As　an　energy　and　carbon　saving　process　for　nitrogen　removal　from　wastewater,　the　partial　nitrification　and　denitrification　process　(PN/D)　has　been　extensively　researched.　However,　achieving　stable　PN　in　municipal　wastewater　has　always　been　challenging.　In　this　study,　a　gel　immobilized　PN/D　nitrogen　removal　process　(GI-PN/D)　was　established.　A　94d　pilot-scale　experiment　was　conducted　using　real　municipal　wastewater　with　an　ammonia　concentration　of　43.5　±　5.3　mg　N/L　at　a　temperature　range　of　11.3–28.7℃.　The　nitrogen　removal　performance　and　associated　pathways,　shifts　in　the　microbial　community　as　well　as　sludge　yield　were　investigated.　The　results　were　as　follows:　the　effluent　TN　and　COD　were　0.6　±　0.4　mg/L　and　31.1　±　3.8　mg/L　respectively,　and　the　NAR　exceeding　95　%.　GI-PN/D　achieved　deep　nitrogen　removal　of　municipal　wastewater　through　stable　PN　without　taking　any　other　measures.　The　primary　pathways　for　nitrogen　removal　were　identified　as　denitrification,　simultaneous　nitrification-denitrification,　and　aerobic　denitrification.　High-throughput　sequencing　analysis　revealed　that　the　immobilized　fillers　facilitated　the　autonomous　enrichment　of　functional　bacteria　in　each　reactor,　effectively　promoting　the　dominance　and　stability　of　the　microbial　communities.　In　addition,　GI-PN/D　had　the　characteristic　of　low　sludge　yield,　with　an　average　sludge　yield　of　0.029　kg　SS/kg　COD.　This　study　provides　an　effective　technical　for　nitrogen　removal　from　municipal　wastewater　through　PN.　©　2024