Aerobic　granulation　promoted　by　static　magnetic　field　had　been　widely　noticed　because　of　its　environmental　friendliness　and　economic　feasibility.　The　mechanism　of　strengthening　aerobic　granulation　by　static　magnetic　field　needed　to　be　clarified.　Consequently,　this　study　aspired　to　promote　aerobic　granulation　by　loading　different　intensities　of　static　magnetic　fields　(R1:　0　mT,　R2:　10　mT,　R3:　50　mT),　and　elucidate　the　potential　mechanism　of　static　magnetic　fields　enhancement　in　terms　of　microbial　interactions,　chemical　structure　and　adhesion　performance　of　extracellular　polymeric　substances　(EPS),　metabolic　pathways.　Compared　to　R1　(day　45),　R3　and　R2　completed　granulation　at　day　34　and　day　42　respectively.　Under　the　influence　of　magnetic　fields,　the　interfacial　adsorption　free　energy　between　microorganisms　decreased　from　−55.88　mJ/m2　(R1)　to　−64.32　mJ/m2　(R2)　and　−75.02　mJ/m2　(R3),　and　the　energy　barriers　preventing　microbial　aggregation　in　R2　and　R3　were　reduced.　This　was　attributed　to　the　fact　that　magnetic　fields　induced　microorganisms　to　secrete　highly　hydrophobic　EPS　and　enhanced　adhesion　to　metal　cations　(Ca2+,　Mg2+,　etc.),　resulting　in　an　enhanced　hydrophobic　interaction　and　a　reduced　electrostatic　repulsion　interaction　between　microorganisms.　Furthermore,　magnetic　fields　increased　the　relative　abundance　of　EPS-producing　bacteria　(Chryseobacterium,　Candidatus_Competibacter,　Thauera,　Zoogloea)　and　upregulated　the　abundance　of　functional　genes　associated　with　the　synthesis　of　hydrophobic　amino　acids　(trpA,　trpB,　ADT,　ilvE,　proC,　metH)　and　energy　supply　(mdh,　cs,　acn,　IDH,　sucA,　frdA).　The　above　results　proved　that　the　static　magnetic　field　promoted　aerobic　granulation　by　enhancing　microbial　aggregation　and　adhesion,　which　provided　sufficient　theoretical　support　for　the　construction　of　a　new　wastewater　treatment　plant.　©　2024