Membrane concentrate management for textile wastewater with thermally activated persulfate oxidation method

In this study, concentrated textile wastewater using NF270 membrane was further treated by thermally activated persulfate (TAP) oxidation method. First, the effluent of the textile wastewater treatment plant was treated using NF270 membrane, and the concentrated stream was obtained. Second, the TAP method was applied using the central composite design (CCD) optimization method. The steady-state permeate flux of NF270 was obtained as 3.4, 6.8, 17.4 L/m².h, respectively, for 10, 15, 20 bars pressure. COD concentration and color in concentrated stream increased from 880 mg/L and 2960 Pt-Co to 1120 mg/L and 4860 Pt-Co, respectively, when operating pressure increased from 10 to 20 bars. The results obtained from the CCD optimization method showed that the experimental and predicted values showed a good fit in both chemical oxygen demand (COD) and color removals models. The maximum experimental values of COD and color removal efficiencies were obtained 69% and 95%, respectively, at 370 K temperature, 60 mM K₂S₂O₈ concentration, and 80 min treatment time. The NF270 concentrated stream was also filtrated from the 2^nd stage of NF270 membrane after TAP treatment. The results showed that TAP degradation of concentrated stream improved the 2^nd stage of NF270 membrane flux compared without degradation. The proposed TAP method was successfully used to further the treatment of textile wastewater concentrated stream for NF270 membrane.