Highly efficient removal of contaminant from typical dye wastewater by using individual AOPs-A/O processes: Design, performance, and mechanism

Abstract

The individual process design suitable for different types of dye wastewater is less reported, and the performance and mechanism of advanced oxidation processes (AOPs)–anaerobic/aerobic (AOPs-A/O) is also unclear. In this experiment, different processes were designed to treat three typical dyes, namely, Disperse Blue (DB), Indigo Blue (IB), and Reactive Red (RR). Their performance and mechanism were studied. Results showed that sodium persulphate oxidation (SPO)/Fenton oxidation (FO) coupling treatment was the optimal treatment process for DB and IB wastewater, and SPO/ozone oxidation (OO) coupling treatment was the optimal treatment process for RR wastewater. After individual AOPs-A/O, the total chemical oxygen demand (COD) removal efficiency (CODre) of DB, IB, and RR were 96.25%, 96.35%, and 96.73%, respectively, and the overall mineralisation efficiency (ME) was 67.04%, 85.97%, and 72.24%, respectively. The contribution efficiency of the three treatment units to wastewater decreased as follows: AOPs > anoxic > aerobic. The initial B/C (B/C is the ratio of BOD to COD, which can indicate the biodegradability of wastewater) of DB, IB, and RR was 0.064, 0.065, and 0.262, respectively. The effluent B/C of DB, IB, and RR increased to 0.292, 0.392, and 0.795, respectively. Sequencing results showed that at the phylum level, its dominant group changed from Proteobacteria to Firmicutes. At the class level, its dominant group changed from Gammaproteobacteria to Clostridia.