During　partial　denitrification　(PD),　the　rapid　realization　of　significant　nitrite　accumulation　and　precise　addition　of　organic　carbon　are　critical　for　reducing　costs.　In　this　study,　low　C/N　nitrate　industrial　wastewater　was　utilized　to　domesticate　PD　sludge.　The　application　of　specific　strategies　resulted　in　rapid　nitrite　accumulation　and　high　nitrate-to-nitrite　transformation　rates　(NTRs)　of　94　%,　93　%,　and　96　%.　Rational　adjustment　of　the　C/N　ratio　and　HRT　according　to　microbial　activity　and　effluent　quality　is　essential　for　the　success　of　PD.　With　the　rapid　transformation　of　sludge,　the　sedimentation　performance　improved,　and　the　sludge　aggregated　into　particles.　Microbiological　analyses　showed　that　Thauera　exhibited　the　highest　relative　abundance　at　60　%,　which　significantly　contributed　to　the　stability　of　the　system.　The　results　of　batch　tests　on　the　effects　of　C/N　and　NO₃−-N　showed　that　the　optimal　C/N　for　PD　varies　under　different　NO₃−-N　conditions.　The　pH　effect　tests　showed　that　the　NTR　was　maintained　above　90　%　at　pH　6–9,　with　higher　pH　values　promoting　the　accumulation　of　nitrite.　This　study　highlights　the　potential　of　PD　and　its　integration　with　other　processes　for　the　treatment　of　low-C/N　wastewater.　©　2024　Elsevier　Ltd