BACKGROUND　Toilet　water　is　a　typical　wastewater　that　is　abundant　and　has　a　low　organic　carbon-to-nitrogen　ratio;　therefore,　it　is　necessary　to　explore　an　economical　and　efficient　treatment　option.　Partial　nitrification-anammox　(PN/A)　technology　is　characterized　by　low　aeration　energy　consumption　and　a　high　nitrogen　removal　rate.　As　a　process　technology　that　has　emerged　in　recent　years,　PN/A　technology　involves　operating　conditions　that　require　further　study.　RESULTS　In　this　work,　two　one-stage　partial　nitrification-anammox　(S-PN/A)　reactors　were　operated　to　achieve　nitrogen　removal　from　toilet　water.　The　total　nitrogen　removal　rate　of　the　two　reactors　reached　85%.　The　hydraulic　nitrogen　load　of　the　first　reactor　was　only　0.03　kg　N　m(-3)center　dot　d(-1),　while　the　hydraulic　nitrogen　load　of　the　second　reactor　reached　0.09　kg　N　m(-3)center　dot　d(-1).　Nitrosomonas　and　Candidatus　Kuenenia　in　the　reactor　were　the　main　functional　bacteria　for　partial　nitrification　and　anammox.　Kinetic　simulations　were　performed　using　AQUASIM　2.0　software.　The　results　showed　that,　in　the　partial　nitrification　system,　the　higher　the　(sludge　retention　time)　SRT　,　the　lower　the　effluent　ammonia　nitrogen　concentration;　the　optimal　operating　condition＇s　sludge　retention　time　(SRT)　was　10　days　and　dissolved　oxygen　(DO)　was　0.2　mg　L-1.　The　higher　the　SRT　in　the　anammox　system,　the　lower　the　concentration　of　ammonia　and　nitrite　nitrogen　in　the　effluent;　in　addition,　the　SRT　should　be　greater　than　60　days　to　ensure　that　as　much　nitrogen　was　removed　as　possible.　CONCLUSION　In　summary,　the　research　results　confirm　that　it　is　feasible　to　use　PN/A　technology　to　remove　nitrogen　from　toilet　water.　(c)　2021　Society　of　Chemical　Industry　(SCI).