Much　attention　has　been　paid　to　coagulation　as　a　pretreatment　for　controlling　membrane　fouling.　Until　now,　however,　there　has　been　no　literature　available　on　the　application　of　Zr-based　coagulants　in　the　coagulation-ultrafiltration　process.　The　aim　of　this　work　is　therefore　to　investigate　the　coagulation　behavior　of　ZrOCl2　and　its　influence　on　membrane　fouling,　in　comparison　with　that　of　the　commonly　used　Al-based　coagulants,　Al-2(SO4)(3)　and　PACl.　Floc　formation　kinetics　were　studied　via　`　a　turbidity　fluctuation　technique＇　(PDA　measurement).　A　variation　in　the　pH　and　temperature　of　raw　water　was　also　considered　in　order　to　test　the　performance　of　the　three　targeted　coagulants.　The　results　indicated　that　the　best　coagulation　efficiency　was　achieved　with　the　Zr　coagulant,　under　neutral　pH　conditions　and　at　a　room　temperature　of　25　degrees　C.　This　coagulant　resulted　in　minimum　turbidity　(0.72　NTU)　and　the　lowest　concentration　of　the　supernatant　at　UV254　(0.005　cm(-1));　the　corresponding　values　for　Al-2(SO4)(3)　were　2.79　NTU　and　0.011　cm(-1),　respectively,　while　those　for　PACl　being　6.78　NTU　and　0.015　cm(-1).　The　flocs　obtained　by　the　addition　of　this　Zr　coagulant　were　larger　in　size　and　had　superior　strength,　recovery　potential　and　settleability.　In　addition,　membrane　fouling　was　apparently　alleviated　through　use　of　the　Zr　coagulant,　especially　in　terms　of　the　irreversible　fouling,　followed　by　PACl　and　Al-2(SO4)(3).　The　superior　removal　efficiency　of　low-medium　MW　HA　may　be　a　plausible　explanation　for　this　phenomenon.　Particularly,　this　work　describes　a　novel　Zr　coagulant　as　an　important　potential　candidate　for　application　to　the　coagulation-ultrafiltration　process　in　the　future.