Start-up and operation of anammox biofilter in treating low-strength ammonia wastewater prepared by tail water from a municipal wastewater treatment plant

BACKGROUND: Economic technology of advanced nitrogen removal of municipal wastewater is urgently needed. In this study, anammox biofilter (A-BF) as a carbon- and energy-saving advanced nitrogen removal process was tested under the conditions of sewage secondary effluent. RESULTS: The results showed that A-BF could be successfully started up under total nitrogen (TN) of both 25 and 75 mg L⁻¹ within 30 days at 25 °C. It achieved a nitrogen removal rate of 0.62 ± 0.08 kg-N m⁻³ d⁻¹ with nitrogen loading rate of 1.35 kg-N m⁻³ d⁻¹ at TN of 17 mg L⁻¹. The ceramsite bed was conducive to the formation of biofilm and enrichment of functional microorganisms. The volatile suspended solid reached 1.39–7.33 g L⁻¹, in which the abundance of the typical anammox bacteria Candidatus_Brocadia and Candidatus_Kuenenia occupied 0.96–1.35% and 0.29–0.92%, respectively. CONCLUSIONS: Overall, under low TN concentration and high nitrogen load, A-BF could be a candidate technique for advanced nitrogen removal of municipal sewage.