Deficient seed sludge, low substrate concentrations are recognized as the major barriers for the application of anaerobic ammonia oxidation (Anammox) to treat mainstream wastewater. In this work, anammox biofilter (A-BF) was started up by inoculating denitrification sludge at low nitrogen strength at 25 °C. The total nitrogen removal efficiency (TNRE) and nitrogen removal rate (NRR) reached 74.8 ± 3.4% and 0.81 kg-N m-3 d-1 under nitrogen loading rate (NLR) of 1.20 kg-N m-3 d-1 with 7.00 mg-NH4+-N L-1 and 10.00 mg-NO2--N L-1 as influent. 1.00-2.00 mg-DO L-1 negatively impacted effluent, but the total nitrogen of effluent (TNeff) was 10.65 ± 2.76 mg L-1, in limit of the standard of Class 1A for municipal WWTP discharge (GB18918-2002). The abundance of Planctomycetes increased from 0.6% to 1.4-2.6%, in which, Candidatus_Brocadia was the dominant genera. The results establish the application feasibility of A-BFs as advanced nitrogen removal technique in treating mainstream wastewater.
Keywords: Anammox; Biofilter; Denitrification inoculum; Low nitrogen strength.
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