Anammox　has　received　increased　attention　due　to　its　enhanced　and　cost-efficient　approach　to　nitrogen　removal.　However,　its　practical　application　is　complicated　by　strict　influent　NO2--N　to　NH4+-N　ratio　demands　and　an　11%　nitrate　production　from　the　anammox　process.　This　study　was　the　first　known　research　to　propose　and　verify　a　system　of　zeolite　integrated　with　partial　denitrification　and　anammox　(Z-PDA)　in　an　up-flow　anaerobic　sludge　bed　(UASB)　reactor.　The　enhanced　and　robust　nitrogen　removal　resulted　in　an　ultra-high　nitrogen　removal　efficiency　(NRE,　93.0　+/-　2.0%).　Zeolite　adsorption　and　biological　desorption　of　ammonium　contributed　to　robust　nitrogen　removal　with　fluctuating　influent　NO2--N　to　NH4+-N　ratios.　Applying　16S　rRNA　gene　sequencing　found　that　Candidatus　Brocadia　and　Thauera　were　the　key　bacteria　responsible　for　anammox　and　partial　denitrification　(PD),　respectively.　Zeolite　also　acted　as　a　biological　carrier.　This　significantly　enriched　anammox　bacteria　with　a　higher　relative　abundance　of　Candidatus　Brocadia,　reaching　49.2%.　Metagenomic　analysis　demonstrated　that　the　multiple　functional　genes　related　to　nitrogen　removal　(nrfA/H,　narG/H/I)　and　the　metabolic　pathways　(Biosynthesis　of　cofactors,　the　Two-component　system,　the　Biosynthesis　of　nucleotide　sugars,　and　Purine　metabolism)　ensured　the　resilience　of　the　Z-PDA　system　despite　influent　fluctuations.　Overall,　this　study　provided　novel　insights　into　the　impacts　of　zeolite　in　the　PDA　system.　It　described　the　fundamental　mechanism　of　zeolite　based　on　adsorption　and　biological　desorption,　and　demonstrated　a　meaningful　application　of　the　anammox　process　in　sewage　treatment.