Recovery of Protein from High-Concentration Cheese Wastewater and Subsequent Coagulation—Flocculation Treatment

The production of cheese generates copious wastewater with very high organic load, which requires a series of treatments prior to discharge. In this study, protein was ultrasonically treated and then recovered from cheese wastewater using isoelectric precipitation. After initial ultrasonic treatment with an ultrasonic energy of 1,800 kJ/L, the protein could be effectively precipitated at pH = 4.5, and about (67.7 ± 0.5) % of the protein was separated out. Because the chemical oxygen demand (COD) load remained high, the supernatant was treated by flocculation and coagulation. Treatment using polyferric sulfate (PFS) coagulation of 200 mg/L and nonionic polyacrylamide (PAM) flocculation of 4 mg/L reduced the turbidity by (98.6 ± 0.4)%, and COD by (89.2 ± 0.9)%.