Coupling of biological methods with membrane filtration using ozone as pre-treatment for water reuse Original Research Article

This work focused on the advanced treatment of the biologically treated wastewater of a textile plant. Nowadays, treatment methods for water reuse are mainly membrane technologies. According to the difficulty of concentrate stream treatment and fouling problem in membrane process, a combination pre-treatment process including ozonation, biological aerated filter (BAF) and reverse osmosis was developed for textile wastewater treatment. Comparing different ozone dosing methods, the ozone–BAF integrated device allowed a higher COD (chemical oxygen demand) and color reduction. The optimal ozone dosage in the integrated device was 20–30 mg/L. After the two-stage BAF treatment, an effluent was obtained with an average COD of 27.4 mg/L, a turbidity of 4.2 NTU, a SS (suspended solid) of 3.0 mg/L, an ammonia nitrogen of 0.7 mg/L and a color of 2 degree.