<p>The high energy consumption of conventional activated sludge process is posing significant challenge on the current wastewater industry worldwide. Therefore, the development of energy-efficient wastewater treatment processes is urgently needed. This study proposed an energy self-sufficient biosorption/partial nitrification/anammox process by using functionalized carriers to augment the efficiency of partial nitrification and anammox. Specifically, in biosorption stage, COD was captured into sludge, which could further be converted into bio-methane by anaerobic digestion for energy recovery. In the partial nitrification stage, nitrification-functionalized carriers were used for selective enrichment of ammonia-oxidizing bacteria (AOB) to maintain efficient and stable nitrite accumulation, while anammox-functionalized carriers were utilized in anammox stage for massive anammox bacteria accumulation. Long-term operation results showed that with an averaged influent COD concentration of 200.0 mg/L and total nitrogen (TN) concentration of 60.0 mg/L, the effluent consistently achieved an average COD concentration of 25.4 mg/L and an average TN concentration of 13.6 mg/L, which could meet the national discharge standard (GB18918-2002, China). The use of nitrification-functionalized carriers promoted the survival and enrichment of AOB, while anammox-functionalized carriers similarly facilitated the survival and enrichment of anammox bacteria. The effective colonization resulted in a significant upregulation of genes associated with nitrogen metabolism. This study proposes a novel approach for the <i>in-situ</i> selective enrichment of AOB and anammox bacteria to realize efficient partial nitrification-anammox process, which holds potential for achieving energy-neutral mainstream municipal wastewater treatment with low carbon emissions.</p>