Integrated fixed-film activated sludge systems in continuous-flow and batch mode acclimated from low to high aniline concentrations: Performance, mechanism and metabolic pathways

• DOI: 10.1016/j.biortech.2023.129043
• Publication Date: 2023-04-10T15:28:28Z
• Authors: Nan-ping Wu; Qian Zhang; Bin Tan; Meng Li; Bing Lin; Jing He; Jun-hao Su; Hao-nan Shen
• Keywords: Bioreactors; Sewage; Nitrogen; Biofilms; Denitrification; Wastewater; Nitrification; 6. Clean water; Metabolic Networks and Pathways

Integrated fixed-film activated sludge (IFAS) system has considerable advantages in treating aniline wastewater economically and efficiently. However, the response mechanism of IFAS to aniline needs further study. Herein, IFAS in continuous-flow (CF-IFAS) and batch mode (B-IFAS) were set up to investigate it. The removal efficiency of aniline exceeded 99% under different stress intensities. At low stress intensity (aniline ≈ 200 mg/L), the total nitrogen removal efficiency of B-IFAS was approximately 37.76% higher than CF-IFAS. When the stress intensity increased (aniline ≥ 400 mg/L), both were over 82%. CF-IFAS was restrained by denitrification while nitrification in B-IFAS. The legacy effect of perturbation of B-IFAS made microflora quickly reach new stability. The closer interspecific relationship in B-IFAS and more key species: Leucobacter, Rhodococcus, Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium, Ellin6067 and norank_f_NS9_marine_group. Metabolic and Cell growth and death were the most abundant metabolic pathways, resulting both systems the excellent pollutant removal and stability under high stress intensity.