Denitratation　(NO3--＞　NO2-)/anammox　is　a　promising　method　for　anammox　application　in　mainstream　wastewater　treatment　plants　(WWTPs)　to　reduce　oxygen　and　organic　matter　consumption.　Achieving　nitrite　production　via　denitratation　and　controlling　denitritation　(NO2--＞　N-2)　is　the　basis　of　the　denitratation/anammox　process.　To　control　denitritation,　the　denitrifying　biocommunity　and　growth　rate　are　critically　reviewed　for　biocommunity　optimization.　Then,　the　short-term　and　long-term　effects　of　pH　on　denitritation　were　summarized　and　the　possible　mechanism　was　discussed,　along　with　the　effect　of　C/N　ratio　and　organic　matter　type　on　denitritation.　Meanwhile,　the　strategies　for　producing　nitrite　via　controlling　denitritation　are　discussed,　as　well　as　the　processes　for　achieving　nitrogen　removal　via　denitratation/anammox　in　WWTPs.　Finally,　the　practical　application　of　denitratation/anammox　in　a　full-scale　mainstream　WWTP　is　documented.