The　role　of　extracellular　polymeric　substances　(EPS)　in　the　enhanced　biological　phosphorus　removal　(EBPR)　process　was　investigated　in　a　P-accumulating　granular　sludge　system　by　analyzing　the　distribution　and　transfer　of　P,　K+,　Mg2+　and　Ca2+　in　the　sludge　phase,　EPS,　and　the　bulk　liquid.　In　the　sludge　phase,　about　30%　P,　44.7%　K+,　27.7%　Mg2+,　28%　Ca2+　accumulated　in　the　EPS　at　the　end　of　aeration.　The　rate　of　P,　K+,　Mg2+　and　Ca2+　released　from　the　EPS　matrix　into　the　bulk　liquid　in　the　anaerobic　phase　was　faster　than　the　rate　they　were　adsorbed　from　the　bulk　liquid　into　the　EPS　in　the　aerobic　phase.　P,　K+,　Mg2+　and　Ca2+　were　retained　in　EPS　before　transferring　into　the　phosphorus　accumulating　organisms　(PAOs).　These　results　suggest　that　EPS　play　a　critical　role　in　facilitating　the　accumulation　and　transfer　of　P,　K+,　Ca2+　and　Mg2+　between　PAO　cells　and　bulk　liquid.　(C)　2014　Elsevier　Ltd.　All　rights　reserved.