temperature on the performances of the wastewater were investigated. The results showed that when the conditions of the first stage were protein concentration 4.0 g/L, initial pH 7, inclined angle 50 degrees, volumetric air flow rate 100 mL/min and temperature 50 degrees C, enrichment ratio of the proteins was 8.5 and the residual solution went into the second stage as the feeding stream. When the conditions of the second stage were temperature 20 degrees C and volumetric air flow rate 200 mL/min, recovery percentage of the proteins reached 70%, the footnote was added to the wastewater as the feeding stream of the first stage. Total recovery percentage of the proteins reached to 80% by the two-stage foam separation. (C) 2011 Elsevier B.V. All rights reserved.
