Optimize Motion Of Reverse Osimosis (RO) Membrane Advanced Purifying Water System

Optimize motion of reverse osimosis(RO) membrane advanced purifying water system was important method to solve and prevent membrane fouling, and to improve reliability of system operation. The economic target function of system operation was proposed systematically. Electricity cost of membrane operation and reverse flushing water cost of granular actived carbon(GAC) were considered primary changing parts of operation cost. So the researches were carried out with GAC-RO.The permeation flux model of RO membrane was constructed through GAC-RO in tap wter as resource. And electricity cost model of membrane operation was gained. It was concluded that reducing permeation flux or increasing recovery rate could reduce electricity cost of membrane operation and improve economical efficiency of system. Furthermore influence of inlet water characteristic and operation condition on membrane primary characteristic was researched. It was indicated that the effect factors such as increasing operating pressure or temperature, or reducing the value of pH or inlet concentration were advantaged factors for increasing permeation flux. And increasing operating pressure or recovery rate or the value of pH, or reducing temperature or inlet concentration, the desalination performance would increase. Velocity of flow change or operation time change had little influence on membrane primary characteristic.The reverse flushing water cost model of GAC was studied with different raw water quality. Integrating the permeation flux model, the changing cost model for system was constructed. It was concluded that the most prominent factor influencing changing cost was the permeation flux, the secondly most prominent factor was the recovery rate, and inlet turbidity of GAC was the least prominent factor. It was also known that electricity cost of membrane operation was far higher than reverse flushing water cost of GAC. In the test, when operating pressure was 520Kpa and recovery rate was 14.36% and permeation flux was 0.47 m³/(m²Â·d) and inlet turbidity of GAC was 5ntu, the changing cost was the most economical, about 2.21yuan/m³. The effect of outlet turbidity standard of GAC on system operation was also discussed. The experimental results showed that the reverse flushing water cost of GAC increased with increasing outlet quality standard, which improved the most economical changing cost of experimental system and improved cost of system.In addition, the important binding condition of the reverse flushing water cost model of GAC was disscused. The result indicated that the outlet COD_Mn and UV₂₅₄ of GAC were mainly effected by raw water turbidity of GAC. According to that outlet quality of GAC consisting with standard, raw water turbidity of GAC was confirmed. In this experiment, when raw water turbidity of GAC increased by 3 times, the outlet COD_Mn and UV(254) of GAC increased by 7 percent respectively within a narrow range.