Effectiveness of reverse osmosis (SWRO) permeate backwash on fouling control of seawater ultrafiltration was investigated at a pilot scale.A standard membrane module was used in this pilot to represent full scale desalination plants.Performance of this pilot was also compared with a desalination plant of Evides Company,because the same seawater was used for both cases.Results of the pilot show a good reproducibility.When the UF permeate was used for backwash,the frequency of chemically enhanced backwash (CEB) was around 24 hours in low fouling period.Under the same filtration settings,the Evides desalination plant showed a similar frequency of CEB conduction.Furthermore,results of the pilot show that SWRO permeate backwash could reduce the CEB frequency to 1/2 of UF permeate backwash at the same operational conditions in low fouling period.