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 S0 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 S0 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 S0-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.
Keywords: Anammox; Coupling; Enhanced nitrogen removal; Sulfur autotrophic denitrification with S(0) as electron donor (S(0)-SADN).
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