进水亚硝氮限制下Anammox去除氨氮研究

Study on removal of ammonia nitrogen by Anammox with or free of nitrite nitrogen

利用UASB反应器分别在降低进水亚硝氮/氨氮比(R)和停供亚硝氮条件下研究了Anammox体系运行特性.发现随着进水亚硝氮减少,亚硝氮与氨氮去除摩尔比减小,发生氨氮超量去除现象,即使进水无亚硝氮时也可去除氨氮.当R为1:2时,氨氮超量去除量达最大,均值为57.2mg/L;长期停供亚硝氮条件下氨氮能够稳定去除,平均去除量为45.6mg/L.停供亚硝氮后Anammox体系中微生物群落多样性增加,AnAOB、氨氧化菌和反硝化菌相对丰度均增加.其中AnAOB相对丰度从9.44%增长到13.26%;氨氧化菌相对丰度从3.29%增长到7.3%;反硝化菌相对丰度由0.54%增加到3.14%.研究表明,溶解氧是氨氮超量去除量的限制性因素,氨氮超量去除的途径包括:好氧氨氧化、厌氧氨氧化与部分内碳源反硝化.在微量溶解氧作用下,主要是氨氧化菌与厌氧氨氧化菌协同实现了氮的去除.

Operation characteristics of an anammox system under the conditions of constantly reducing influent NO2--N/NH4+-N ratio(R)and even no nitrite feeding in the UASB were studied.It has been found that as the influent nitrite decreased,the removal ratio of nitrite to ammonium also declined.The phenomenon of ammonium excess removal occurred.Even if there was no nitrite in the influent,ammonium had been removed.When the R was 1:2,the excess removal of ammonium reached the maximum,with an average of 57.2mg/L.The ammonium was removed stably in the reactor even without any nitrite supply,with an average removal of 45.6mg/L.The microbial diversity increased and the abundance of ammonia oxidizing bacteria,anaerobic ammonia oxidizing bacteria,denitrifying bacteria increased in the system.The relative abundance of AnAOB increased from 9.44%to 13.26%,ammonia oxidizing bacteria and denitrifying bacteria,from 3.29%and 0.54%to 7.3%and 3.14%,respectively.This study shows that dissolved oxygen was the limiting factor for the excess removal of ammonium.The pathways of excess removal of ammonium included aerobic ammonia oxidation,anammox and partial endogenous denitrification.While with a small amount of dissolved oxygen,ammonia oxidizing bacteria and anaerobic ammonia oxidizing bacteria removed ammonium collaboratively.