LAUSR

The anaerobic nitrogen removal performance of anammox at 30°C, 25°C, and 16°C were studied by using the UASB (Up flow Anaerobic Sludge Blanket) reactor and the influent concentration of NH4+-N and NO2−-N were 16.9 and 20.6 mg L−1 respectively. Experimental results showed that high-efficiency anammox nitrogen removal could be achieved at 30°C, when hydraulic retention time (HRT) was 0.14 h, the nitrogen removal rate (NRR) was 5.73 kg N m−3 d−1. The anammox reactor operated stably for more than 80 days under the condition of 16°C–20°C, and the high NRR of 2.78 kg N m−3 d−1 was obtained. In this experiment, DO had little effect on the activity of anammox granular sludge, and the nitrogen removal performance could be quickly recovered in a short period of time after being affected by DO. Moreover, the stoichiometric ratio of NO2−-N and NH4+-N consumption (ΔNO2−-N/ΔNH4+-N) and the stoichiometric ratio of NO3−-N production and NH4+-N conversion (ΔNO3−-N/ΔNH4+-N) were 1.21 ± 0.11and 0.25 ± 0.06 respectively at 30°C, which were very close to the theoretical value, it indicated that anammox bacteria were the dominant bacteria at 30°C.