Effects of S2-/NO3--N on sulfur autotrophic denitrification and anaerobic ammonia oxidation combined process for nitrogen and sulfur removal

The startup of sulfur autotrophic denitrification (SAD) and anaerobic ammonia oxidation (anammox) combined process and the effect of S2-/NO3--N on the system performance was investigated using a Hybrid Anaerobic Baffled Reactor (HABR). Anammox sludge was filled as the seeding sludge, and artificial simulated wastewater was used as the influent. The reactor was continuously operated for 54 days under the conditions pH 8.0, temperature (32±1) and HRT 6.5 h. The results showed that S2- was inadequate for NO3--N reduction, and insufficient NO2--N product led to lower NH4+-N removal rate by anammox when S2-/NO3--N3--N continuously oxidized from elemental sulfur to sulphate, which caused higher sulphate concentration in the effluent. When S2-/NO3--N=1, S2- was adequate for NO3--N reduction, and the maximum NO2--N was generated. The NH4+-N average removal rate was 65.1%, which was the highest by anammox. When S2-/NO3--N>1, the S2- removal rate declined for excessive concentrations. SAD and anammox were successfully coupled in HABR. The maximum removal rates of NH4+-N, S2-, NO3--N were 74.3%, 99.0% and 99.5%, respectively. The optimum ratio of S2-/NO3--N was 1 for SAD and anammox combined process. ©, 2015, Editorial department of Molecular Catalysis. All right reserved.