A pilot-scale anaerobic sequencing batch reactor (ASBR, working volume 530 L), inoculated with oxygen-segmented sludge in an oxidation ditch process, was developed to investigate the start-up of anaerobic ammonium oxidation (ANAMMOX) and its combination with denitrification for deep-level nitrogen removal from desulfurization and denitrification tailings of a thermal power plant. The results showed that, under conditions with a temperature of (35±1)℃and reaction time of 20 h, ANAMMOX was successfully started up after 180 days. During the stable operations phase, total nitrogen (TN) removal rate and removal efficiency reached 91.1% and 0.3 kg·(m3·d)-1, respectively. During the activity suppression stage of the ANAMMOX-ASBR treating real desulfurization and denitrification tailings, the recovery of its activity could be achieved in 93 days by removing inhibitory factors (Cl- concentration) and reducing the concentration of influent substrate. In addition, by gradually increasing the addition ratio of desulfurization and denitrification tails (30%, 70%, and 100%), the coupling of ANAMMOX and denitrification was achieved in the ASBR to ensure stable effluent TN removal rate and COD concentrations below 92% and 88.5 mg·L-1, respectively. The modified logistic model was more suitable for the NRR recovery process after ANAMMOX was impacted by desulfurization and denitrification tailings. The NRR recovery delay time λ was 17.777 cycles, the and R2 was 0.92948.
Keywords: anaerobic ammonia oxidation(ANAMMOX); denitrification; desulfurization and denitrification tailings; recovery characteristics; recovery kinetics.