The most common method of biological nitrogen removal is by combining the nitrification of the autotrophic nitrobacter and nitrosomonas with the denitrification of heterotrophic denitrifying bacteria.

生物除氮最常利用的是将自营性硝酸菌、亚硝酸菌之硝化作用与异营性脱硝菌之脱硝作用结合。