The integration of denitrifying anaerobic methane oxidation (DAMO) and anaerobic ammonium oxidation (Anammox) simultaneously converts ammonium, methane, and oxidized nitrogen species (nitrite and nitrate) to harmless N2 and CO2. This integrated and complementary process achieves the nitrogen and carbon cycles in wastewater with the potential to be applied widely at full scale to realize energy-positive wastewater treatment plants (WWTPs). In this review, we summarize the collaborative and competitive interactions of DAMO–Anammox microorganisms and systematically evaluate...