If　we　can　use　toxic　aromatic　compounds　as　supplementary　carbon　source,　the　simultaneous　removal　of　nitrate　(NO3−)　and　aromatic　compounds　may　be　achieved　at　much　lower　chemical　costs.　This　study　uses　the　expanded　granular　sludge　bed　(EGSB)　reactors　to　investigate　the　hypersaline　(＞　3%)　denitrification　performance,　the　removal　of　aromatic　compounds,　i.e.,　aniline,　phenol,　and　their　mixture,　and　the　mechanisms　involved　in.　The　four　reactors　exhibit　high　removal　efficiency　of　NO3−　(＞　92.8%)　and　aromatic　compounds　(＞　73.9%)　at　0–1200　mg/L　of　aromatic　compounds.　The　formation　of　toxic　intermediates　such　as　catechol　and　azo　dyes　is　revealed　by　gas　chromatography　mass　spectrometry　(GC–MS)　with　and　without　N,O-Bis(trimethylsilyl)　trifluoroacetamide　(BSTFA)　derivation,　and　their　toxic　effects　lead　to　the　lower　cell　survival　ratios　after　exposing　to　phenol　(64.2%　∼　68.9%)　than　to　aniline　and　mixture　(72.7%　∼　78.0%).　The　stable　performance　is　associated　with　the　more　secretion　of　extracellular　polymeric　substances　(EPS)　and　the　adsorption　of　pollutants　on　EPS,　and　this　was　indicated　from　the　higher　fluorescence　intensity　in　three-dimensional　excitation-emission　matrix　(3D-EEM).　Moreover,　the　Halomonas　and　Azoarcus　show　high　abundance　and　play　important　roles　in　the　removal　of　both　NO3−　and　aromatic　compounds.　Besides,　quantitative　real　time　PCR　(RT-qPCR)　results　demonstrate　the　key　role　of　highly　abundant　nosZ　and　nirS　genes　in　denitrification.　The　toxic　organics　in　industrial　wastewaters　are　potentially　feasible　carbon　sources　for　denitrification　even　under　high-salinity　stress.　©　2022