ABSTRACT
The double membrane method of ultrafiltration reverse osmosis system uses the drive of pressure difference to supplement the fluoride removal capacity that cannot be met by conventional treatment process through the selective permeability of membrane. It can stably remove fluoride from water, meet the requirements of national standards and ensure the health of people's drinking water. The water source of a large urban water purification plant is a lake reservoir in the city, with a daily treatment capacity of 250000 tons. The Conventional treatment processes are mechanical mixing tank, small perforated grid reaction tank, lateral flow inclined plate sedimentation and V-shaped filter tank. The advanced treatment process includes ozone and activated carbon filtration. Because the fluoride in the raw water exceeds the standard, the existing process cannot fully meet the needs of national standards. Therefore, the ultrafiltration-reverse osmosis double membrane method is used for advanced treatment of the original process effluent. The water quality of the factory water after the transformation was continuously monitored, and the fluoride concentration was kept below 1mg/L, the water quality met the national drinking water standard, and the operation was stable. Through the analysis of the monitoring results, the experience of the system operation is summarized, which provides support for the follow-up application of this method.
