[Lab-scale ANAMMOX Process in a Wastewater Treatment Plant]

A lab-scale, completely anaerobic ammonium oxidation (ANAMMOX) process was operated in a municipal wastewater treatment plant (WWTP). Sewage effluent treated by an A/O process and nitrification process was input as the substance to start up the up-flow ANAMMOX filter reactor. After the 109^th day, the ammonia removal rate and nitrite removal rate were greater than 90% for 15 successive days and the nitrogen removal rate was higher than 70%. The ANAMMOX filter reactor successfully started up. From days 245 to 333, the reactor was running during the winter. The weight of biomass reached 12.24 mg·g^-1, and the average nitrogen removal rate was 54.3%. Backwash was adopted at day 461, and the weight of biomass decreased to 8.01 mg·g^-1. From days 605 to 693, the reactor was running in the winter again. The weight of biomass was 10.41 mg·g^-1, and the average nitrogen removal rate was sustained at 69.7%. Compared with the previous winter, the weight of biomass was lighter but the total nitrogen removal loading was 23% greater. For the entire operation, the ANAMMOX rate at high temperature was stable but that at low temperature increased from 1.5 kg·(kg·d)^-1 to 3.6 kg·(kg·d)^-1. The results show:Long-term domestication at low temperature was in favor of improving treatment efficiency of ANAMMOX process in cold environment and realized ANAMMOX process operated efficiently in winter.