An efficient way to enhance the total nitrogen removal efficiency of the Anammox process by S0-based short-cut autotrophic denitrification

In order to reduce the amount of NO3--N generated by the Anammox process, and alleviate the competition between denitrification and Anammox for NO2--N in a single reactor, the preference of S-0 for reacting with coexisting NO2--N and NO3--N in the sulfur autotrophic denitrifying (SADN) process and the coupling effect of short-cut SADN and the Anammox process were studied. The results showed that S-0 preferentially reacted with NO3- to produce NO2--N, and then reacted with NO2--N when NO3--N was insufficient, which could effectively alleviate the competition between SADN bacteria (SADNB) and Anammox bacteria (AnAOB) for NO2--N. After 170 days of operation, coupling between short-cut S-0-SADN and the Anammox process was first successfully achieved. SADNB converted the NO3--N generated by the Anammox process into NO2--N, which was once again available to AnAOB. The total nitrogen removal efficiency eventually stabilized at over 95%, and the effluent NO3--N was controlled within 10 mg/L, when high NH4+-N wastewater was treated by the Anammox process. Microbial community analysis further showed that Candidatus Brocadia and Thiobacillus were the functional microorganisms for AnAOB and SADNB. (C) 2019 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V.