Shortcut Nitrogen Removal—Nitrite Shunt and Deammonification is an essential resource for facility owners and practitioners evaluating the implementation of these advancements, including guidelines for assessing the application of various technologies. Shortcut nitrogen removal, an emerging economical solution for water resource recovery facilities, refers to the biological nitrogen removal (BNR) process whereby ammonia is not converted to nitrate, but instead stops at nitrite to shortcut the conventional nitrification/denitrification process. The resulting breakthrough single-step deammonification has significant advantages compared to conventional BNR processes, including reduced energy requirements, reduced carbon requirements, and reduced chemical costs.