Abstract: The bacteria breed easily on the conventional RO security filter, which may cause pollution and plugging of the RO membrane. Simultaneously, the short circuit of input and output water often occurs in the conventional RO security filter. A new double security filter was installed on the front of RO device No.5 in the water supply workshop of a petrochemical plant, and a performance comparison test was carried out under the same condition. The test result shows that the hidden troubles of short circuit and leakage are eliminated in the filter, the pollution index of output water of the filter is superior to that of conventional filter, and the antibacterial effect of the new filter is obvious.

Key words: double security filter, reverse osmosis (RO) device, precision filtration, pollution index, antibacterial effect