Treatment of Liquor Wastewater by an Integration of Anaerobic Digestion, Partial Nitrification/Anammox, and Fenton Process: Performance and Microbial Analysis

This study designed an integration of anaerobic digestion, partial nitrification/Anammox (PN/A), and Fenton process to efficiently treat high-concentration organic liquor wastewater (HCLW). Results indicated that when the diluted ten-fold mixture of boiler bottom water and cellar bottom water with the ratio of 5:1 was used as influent, the average concentrations of COD, TN, NH4+-N, NO2−-N, and NO3−-N in effluent of biological treatment for this process were 180.00, 12.64, 1.74, 0.13, and 2.45 mg/L, respectively. To meet the requirement for direct discharge of HCLW, Fenton oxidation with 600 mg H2O2/L and 300 mg Fe2+/L was used to further reduce the COD concentration. Three-dimensional fluorescence spectra analysis revealed that the process effectively altered the organic molecular structure and degraded some large molecular proteins. Microbial community analysis showed that Methanobacterium (20.98% → 31.52%) and Methanosaeta (9.70% → 19.34%) in AD, Azoarcus (no detected → 10.49%) and Nitrosomonas (1.68% → 6.16%) in PN, and Candidatus_Brocadia (18.80% → 20.31%) and Ignavibacterium (no detected → 5.11%) in Anammox were dominant in this system. This study provided a pioneering industrial solution for the efficient and stable treatment of HCLW.