Vacuum-UV　(VUV)　(wavelength　185　nm)/　UV　(wavelength　254　nm)　are　applied　to　improve　performances　of　UV-based　advanced　oxidation　processes.　However,　the　improvements　were　strongly　affected　by　water　depth　because　of　poor　VUV　transmittance　in　water.　In　this　study,　VUV/UV　and　peroxydisulfate　(PDS)　were　used　to　degrade　carbamazepine.　More　SO4　center　dot-　oxidation　occurred　in　VUV/UV/PDS　than　VUV/UV　with　similar　(OH)-O-center　dot　oxidation　occurring.　The　additional　SO4　center　dot-　oxidation　could　be　caused　by　VUV/PDS　in　superficial　water　or　UV/PDS　in　deeper　water.　The　synergistic　factor　for　VUV/UV/PDS　processes　relative　to　VUV/UV　and　UV/PDS　processes　was　1.32.　VUV/UV/PDS　performances　were　affected　by　competition　for　photon　absorption　by　dissolved　organic　matter　(32-58　%　inhibition),　radical　quenching　by　CO32-/HCO3-　and　NO3-,　and　conversion　of　(OH)-O-center　dot　and　SO4　center　dot-　into　reactive　chlorine　species　by　Cl-.　Radical　probe　experiments　and　steady-state　kinetic　modeling　simulations　indicated　that　34　%,　25　%,　and　40　%　of　carbamazepine　degradation　occurring　in　2-cm-deep　bulk　solution　was　due　to　(OH)-O-center　dot　oxidation　through　VUV/H2O,　SO4　center　dot-　oxidation　through　VUV/PDS,　and　SO4　center　dot-　oxidation　through　UV/PDS,　respectively.　Contribution　of　VUV-driven　processes　decreased　with　increasing　water　depth　and　became　equivalent　to　contribution　of　3.5-cm-deep　UV-driven　processes,　which　indicated　the　importance　of　optimizing　water　depth　in　VUV/UV-advanced　oxidation　process　reactors.