[Enhanced Treatment of Printing and Dyeing Wastewater Using H₂O₂-Biochemical Method]

The traditional biochemical treatment of printing and dyeing wastewater has limited efficiency. This study investigated whether H₂O₂ could strengthen the biological ability of the hydrolytic acidification/biological contact oxidation process (A/O), which effectively treats the printing and dyeing wastewater. After biofilm formation and the biochemical system startup and operation by H₂O₂, the system was successfully started and steadily operated when H₂O₂was added into reactor A with the H₂O₂ voluve fraction of 3 mL·L^-1, doses of 100.0 mL, the flow velocity of 0.67 mL·min^-1, and dosing frequency of once a day. The experimental results showed that the average removal efficiencies of COD, ammonia nitrogen, PVA, and color of printing and dyeing wastewater were 89.8%, 96.7%, 87.4%, and 92.1%, respectively. The microorganism community structures of reactor A and reactor O in this system were analyzed by high-throughput sequencing of 16S rDNA amplicon. The results demonstrated that the three dominant microbial strains in reactor A were Proteobacteria, Bacteroidetes, and Verrucomicrobia, and in reactor O were Planctomycetes, Proteobacteria, and Acidobacteria.